WO2024151708A1 - Flexible intramedullary passive strain sensing insert - Google Patents

Abstract

A flexible insert for an orthopedic implant, such as, for example, an intramedullary nail, and operation thereof. The flexible insert includes a proximal end, a distal end, and a body disposed between the proximal and distal ends. The body includes one or more surface acoustic wave (SAW) sensors communicatively coupled to an antenna. The flexible insert is configured to insertion into an interior of the nail implanted into one or more bones of a patient. The SAW sensor(s) monitor and/or detect one or more strain forces/tension applied to nail and the body of the flexible insert, where the forces/tension are applied by the bone(s) of the patient during a treatment process. Upon detection of such forces/tension, the SAW sensor(s) transmits one or more signals via the antenna to one or more external devices.

Description

FLEXIBLE INTRAMEDULLARY PASSIVE STRAIN SENSING INSERT

TECHNICAL FIELD

[0001] This is a non-provisional of, and claims the benefit of the filing date of, U.S. provisional patent application number 63/479,780, filed January 13, 2023, entitled “Flexible Intramedullary Passive Strain Sensing Insert,” the entirety of which application is incorporated by reference herein.

TECHNICAL FIELD

[0002] The present disclosure is generally directed to orthopedic implants (e.g., intramedullary (“IM”) nails) for stabilizing one or more patient’s bones, bone portions, bone fragments, etc., and, more specifically to one or more mechanisms (e.g., flexible inserts) for use with IM nails arranged and configured to detect and/or monitor changes in axial, bending, and/or torsional strain along one or more axis of the IM nail without a need for an implantable battery.

BACKGROUND

[0003] Orthopedic surgical procedures such as, for example, hip procedures, knee procedures, shoulder procedures, etc., have become common place in today’ s society. During such procedures, orthopedic fixation devices (implants) may be used, for example, to stabilize an injury, to support a bone fracture, to fuse a j oint, and/or to correct a deformity. Orthopedic fixation devices may be attached permanently or temporarily, and may be attached to the bone at various locations, including implanted within a canal or other cavity of the bone, implanted beneath soft tissue and attached to an exterior surface of the bone, or disposed externally and attached by fasteners such as screws, pins, and/or wires. Some orthopedic fixation devices allow the position and/or orientation of two or more bone pieces, or two or more bones, to be adjusted relative to one another. Orthopedic fixation devices are generally machined or molded from isotropic materials, such as metals including, for example, titanium, titanium alloys, stainless steel, cobalt-chromium alloys, and tantalum.

[0004] An intramedullary (“IM”) nail is one type of an orthopedic fixation device. The primary function of the IM nail is to stabilize the fracture fragments, and thereby, enable load transfer across the fracture site while maintaining anatomical alignment of the bone. Currently, there are a large number of different commercially available IM nails in the marketplace, such as, for example, femoral IM nails, retrograde femoral IM nails, tibial IM nails, etc. A femoral nail is arranged and configured to be inserted into the medullary canal of a patient’s femur through the proximal end of the femur (e.g., hip area). A retrograde femoral nail is arranged and configured to be inserted into the medullary canal of a patient’s femur through the distal end of the femur (e.g., patient’s knee). A tibial IM nail is arranged and configured to be inserted into the medullary canal of a patient’s tibia. However, existing IM nails and/or IM nail systems are not capable of performing monitoring of a bone healing process, such as, for example, through detection of various forces that may be acting on the implanted IM nail.

SUMMARY

[0005] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter. [0006] In one example, the current subject matter relates to a flexible insert for an orthopedic implant, such as for example, an intramedullary nail. The flexible insert may include a proximal end, a distal end, and a body disposed between the proximal and distal ends. The body may be configured to include one or more surface acoustic wave (SAW) sensors communicatively coupled to an antenna, which can be utilized as the energy and detection unit when attached to an implant.

[0007] The flexible insert is configured for insertion into an interior (e.g., counter-bore and/or cannulation) of the nail. The nail may be implanted into one or more bones of a patient. The flexible insert may be inserted prior to and/or subsequent to and/or during implantation of the nail. The SAW sensors may be configured to passively monitor and/or detect one or more strain forces/tension applied to nail and the body of the flexible insert, where the forces/tension is applied by the bone(s) of the patient during a treatment process. Upon detection of such forces/tension, the SAW sensor may be configured to transmit one or more instructions (e.g., signals, etc.) via the antenna to one or more external devices.

[0008] In any preceding or subsequent examples, the flexible insert may be configured to include one or more openings, holes, etc. In some examples, the one or more openings, holes, etc. may be disposed proximate to the distal end and/or proximate to the proximal end of the flexible insert. Such one or more openings, holes, etc. may be configured to be aligned with one or more openings, holes, etc. of the intramedullary nail. The openings, holes, etc. may be used for insertion of one or more nails, screws, etc. that may be used to secure the nail and the flexible insert to one or more bones of the patient.

[0009] In any preceding or subsequent examples, the SAW sensor(s) may be one or more passive sensors. One or more external devices may be configured to provide power to the SAW sensor(s) via the antenna. Upon being powered, the SAW sensor(s) may be configured to perform detection of forces/tension applied to the nail/flexible insert and transmit instructions corresponding to the detected forces/tension, via the antenna, to the external devices. In any preceding or subsequent examples, the power may be transmitted to the SAW sensor(s) using a near field communication (NFC) interface.

[0010] In any preceding or subsequent examples, the SAW sensor(s) may be one or more active sensors that may be coupled to one or more power sources disposed within the flexible insert.

[0011] In any preceding or subsequent examples, the antenna may be incorporated into an antenna module that may be coupled to a proximal end of the intramedullary nail. For example, the antenna module may be threaded into at least a portion of the interior of the intramedullary nail. The antenna module may be configured as a hermetic plug to the interior portion of the intramedullary nail.

[0012] In any preceding or subsequent examples, the SAW sensor(s) may be configured to be disposed within an interior of the flexible insert. For example, the SAW sensor(s) may be disposed on a flat portion or a platform positioned within the interior of the flexible insert. Further, the SAW sensor(s) may be hermetically sealed within the interior of the flexible insert using one or more covers.

[0013] In one example, the current subject matter relates to an intramedullary nail. The intramedullary nail may include an intramedullary nail body having an interior, and a flexible insert positioned in the interior of the intramedullary nail body. The flexible insert may include one or more surface acoustic wave (SAW) sensors communicatively coupled to an antenna. The SAW sensor(s) may be configured to monitor application of one or more forces or tension to at least one of: the intramedullary nail body and the flexible insert.

[0014] In any preceding or subsequent examples, the intramedullary nail may be configured to be implanted into a bone of a patient. The forces and/or tension may be applied by the bone of the patient during a treatment process.

[0015] In any preceding or subsequent examples, upon detection of the forces and/or tension by the SAW sensor(s), the SAW sensor(s) may be configured to transmit, using the antenna, one or more instructions to one or more external devices.

[0016] In any preceding or subsequent examples, the SAW sensor(s) may be configured to receive, via the antenna, power from one or more external devices communicatively coupled to the antenna.

[0017] In any preceding or subsequent examples, the SAW sensor(s), upon receiving power from one or more external devices, may be configured to transmit, via the antenna, one or more instructions corresponding to forces and/or tension detected by the SAW sensor(s), to one or more external devices.

[0018] In any preceding or subsequent examples, the SAW sensor(s) may be configured to receive power from one or more external devices using a near field communication (NFC) interface.

[0019] In any preceding or subsequent examples, the intramedullary nail may also include one or more power sources.

[0020] In any preceding or subsequent examples, one or more power sources may be configured to provide power to the SAW sensor(s). At least one of the SAW sensor(s) may be an active SAW sensor. [0021] In one example, the current subject matter relates to a method that may include monitoring, using one or more surface acoustic wave (SAW) sensors, application of one or more forces or tension to at least one of: an intramedullary nail and a flexible insert, where the SAW sensor(s) may be disposed in the flexible insert positioned in an interior of the intramedullary nail, where the intramedullary nail may be configured to be positioned in a bone of a patient. The method may also include receiving, using the SAW sensor(s), via an antenna communicatively coupled to the SAW sensor(s), a power to power the SAW sensor(s), and transmitting, using the powered SAW sensor(s), via the antenna, one or more instructions corresponding to the forces and/or tension detected by the SAW sensor(s), to one or more external devices communicatively coupled to the SAW sensor(s) via the antenna.

[0022] Examples of the present disclosure provide numerous advantages. For example, use of a current subject matter’s surface acoustic wireless wave sensor nail insert provides an ability to passively monitor implant strain. This is in contrast to various existing nail designs, which require extensive modification to the implant to house the active electronics that are typically powered using external inductive coupling. The current subject matter’s SAW sensor may also be optionally selected during surgery based on a variety of requirements. The SAW sensor can operate at substantially higher frequencies where attenuation in muscle and/or fat tissues is significant making it suitable for in various vivo applications, e.g., license-free 2.4 GHz. Moreover, the current subject matter’s wireless SAW sensor is relatively inexpensive to manufacture, eliminates the hazards associated with implantable batteries, is more reliable and can be optionally selected during surgery to provide additional strain-monitoring capability. [0023] Further features and advantages of at least some of the examples of the present disclosure, as well as the structure and operation of various examples of the present disclosure, are described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, show certain features of the subject matter disclosed herein and, together with the description, help explain some of the principles associated with the disclosed implementations. In the drawings,

[0025] FIG. 1 illustrates a perspective view of an example prior art retrograde femoral IM nail;

[0026] FIG. 2 illustrates a perspective view of an example prior art tibial intramedullary (IM) nail;

[0027] FIG. 3a illustrates a perspective view of an IM nail including an example flexible insert, in accordance with one or more features of the present disclosure;

[0028] FIG. 3b illustrates a perspective view of an example antenna module that may be used with the IM nail of FIG. 3a, in accordance with one or more features of the present disclosure;

[0029] FIGS. 3c-d illustrate various views of an example surface acoustic wave (SAW) sensor that may be used with the IM nail of FIG. 3 a, in accordance with one or more features of the present disclosure;

[0030] FIG. 3e illustrates a perspective view of an example IM nail, in accordance with one or more features of the present disclosure; [0031] FIGS. 3f-h illustrate various views of the IM nail of FIG. 3e, the IM nail including a flexible insert, in accordance with one or more features of the present disclosure;

[0032] FIG. 3i illustrates a perspective view of a SAW sensor being inserted in a HEX capture cavity for measuring of strain in bone screws, in accordance with one or more features of the present disclosure;

[0033] FIGS. 4a-b illustrate various views of an example operation of a SAW sensor that may be used with an IM nail that may include a piezoelectric substrate, one or more metallic interdigital transducers (IDTs), and a delay line using which a generated wave may propagate, in accordance with one or more features of the present disclosure;

[0034] FIG. 5 illustrates an example system for communication with the SAW sensor, in accordance with one or more features of the present disclosure;

[0035] FIG. 6 illustrates an example SAW sensor and SAW sensor operation;

[0036] FIG. 7 is a plot illustrating use of SAW sensor nominal frequency to distinguish and identify two SAW sensors while avoiding any potential overlap in signal output;

[0037] FIGS. 8a-b illustrate an example packaging of a SAW sensor with a dedicated frequency-modulated continuous wave (FMCW) interrogation system;

[0038] FIG. 9 illustrates an example computing apparatus, in accordance with one or more features of the present disclosure;

[0039] FIG. 10 illustrates an example of a storage medium, in accordance with one or more features of the present disclosure; and

[0040] FIG. 11 illustrates an example computing platform, in accordance with one or more features of the present disclosure. [0041] It should be understood that the drawings are not necessarily to scale and that the disclosed examples are sometimes illustrated diagrammatically and/or in partial views. In certain instances, details that are not necessary for an understanding of the disclosed methods and devices or which render other details difficult to perceive may have been omitted. It should be further understood that this disclosure is not limited to the particular examples illustrated herein. In the drawings, like numbers refer to like elements throughout unless otherwise noted.

DETAILED DESCRIPTION

[0042] To address these and potentially other deficiencies of currently available solutions, one or more implementations of the current subject matter relate to methods, systems, articles of manufacture, and the like that can, among other possible advantages, provide one or more orthopedic implants (e.g., intramedullary (“IM”) nails) for stabilizing one or more patient’ s bones, bone portions, bone fragments, etc., and, more specifically, one or more mechanisms (e.g., flexible inserts) for use with IM nails arranged and configured to detect and/or monitor changes in axial, bending, and/or torsional strain along one or more axis of the IM nail.

[0043] As discussed above, intramedullary nails are implanted surgically to stabilize one or more bones such as, for example, femoral, tibial, and/or humeral fractures (e.g., during healing). However, fracture healing does not always occur properly, which can result in either malunion, nonunion, etc. of bones, fragments of bones, etc. Conventional assessment of fracture healing is marked by a subjective and diffuse outcome due to the lack of clinically available quantitative measures. Without reliable information on the progression of healing and uniform criteria for union and/or non-union, therapeutic decision-making, such as, for example, targeted weight bearing, hinges on the experience and/or the subjective evaluation of medical professionals supervising the treatment protocol. Thus, monitoring bone healing process in-situ provides an opportunity for earlier intervention when necessary.

[0044] Existing instrumented implants having sensor capabilities (e g., “smart implants”) can provide (e.g., X-ray free) timely reliable feedback upon the biomechanical competence of the repair tissue and the healing environment to support therapeutic decision-making and individualized after-care. Conventional smart implants include a modified external surface to accommodate various electronics and protect such electronics from bodily fluids and mechanical abrasion forces. However, this approach adds significant cost and complexity to the manufacturing process making the technology less viable and/or reliable during use. Further, existing instrumented nail designs require active electronics powered from external magnetic inductive coupling, which adds various hazards as well as reliability issues.

[0045] To address the above deficiencies, the current subject matter implements use of surface acoustic wave (SAW) sensors. A SAW is a non-electromagnetic wave that travels along the surface of a piezo-electric substrate. SAW sensors can measure temperature, strain and pressure wirelessly and without any energy source, with radio-frequency interrogation similar to radar without the need for any embedded electronics. The physical effect of a change of the elastic constants of the substrate material or a change in the mass loading under the influence of changing conditions in the environment, lead to a change in the phase velocity of the surface acoustic wave and commonly to a frequency shift in the SAW devices.

[0046] SAW sensors are compact piezoelectric-based sensors that are wireless and passive, i.e., the sensors do not require a power supply, which eliminates a need for an attached battery and/or wired connection. A typical SAW sensor can include the following components: one or more SAW sensing elements connected to one or more antennas and an electronic interrogation unit, referred to as a reader (referred to interchangeably herein), connected to its respective antenna.

[0047] FIG. 6 illustrates an example SAW sensor system 600. The system 600 includes a transmitter portion 602 and a receiver portion 604. The transmitter portion 602 includes a SAW sensor/sensing element 601 coupled to an antenna 603 and can be configured to generate and transmit a back-scattered signal or interrogated pulse 606 toward the receiver portion 604. The receiver portion 604 includes an interrogator or reader 605 coupled to an antenna 607 and can be configured to generate and transmit a radio frequency (RF) interrogation signal 608 toward the transmitter portion 602, The interrogator 605 can also include one or more amplifiers/filters and/or one or more signal processing detectors. The interrogator 605 can be communicatively coupled to a network analyzer component 609, which in turn, can be communicatively coupled to one or more processors 611 that may be configured to process data received from the network analyze for display on one or more user interfaces 613.

[0048] As shown in FIG. 6, the reader 605 transmits the interrogation signal 608, which can be picked up by the sensor's antenna 603. The sensing element 601 does not contain any power (e.g., DC, AC, etc.) source, and can be configured to operate as a passive back-scatterer reflecting the interrogation signal back to the reader, as signal 606. The backscattered signal 606 reflects the frequency of oscillation that may be affected by a physical measurand. The reader 605 can analyze the received back- scattered signal 606 and determine a value of the physical measurand.

[0049] Conventional SAW sensors are used in many different applications to monitor parameters, such as, for example, temperature, strain, pressure, torque, magnetic field, chemical detection, etc. During operation, a SAW sensor (e.g., as shown in FIG. 6), based on the resonator principle, shifts its center frequency f_c) over strain and/or temperature. The frequency can be measured by the reader 605 and the resulting strain and/or temperature can be determined based on this frequency.

[0050] SAW sensors have a superior dynamic range, low system complexity, and are inexpensive compared to alternatives, such as, piezoresistive and/or optical fiber strain sensors. SAW sensors, which are used as strain sensors, can be based on various design configurations. For example, a SAW strain sensor can be 1-port SAW resonator, where the resonance frequency of an interdigital transducer (IDT) is used as a measurand. When strained, the surface acoustic wave velocity and pitch of the IDT are affected, leading to shifts in the IDT’ s resonant frequency. 1-port SAW resonators typically include one or more arrays of reflecting metal strips on either side of the device to enhance a Q-factor (quality factor corresponding to a measure of energy loss in a resonator) of the IDT resonance. Alternatively, or in addition, SAW strain sensors that are based on 2-port SAW resonators include two IDTs separated by a free surface length, thereby enabling transmission measurements from one IDT to the other.

[0051] Conventional SAW devices typically suffer from instability, mainly due to the high temperature coefficient of frequencies (TCF) often associated with SAW substrates. 128° Y-X LiNbO3 is one of the most popular SAW substrates due to its low SAW attenuation and high piezoelectric coupling, however, it has a large linear TCF of ~ 75 ppm/°C, leading to large SAW frequency fluctuations when temperature is not well controlled. Approaches used to reduce temperature dependence include selecting a piezoelectric substrate with a flat temperature dependence near the operating temperatures, subtracting the response of a secondary unstrained reference device, and/or fabricating SAW devices on thin film piezoelectric substrates that can excite the transverse shear mode in addition to SAW modes, allowing for temperature compensation through knowledge of the strain and TCF of both acoustic modes. While these methods are effective at compensating for slowly changing environmental temperatures, thermal noise arising from the electronic circuitry used to interrogate the sensors also contributes and should be considered in the system design.

[0052] It is possible to use several sensors simultaneously in the same industrial, scientific, and/or medical radio band (ISM band). These sensors can be distinguished and identified by the nominal frequency. To avoid an overlap of sensors, which would result in a loss of assignability of the sensor data, a frequency gap between sensors can be used. FIG. 7 illustrates an exemplary center frequency plot 700. The plot 700 shows an overlap protection region 706 between center frequencies of two SAW sensors sensor 1 702 and sensor 2 704. As shown in FIG. 7, a center frequency shift may occur in sensor 2 702 upon detection of a change in temperature (e.g., 275 degree Celsius to 0 degree Celsius).

[0053] FIGS. 8a-b illustrate example, non-limiting, SAW sensor system 802 and reader 804 as used herein for experimental purposes. The sensor system 802 may include a flexible printed circuit board (PCB) 801, a temperature SAW sensor 803, an inductor 805, and an antenna 805. The sensor 803, the inductor 805, and the antenna 807 are disposed on the PCB 801, where the sensor 803 is disposed opposite the antenna 807.

[0054] In the current subject matter example, non-limiting, experimental implementations, the SAW sensor 803 selected for the wireless and passive flexible component was a SAW strain sensor with a working range up to 500-800 micro-strain (e.g., as available from SAW COMPONENTS Dresden GmbH, Dresden Germany) with sensor dimensions of 3><3x l mm and strain sensitivity of approximately 100 ± 0.2 Hz/ps. The operating range for the sensor was up to 3 meters with a typical nominal frequency of either ISM Band 2.4 GHz or ISM 433 MHz or 872 MHz. Other sensors operating simultaneously in the same ISM band (2.4 GHz or 433 MHz) may be used. An exemplary operating frequency may be selected as a compromise between a low frequency (e.g., for reduced attenuation in fat and muscle tissue) and a high frequency (e.g., for best strain sensitivity). The sensor 803 may be attached to a surface mounted device (SMD) patch antenna 807 using the flexible PCB 801. A suitable medical grade adhesive, epoxy resin may be used to attach the SAW sensor 803 to the PCB 801. When a stretching force is applied to the PCB 801 under the condition that one side of the PCB 801 is fixed and the other side is modulated, the actual length of the SAW delay line between the two interdigital transducers (IDTs) may be increased. The increase in the delay line length causes a change in the time for the propagating SAW to reach the output IDT. If strain energy is applied to the piezoelectric substrate, the substrate density is changed, which then changes the propagation velocity of the SAW.

[0055] The exemplary antenna 801 may be designed to be used on a metal reflector plane of at least 4 x 4 cm. An inductor 805 may also be attached in the assembly 802 for electrostatic discharge (ESD) protection and the entire assembly 802 may be designed to resist the same temperature range of the sensor. To read the sensor data, a dedicated frequency modulated continuous wave (FMCW) interrogation system 804 (e.g., as available from SAW COMPONENTS Dresden GmbH, Dresden, Germany) may be used, as shown in FIG. 8b. As can be understood, any other SAW sensors and/or SAW sensor systems and/or interrogation systems may be used, and the current subject matter is not limited to the implementations shown and discussed above in connection with FIGS. 6-8b.

[0056] In some implementations, the current subject matter relates to a flexible cylindrical insert (e.g., having a diameter of approximately 5.8 mm), which may be adapted to receive at least one surface acoustic wave (SAW) strain sensorthat may be configured to monitor changes in axial, bending, and/or torsional strain along a single axis of an IM nail and depending upon the orientation of the SAW sensor, if so selected by the surgeon. The flexible insert may be made from an implantable grade polymer, composite, metal, alloy, and/or any other material and/or any combination of materials. The insert may be contoured to precisely fit an interior space and/or shape of an IM nail (e.g., the Herzog proximal bend and distal bow of a tibial IM nail, such as, for example, the TRIGEN® nail manufactured and sold by Smith & Nephew Pic., London, United Kingdom). In some examples, the insert may also be thinned from a circular rod to provide additional flexibility and concentrate the strain at the SAW sensor. Further strain concentration may be achieved for the purpose of strain measurement by thinning the flexible insert at the back of the SAW sensor. The flexible insert may also be equipped with a set of proximal and distal interlocking holes that may be configured to line up precisely with the corresponding holes in the IM nail. The flexible insert may be introduced down the cannulation of the IM nail either before, during, and/or after the IM nail has been inserted into the reamed bone canal. The flexible insert’s holes may also provide additional fixation for the interlocking screws using a standard implantation surgical technique. A nail cap may be adapted to engage with the proximal end of the flexible insert to ensure that it may be locked in place with either a thread, interference fit, a grub screw, and/or any other locking mechanisms, and remain centrally located down the cannulation after implantation. The flexible insert may be communicatively coupled to a protruding antenna (e.g., another transponder) that may be configured to exit through the top of the nail cap. The nail cap and/or the antenna may be fabricated from, for example, copper, magnesium, and/or any other metal, and/or any other conductive material, which may be slowly absorbed by the body without detrimental effects. The antenna may allow strain data to be obtained wirelessly and passively using an external near field wireless power charging receiver device worn by the patient, which may negate the need for an implantable battery. The strain data received from the sensor, via the antenna, may be interrogated using a network analyzer component (which may be located up to 3 meters away). The strain data may describe a frequency shift with the strain applied on the flexible insert over time and may be used to determine a progression of bone healing.

[0057] FIG. 1 illustrates an exemplary retrograde IM nail 100. The retrograde IM nail 100 may be configured to be implanted into the medullary canal of a patient’s femur via the distal end of the patient’ s femur (e.g., via the patient’ s knee). The retrograde IM nail 100 may also be referred to as a retrograde femoral nail. The nail 100 may include a cannulated body 102, which, in turn, may include a leading and/or proximal end portion 110 (leading proximal end portion) and a distal end portion 130. The proximal end portion 110 may include a plurality of screw openings, holes, slots, etc. 112 that may be configured to receive a fastener, screw, etc. (terms used interchangeably herein without the intent to limit). The screw openings, holes, slots, etc. may be threaded, nonthreaded, and/or have any other configuration now known or hereafter developed. As illustrated, the proximal end portion 110 may include first and second screw holes 112, although more or less screw holes may be incorporated. In addition, the proximal end portion 110 may include a slot 114 positioned between the first and second screw holes 112. In the illustrated example, the first and second holes 112 may be configured to receive a screw in the anterior-posterior direction in situ. Meanwhile, the slot 114 may be arranged and configured to receive a screw in the medial-lateral direction in situ. That is, the medial-lateral screw hole and/or slot 114 may extend in a direction substantially perpendicular to the first and second screw holes 112. The medial-lateral screw hole 114 may be in the form of a slot, whereby, by utilizing the slot, dynamization and/or micro-motion of the nail 100 in situ may be achieved. Alternatively, and/or in addition, the medial-lateral slot 114 may be used to enable a medical professional (e.g., a surgeon, a doctor, etc.) to position a fastener into a femoral neck and head of the patient’ s femur. In some cases, the nail 100 may have a length sufficient to extend the nail 100 into the patient’s femur to target the femoral neck and head area. The medial -lateral slot 114 may have a larger size or height to enable improved positioning and/or angulation of the fastener into the femoral neck and head. Further, the medial- lateral screw hole and/or slot 114 may be non-perpendicular to the first and second screw holes 112. The medial-lateral screw hole and/or slot 114 may be configured to enable some anteversion. It may also be positioned proximate to the proximal leading edge (e.g., the medial-lateral slot 114 may take the position of the first screw hole 112). By positioning the medial-lateral slot 114 adjacent to the proximal leading edge, the medial-lateral slot 114 may provide enhanced neck targeting. Alternatively, or in addition to, the nail 100 may include a second slot (e.g., one or more of the screw holes 112 may be converted to a slot), where the slots need not extend purely in the medial-lateral direction.

[0058] As shown in FIG. 1, the proximal end portion 110 of the nail 100 may include first and second screw holes 112 extending in the anterior-posterior direction for receiving first and second screws, respectively. The medial-lateral screw hole and/or slot 114 may be positioned inbetween the first and second screw holes 112 extending in the anterior-posterior direction. As can be understood, the proximal end portion 110 of the nail 100 may include more or less screw holes extending in the anterior-posterior direction and more screw holes or slots extending in the medial - lateral direction. In addition, the screw holes may include alternate configurations such as, for example, the screw hole or slot extending in the medial-lateral direction may be positioned above or below (e.g., proximal or distal) of the screw holes extending in the anterior-posterior direction.

[0059] The first and/or proximal anterior-posterior screw hole 112 may be positioned as close as possible to the leading proximal end of the nail 100. In some cases, the first, second, and/or third screw holes 112, 114 may be positioned as close as possible while maintaining structural integrity of the nail 100.

[0060] By providing a medial-lateral screw opening, hole and/or slot 114 in the proximal end portion 110 of the nail 100, improved fixation of the proximal end portion 110 of the nail 100 may be achieved. Further, providing one or more medial -lateral screw openings, holes and/or slots 114 in the proximal end portion 110 of the nail 100 may facilitate easier connection to a bone plate via, for example, a screw passing through the bone plate and through the medial-lateral screw opening, hole, and/or slot.

[0061] Further, the medial-lateral screw opening, hole and/or slot 114 may be targeted (e.g., located) using, for example, a targeting device that includes a low-profile medial component. Alternatively, or in addition, the medial -lateral screw opening, hole and/or slot 114 formed in the proximal end portion 110 of the nail 100 may be targeted using an instrument that indexes from one or both of the screw holes 112 extending in the anterior-posterior direction.

[0062] In some implementations, a system may include one or more nails 100 that have one or more medial-lateral screw openings, holes, and/or slots 114 formed in the proximal end portion 110, a targeting system for identifying and placing a screw through one or more medial- lateral openings, holes, and/or slots 114. For example, the nail 100 may be implanted into the medullary canal of a patient’s femur via the distal end or knee. Once properly implanted, one or more screws may be inserted into the proximal end portion 110 of the nail 100 using the targeting system. For instance, a screw may be positioned and inserted into the medial-lateral slot 114 formed in the proximal end portion 110. Alternatively, or in addition, one or more screws may be inserted into the anterior-posterior openings, holes, and/or slots 112 formed in the proximal end portion 110. [0063] Further, as illustrated, the distal end portion 130 of the nail 100 may include a plurality of screw openings, holes, slots, etc. 132 (A, B, C, D) that may be configured to receive a screw. The holes 132 may be positioned at different distances away from the distal end of the nail 100 and may provide additional screw fixation to potentially more bone fragments. As shown in FIG. 1, the screw hole 132A (e.g., screw hole closest to the distal end of the nail 100) may extend in substantially the medial-lateral direction in situ. The screw holes 132B, 132C, 132D may be angled or oblique. In some cases, the hole 132D may be substantially parallel to the hole 132A, and thus, extend in a substantially medial-lateral direction in situ. Alternatively, or in addition, the one or more of the screw holes may be in the form of an elongated slot. For example, the holes 132B, 132C may be in the form of an elongated slot, and thus, may be used to compress a fracture. Fracture compression may be accomplished using slotted holes in combination with a reduction instrument, which may include, for instance, a reducer, a buttress, a locking device, etc. that engages a proximal bone fragment and a distal bone fragment. The nail 100 may be secured to the distal bone fragment using the locking device. The buttress engages the nail 100 through an opening (e.g., slots 132B and/or 132C). The reducer may include a compressing screw that applies a force on the buttress, reducing the fracture.

[0064] FIG. 2 illustrates an exemplary tibial IM nail 200, which may be configured to be implanted into the medullary canal of a patient’s tibia. The nail 200 may include a body 202 including a proximal end portion 210 and a distal end portion 230 (e.g., distal end portion 230 now being the leading end portion). The distal end portion 230 may include a plurality of screw openings, holes, slots, etc. 232 that may be configured to receive a screw. The distal end portion 230 may include holes 232(A, B, C, D). The holes 232B, 232C may extend at oblique angles (e.g., holes 232B, 232C may be angled relative to the medial-lateral plane by angle a). The holes 232A and 232D may extend substantially in the medial-lateral direction. Thereafter, the hole 232B and the hole 232C may extend at oblique angles. As such, by properly orientating the configuration and positioning of the oblique screw holes 232B, 232C, anatomical structures may be avoided.

[0065] Further, the oblique screw holes 232B, 232C may be tilted (e.g., angled vertically), although the screw holes 232B, 232C may be horizontally positioned (e.g., parallel with respect to the screw holes 232A, 232D). That is, one or both of the oblique screw holes 232B, 232C may be angulated relative to a central longitudinal axis of the distal portion of the nail 200. As can be understood, the holes 232 and/or other features of the nail 200 may be so arranged as to optimize the position and angulation of the screw holes, maximum securement while avoiding anatomic structures, such as, for example, the nerves, vessels, and tendons.

[0066] Further, the proximal end portion 210 of the nail 200 may be configured with a plurality of screw openings, holes, and/or slots 212 (A, B, C, D). The most proximal hole 212A may be configured to align a screw approximately parallel with a tibial plateau through which the nail 200 is inserted. The most proximal screw hole 212A formed in the proximal end portion 210 may be configured to achieve approximate parallel screw alignment with the tibial plateau. Additionally, the hole 212A formed in the proximal end portion 210 may be tilted and/or angled downwards away from the proximal end of the nail 200, e.g., the hole 212A may be angled downwards so that a screw inserted therein is positioned substantially parallel to the tibial plateau through which the nail 200 is inserted. For example, the hole 212A may be configured to align a screw or other fastener approximately parallel with the tibial plateau and/or, at a minimum, to avoid penetration of the tibial plateau.

[0067] The proximal end portion 210 may also include additional screw openings, holes or slots. For example, as shown in FIG. 2, the proximal end portion 210 may include openings, holes, and/or slots 212B, 212C, 212D. The hole 212B may also be tilted or angled and/or may include a downward tilt and/or angle. Alternatively, or in addition, the hole 212B may include an upward tilt and/or angle. The angulation of the hole 212B may facilitate increased bone fixation in the cortical bone (e.g., increased screw lengths may be utilized to achieve increased bone fixation while avoiding penetration of the tibial plateau TP). In some cases, the holes may be in the form of elongated slots, which may assist in achieving compression at the proximal end portion 210.

[0068] As should be readily appreciated by one of ordinary skill in the art, the present disclosure describes a flexible insert that is arranged and configured to be inserted into, for example, a hollow interior portion, bore, cannulation, etc. of an IM nail. In use, the flexible insert can be used with any IM nail now known or hereafter developed. As such, the present disclosure should not be limited to any particular type or configuration of IM nail unless explicitly claim.

[0069] FIG. 3a illustrates an exemplary flexible insert 300, according to some implementations of the current subject matter. The insert 300 may be configured to be inserted into a hollow interior portion of an IM nail (e.g., nail 100 and/or nail 200 shown in FIGS. 1 and 2, respectively), and/or any other implantable medical device, prior to implantation.

[0070] The insert 300 may be flexible, cylindrical in shape, and may include a distal end 302, a proximate end 304, and an insert body 306 disposed between the ends 302, 304. The body 306 may have a solid interior, a hollow interior, and/or partially filled/partially hollow interior. In some example, non-limiting implementations, the insert 300 may have a diameter of approximately 5.8 mm. As can be understood, other shapes, flexibility capabilities, and/or diameters of the insert 300 are possible. [0071] The insert 300 may include one or more proximal openings, slots and/or holes 310 (a, b, c) disposed at and/or proximate to the proximal end 304 and created in the body 306. It may also include one or more distal openings 308 (a, b, c) disposed at and/or proximate to the distal end 302 and created in the body 306. The holes 308 and 310 may be configured to allow protrusion of one or more screws that secure the nail (not shown in FIG. 3a) to one or more bones. The holes 308, 310 may be aligned with the corresponding holes of the nail (e.g., as shown in FIGS. 1 and 2, but not shown in FIG. 3a) and may be appropriately positioned and/or aligned and/or angled and/or tilted on the body 306 of the insert 300 in accordance with the holes of the IM nail. Such positioning may be configured to ensure that the screws protruding through holes of the IM nail also protrude through the corresponding holes 308, 310.

[0072] The insert 300 may also include a bent and/or an angular curvature 320 that may be positioned between a proximal portion 301 of the insert 300 and a distal portion 303 of the insert 300. The angular curvature 320 may be characterized by an angle a. The angle a may be any desired angle that may be selected in accordance with a particular application and/or use. The angular curvature 320 may correlate to the angular curvature of the IM nail (as for example, is shown in FIG. 3e).

[0073] The proximal end 304 may accommodate positioning of an antenna module 311. The antenna module 311 may include an antenna 312. The antenna module 311 may be configured to be partially inserted into the hollow interior of the insert 300 at the proximal end 304. Alternatively, or in addition, the antenna module may be positioned at the proximal end 304 without being inserted into the insert 300, and instead, be threaded into the hollow interior of the

IM nail. [0074] FIG. 3b illustrates an exemplary antenna module 311, according to some implementations of the current subject matter. The module 311 is shown without the antenna 312 (as illustrated in FIG. 3a). As shown in FIG. 3b, the module 311 may be configured to include threads 313, which may be configured to interact with one or more interior threads of the IM nail (not shown in FIG. 3b) to create a secure (and/or hermetically secure) connection between the antenna module 311 and the interior of the IM nail. By being threaded into the interior of the IM nail, the antenna module 311 may serve as a plug to the interior of the IM nail and, thereby, protect the insert 300 when the latter is inserted into the interior of the IM nail.

[0075] The antenna 312 may be fabricated from copper, magnesium, and/or any other metal wire, which may be slowly absorbed by the patient’s body without detrimental effects. As discussed herein, the antenna 312 may allow strain data (resulting from application of forces to IM nail by a healing bone) to be obtained wirelessly and/or passively using an external near field wireless power charging device, that may be brought close to the implantation location of the nail (and/or may be worn by the patient), which may negate the need for an implantable battery. The strain data may be received from the insert 300 and may be used to determine the progress of bone healing.

[0076] Assuming that the antenna module 311 constitutes a separate module from the insert 300, to position the antenna module 311, the insert 300 may be inserted into the interior of the IM nail (while observing alignment of the holes 308 and 310 with corresponding openings of the IM nail) and then, the antenna module 311 may be threaded, using threads 313, into the interior of the IM nail. Upon insertion of the antenna module 311 into the IM nail, the module 311 may be configured to create an electrical contact within one or more contact leads connected to the electronics module 314 and/or the sensor 316 (not shown in FIG. 3b). In case, the insert 300 and the antenna module 311 form a unitary structure, the insert 300 (while being attached to the module 311) may be protruded into the hollow interior of the IM nail until threads of the module 311 reach interior threads of the IM nail. At this point, the module 311 and the insert may be rotated to thread the module 311 into the interior of the IM nail. As can be understood, any other way and/or combination of ways may be used to secure the antenna module 311 and/or the insert 300 within the interior of the IM nail, and the current subject matter is not limited to use of threads.

[0077] The antenna 312 may be communicatively coupled to the electronics module 314 (which may be optional) and/or the sensor 316 and may be further configured to transmit and/or receive one or more signals to and/or from an external communication and/or computing device (not shown in FIG. 3a). The communicative coupling may be via a wired and/or wireless connection. A wired connection may be accomplished using one or more wires positioned inside walls of the insert 300 and/or on an exterior surface of the insert 300. A wireless connection may be achieved using any known wireless communication means.

[0078] The sensor 316 and/or the electronics module 314 (if equipped) may be disposed in distal portion 303 of the insert 300 and, as shown in FIG. 3a, proximate to the point of angular curvature 320. As can be understood, sensor 316 and/or the electronic module 314 may be disposed in any desired location of the insert 300. Further, sensor 316 and/or the module 314 may be disposed and/or secured within a cavity that may be created for the purposes of positioning the sensor 316 and/or module 314. The sensor 316 and/or module 314 may be glued, welded, screwed and/or attached within the cavity of the insert 300 in any desired fashion. The sensor 316 and/or module 314 may protected by a cover and/or a lid 318 that may be configured to hermetically seal the sensor 316 and/or module 314 within the insert 300 in order to protect its components from external elements. The cover 318 may be shaped in a way so as it create a smooth exterior surface of the insert 300.

[0079] If so equipped, the module 314 may be configured to include one or more printed circuit boards (PCBs), one or more processors, one or more memory, one or more communication components, one or more sensors, such as, for example, surface acoustic wave (SAW) sensors, such as sensor 316, and/or any other electronics components, and any combinations thereof. The sensor 316 and/or module 314 may be configured to be powered using one or more external power sources that may be transmitted to the sensor 316 and/or module 314 (e.g., via the antenna 312) via, for example, a near field communication interface, and/or any other interface. Alternatively, or in addition, the electronics module 314 may include a power source, such as, for example a battery, that may power one or more components of the module 314. The battery may serve as a backup power source, if so desired.

[0080] The insert 300 may also include a working portion 322 that may be configured to be disposed within the distal portion 303, e.g., between sensor 316 and/or electronics module 314 and the hole 308a. The working portion 322 may be configured to be used for measuring forces that may be applied to the IM nail, while the insert 300 is positioned within such nail, during the bone healing process. The applied forces may create tension on the working portion 322, which may be detected and/or measured by one or more sensors, such as, for example, the SAW sensor 316. Further, the SAW sensor 316 may be configured to monitor changes in axial, bending and/or torsional strain along a single axis of the IM nail and depending upon the orientation of the SAW sensor 316. The SAW sensor 316 may detect and/or measure a magnitude and/or a direction of the applied force and transmit them directly to the antenna 312 and/or to the processor of the electronics module 314, which in turn, may transmit the detected/measured tension data, via the antenna 312, to one or more external computing devices for further analysis. Alternatively, or in addition, the processor of the module 314 may be configured to execute an analysis of the measured/detected data to determine whether bone healing process is proceeding in accordance with a treatment plan and/or whether the bone is healing correctly.

[0081] FIGS. 3c-d illustrate exemplary SAW sensor 316, according to some implementations of the current subject matter. In particular, FIG. 3c is a cross-section cut-out view of the body 306 of the insert 300 shown in FIG. 3a and FIG. 3d is an enlarged view of a portion of the body 306 of the insert 300.

[0082] As shown in FIG. 3c, the SAW sensor 316 and/or the electronics module 314 may be configured to be positioned within an interior cavity 353 on a flat portion 354 (as shown in FIG. 3d) that may be surrounded by a wall 351 of the insert 300. In some example, non-limiting, implementations, the machined flat portion 354 having approximately 20 mm x 4 mm size, may be created in the body 306 and proximate to the curvature 320 of the insert 300 for the purposes of positioning the SAW sensor 316 and/or the electronics module 314. The SAW sensor 316 and/or the module 314 may then be bonded inside the cavity 353 on the flat portion 354 using any suitable medical grade adhesive, such as, for example, silver-based epoxy resin, silicone, a polyurethane- based compound, and/or any other type of compounds. Strain concentration may then be achieved by thinning the insert 300 at the back of the SAW sensor 316. The SAW sensor 316 may then be hermetically sealed with an enclosure (e.g., cover 318, as shown in FIG. 3a) that may be bonded and/or welded to the insert body 306. Alternatively, or in addition, on the SAW sensor 316 may be positioned within the cavity 353 of the insert 300, i.e., no electronics module 314 may be included, whereby the SAW sensor 316 may be powered using an external power source (e.g., worn outside by the patient). [0083] As shown in FIG. 3d, the sensor 316 may be communicatively coupled to the antenna 312 (not shown in FIG. 3d) using one or more electrical contacts 355. The contacts 355 may be sealed inside the cavity 353 along with the sensor 316 and may be configured to protrude through the walls 351 of the insert 300 to connect with the antenna 312. Alternatively, or in addition, if the insert 300 is equipped with the electronics module 314, the contacts 355 may be configured to communicatively couple the module 314 and the antenna 312. The contacts 355 may be used to transmit/receive signals, corresponding to forces/tension/etc. applied to the IM nail 300, between the sensor 316 and the antenna 312. The contacts 355 may also be used to receive power signals (e.g., from an external power source). Alternatively, or in addition, the sensor 316 (and/or the module 314, if so equipped) may be configured to receive and/or transmit signals directly to external device without use of the antenna 312.

[0084] In some example, non-limiting implementations, the SAW sensor 316 may be a battery-free sensor that may constitute a wireless and passive smart component of the flexible insert. It may use piezoelectric crystals, e.g., quartz crystals, etc. as a medium. It may generate sound waves by an additional positive voltage facilitated by electrodes patterned on the surface, which may propagate across a substrate, such as, the flexible insert 300. These electromechanical properties may be used as a sensing mechanism whereby the input signal is converted into an electrical signal output for subsequent interrogation.

[0085] An exemplary, non-limiting strain sensing SAW sensor 316 may have an operating range of approximately 3 meters (m). As can be understood, any other sensors with any other operating ranges may be used. The SAW sensor 316 dimensions may be approximately 3x3x 1 millimeters and the sensor may be attached to a surface mounted device (SMD) patch antenna via a flexible printed circuit board (PCB). The SAW sensor 316 may be operated in a pulse mode where a short radiofrequency (RF) pulse may excite the emitting interdigital transducer (IDT), launching a surface wave. The surface wave may be reflected by the three reflecting IDTs and is reconverted to an electrical signal. The phase difference between the exciting pulse and the return pulses may be measured to determine strain.

[0086] As shown in FIGS. 4a-b, illustrating an exemplary operation of a SAW sensor 400, the SAW sensor 400 may include a substrate 402 having a surface 404, one or more interdigital electrodes or transducers 406 (a, b), one or more excitation sources 408, and one or more reflectors 410. The interdigital electrodes or transducers may include one or more interdigital fingers 412 that may be spaced in accordance with a wavelength of center frequency 414. The electrode/transducer 406a may be configured to receive an input wave 416 that may be configured to propagate along the surface 404 and may output a SAW 418 for processing by the electrode 406b, which in turn may generate an output wave 420.

[0087] In some implementations, as the wave 416 propagates along the surface 404 of the piezoelectric substrate/material 402, any changes in strain and/or temperature (e.g., resulting from forces/tension being applied to the IM nail 330 and insert 300 caused by bone healing process) may be configured to cause one or more shifts in speed of an acoustic wave, by which such SAW devices can also serve as sensors. Further, an electrode (e.g., electrode/transducer 406b) on the SAW device 400 may be terminated as an antenna and/or interrogated using a wireless RF probe to process the output wave 420 and determine a magnitude of such force/tension, thereby allowing the device 400 to act as a passively powered device.

[0088] In some example, non-limiting implementations, an operating frequency of the senor resonator may be set in approximate range of 430-480 MHz (e.g., between a low frequency (for reduced attenuation in fat and muscle tissue) and a high frequency (e.g., 2.45 GHz) (for optimum strain sensitivity)). As can be understood, any other frequencies and/or frequency ranges are possible. As an intramedullary nail may observe bending forces in the anterior-posterior plane, the SAW device 400 may be oriented to experience maximum bending strain under that imposed curvature.

[0089] As discussed herein, SAW sensors may employ elastic waves at frequencies in the MHz to low GHz range. As shown in FIGS. 4a-b, the SAW sensor devices may include metallic interdigital transducers (IDT) (e.g., IDTs 406a, 406b) generating waves that propagate over a piezoelectric substrate (e.g., substrate 402). The acoustic waves may propagate along the surface of a solid in which the properties of the propagation (for example, amplitude, velocity, etc.) may be influenced by a measurand. Response signals may form a sequence of short pulses in accordance with the number and/or position of reflectors (e.g., reflectors 410) on the substrate’s surface. The time delay of response pulses may depend on the SAW propagation velocity, which may be affected by several physical quantities (e.g., temperature, pressure, strain, etc.) and/or the distance between the IDT and the reflectors. The SAW sensor may convert these physical quantitates directly to a change-in-time and frequency domain.

[0090] SAW devices are compact in size, have a low manufacturing cost, capable of robust operation in harsh environments and are able to operate passively and/or wirelessly by connecting an antenna to the IDT input, where a radio frequency (RF) pulse is detected. Thus, no power supply and/or active components, such as, for example, a battery is required to drive the SAW device. This is beneficial for implants that are not deemed to have life-saving applications.

[0091] As discussed herein, SAW sensors may be classified into two types: one-port SAW devices and two-port SAW devices, as shown in FIGS. 4a-b. A one port SAW device may operate with an IDT located between two reflectors (as shown in FIG. 4b), and the reflectors may be added to avoid interference patterns and/or to reduce insertion losses. The two-port SAW device may include two IDTs (as shown in FIG. 4a) with a separation, where the separation may be referred to as a delay line. The delay line area in two-port SAW devices may be used as a sensing area to measure one or more physical quantities, e.g., temperature, humidity, strain, etc. The IDT(s) may convert the received electrical signal into a mechanical signal that propagates over the piezoelectric substrate (e.g., substrate 402). Due to physical changes, e.g., temperature, force, humidity, etc., the mechanical signal may change, thereby causing a change in response of the SAW sensor. The IDT may also convert one or more portions of the mechanical signal back to an electrical signal.

[0092] In some examples, lead zirconate titanate (PZT) and/or LiNbO3 may be used as materials for substrate of the SAW sensor (e.g., substrate 402). LiNbO3 is capable of generating Rayleigh waves, and has a high electromechanical factor compared to other piezoelectric materials. An example of non-limiting SAW device specification for an intramedullary nail is illustrated in Table 1 below.

[0093] Table 1. Example SAW device specification.

[0094] In some non-limiting examples, operating frequency of the SAW sensor may be set at 872 MHz, which may be compatible with frequency used in various radio frequency (RF) interrogator units. Further, the size of the SAW sensor may be sufficiently small in order to fit within an interior of the intramedullary nail, as discussed herein. As such, a small number (e.g., 25 as shown in Table 1) of IDT finger pairs (e.g., fingers 412) may be used while ensuring performance. Additionally, higher sensitivity the SAW sensor may be accomplished through a higher operating frequency of the SAW sensor. Aluminum may be used IDT material due to its low resistivity and low manufacturing cost. As can be understood, the current subject matter is not limited to the above parameters of the SAW sensor and any other parameters may be used. Further, any other type of sensors may be used instead of the SAW sensors.

[0095] One of the benefits of using SAW sensors may be that they overcome limitations of existing intramedullary nail-fracture healing detection sensors, such as, for example, strain gauges. In particular, the SAW sensors provide long-term quartz durability, nontoxicity, and an ability to operate at substantially lower power levels while retaining accurate frequency estimation and functioning with extremely high Q sensors

[0096] FIG. 3e illustrates an exemplary IM nail 330, according to some implementations of the current subject matter. The IM nail 330 may be configured to accommodate insertion of the insert 300 shown in FIG. 3a as well as the antenna module 311.

[0097] The IM nail 330 may have a cylindrical shape, and may include a distal end 332, a proximate end 334, and nail body 306 disposed between the ends 332, 334. The body 336 may have a hollow interior that may be configured to accommodate insertion of the insert 300 shown in FIG. 3a. The IM nail 330 may be rigid, semi-rigid, partially flexible, partially rigid, and/or have any other desired rigidity/flexibility characteristics. As can be understood, other shapes, rigidity/flexibility characteristics, etc. of the IM nail 330 are possible. [0098] Similar to the nails shown in FIGS. 1 and 2, the IM nail 330 may include one or more proximal openings, slots and/or holes 309 (a, b, c) disposed at and/or proximate to the proximal end 334 and created in the body 336. It may also include one or more distal openings 307 (a, b, c) disposed at and/or proximate to the distal end 332 and created in the body 336. The holes 307 and 309 may be configured to allow protrusion of one or more screws that secure the nail with the insert 300 inside to one or more bones. The holes 307, 309 may be aligned with the corresponding holes 308, 310 of the insert 300 (shown in FIG. 3a) and may be appropriately positioned and/or aligned and/or angled and/or tilted on the body 336 so that there is precise alignment with the holes of the insert 300. Such positioning may be configured to ensure that the screws protruding through holes of the IM nail 330 also protrude through the corresponding holes 308, 310 of the insert 300.

[0099] The IM nail 330 may also include a bent and/or an angular curvature 340 that may be positioned between a proximal portion 331 of the IM nail 330 and a distal portion 333 of the IM nail 330. The angular curvature 340 may be characterized by an angle a The angle a ’ may be any desired angle that may be selected in accordance with a particular application and/or use. The angle a ’ may be configured to match angle a of the insert 300.

[00100] The proximal end 334 may accommodate positioning of the antenna module 311 with the antenna 312 protruding away from the end 334 of the IM nail 300. As shown in FIG. 3e, antenna module 311 may be configured to be threaded into the hollow interior of the IM nail 330 at the proximal end 334.

[00101] Similar to the insert 300, the IM nail 330 may include a working portion 342 that may be configured to be disposed within the distal portion 333 and may be aligned with the working portion 322 of the insert 300. The working portion 342 may be configured to be used for measuring forces that may be applied to the IM nail 330, while it is positioned in the bone, during the bone healing process. The applied forces may create tension on the working portion 342, which may be transferred to the working portion 322. As described above, such forces/tension may be detected and/or measured by the SAW sensor 316 of the module 314 of the insert 300.

[00102] In some example, non-limiting implementations, the insert 300 may be manufactured from an implantable grade polymer, a composite, a metal, an alloy, and any other material, and/or any combination thereof. As stated above, the insert 300 may be contoured to precisely fit within an interior portion of an IM nail. The insert 300 may also be thinned from a circular rod to provide additional flexibility and concentrate the strain at the SAW sensor 316. Further, strain concentration may be achieved for the purpose of strain measurement by thinning the insert at the back of the SAW sensor 316.

[00103] In some example, non-limiting implementations, the insert 300 may be approximately 6 mm in diameter that, as described herein, may be inserted into a cannulation interior portion of a TRIGEN intramedullary nail (as available from Smith & Nephew Pic, London, United Kingdom), and may be used for measuring changes in bending strain along a single axis of the IM nail. The diameter of the insert 300 may be scaled appropriately to the internal diameter of the IM nail of increasing length and external diameter, e.g., approximately 5.5 mm diameter insert, approximately 8.5 mm outer diameter nail; approximately 5.8 mm diameter insert, approximately 10 mm outer diameter nail; approximately 5.8 mm diameter insert, approximately 11.5 mm outer diameter nail; approximately 6.6 mm diameter insert, approximately 13 mm outer diameter nail; etc. The insert 300 may be manufactured using at least one of the following: a flexible implant grade material, PEEK, polyethylene, nylon, polyurethane, carbon-fiber reinforced PEEK, aluminum, Nitinol, carbon steel, titanium, and/or any other materials, and/or any combinations thereof. The curvature of the insert 300 may be designed such that it reflects the proximal bends and distal bows of the IM nail allowing it to be located centrally within the cannulation (as shown in FIG. 3 a).

[00104] Referring to FIGS. 3f-g, the IM nail 330 and the insert 300 may be implanted into the bone tissue in a variety of ways. Once implanted, one or more screws, nails, and/or any other mechanism may be used to secure the nail 330 (with the insert 300 inside it) to the bone tissue. By way of a non-limiting example, in tibial nail implantation, a standard knee arthrotomy may be made and an appropriate starting point for the nail may be drilled. An opening cannulated drill may be used to widen the opening hole, so that a long ball-tip guidewire 3.2 mm in diameter may be placed into the medullary canal. The medullary canal may then be sequentially reamed with flexible reamers until a tight diaphyseal fit is achieved, e.g., up to 1.5 mm over the diameter of the nail. The nail 330 with the standard insertion handle may then be impacted with a mallet into the tibia over the guidewire to the required depth. The guide wire may then be removed. A nail cap (e.g., module 311 as shown in FIG. 3b), which is adapted to receive the flexible insert 300, may then be coupled to the proximal end 334 of nail 330 to ensure that it can be located and locked centrally down the cannulation or hollow interior 362 of the nail body 306.

[00105] As shown in FIG. 3f, the flexible insert 300 may be positioned inside the hollow interior 362 of the nail 330 after the removal of the guide wire but before insertion of one or more interlocking nails, screws, etc. as shown in FIGS. 3g-h. For example, screws 361a and 361c may be inserted into holes 307a and 307c, respectively, which are aligned with respective holes 308a and 308c of the insert 300 (not shown in FIGS. 3g-h). Similarly, screws 363a, 363b and 361c may be inserted into holes 309a, 309b, and 309c, respectively, which, in turn, are aligned with respective holes 310a, 310b and 310c of the insert 300 (not shown in FIGS. 3g-h). The screws 361 and 363 secure the nail 330 (with the insert 300) to the patient’s bone(s) (not shown in FIGS.

3g-h).

[00106] FIG. 3i illustrates an alternative implementation of an SAW system module 371, according to some implementations of the current subject matter. The module 371 may be configured for insertion into the proximate end 304 of the IM nail and/or a bone screw for measurement of strain forces applied to the IM nail/bone screw. The module 371 may include a housing 372 having exterior threads 373, which may be used for threading the module 371 into the IM nail and/or a bone screw (not shown in FIG. 3i). The housing 373 may include a proximate end 375 and a distal end 377. A hollow (and/or a partially hollow) interior 378 may be disposed between the proximate end 375 and the distal end 377. The distal end 377 may be configured for insertion into the interior housing (e.g., interior bore) of the IM nail and/or a bone screw. The proximate end 375 may include a capture cavity 374. By way of a non-limiting example, the capture cavity 374 may have an interior hexagonal (HEX) shape.

[00107] The capture cavity 374 may be configured to accommodate position of a transponder (e.g., antenna) 380 and a SAW micro-sensor 382 that may be coupled to the transponder 380. In some example implementations, the transponder 380 may be further communicatively coupled to other electronic components (that may be disposed in other parts of the IM nail and/or bone screw) via the interior 378. Alternatively, or in addition, the transponder 380 and the sensor 382 may form a self-sufficient single module without a need for connection to any other electronic components. In some example, non-limiting implementations, the SAW module (e.g., 4.5 diameter x 3 mm height) may be press fit into the capture cavity 374 (e.g., of a TRIGEN® bone screw). The protruding antenna 380 may be configured to communicate with one or more external interrogators (not shown in FIG. 3i) to track changes in strain over time. For example, strain from separate different screws (e.g., 4 screws) using SAW sensors with nominal frequencies may be measured to determine whether there is any implant loosening occurring at either the distal or proximal end of the nail.

[00108] FIG. 5 illustrates an exemplary system 500 for communication with the sensor 316 in the insert 300, according to some implementations of the current subject matter. The system 500 may include a computing system 502, a SAW reader or interrogation device 504, a reading antenna device 506, antenna 312, and the saw sensor 316 positioned in the insert 300 (not shown in FIG. 5), which may, in turn, be disposed within the nail 330. One or more components of the system 500 may be configured as one or more processors, one or more servers, one or more databases, one or more memory locations, etc. In some implementations, one or more combinations of software and/or hardware may be part of one or more components of the system 500.

[00109] As shown in FIG. 5, the reader or interrogation unit 504 may be configured to transmit and/or receive one or more wireless signals, using antenna device 506, with the SAW sensor 316 (not shown in FIG. 5) via the antenna 312. The transmitted and/or received signals may be processed by the computing system 502. For example, the system 502 may be configured to determine whether the bone healing process is going according to the treatment plan that may have been prescribed upon implantation of the nail 330. The system 502 may be configured to make this determination based on the force/tension values that it receives from the SAW sensor 316 (via the antenna 506 and the device 504). Alternatively, or in addition the device 504 may be configured to perform this analysis.

[00110] In some example, non-limiting implementations, wireless measurement from the insert 300 may be achieved using the interrogation or reader unit 504 using frequency domain methods. The unit 504 may be configured to interrogate a specific frequency with a narrow band pulse and then measure signal power of a signal returned from the sensor 316. The interrogation unit 504 may also be used to wirelessly power (e.g., using near field communication (NFC) interface) the sensor 316.

[00111] Further, in some example, non-limiting implementations, the antenna device 506 may include two dipole antennas having operational frequency of 430-480 MHz and a bandwidth of approximately 20 MHz for the interrogation and a SAW responder, respectively. The applied strain modulates the SAW velocity, and corresponding shift in sensing device frequency (Af) may be extracted as the sensing signal (as shown by a user interface 510). The devices 502 and/or 504 may be configured to record and/or display the sensing signal in real time (e.g., on an external device’s user interface). Signal strength may be calibrated by controlling impedance levels and provision of inductive loading of the antenna.

[00112] In some example, alternate implementations, the curvature and/or length of the flexible insert 300 may be adapted for measuring bending strains in other lower (e.g., femoral) extremity and/or upper extremity (e.g., humeral) nails, where bone healing monitoring may be needed. The SAW sensor 316 may be adapted to determine positioning of the nail within a bone, thereby making it possible to target screw hole positions without any restrictions imposed on whether the distal and/or proximal holes are targeted first.

[00113] Moreover, the flexible insert 300 may be reduced in length to match the working length of the nail 330, e.g., the length of the nail 330 spanning the fracture site from its distal point of fixation in the proximal fragment to proximal point of fixation in the distal fragment. This may be helpful in overcoming technical challenges of aligning and/or matching the diameter of the screw holes in the nail 330 (e.g., 5.3 mm) with the flexible insert 300 and occluding the proximal end of the nail counter-bore. In this case, the antenna 312 may be extended to ensure that it is able to pass through the proximal end of the nail and/or through one of the screw holes. The sensor(s) 316 may be powered externally using a near field communication charging device that may be worn by the patient during a prescribed measurement period.

[00114] FIG. 9 illustrates an exemplary computing apparatus 900, according to some implementations of the current subject matter. The apparatus 900 may be a computing device that may be incorporated as one or more elements of the system 500 shown in FIG. 5, such as, computing system 502. The apparatus 900 may be a computer in the form of a smart phone, a tablet, a notebook, a desktop computer, a workstation, or a server. The apparatus 900 can combine with any suitable example of the systems, devices, and methods disclosed herein. The apparatus 900 can include processor(s) 910, a non-transitory storage medium 920, communication interface 930, and a display 935. The processor(s) 910 may comprise one or more processors, such as a programmable processor (e g., a central processing unit (CPU)). The processor(s) 910 may comprise processing circuitry to implement processing of various signals that may be transmitted and/or received to and/or from the SAW sensor 316.

[00115] The processor(s) 910 may include memory such as flash memory to contain program code for execution by the processor(s) 910. In some examples, the processor(s) 910 may have random access memory to contain a copy of code from flash memory or read only memory to facilitate faster execution of code. In some examples, the processor(s) 910 may include cache to contain data for faster calculations or execution. In some examples, the processor(s) 910 may include a logic circuitry 915, which may include a user interface manager 917. The user interface manager 917 may function as a state machine controlled by keypad inputs, internal events and/or alarms, boundary conditions, exceptions and supervisory input to the user interface manager 917. The user interface manager 917 may be coupled to a main screen on the display 935 that may be used to display various strain data and/or healing process data associated with the implanted nail.

[00116] The processor(s) 910 may operatively couple with a non-transitory storage medium 920. The non-transitory storage medium 920 may store logic, code, and/or program instructions executable by the processor(s) 910 for performing one or more instructions including the logic circuitry 925. The non-transitory storage medium 920 may include one or more memory units (e.g., fixed and/or removable media or external storage such as electrically erasable programmable read only memory (EEPROM), a secure digital (SD) card, random-access memory (RAM), a flash drive, solid-state drive, a hard drive, and/or the like). The memory units of the non-transitory storage medium 920 may store logic, code and/or program instructions executable by the processor(s) 910 to perform any suitable implementation of the methods described herein.

[00117] The logic circuitry 925 may include operation code 927, panels 928, and a configuration file 929. The operation code 927 may include various functionalities associated with processing of signals, data, etc. transmitted and/or received from the SAW sensor 316. The panels 928 may be used to define graphical user interfaces for display of information and for receiving input parameters and/or configurations from a user associated with the bone healing process. The configuration file 930 may include user selected parameters associated with signal transmissions between components of the system 500.

[00118] The processor(s) 910 may couple to a communication interface 930 to transmit the data, code, or commands to and/or receive data, code, or commands from one or more external devices (e.g., a terminal, display device, a smart phone, a tablet, a server, or other remote device). The communication interface 930 includes circuitry to transmit and receive communications through a wired and/or wireless media such as an Ethernet interface, a wireless fidelity (Wi-Fi) interface, a Bluetooth interface such as a Bluetooth Low Energy (BLE) interface, a cellular data interface, and/or the like. In some examples, the communication interface 930 may implement logic such as code in a baseband processor to interact with a physical layer device to transmit and receive wireless communications. For example, the communication interface 930 may implement one or more of local area networks (LAN), wide area networks (WAN), infrared, radio, Bluetooth, Wi-Fi, point-to-point (P2P) networks, telecommunication networks, cloud communication, and the like.

[00119] The processor(s) 910 may couple to a display 930 to display panels 928 for a user interface and/or other user interface items such as a message or notification via, graphics, video, text, and/or the like. In some examples, the display 930 may include a display on a terminal, a display device, a smart phone, a tablet, a server, or a remote device.

[00120] FIGS. 10-11 illustrate example implementations of a storage medium and computing platform for processing one or more signals, data, etc. associated with the bone healing process that may be monitored by the SAW sensor 316. FIG. 10 illustrates an example of a storage medium 1000 to store various operational logic. Storage medium 1000 may include an article of manufacture. In some examples, storage medium 1000 may include any non-transitory computer readable medium or machine-readable medium, such as an optical, magnetic or semiconductor storage. Storage medium 1000 may store various types of computer executable instructions 1002, such as instructions to implement logic flows and/or techniques associated with processing of signals, data, etc. as described herein. Examples of a computer readable or machine-readable storage medium may include any tangible media capable of storing electronic data, including volatile memory or non-volatile memory, removable or non-removable memory, erasable or nonerasable memory, writeable or re-writeable memory, and so forth. Examples of computer executable instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, object-oriented code, visual code, and the like. The examples are not limited in this context.

[00121] FIG. 11 illustrates an example computing platform 800. In some examples, as shown in FIG. 11, the computing platform 1100 may include a processing component 1110, other platform components or a communications interface 1130. According to some examples, computing platform 1100 may be implemented in a computing device such as a server in a system such as a data center or server farm that supports a manager or controller for managing configurable computing resources as mentioned above. Furthermore, the communications interface 1130 may include a wake-up radio (WUR) and may be capable of waking up a main radio of the computing platform 1100.

[00122] According to some examples, processing component 1110 may execute processing operations or logic for apparatus 1115 described herein, such as, for example, one or more components of the system 500. Processing component 1110 may include various hardware elements, software elements, or a combination of both. Examples of hardware elements may include devices, logic devices, components, processors, microprocessors, circuits, processor circuits, circuit elements (e.g., transistors, resistors, capacitors, inductors, and so forth), integrated circuits, application specific integrated circuits (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate array (FPGA), memory units, logic gates, registers, semiconductor device, chips, microchips, chip sets, and so forth. Examples of software elements, which may reside in the storage medium 1120, may include software components, programs, applications, computer programs, application programs, device drivers, system programs, software development programs, machine programs, operating system software, middleware, firmware, software modules, routines, subroutines, functions, methods, procedures, software interfaces, application program interfaces (API), instruction sets, computing code, computer code, code segments, computer code segments, words, values, symbols, or any combination thereof. Determining whether an example is implemented using hardware elements and/or software elements may vary in accordance with any number of factors, such as desired computational rate, power levels, heat tolerances, processing cycle budget, input data rates, output data rates, memory resources, data bus speeds and other design or performance constraints, as desired for a given example.

[00123] In some examples, other platform components 1125 may include common computing elements, such as one or more processors, multi-core processors, co-processors, memory units, chipsets, controllers, peripherals, interfaces, oscillators, timing devices, video cards, audio cards, multimedia input/output (I/O) components (e g., digital displays), power supplies, and so forth. Examples of memory units may include without limitation various types of computer readable and machine readable storage media in the form of one or more higher speed memory units, such as read-only memory (ROM), random-access memory (RAM), dynamic RAM (DRAM), Double-Data-Rate DRAM (DDRAM), synchronous DRAM (SDRAM), static RAM (SRAM), programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, polymer memory such as ferroelectric polymer memory, ovonic memory, phase change or ferroelectric memory, silicon-oxide-nitride- oxide-silicon (SONOS) memory, magnetic or optical cards, an array of devices such as Redundant Array of Independent Disks (RAID) drives, solid state memory devices (e.g., USB memory), solid state drives (SSD) and any other type of storage media suitable for storing information. [00124] In some examples, communications interface 1130 may include logic and/or features to support a communication interface. For these examples, communications interface 1130 may include one or more communication interfaces that operate according to various communication protocols or standards to communicate over direct or network communication links. Direct communications may occur via use of communication protocols or standards described in one or more industry standards (including progenies and variants) such as those associated with the PCI Express specification. Network communications may occur via use of communication protocols or standards such as those described in one or more Ethernet standards promulgated by the Institute of Electrical and Electronics Engineers (IEEE). For example, one such Ethernet standard may include IEEE 802.3-2012, Carrier sense Multiple access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications, Published in December 2012 (hereinafter “IEEE 802.3”). Network communication may also occur according to one or more OpenFlow specifications such as the OpenFlow Hardware Abstraction API Specification. Network communications may also occur according to Infiniband Architecture Specification, Volume 1, Release 1.3, published in March 2015 (“the Infiniband Architecture specification”).

[00125] Computing platform 1100 may be part of a computing device that may be, for example, a server, a server array or server farm, a web server, a network server, an Internet server, a workstation, a mini-computer, a main frame computer, a supercomputer, a network appliance, a web appliance, a distributed computing system, multiprocessor systems, processorbased systems, or combination thereof. Accordingly, functions and/or specific configurations of computing platform 1100 described herein, may be included or omitted in various implementations of computing platform 1100, as suitably desired. [00126] The components and features of computing platform 1100 may be implemented using any combination of discrete circuitry, ASICs, logic gates and/or single chip architectures. Further, the features of computing platform 1100 may be implemented using microcontrollers, programmable logic arrays and/or microprocessors or any combination of the foregoing where suitably appropriate. It is noted that hardware, firmware and/or software elements may be collectively or individually referred to herein as “logic”.

[00127] It should be appreciated that the exemplary computing platform 1100 shown in the block diagram of FIG. 11 may represent one functionally descriptive example of many potential implementations. Accordingly, division, omission or inclusion of block functions depicted in the accompanying figures does not infer that the hardware components, circuits, software and/or elements for implementing these functions would necessarily be divided, omitted, or included in implementations.

[00128] One or more features of at least one example may be implemented by representative instructions stored on at least one machine-readable medium which represents various logic within the processor, which when read by a machine, computing device or system causes the machine, computing device or system to fabricate logic to perform the techniques described herein. Such representations, known as “IP cores”, may be stored on a tangible, machine readable medium and supplied to various customers or manufacturing facilities to load into the fabrication machines that actually make the logic or processor.

[00129] The foregoing description has broad application. While the present disclosure refers to certain implementations, numerous modifications, alterations, and changes to the described implementations are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claim(s). Accordingly, it is intended that the present disclosure not be limited to the described implementations. Rather these implementations should be considered as illustrative and not restrictive in character. All changes and modifications that come within the spirit of the present disclosure are to be considered within the scope of the disclosure. The present disclosure should be given the full scope defined by the language of the following claims, and equivalents thereof. The discussion of any implementation is meant only to be explanatory and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these implementations. In other words, while illustrative implementations of the disclosure have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs.

[00130] Directional terms such as top, bottom, superior, inferior, medial, lateral, anterior, posterior, proximal, distal, upper, lower, upward, downward, left, right, longitudinal, front, back, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) and the like may have been used herein. Such directional references are only used for identification purposes to aid the reader’ s understanding of the present disclosure. For example, the term “distal” may refer to the end farthest away from the medical professional/operator when introducing a device into a patient, while the term “proximal” may refer to the end closest to the medical professional when introducing a device into a patient. Such directional references do not necessarily create limitations, particularly as to the position, orientation, or use of this disclosure. As such, directional references should not be limited to specific coordinate orientations, distances, or sizes, but are used to describe relative positions referencing particular implementations. Such terms are not generally limiting to the scope of the claims made herein. Any implementation or feature of any section, portion, or any other component shown or particularly described in relation to various implementations of similar sections, portions, or components herein may be interchangeably applied to any other similar implementation or feature shown or described herein.

[00131] It should be understood that, as described herein, an "implementation" (such as illustrated in the accompanying Figures) may refer to an illustrative representation of an environment or article or component in which a disclosed concept or feature may be provided or embodied, or to the representation of a manner in which just the concept or feature may be provided or embodied. However, such illustrated implementations are to be understood as examples (unless otherwise stated), and other manners of embodying the described concepts or features, such as may be understood by one of ordinary skill in the art upon learning the concepts or features from the present disclosure, are within the scope of the disclosure. Furthermore, references to “one implementation” of the present disclosure are not intended to be interpreted as excluding the existence of additional implementations that also incorporate the recited features.

[00132] In addition, it will be appreciated that while the Figures may show one or more implementations of concepts or features together in a single implementation of an environment, article, or component incorporating such concepts or features, such concepts or features are to be understood (unless otherwise specified) as independent of and separate from one another and are shown together for the sake of convenience and without intent to limit to being present or used together. For instance, features illustrated or described as part of one implementation can be used separately, or with another implementation to yield a still further implementation. Thus, it is intended that the present subject matter covers such modifications and variations as come within the scope of the appended claims and their equivalents. [00133] As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. It will be further understood that the terms “includes” and/or

“comprising,” or “includes” and/or “including” when used herein, specify the presence of stated features, regions, steps, elements and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components and/or groups thereof.

[00134] The phrases “at least one”, “one or more”, and “and/or”, as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. The terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein.

[00135] Connection references (e.g., engaged, attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative to movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. Identification references (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to connote importance or priority but are used to distinguish one feature from another. The drawings are for purposes of illustration only and the dimensions, positions, order and relative to sizes reflected in the drawings attached hereto may vary.

[00136] The foregoing discussion has been presented for purposes of illustration and description and is not intended to limit the disclosure to the form or forms disclosed herein. For example, various features of the disclosure are grouped together in one or more implementations or configurations for the purpose of streamlining the disclosure. However, it should be understood that various features of the certain implementations or configurations of the disclosure may be combined in alternate implementations or configurations. Moreover, the following claims are hereby incorporated into this Detailed Description by this reference, with each claim standing on its own as a separate implementation of the present disclosure.

Claims (32)

WHAT IS CLAIMED:

1. An implantable medical apparatus, comprising: an insert having a proximal end; a distal end; and a body disposed between the proximal end and the distal end, the body includes one or more surface acoustic wave (SAW) sensors communicatively coupled to an antenna, wherein the one or more SAW sensors are configured to monitor an application of one or more forces or tension to at least one of: the implantable medical device and the body of the insert.

2. The apparatus of claim 1, wherein the insert is configured to be positioned in an orthopedic implant.

3. The apparatus of claim 2, wherein the orthopedic implant is an intramedullary nail.

4. The apparatus of claim 2, wherein the insert is configured to be positioned in an interior of the orthopedic implant.

5. The apparatus of claim 4, wherein the flexible insert is configured to be positioned into the interior of the orthopedic implant prior to or subsequent to or during implantation of the orthopedic implant into a bone of a patient.

6. The apparatus of any of the preceding claims, wherein the insert is flexible.

7. The apparatus of any of the preceding claims, wherein the one or more forces or tension are applied by a bone of a patient during a treatment process.

8. The apparatus of claim 7, wherein, upon detection of the one or more forces or tension by the one or more SAW sensors, the one or more SAW sensors are configured to transmit, using the antenna, one or more instructions corresponding to the detected one or more forces or tension to one or more external devices.

9. The apparatus of claim 4, wherein the insert includes one or more first openings.

10. The apparatus of claim 9, wherein at least one of the one or more first openings is disposed proximate to at least one of the distal end of the insert, the proximal end of the insert, and any combination thereof.

11. The apparatus of claim 10, wherein the orthopedic implant includes one or more second openings, wherein, upon positioning of the insert in the interior of the orthopedic implant, the one or more first openings are configured to be aligned with the one or more second openings.

12. The apparatus of claim 11, wherein at least one securing screw is configured to be inserted through at least one first opening in the one or more first openings and at least one second opening in the one or more second openings, wherein the at least one first opening is aligned with the at least one second opening, and the at least one securing screw is configured to secure the orthopedic implant and the insert to the bone of the patient.

13. The apparatus of any of the preceding claims, wherein the one or more SAW sensors are passive sensors.

14. The apparatus of any of the preceding claims, wherein the one or more SAW sensors are configured to receive, via the antenna, a power from one or more external devices communicatively coupled to the antenna.

15. The apparatus of claim 14, wherein the one or more SAW sensors, upon receiving the power from the one or more external devices, are configured to transmit, via the antenna, one or more instructions corresponding to the one or more forces or tension detected by the one or more SAW sensors, to the one or more external devices.

16. The apparatus of any of claims 14-15, wherein the one or more SAW sensors are configured to receive power from the one or more external devices using a near field communication (NFC) interface.

17. The apparatus of any of the preceding claims, further comprising one or more power sources.

18. The apparatus of claim 17, wherein the one or more power sources are configured to provide power to the one or more SAW sensors, wherein at least one of the one or more SAW sensors is an active SAW sensor.

19. The apparatus of claim 4, further comprising an antenna module, wherein the antenna module houses the antenna.

20. The apparatus of claim 19, wherein antenna module is positioned proximate to a proximal end of the orthopedic implant or a distal end of the orthopedic implant.

21. The apparatus of claim 20, wherein the antenna module is configured to be threaded into at least a portion of the interior of the orthopedic implant.

22. The apparatus of claim 21, wherein the antenna module, upon being positioned in the at least a portion of the interior, is configured to hermitically seal the interior of the orthopedic implant.

23. The apparatus of any of the preceding claims, wherein the insert includes an insert interior, wherein the one or more SAW sensors are disposed within the insert interior of the insert and are hermitically sealed within the insert interior of the insert using one or more covers.

24. An intramedullary nail, comprising: an intramedullary nail body having an interior; and a flexible insert positioned in the interior of the intramedullary nail body, wherein the flexible insert includes one or more surface acoustic wave (SAW) sensors communicatively coupled to an antenna, wherein the one or more SAW sensors are configured to monitor application of one or more forces or tension to at least one of: the intramedullary nail body and the flexible insert.

25. The intramedullary nail of claim 24, wherein the intramedullary nail is configured to be implanted into a bone of a patient, wherein the one or more forces or tension are applied by the bone of the patient during a treatment process.

26. The intramedullary nail of claim 25, wherein, upon detection of the one or more forces or tension by the one or more SAW sensors, the one or more SAW sensors are configured to transmit, using the antenna, one or more instructions corresponding to the detected one or more forces or tension to one or more external devices.

27. The intramedullary nail of any of the preceding claims 24-25, wherein the one or more SAW sensors are configured to receive, via the antenna, a power from one or more external devices communicatively coupled to the antenna.

28. The intramedullary nail of claim 27, wherein the one or more SAW sensors, upon receiving the power from the one or more external devices, are configured to transmit, via the antenna, one or more instructions corresponding to the one or more forces or tension detected by the one or more SAW sensors, to the one or more external devices.

29. The intramedullary nail of any of claims 27-28, wherein the one or more SAW sensors are configured to receive the power from the one or more external devices using a near field communication (NFC) interface.

30. The intramedullary nail of claim 24, further comprising one or more power sources.

31. The intramedullary nail of claim 30, wherein the one or more power sources are configured to provide a power to the one or more SAW sensors, wherein at least one of the one or more SAW sensors is an active SAW sensor.

32. A method, comprising: monitoring, using one or more surface acoustic wave (SAW) sensors, application of one or more forces or tension to at least one of: an intramedullary nail and a flexible insert, wherein the one or more SAW sensors are disposed in the flexible insert positioned in an interior of the intramedullary nail, the intramedullary nail is configured to be positioned in a bone of a patient; receiving, using the one or more SAW sensors, via an antenna communicatively coupled to the one or more SAW sensors, a power to power the one or more SAW sensors; and transmitting, using the powered one or more SAW sensors, via the antenna, one or more instructions corresponding to the one or more forces or tension detected by the one or more powered SAW sensors, to one or more external devices communicatively coupled to the one or more SAW sensors via the antenna.