CN111214314A

CN111214314A - Movable space occupying device

Info

Publication number: CN111214314A
Application number: CN202010140753.8A
Authority: CN
Inventors: 王敏; 冉天飞; 宋鑫; 周媛媛; 柯松
Original assignee: Second Affiliated Hospital Army Medical University
Current assignee: Second Affiliated Hospital Army Medical University
Priority date: 2020-03-03
Filing date: 2020-03-03
Publication date: 2020-06-02

Abstract

The invention discloses a movable spacer, which belongs to the technical field of medical instruments and comprises a femur side part and a tibia side part which are matched, wherein the femur side part and the tibia side part are both hollow cavities, antibiotic chain beads are placed in the cavities, and the cavities are designed to be porous; the femoral side part and the tibial side part are both connected with drainage tubes; the femoral side member and the tibial side member are both manufactured by 3D printing. The invention is suitable for debridement of infection around knee joint prosthesis, and the femoral side component and the tibial side component are manufactured by 3D printing, so that shape application and structural firmness can be ensured; the thighbone side parts and the shin bone side parts are hollow cavities, antibiotic chain beads can be filled in the cavities, and the cavities are provided with porous designs and are connected with drainage tubes, so that continuous lavage can be performed, and better anti-infection and debridement effects can be achieved.

Description

Movable space occupying device

Technical Field

The invention relates to the technical field of medical instruments, in particular to a movable spacer for infection debridement around a knee joint prosthesis.

Background

Periprosthetic infection is one of the most serious complications of artificial joint replacement. The existing 'gold standard' for treating infection around knee joint prosthesis is second-stage revision, and the cure rate of the second-stage revision can exceed 90%. Second phase revision surgery consists in debriding and removing the prosthesis after infection around the knee prosthesis, placing a spacer (spacer) made of hand-held or moulded bone cement in the joint space, and waiting for another surgery to reposition the joint prosthesis. The space occupying device can avoid scar tissue in the joint cavity from being occupied, prevent surrounding muscle and soft tissue from contracture, and create conditions for secondary operation; at the same time, the space occupying device can be mixed with antibiotics and locally released to better control infection.

The space occupying devices used for debridement of infection around the knee joint prosthesis at present are mainly divided into 2 types: a static placeholder and an active placeholder. Static type spacer is simple clearance bone cement piece, and the knee joint keeps the functional position state, and the knee joint can not move about. The movable spacer is generally divided into 2 parts on the femoral side and the tibial side, and the two parts are similar to a knee joint prosthesis, so that the knee joint keeps a certain mobility, and the functional recovery of the knee joint after operation is facilitated. Although there was no significant difference in infection control rates, the average activity of the active placeholder patients after second phase revision was significantly higher than that of the static placeholder patients.

At present, the movable placeholders mainly comprise the following components: 1. prefabricated and commercialized active placeholders; 2. a movable spacer manufactured by using a commercial mold in the operation; 3. non-commercial molds or freehand fabricated active placeholders are used intraoperatively. Commercially prefabricated active placeholders are convenient to purchase, but are limited in size and antibiotic usage categories and dosage options. The problem that the movable spacer which is not manufactured by commercial die and hands is not applied is solved. Some scholars can not apply ointment or plaster in the shape of the spacer, dislocate the spacer and even break the spacer in the use process by manually manufacturing the antibiotic bone cement spacer.

The currently used movable spacer is made of bone cement materials, antibiotics such as vancomycin and gentamicin are usually mixed into the bone cement when the spacer is used, the strength of the bone cement is affected by the mixing of the antibiotics, the strength of the bone cement is reduced by mixing of more antibiotics, a good anti-infection effect cannot be achieved if the dosage of the mixed antibiotics is not enough, the titer of the antibiotics can also be damaged by a large amount of heat generated during polymerization of the bone cement, the release time of the mixed antibiotics is limited, and whether the mixed antibiotics are sensitive or not cannot be determined before the bacteria culture drug sensitivity results. In addition, the toxic reaction of bone cement caused by the continuous release of monomer into blood after a large amount of bone cement is implanted into human body is not rare in clinic.

These problems with current active placeholders, in particular the limited use of antibiotics for bone cement materials, affect to some extent the debridement effect of infection around the prosthesis. Therefore, there is a great need for an improved active placeholder.

Disclosure of Invention

The invention aims to provide a movable spacer which is shaped like an application, firm in structure and good in debridement effect.

In order to solve the technical problems, the invention provides the following technical scheme:

a movable spacer comprises a femur side part and a tibia side part which are matched, wherein the femur side part and the tibia side part are both hollow cavities, antibiotic chain beads are placed in the cavities, and the cavities are designed to be porous;

the femoral side part and the tibial side part are both connected with drainage tubes;

the femoral side member and the tibial side member are both manufactured by 3D printing.

Furthermore, a supporting structure is arranged in the cavity, and the supporting structure is a supporting column and/or a supporting plate.

Furthermore, a chain bead inlet is formed in the cavity.

Further, each hole in the multi-hole design has a diameter of 0.5-1.5mm and a density of 10-20 holes/cm²。

Further, the wall thickness of the cavity is 1-2 mm.

Furthermore, the drainage tube on the femoral side part is a water inlet tube, and the drainage tube on the tibial side part is a water outlet tube.

Furthermore, the connection parts of the femoral side part and the tibial side part and the drainage tube are provided with cannula openings, and the drainage tube is sleeved with a C-shaped elastic plastic piece and is clamped in the cannula openings through the C-shaped elastic plastic piece.

Furthermore, the tibia side part is provided with a pair of accommodating grooves extending along the front and back directions of the human body, and the femur side part is provided with strip-shaped bulges matched with the accommodating grooves.

Furthermore, the femur side part and the tibia side part are communicated at the strip-shaped protrusions and the accommodating grooves.

Further, the material adopted for 3D printing is medical nylon PA 2200.

The invention has the following beneficial effects:

according to the movable spacer, the femoral side component and the tibial side component are manufactured through 3D printing, so that the shape application and the structural firmness can be ensured; the thighbone side parts and the shin bone side parts are hollow cavities, antibiotic chain beads can be filled in the cavities, and the cavities are provided with porous designs and are connected with drainage tubes, so that continuous lavage can be performed, and better anti-infection and debridement effects can be achieved.

Drawings

FIG. 1 is a schematic diagram of the usage status of the active placeholder of the present invention;

FIG. 2 is a schematic cross-sectional view of the active placeholder shown in FIG. 1;

fig. 3 is a schematic perspective view of the movable placeholder shown in fig. 1.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

The invention provides a movable spacer for debridement of infection around a knee joint prosthesis, which comprises a femur side component 1 and a tibia side component 2 which are matched with each other, as shown in fig. 1-3, wherein the basic shapes of the femur side component 1 and the tibia side component 2 can be designed according to the prior art (for example, the femur side component is integrally in a C-shaped arc plate shape, and the tibia side component is in a T-shape), parts which are the same as the prior art are not repeated, and the following description focuses on the improvement of the present application:

the femur side part 1 and the tibia side part 2 are both hollow cavities, antibiotic chain beads 3 are placed in the cavities, and the cavities 1 are designed to be porous 4;

the femoral side part 1 and the tibial side part 2 are both connected with

drainage tubes

5 and 6;

the femoral side member 1 and the tibial side member 2 are both manufactured by 3D (three-dimensional) printing, and the material adopted by the 3D printing can be a safety material capable of being implanted into a body, such as medical nylon PA 2200.

The movable spacer can introduce software through CT data of the preoperative affected knee or CT mirror image data of the contralateral knee joint, and designs size-adaptive and well-applied space occupying components/parts of the femoral side and the tibial side according to the shape and the space configuration of the original knee joint prosthesis. Hollow (namely hollow) design and porous design processing are carried out in the middle of the occupying assembly on the software, the hollow structure can be implanted with antibiotic chain beads, and the porous structure can enable the antibiotic to be continuously released to enter the joint cavity. Simultaneously, a connector can be designed on the side surface of the occupying component and used for connecting the drainage tube to be placed outside the body. The fashioned occupy-place subassembly of design can select to accord with FDA authentication and implant the internal safe material of formation through 3D printing process.

The movable spacer of the invention has the advantages that:

1. the movable spacer based on the 3D printing design can be customized individually, and a set of spacer components from small to large can be designed according to the size data of the knee joints of Chinese people, so that the cost and the preoperative preparation time are saved. The design is not only used for infection around a prosthesis after TKA (Total Knee Arthroplasty), but also can be used for designing a thin spacer in a Knee joint with primary infection or even tuberculosis infection, and the thin spacer is used for continuously releasing antibiotics or antitubercular drugs in a joint cavity after debridement, and is used for continuous lavage and drainage.

2. The middle hollow structure can be used for filling antibiotic chain beads: obtaining bacteriological results of infected patients after TKA replacement operation such as preoperative operation through puncture or sinus tissue culture, and primarily selecting sensitive antibiotics according to preoperative drug sensitivity results to prepare targeted antibiotic chain beads; if bacteriological results cannot be obtained before operation, a plurality of antibiotic beads can be prepared according to experience by using medicines capable of covering bacteria or fungi (such as staphylococcus aureus, escherichia coli, pseudomonas aeruginosa and candida albicans) which are common to infection around the prosthesis. The antibiotic bead can release medicine into joint cavity via porous structure to resist infection.

3. In the external drainage tube connector, specifically, the inlet tube can be connected to thighbone side spacer, and the outlet pipe can be connected to shin bone side spacer. And after operation, the operator can continuously irrigate the space occupying device by using an antibiotic solution according to the result of bacteriology before the operation or experience, so that the insufficient release of the antibiotic bead can be supplemented, and the porous space occupying device can be prevented from being blocked by continuously flushing the porous space occupying device. After the culture result of the tissue bacteria taken in the operation is obtained, the lavage antibiotic solution can be adjusted according to the corresponding drug sensitive result. After the symptoms of the patient disappear and the inflammation index returns, joint fluid can be extracted through the water outlet pipe to carry out culture and the treatment effect can be evaluated through routine biochemical examination.

4. The space occupying device is arranged on the femur side and the tibia side respectively, so that the movement of the joint can be better ensured, the postoperative non-load bearing functional exercise of a patient can be guided, the soft tissue contracture around the joint and the knee stretching device atrophy can be prevented, and conditions are created for the second-stage revision operation.

5. The antibiotic chain beads replace antibiotic bone cement, sensitive antibiotics can be selected in a targeted manner, and individual adjustment of dosage and variety is facilitated; can also avoid complications such as bone cement fracture, bone cement toxic reaction syndrome, bone mass loss, etc.

In conclusion, according to the movable spacer, the femoral side component and the tibial side component are manufactured by 3D printing, so that the shape application and the structural firmness can be ensured; the thighbone side parts and the shin bone side parts are hollow cavities, antibiotic chain beads can be filled in the cavities, and the cavities are provided with porous designs and are connected with drainage tubes, so that continuous lavage can be performed, and better anti-infection and debridement effects can be achieved.

For improved structural strength, the femoral side member 1And the tibial side component 2 may be provided with a support structure (not shown) within the cavity, which may be a support post and/or a support plate or the like. In order to facilitate the placement of the antibiotic beads 3, in addition to the porous design 4 of the chamber, a special bead placement port (not shown) may be provided on the chamber, and the position of the bead placement port may be flexibly selected as desired. In the multi-hole design 4, it is preferable that each hole has a diameter of 0.5 to 1.5mm, for example, 1 mm; the density is 10-20 holes/cm²E.g. 16 holes/cm². The wall thickness of the cavity is preferably 1-2mm, for example 1.5 mm.

Considering the posture of the human body, in order to facilitate drainage and lavage, it is preferable that the drainage tube 5 on the femoral side member 1 is a water inlet tube and the drainage tube 6 on the tibial side member 2 is a water outlet tube. For the convenience of connecting the

drainage tubes

5 and 6, the joints of the femoral side part 1 and the tibial side part 2 and the

drainage tubes

5 and 6 can be provided with spigots (not shown), the

drainage tubes

5 and 6 are connected by inserting the

drainage tubes

5 and 6 into the spigots, and the

drainage tubes

5 and 6 can be sleeved with C-shaped elastic plastic parts and clamped in the spigots through the C-shaped elastic plastic parts, so that the

drainage tubes

5 and 6 are firmly fixed.

In the embodiment of the present invention, as shown in fig. 1 and 3, the tibia side member 2 may be provided with a pair of receiving grooves 21 extending along the anterior-posterior direction of the human body, and the femur side member 1 may be provided with the strip-shaped protrusions 11 engaged with the receiving grooves 21, so that the femur side member 1 and the tibia side member 2 can be better prevented from dislocating during the movement process when the femur side member and the tibia side member are engaged with each other. Moreover, in order to improve the irrigation efficiency, the femur-side member 1 and the tibia-side member 2 are preferably communicated with each other at the strip-shaped protrusion 11 and the receiving groove 21, that is, the strip-shaped protrusion 11 and the receiving groove 21 are provided with communicated openings with a larger size (much larger than the diameter of a single hole in a porous design), so that the irrigation solution can flow smoothly from the cavity of one side member to the cavity of the other side member.

The design method of the movable placeholder can refer to the following steps:

(1) data acquisition:

CT scan parameter scheme: enabling the patient to enter a CT coil (FFS) in a supine position, wherein the scanning range comprises 15cm above and below the knee joint, and the scanning layer thickness is 0.625 mm; CT scanning data is stored in a Dicom sequence format;

b. x-ray film of whole lower limb: the X-ray film of the whole length position of the double lower limbs is irradiated conventionally.

(2) Model reconstruction:

a. importing CT scanning data, processing the data obtained by CT scanning by using Mimics 17.0 software, separating image information of two parts of the femur and the tibia, separating bone boundaries according to image gray scale to obtain clear bone images, extracting bone models, and reconstructing the femur and the tibia by using the software;

b. optimizing the 3D model: and (3) using the Mimics to optimize model fracture surfaces, self-intersection surfaces, CT artifacts and the like, and storing the three-dimensional model in an STL format.

(3) Planning before operation:

a. preoperative simulation: supplementing possible bone defects according to the appearance of the knee joint prosthesis, and designing an placeholder;

b. placeholder parameters: porous diameter of 1mm and density of 16 pores/CM²The wall of the placeholder is 1.5mm thick, and the middle part is designed to be hollow, as shown in figure 1;

c. spacer material and processing method: the guide plate is made of medical nylon (PA2200), and the material can be sterilized at high temperature, is not easy to deform and can be clinically used after FDA certification. Inputting the data of the femur tibia osteotomy guide plate model into a self-contained software program of a 3D printer (EOS P110), and printing and molding.

The intraoperative method of use of the active placeholder of the invention can be referred to as follows:

1) removing and taking out the joint prosthesis in the operation, keeping the bone as much as possible and thoroughly debriding;

2) carefully placing the space occupying device, fitting the bone surface as much as possible, and placing antibiotic beads in the space occupying device cavity according to the condition in the operation or the result before the operation;

3) the strip-shaped bulges on the femoral side part and the accommodating groove on the tibial side part are arranged in an aligned way;

4) carefully placing a drainage tube, placing a water inlet tube on the femur side and a water outlet tube on the tibia side, implanting one end of each tube into the spacer, if the aperture is too small, expanding the tubes until the tubes are implanted, implanting the tubes into the cavity for more than 3cm, clamping to avoid falling off, and avoiding difficulty in taking out;

5) adjusting the type and time of the input antibiotics according to the conditions at the later stage, and determining the tube drawing time according to the conditions;

6) knee joint function exercise is started 1 week after the operation, and knee joint stiffness is avoided.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A movable spacer comprises a femur side part and a tibia side part which are matched, and is characterized in that the femur side part and the tibia side part are both hollow cavities, antibiotic chain beads are placed in the cavities, and the cavities are designed to be porous;

2. The movable placeholder of claim 1, wherein a support structure is provided within the cavity, the support structure being a support post and/or a support plate.

3. The movable placeholder of claim 1, wherein the cavity is provided with a bead access opening.

4. The movable placeholder of claim 1, wherein each hole of the porous design has a diameter of 0.5-1.5mm and a density of 10-20 holes/cm²。

5. The movable placeholder of claim 1, wherein the cavity has a wall thickness of 1-2 mm.

6. The movable spacer of claim 1 wherein the drainage tube on the femoral side member is an inlet tube and the drainage tube on the tibial side member is an outlet tube.

7. The movable spacer as claimed in claim 1, wherein the femoral side member and the tibial side member are provided with spigots at the joints with the drainage tubes, and the drainage tubes are sleeved with C-shaped elastic plastic members and clamped in the spigots through the C-shaped elastic plastic members.

8. The active spacer of any one of claims 1-7 wherein the tibial side member has a pair of receiving slots extending anteroposteriorly along the body and the femoral side member has bar-like protrusions that mate with the receiving slots.

9. The movable spacer of claim 8 wherein the femoral and tibial side members communicate at the bar-shaped protrusion and receiving slot.

10. The active placeholder of claim 8, wherein the 3D printing is of medical nylon PA 2200.