MXPA99011464A - Biaxial ligamentous-restrained prostheses for upper and lower extremity arthroplasties - Google Patents

Abstract

Se presentan prótesis (52) para restaurar huesos dañados de las extremidades superiores e inferiores, las prótesis se amarran, suspenden y restringen a lo largo de al menos dos ejes que se entrecruzan.

Description

PROSTHESIS WITH BIAXIAL LIGAMENT RESTRAINT FOR ARROPLASTY OF UPPER AND LOWER LIMBS CROSS REFERENCE OF THE RELATED APPLICATIONS This is a continuation in part of the application Serial Number 08 / 401,448 filed on March 9, 1995.

FIELD OF THE INVENTION This invention relates to prostheses.

More particularly, this invention relates to new prostheses and methods for safely and effectively performing upper and lower extremity arthroplasties when tying, suspending and restraining prostheses using ligamentous means disposed along at least two intersecting axes.

BACKGROUND OF THE INVENTION Implants or prostheses are used to restore damaged bones of the upper and lower extremities such as fingers, wrists, elbows, knees and ankles of human patients. These implants are especially useful in the reconstruction of joints that, for example, have been damaged by pathological conditions such as rheumatoid arthritis, degenerative arthritis, aseptic necrosis and for treatment of trauma that could have a P1 4743 / 99MX debilitating effect on joint joints. Unfortunately, some designs of joint implants currently available or described in the past have drawbacks that arise from their construction and from the fact that they act only as spacers that replace damaged bones. For example, current and previous replacements of the scaphoid and lunate carpal bone are usually undesirable, mainly because they can not reproduce the normal and vital ligament restraints. Joint replacement designs that depend on mechanical restraint mechanisms of different types (eg, elbow-joint with semi-constriction) and degrees, also fail to simulate or replace ligamentous and capsular restriction along multiple axes. Many arthroplasties try to change the natural biomechanical properties of the replaced joint instead of reproducing those natural properties. For example, current total wrist arthroplasties replace a "link" system with a "hinge" system. Such substitutions of biomechanical design have been considered acceptable only because until now it has not been possible to satisfactorily reconstruct ligaments for joint replacements that achieve the natural biomechanical properties of the joint.

P1743 / 99MX replaced. There are three types of arthroplasties: 1) unconstrained, 2) semi-constricted and 3) totally constricted. There is a precarious balance between the advantages of unconstrained designs (reduced bone-prosthetic loosening and fracture) and their disadvantages (subluxation and dislocation of the prosthesis and joint). The inherent advantage of a fully constricted device is stability (reduced subluxation and dislocation), while the disadvantage is that most vector forces are transferred to the prosthetic-bone interface. This often results in loosening or fracture of the bone or prosthesis itself. Semi-constricted devices have traditionally employed a variety of biomechanical mechanisms that attempt to minimize the disadvantages of both unconstrained and fully constricted implants. Examples of semi-constricted implants are total elbow arthroplasties with the so-called "loose hinge". The common misconception in all these current joint replacement designs is the inability to reconstruct and reconnect the capsular and ligamentous constraints of the replaced joint, which largely dictate the behavior and stability of the joint.

P1743 / 99HX Each joint has its own unique biomechanical properties that are dictated by the shape of the articulating bones / cartilages, by their function and most importantly, by their three-dimensional capsular ligament restraints. To the date, no joint replacement prosthesis has been designed to successfully reconstruct those vital ligamentous / capsular constraints in the replacement prosthesis or through it in two or more axes. Restricting a prosthesis on two or more intersecting axes, as discussed below, has the mechanical effect of minimizing undesirable transitional and shear forces, while allowing the desired rotational movements required for the replaced joint. This must be distinguished, for example, from implants that use two parallel channels (more than criss-cross) to hold a prosthesis "separator" A in position, as illustrated in Figure 16. The biomechanical result of that arrangement is the excessive translation and rotation of the "separator" illustrated, along the parallel channels with their potential clinical waste sequelae of wear, chronic instability of the prosthesis and finally progressive arthritis.

The present invention may be applied to any human or synovial joint Biartroidial P1743 / 99MX. However, the preferred application of the invention is for articulations whose movement is significant both quantitatively and qualitatively and therefore functionally important. The definition of "joints" (in English "joints" and "articulations" are used interchangeably), adopted from the Stedman's Medical Dictionary, 1982, p. 126-7 and p. 737 refers to three types of "joints": fibrous, cartilaginous and synovial. The synovial joint is the preferred application of this invention. A synovial joint (or biartroidial joint) is a union that allows various amounts and types of movement in which the bony surfaces are covered with a layer of hyaline or fibrous cartilage. There is a joint cavity that contains synovial fluid and is lined with a synovial membrane, reinforced by a fibrous capsule and ligaments. To better explain the vital importance of capsular and ligamentous restrictions in a synovial joint and to illustrate the errors of arthroplasties that do not reconstruct these natural restrictions, we will comment on the carpal bones of the wrist. The exhibition will illustrate the anatomy, function and kinematics of the carpus emphasizing the need and P1743 / 99MX unique contribution of the invention to the extent that it is applied to replace the scaphoid and lunatic carpal bones. The invention, however, is not limited to the scaphoid and lunate prostheses but extends to all arthroplasties of the upper and lower extremities in any of the synovial or biartroid joints that are functionally important. The movement of the wrist is distributed between the radiocarpal and mesocarpal joints in a very complex way. The carpus, as discussed above, biomechanically is a link system, not a hinge system, such as the knee. Therefore, it is essential that a carpal implant reproduces the movement of the synchronous link system between it and the adjacent carpal bones to maintain the normal carpal kinematics. This serves to preserve the shape of the implant and prevent wear, fracture, dislocation and particulate synovitis. In other words, the synchronous movement of a carpal implant will help maintain the normal kinematics of the remaining carpal bones and thus prevent the overall carpal instability and surrounding arthritis that results. The most commonly available carpal implants in the past were made of silicone. Unfortunately, there are serious complications P1743 / 99MX potentials associated with the use of silicone in this and other medical applications. Indeed, since the scaphoid and lunatus bones are the ones with the most mechanical effort, they are particularly susceptible to injuries and complications. So, it is not surprising that it has commonly been reported in the literature that patients who had silicone carpal implants experienced complications related to silicone. These complications included subluxation and dislocation of the prosthesis, fragmentation and fracture of the prosthesis and finally synovitis by giant cells of foreign bodies and destruction of the focal carpal bone. Synovitis, mentioned above, is the inflammation of the synovial membrane that lines and lubricates the wrist joint. This causes pain and inhibits the movement of the wrist in the joints bone. The violation of silicone implants with suture techniques can contribute to fragmentation and synovitis induced by waste and silicone. The destruction of the focal carpal bone is still another complication that may arise at a later stage as a result of abnormal kinematics and synovitis for a prolonged period of time. The fragmentation and fracture of silicone implants and the consequent presence of silicone particle debris comes from the effort of the implant P1743 / 99 X related to subluxation of implant translation or implant fracture. Finally, subluxation is a partial dislocation of the carpal bones. Subluxation and complete dislocation of the implant are complications that can result from the inherent lack of restraint of the current carpal implants with their adjacent carpal bones and with the wrist capsule. In the native carpus, the restriction is by means of ligaments and capsule. The thicker parts of the palmar and dorsal capsule have been designed anatomically as quasi-discrete ligaments called "extrinsic ligaments" (eg, radio-scapho-capitate ligament). Whereas, those really discrete interosseous ligaments that directly connect the carpal bones to one another are termed "intrinsic ligaments" (eg, scaled ligaments). The extrinsic and intrinsic ligaments act in a dependent manner to synchronize the complex and balanced intercarpal kinematics. The currently available implants, including those made of both silicone and titanium alloys, do not reproduce the restriction mechanisms neither of the intrinsic nor of the extrinsic ligaments and therefore these prostheses are subjected to subluxation and complete dislocation.

P1743 / 99 X To date, a satisfactory technique for reconstruction of intercarpal ligaments and capsular restraints incorporating carpal replacements has not been achieved. While the present invention is designed only to enable the surgeon to accurately and predictably reconstruct the necessary ligamentous constraints and thus prevent the causes of the aforementioned failures, the prior art fails to meet this need. For example, in U.S. Patent No. 3,745,590 an implant is disclosed which includes parallel ligamentous elements (defining a single plane) molded into the body of a prosthesis at approximately opposite ends of its upper surface. The ligamentous elements are each sutured to adjacent collateral ligaments, tied to the nearest adjacent carpal bone or attached to a ligament or incised tendon. These ligamentous elements connect the prosthesis along a single axis and therefore the implant is restricted in a single plane. This lack of dual axis restriction may result in subluxation and increased cutting. The metacarpal carpal implant shown in the '590 patent referred to above includes a portion of the rod which is integrally formed with the body of the P1743 / 99MX implant and is adapted to fit in the medullary space in the metacarpal bone to be repaired. This implant includes at least one integral ligamentous element that can be attached or otherwise connected to an adjacent bone, ligament or tendon. If the implant body includes more than one ligamentous element, the elements extend from a single opening along one edge of the implant body and are tied to the adjacent tissues in the same manner as described in relation to the first carpal implant above. . This modality also restricts the prosthesis only along a single axis. Another carpal implant is still shown in U.S. Patent No. 4,198,712. This implant includes a stabilizing rod that extends outwardly and generally perpendicularly to the surface of the implant. The stem is adapted to be inserted into an adjacent carpal bone to stabilize the implant in postoperative condition. Wires or sutures may be used together with the rod for temporary fixation and reinforced stabilization of the implant during the early healing process. The wires or sutures are passed to the adjacent carpal bones through the implant. The rod and the wires or sutures are intended to restrict the prosthesis along a single axis. Also, as noted above, it is not convenient to suture directly into the P1743 / 99HX silicone since it is generally believed that it separates and drags silicone waste and potentially leads to synovitis by silicone. Accordingly, an object of the present invention is to provide a method and prosthesis for safely replacing bone (s) of the upper and lower extremities in a human joint. It is another object of the present invention to provide prostheses for replacing bone (s) of the upper and lower extremities of a joint in which the prostheses are suspended, tethered and restrained along multiple axes. It is yet another object of the present invention to provide prostheses to replace bone (s) of upper and lower limb joints in which the reconstruction of effective restraining means stimulates normal global kinematics. It is another object of the present invention to provide a method and prosthesis for replacing bone (s) of joints of upper and lower extremities involving suturing ligamentous means to capsules and adjacent bones, by means of native ligaments or directly in the bone using woven fabrics, natural capsule, bone-capsule-bone or tendon graft. It is still another object of the invention P1743 / 99MX provide prostheses with selected areas of inserted growth surface and / or surface coating that promote limited growth adhesion to the surrounding capsular or ligamentous tissue. Yet another object of the invention is to provide a method for stabilizing a prosthesis as it approaches an adjacent natural capsule and is held directly against it to facilitate natural adhesion of the growth of the surrounding capsular or ligamentous tissue to the surface of the implant for both facilitating the anchoring of the implant body directly to the capsular tissue as well as to the ligamentous tissue while also providing overall stabilization and improved kinematics. These and other objects of the invention will be apparent hereinafter.

SUMMARY OF THE INVENTION The present invention achieves the aforementioned objects by providing a prosthesis comprising a body member and cross-linking ligament means. The crosslinking ligamentous media, as described below, inhibit translation and rotation in the three dimensional axes (x, y and z). This is illustrated in Figure 16 which represents the P1743 / 99MX Biomechanical result of using parallel channels in a "spacer" prosthesis A. In contrast, Figure 17 shows the inhibition of translation and rotation of a suspended and suspended B prosthesis according to the present invention. As discussed below, the suspended prosthesis may be attached such that it is supported on an adjacent capsule. The body member is made wholly or partially of any suitable medically inert biocompatible material such as ceramic, titanium, stainless steel alloys or a non-ceramic substrate with a ceramic coating or other medically inert biocompatible coating. It has contours that resemble the shape of the bone they replace. In the preferred embodiment, the body member includes at least two non-intersecting channels that pass through the body member in a criss-cross manner with the axes of at least two of the channels that are placed in different planes so that the ligamentous media arranged in channels that do not intersect will be biomechanically independent. It is further preferred that only two channels are used and whether they intersect or not, that the channels are substantially perpendicular. In less preferred modalities, all channels may be in direct communication, that is, physically intersect; P1743 / 99MX it is preferred that at least two of the channels be practically perpendicular also in these modalities. In another alternative embodiment, at least one channel passes through the body member and at least one channel passes through contiguous bones and cartilages in a criss-cross shape (preferably substantially perpendicular) with the first channel. Obviously, the channel (s) passing (n) through the contiguous bones and cartilage will not intersect () with the channel (s) passing (n) through the body member. The channel through contiguous bones and cartilage will be made by conventional means. Selected surface areas of the body member may be made receptive to tissue growth to facilitate and promote adhesion to a specific growth area of surrounding capsular or ligamentous tissue. Said ligamentous growth zones are selected based on the natural "non-articular" anatomical surfaces of the replaced bone, since the natural, relatively empty non-articular surfaces of articular cartilage provide the native route for the anatomical connection of the ligament / capsule to that bone. Areas of ligamentous growth may be provided by the manufacture of porosities P1743 / 99MX specifically designed on the surface of the body member in those areas. These areas of ligamentous growth would generally correspond to the natural non-articular anatomical surfaces or areas of any given bone where the ligaments and capsules naturally come together in vivo. Tissue growth, as discussed just before, may be facilitated by squeezing the body member against the adjacent capsule or "supporting" it. This reduces the movement of the body member while tissue growth continues. In one embodiment, the ligamentous means are not secured either to each other or otherwise within the channels prior to implantation. Rather, as discussed below, the body member is allowed minimal sliding movement in each ligamentous means while the combined effect of two or more ligamentous means is to tie and suspend the body member to prevent significant translation of the body member. In another alternative embodiment in which the channels in the body member physically intersect, the ligament means first are joined together near their midpoints and previously joined are mounted on the intersecting channels. It is further preferred that the point of attachment of the ligamentous means be placed at the point of intersection of the channels.

P1743 / 99MX Ligamentous media may be native or artificial and porous or non-porous. In a preferred embodiment, the ligamentous means comprise a porous woven fabric that is receptive to tissue growth that is fixed to adjacent tissues by tissue growth. Alternatively, native tissue such as capsular bands, bone-capsule-bone or tendon graft, for example, may be used as ligamentous means. This would strengthen the fixation of the graft to the surrounding bone. The ligamentous means are preferably attached to the adjacent bones by means of the ligament remaining or fixing from the ligamentous means to the same surrounding native porous bone. The volume of the bone portion of the bone capsule bone grafts can be increased with synthetic bone pastes such as Norian®. The ligament means may be positioned to suspend the prosthesis along at least two intersecting, preferably substantially perpendicular, axes, whereby the body member is restricted to limit translational and destructive shearing of the implant while allowing rotation Limited need of the body member in relation to the adjacent bones. For example, the first restriction axis may be established when the prosthesis is attached to the adjacent bones, while the second restriction axis and the subsequent ones are established when P1743 / 99HX the prosthesis is attached to the adjacent capsules. Alternatively, depending on the application in the joint, the ligamentous means may be fixed only to a ligament and capsule without bone affiliation. Alternatively, the ligament means may be used to tighten or support the body member against the adjacent capsule to limit movement of the body member in one or more directions, as illustrated diagrammatically in Figures 18A and 18B where a prosthesis 2 is shown suspended in crosslinking ligament means 4 and 6 which are respectively attached to adjacent bones 8 and 10 and adjacent capsule 12 and 14. Sutures 16 and 18 are used to fix the ligamentous means to the adjacent capsule. Thus, in Figure 18A, the prosthesis is suspended along two intersecting axes (corresponding to the ligamentous means) but separated from the adjacent bone and capsule. However, in Figure 18B, the prosthesis is also supported on the adjacent capsule at points A and B. This type of binding or joining of the body member to limit movement in one or more directions will be indicated in certain circumstances, between those that are included in a non-exclusive way, circumstances in which areas of ligamentous growth are provided in certain areas of the limb member.

P1743 / 99MX body. The above objects, as well as other objects and advantages of the invention, will be apparent from the following detailed description of the preferred embodiments as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a plan view of the anterior or palmar side of the bones of the wrist joint of the right hand, showing the palm upwards; Figures 1A-1C are respectively plan views of the superficial palmar ligaments, the deep palmar ligaments and the dorsal ligaments; Figures 2A and 2B are perspective views of scaphoid and lunated carpal bone prostheses according to the present invention; Figures 3A and 3B are respectively side and top views of a human hand and wrist illustrating the placement of the perpendicular axes x, y and z; Figure 4 is a partial cross-sectional view of the prosthesis of Figure 2, illustrating the fixation of the ligamentous means within a channel by means of tissue growth; Figure 5 is a partial side view of P1743 / 99MX a scaphoid prosthesis, which illustrates the fixation of the ligamentous means to the adjacent carpal bones; Figure 6 is a partial side view of a scaphoid prosthesis, illustrating the fixation of the ligamentous means to the adjacent carpal ligaments; Figure 7 is an alternative embodiment of the prosthesis of Figure 2A in which the ligamentous means are secured by means of eyes; Figure 8 is a plan view of a scaphoid prosthesis subsequent to its implantation in the wrist; Figure 9 is a plan view of a lunate prosthesis subsequent to its implantation in the wrist; Figure 10 is a plan view of the posterior side of selected bones of the human right hand illustrating a carpometacarpal prosthesis according to the present invention; Figure 11 is a side view of the fifth ray of the right hand illustrating a metacarpal-fricagic arthroplasty according to the invention, of the human right hand; Figure 12 is a front-back view of a biaxially constrained proximal interphalangeal finger joint arthroplasty according to the present invention; P1743 / 99MX Figure 13 is a plan view of a human hand showing a total wrist arthroplasty comprising a three component system in which the middle component, replacing the scaphoid and the lunatus, employs a ligamentous reconstruction according to the present invention; Figure 14 is a dorsal view of the right human foot showing a biaxially-constrained metatarsal-phalangeal arthroplasty of the hallus, according to the present invention; Figure 15 is a front-back view of a metacarpal-phalangeal arthroplasty in which one of the two channels in the metacarpal component of the arthroplasty is completely perforated through the metacarpal bone; Figures 16 and 17 are diagrammatic representations of translation and rotation, respectively, in prostheses having parallel channels and intersecting channels; and Figures 18A and 18B are diagrammatic representations of a suspended prosthesis according to the present invention with and without support in the adjacent capsule.

DETAILED DESCRIPTION OF THE INVENTION Below are described scaphoid carpal bone prostheses and lunatics to illustrate in general the application of the invention. An expert in P1743 / 99MX technique will distinguish from the examples of scaphoid carpal bone and lunatics methods to safely and effectively perform upper and lower extremity arthroplasties using my new prostheses that are tied, suspended and restrained along multiple axes by ligamentous means . Thus, although each human joint has its own unique kinematic forms and properties, the principles of the present invention incorporated in the arthroplasties of scaphoid and lunate carpal bones are applicable to any synovial or biartroidial joint. In general with reference to Figure 1, an anterior or palmar part of the carpal bones of the wrist 20 of a right hand is shown. The bones forming the wrist carpus 20 include a proximal carpal row 22 and a distal carpal row 24. The proximal carpal row 22 is adjacent to the radius 26 and the wrist cube 28 and includes a scaphoid bone 30, a lunar bone 32, a pyramidal bone 34 and a pisiform bone 36. The radial carpal joint 38 is the space between the proximal carpal row 22 and the distal articulating radius 26. The distal carpal row 24 includes a hooked bone 40, a capitate bone 42, a trapezoid bone 44 and a trapezoid bone 46. The mesocarpal 48 joint of the wrist extends between the distal and proximal rows.

P1743 / 99MX The extrinsic palmar carpal ligaments are shown in Figure 1A, the intrinsic ligaments are shown in Figure IB and the dorsal extrinsic ligaments are shown in Figure 1C. The normal movement of the wrist is very complex and involves, in part, movement in the mesocarpal joint and partly movement in the radiocarpal joint. In addition, there is a well-orchestrated specific and different predictable rotational movement for each carpal bone that is generated by the shape of the bone and by its ligamentous and capsular junctions. For example, in radial deviation of the wrist the distal scaphoid pole rotates in a palmar direction, in one direction making "accommodation" so that the distal carpal row passes over the proximal row. Similarly, in the ulnar deviation the normal scaphoid rotates dorsally, in the opposite direction to the palm, tied by its neighbor and surrounding capsule, in a sense making "accommodation" so that the distal carpal row passes more easily "below" the row proximal. In pathological conditions such as severe wrist strain, the ligaments rupture and the synchronous carpal kinematics is damaged. This can lead to pain, arthritis and advanced collapse of the carpus, for example, SLAC (Advanced collapse scafo-lunado) of the wrist. A similar fate to SLAC may occur secondarily to a lack of union in P1743 / 99MX scaphoid fracture or avascular necrosis. During the surgical replacement of a carpal bone (scaphoid or lunatus) those ligaments that still do not break should be cut. Unless those ligaments are reconstructed or replaced, it is possible that they will suffer the same fate: instability of the prosthesis, surrounding carpal arthritis and eventual carpal collapse. All too often this is the fate of current "unrestricted" carpal prostheses. According to the present invention, a prosthesis "With restriction" will preserve the complex carpal movement and prevent collapse with arthritis. In the Figures 2 to 6, the prosthesis is generally indicated by the number 52 and comprises a body member 54 with contours that resemble the shape of the carpal bone it replaces. In Figures 2A and 2B, which respectively denote a scaphoid prosthesis and a lunate prosthesis, the body member includes first and second substantially perpendicular independent channels 56 and 58 and ligamentous means 60 are positioned within the channels to tie the prosthesis 52 to tissues adjacent, among which include surrounding carpal bone and ligaments as well as palmar and dorsal capsule. Figures 3A and 3B illustrate the three-dimensional structures of the carpus. The geometrical axes x, y and z of the hand are shown as reference planes P1743 / 99MX perpendicular to 90 °. To maintain reproducibility, for example, in an x-ray, the following signals are chosen to generate these axes: The x-axis represents the line that best fits between the ulnar and radial styloids in a PA (postero-anterior) view. The y-axis is the line that fits most through the length of the 3rd mesocarpal cane. The z-axis is simply a plane perpendicular to both the x-axis and the y-axis. When creating these axes you have a mathematical tool and language to describe any coordinate or direction within the carpus. For example, each channel within a given carpal prosthesis has coordination capable of being defined in the x, y, and z axes. Turning now to Figure 2A and continuing with the example of the scaphoid prosthesis, it can be said in this modality that the first channel 56 remains on an imaginary anchoring axis 62, basically the z-axis (dorsal to palmar) in Figures 3A and 3B . In this mode, it can be said that the second channel 58 (Figure 2A) is slightly oblique to the x and y axes, articulated with the trapezoid and the lunado. In the preferred embodiment illustrated, the channel 58 is curved to correspond generally with the curvature of the body member, ie, along its long axis, pole proximal to the distal pole. Also, in the illustrated embodiment, channel 56 is substantially perpendicular to channel 58 and the two channels are P1743 / 99MX intersect at a single point within the body member. In alternative modalities, the channels do not need to be intersected or need to be practically perpendicular at all times during the full rotational movement arc of the prosthesis implanted in vivo. That is, in a kinematic analysis, as the implanted body member rotates during the movement of the wrist, the ligamentous means will constantly change its vector alignment, relative to the body member. In Figure 2A, each ligament means 60 extends through the first and second channels 56 and 58 and exits the openings at each end of the channels. In the illustrated embodiments, the channels may be ovoid in cross section to protect the body member against stress elevations. The edge of each channel opening may be rounded to eliminate any sharp interface remaining against the ligament means. However, if desired, the channels may be circular or in any other way in cross section that retains the above desirable characteristics. Channels without a porous coating or other means of fixation or with a porous coating (70) that provides a surface to facilitate tissue growth between the ligament means and the prosthesis may also be used. The ligamentous medium 60 in Figure 2A is P1743 / 99MX placed through channels of the body member and is surgically attached to adjacent ligaments, capsule or bones (see Figure 4). The ligamentous means 60 may be made of Dacron or any other growth receptive tissue (including Tefion), native tendon graft (eg, longus palmaris), capsule or bone-capsule-bone graft. For example, when the ligamentous means 60 is secured to an adjacent carpal bone (Figure 5), various techniques may be used including suturing the ligamentous means directly to the adjacent intrinsic ligament (interosseous). For example, the ligamentous means 60 of a scaphoid prosthesis 52A could be sutured to the scapho-special ligament 76 and the scarred ligament 78 which are placed between the trapezoidal bone 46 and the scaphoid bone 30 (which has been replaced by the prosthesis 52A) and the scaphoid bone. 30 (prosthesis 52A) and lunate 32, respectively, as shown in Figure 6. An alternative technique would include the removal of a very small area of cartilage and endosteum to expose cancellous bone to the skin. Perforations would then be made in the bone for suture passage and the suture would be placed at the end of the ligamentous means. The suture would be passed through the perforations pulling the ligament means P1743 / 99MX firmly against or through the scarified bone and the sutures would be tied together in a horizontal matrix. This technique of suturing is similar to that described by Julio Taleisnick, M.D. (Journal of Hand Surgery 17A, March 1992, p.354-359, "A Technique for Direct Repair of the Scapho-Lunate Interosseous Ligament"). An alternative technique for suturing the ligamentous means to adjacent bone may include the use of small bone anchors, for example, Mitek® anchors that are available from Surgical Products, Inc. of Norwood, Massachusetts or securing the ligamentous means by a screw. interference. Likewise, the lunate prosthesis could be secured by ligamentous means in a manner similar to its adjacent carpal bones, for example, scaphoid (and / or scaphoid ligament) and the pyramidal (and / or lunopiramidal ligament). In a less preferred alternate embodiment, the body member 54B includes one or both of the ligamentous means secured to its outer periphery 92 by movable eyes 80 (Figure 7) that restrict the prosthesis to adjacent tissues. In use, the prosthesis 52 is surgically implanted in a wrist to replace a damaged carpal bone using normal surgical procedures. If the intrinsic and extrinsic natural ligaments are intact, they divide as the damaged carpal bone P1743 / 99MX removes, retaining the neighboring ligament and the capsular junctions. The appropriately sized prosthesis is then inserted and appropriately positioned within the space created by the carpal bone excised so that one axis of the ligamentous means 60 is oriented towards the palmar or dorsal capsule 51 (Figures 4 to 6). The prosthesis is then oriented along the second axis by inserting it into normal articulating alignment with its neighboring carpal bones. Those articulating ends represent the outlets for the second mooring channel through which the ligamentous means have been placed. Finally, the ligamentous means are attached to the adjacent capsule and the intrinsic (interosseous) ligament or bone (see Figures 4 to 6). The following is a description of the method by which the ligamentous medium is fixed through channel 56 to the dorsal and palmar capsule. In this method, again with reference to Figure 2A, the ligamentous means through channel 58 that attach to the bone replace the "intrinsic ligaments" (e.g., short interosseous ligaments) and the ligamentous means through channel 56 replace to extrinsic ligaments (eg, dorsal and palmar capsular junctions). To secure ligamentous means through channel 56 the sutures attached to the ligamentous means at each end may be sewn directly to the capsule and P1743 / 99MX at either end or both. Alternatively, the suture may be worn through the capsule, then onto the skin and tied in a normal fashion over a button. After many weeks of healing the suture is removed and the button could be removed leaving the ligament means held in place. Figures 8 and 9 illustrate scaphoid and lunate prostheses, 52A and 52B respectively, after their implantation in a wrist. First with reference to Figure 8, the scaphoid prosthesis 52A is ligated by ligamentous means 60 through the channel 58 to the trapezium bone 46 and the lunatized bone 32. The scaphoid prosthesis 52A is also attached by a second ligamentous means 60 to the palmar capsules and dorsal by means of channel 56. This second ligamentous means would be practically perpendicular to the plane of the figure (ie, inside and outside the plane of the paper). With reference to Figure 9, the lunate prosthesis 52B is shown attached by means of its two channels by ligamentous means 60 to the scaphoid bone 30 and the pyramidal bone 34 and by the other ligamentous means to the dorsal and palmar capsules. Again, this second ligamentous means is illustrated practically perpendicular to the figure. Figures 10 to 15 are examples of the crosslinked channel restriction of the present P1743 / 99MX invention as they relate to some examples of hand and ankle joints according to the present invention. These examples are not intended to limit the invention in any way. Figure 10 illustrates an arthroplasty with biaxial carpometacarpal restriction 100 in a right hand, which for purposes of illustration, shows only the index finger and the thumb. In this figure the following bones are illustrated: The carpometacarpal 100 biaxial restrained arthroplasty includes a hemifractor component 126 and a metacarpal base component 128 that are respectively in interference fit (and optionally cemented) to preformed cavities.

P1743 / 99MX in the trapezius and metacarpal bones of the thumb. The trapezius arthroplasty illustrated herein is a "hemi" or semi-aartroplasty, which incorporates two ligament means 130 and 132 that pass through intersecting channels that intersect in the trapezius arthroplasty and that are attached, as appropriate, to surrounding ligaments (e.g., spinous ligament), capsule, and bone. The metacarpal base component 128 similarly includes two ligamentous means 134 and 136 that pass through intersecting channels that intersect and that are attached, as appropriate, to surrounding ligaments, capsule and bone. Figure 11 is a side view of the fifth ray of the hand showing a two-component metacarpal-phalangeal prosthesis (MCP) 150, which uses the ligamentous means according to the present invention. In this figure the following bones are illustrated: P1743 / 99HX The two components of the MCP arthroplasty are the base component of the proximal phalanx 170 and the metacarpal head component 172 that expands the metacarpal-phalangeal joint 164 and are inserted respectively into preformed cavities in the metacarpal bones and proximal phalanx. Pairs of ligamentous media pass through channels 178 and 180 in the metacarpal main component 172 and attach, if appropriate, to surrounding ligaments and capsule. Figure 12 illustrates a biaxially constrained arthroplasty of proximal finger interphalangeal joint. The main part of this articulated stent of two rods illustrated is ceramic, although other biocompatible materials can be used. The prosthesis is formed in a manner that matches the morphology of the base of the middle phalanx and the head of the proximal phalanx, illustrating that the principles described above of the carpal prosthesis are applied to the joints of the hand and fingers. In this figure the following bones and joints are illustrated, to establish the environment of the arthroplasty: P1743 / 99 X The two component proximal interflangeal arthroplasty 200 includes the middle phalangeal base component 216 and the proximal phalangeal head component 218 that tie the proximal interphalangeal joint 209. The middle phalangeal base component 218 includes ligamentous media that crosslink 224 and 226 and the proximal phalangeal head component 216 includes criss-cross ligament means 220 and 222. Figure 13 illustrates a single three-component total wrist arthroplasty in which the middle component is restricted according to the present invention. To establish the location of the arthroplasty, the following characteristics of the wrist and its environment are shown: P1743 / 99MX Total wrist arthroplasty 250 includes a proximal component 278, which represents a replacement of the distal radius, which is fixed in place using conventional means including the formation of a receiving cavity in the radius and the joint by means of an interference fit , screws, tissue growth surface and / or bone cement. The middle component 276, which represents a combined scaphoid and lunatic replacement, is tied, suspended and constrained between the native pyramid 268 and the trapezoid 270 through ligamentous means 284 in a channel through the middle component 276. The ligamentous means are joined by conventional means (for example, perforations and screws) to the native pyramidal and the trapezium. Ligamentous medium 282 is attached to the palmar and dorsal capsule (not shown), P1743 / 99MX also by conventional means. The distal component 286, which represents partial replacement of the distal carpal row is fixed to the remaining distal carpus and metacarpals using conventional means similar to those used to fix the proximal component. By employing a three-component system with the medium component suspended and constrained by ligamentous joints, a native biomechanical "link" system is recreated that is superior to current two-component designs that create a non-natural hinge system. Figure 14 illustrates a biaxially-constrained metatarsal-phalangeal arthroplasty of hallus 300 in the right human foot. Foot bones related to this exposure include: The biaxially restricted arthroplasty 300 includes two components, a component of proximal phalanx 316 and a component of metatarsal head 318 that ties the metatarsal-phalangeal joint P1743 / 99MX 320. The proximal phalangeal component 318 includes ligament means 322 and 324. The metatarsal head component includes ligament means 326 and 328. Figures 15 (a) and 15 (b) illustrate an alternative embodiment of the invention, as it is applied in metacarpal-phalangeal arthroplasty. Turning to Figure 15 (a), a body member in the form of a metacarpal head component 500 has a channel 502 that passes through the body member, with a segment 503 of the central portion of the metacarpal head component cut, in a shape that generates bevels 505. This beveled preparation of the distal metacarpal ensures rotational stability of the metacarpal head component. In contrast, the preferred embodiment employs removal with straight perpendicular cutting of the metacarpal head. The alternative modality adds bone-implant rotational stability with respect to chamber cuts, while maintaining stability of ligaments and capsular joint with respect to ligamentous media that cross-link. As shown in Figure 15 (b), the body member 500 snaps into the distal end of the metacarpal 504 that has been prepared for this purpose. A perforation (not shown) passes through channel 502, through the P1743 / 99 X portion cut through the bone that resides there and outside the other end of the channel, to form a first channel. A second channel 506 is then pierced substantially perpendicular to the first channel 502, through the portion of the metacarpal bone at the level of the body member 500. Consistent with the design of the preferred embodiment, the base component of the proximal phalanx 508 conforms to the proximal phalanx 509 with its stem 511 fixed in place by conventional means. The ligamentous means 510 and 512 are passed through substantially perpendicular channels in the metacarpal head component 500 and the metacarpal bone 504 and the ligamentous means 514 and 516 are passed through the substantially perpendicular channels of the proximal phalangeal base component. As in the preferred embodiment, the channels that intersect the alternative mode may intersect or not intersect. All ligamentous media are then attached to adjacent ligaments and capsule, just as in the preferred embodiment. Thus, while the modality of alternative design employs beveled cuts, we also use the interlocking ligamentous means of inventiveness. By doing so, the rotational stability of the implant-bone interface is improved, and the capsular-ligament suspension mechanism of the invention is still maintained.

P1743 / 99MX It should be admitted that while the invention has been described in relation to a preferred embodiment thereof, those skilled in the art will be able to develop a wide variety of structural details without deviating from the principles of the invention. Accordingly, the appended claims will be construed to cover all equivalents that fall within the scope and spirit of the invention.

P1743 / 99MX

Claims (46)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property. A prosthesis of bone susceptible of being surgically implanted comprising: one or more medically inert, biocompatible body members with contours that resemble the shape of a bone, bones or a portion of a bone or bones that are to be replaced with the prosthesis; and means for restraining the one or more body members along at least two intersecting axes passing through each body member, the body member includes at least one channel passing through there, to along one of the intersecting axes. The bone prosthesis according to claim 1, wherein each body member is made of a material selected from the group consisting of ceramic, titanium or stainless steel alloys. The bone prosthesis according to claim 1, wherein each body member comprises a non-ceramic substrate with a medically inert ceramic coating or other medically inert and biocompatible coating. 4. The bone prosthesis according to P1743 / 99MX claim 1, wherein the bone, bone or bone or bone portion is selected from the group consisting of: proximal-interphalangeal joint, metacarpo-phalangeal joint, carpometacarpal joint, trapezius, scaphoid, lunatus, total wrist replacement, radial head, total elbow replacement, shoulder hemi-arthroplasty, total shoulder, total hip, hemi-ankle, total ankle, total knee replacement, hip hemiarthroplasty and metatarsal-phalangeal joint. The bone prosthesis according to claim 1, wherein the restriction means comprises ligamentous means that pass through the channels. The bone prosthesis according to claim 6, wherein the ligament means is bonded to bone, capsule or adjacent ligament. The bone prosthesis according to claim 6, wherein the ligamentous means have an open pore surface that is receptive to tissue growth to anchor the ligamentous means within the channels. The bone prosthesis according to claim 1, wherein the inert body member is configured to accept a portion of the native bone so that at least one of the intersecting channels may be formed through the native bone portion. P1743 / 99MX 9. The bone prosthesis according to claim 1, wherein selected areas of the body member are receptive to growth adhesion. The bone prosthesis according to claim 1, wherein selected areas of the body member are receptive to adhesion of the ligament growth. The bone prosthesis according to claim 1, wherein selected areas of the body member are receptive to adhesion of the capsule growth. The bone prosthesis according to claim 1, wherein selected areas of the body member are receptive to bone growth adhesion. The bone prosthesis according to claim 5, wherein the ligament means comprises native tissue. The bone prosthesis according to claim 5, which includes only two channels in these ligamentous means through the two channels and are bonded to adjacent bone, capsule and / or ligament. 15. The carpal bone prosthesis according to claim 6, wherein the ligamentous means are anchored within the channels with adhesive. 16. The bone prosthesis according to P1743 / 99MX claim 5, wherein the restriction means comprise ligament means secured to the periphery of each body member along two mutually intersecting axes. The bone prosthesis according to claim 5, wherein at least two of the channels physically intersect within each body member. 18. The bone prosthesis according to claim 5, wherein at least two of the channels do not physically intersect within each body member. 19. The bone prosthesis according to claim 5, wherein there are only two channels within each body member. 20. The prosthesis according to claim 16, wherein the ligament means is secured to the outer periphery of each body member by means of eyes. 21. The bone prosthesis according to claim 5, wherein the edges of the channel openings are rounded. 22. The bone prosthesis according to claim 5, wherein the channels have a porous coating. 23. The bone prosthesis according to claim 5, wherein the ligament means is in the form of a rounded cord. P1743 / 99MX 24. The bone prosthesis according to claim 5, wherein the channels are ovoid in cross section. 25. The bone prosthesis according to claim 1, wherein the axes are practically perpendicular. 26. A method for replacing a bone or portion of damaged bone in a synovial or biartroidial joint comprising: removing the bone or damaged bone portion; placing a medically inert, biocompatible body member with contours that resemble the shape of the bone to be replaced at the site previously occupied by the damaged bone, the body member having at least two intersecting channels; and restricting the body member along at least two axes passing through the channels. 27. The method according to claim 26, wherein the ligament means is used to restrain the body member. The method according to claim 27, wherein the ligamentous means have an open pore surface that is receptive to tissue growth. 29. The method according to claim 27, wherein the ligamentous means are anchored within the P1743 / 99HX channels by adhesive, by a porous growth coating or by both an adhesive and a porous growth coating. 30. The method according to claim 26, wherein the ligamentous means are anchored within the channels by means of adhesive. 31. The method according to claim 26, wherein the channels are ovoid in cross section. 32. The method according to claim 26, wherein the edges of the channel openings are rounded. 33. The method according to claim 26, wherein the channels have a porous coating. 34. The method according to claim 26, wherein the ligamentous means are planar. 35. The method according to claim 26, wherein the ligament means is in the form of a rounded bead. 36. A surgically implantable bone prosthesis comprising: a medically inert, biocompatible body member with contours that resemble the shape of the bone to be replaced; and means for restraining the body member along intersecting shafts passing through the body member, the body member including at least two channels passing therethrough the shafts P1743 / 99MX and restriction media comprising ligamentous media passing through the channels. 37. The bone prosthesis according to claim 36 which includes adjacent bone and capsule wherein the restriction means comprises ligamentous means attached to adjacent bone and capsule which pass through the body member into the two channels. 38. The bone prosthesis according to claim 36 wherein the ligamentous means have an open pore surface that is receptive to tissue ingrowth to anchor the ligamentous means within the channels. 39. The bone prosthesis according to claim 36 wherein the ligament means comprises native tissue. 40. The bone prosthesis according to claim 36, wherein at least two of the intersecting channels intersect. 41. The bone prosthesis according to claim 36, wherein the intersecting channels do not intersect. 42. A method for replacing a damaged bone in a human with a bone prosthesis comprising: removing the damaged bone; place a medically inert, biocompatible body member with contours that resemble the P1743 / 99MX form of the bone to be replaced at the site previously occupied by the damaged bone, the body member having at least two intersecting channels; and permanently restraining the body member along at least two axes passing through the intersecting channels. 43. The method according to claim 42, wherein the ligamentous medium is anchored within the channels by adhesive, by porous growth coating or both by adhesive and by porous growth coating. 44. The method according to claim 42, wherein the medically inert, biocompatible body member is supported in an adjacent capsule. 45. The bone prosthesis according to claim 5, wherein at least two of the channels physically intersect within a body member. 46. A total three component wrist arthroplasty comprising: a proximal component adapted to be rigidly attached to the radius; a distal component adapted to be rigidly fixed to the remaining carpal and distal metacarpals; and an average component that has at least two intersecting channels passing through there and P1743 / 99MX means that pass through the channels to suspend and restrict the middle component between the proximal and distal components. P1743 / 99 X