Malleolar Replacement Devices
A prosthesis and kit for replacing an ankle joint, and methods of applying the devices or systems. The prosthesis is an intramedullary device directed towards replacement of either of the tibia or fibula bone, wherein the prosthesis is a replacement for the lateral malleolus or the medial malleolus, respectively.
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The present application is a divisional application of U.S. patent application Ser. No. 13/178,208, filed on 7 Jul. 2011, and entitled “Malleolar Replacement Devices,” which claims the benefit of U.S. Provisional Application, Ser. No. 61/362,122, filed on 7 Jul. 2010, which are both incorporated by reference herein in their entireties.
BACKGROUND OF THE INVENTIONThe invention relates to ankle replacement prostheses and systems, as well as associated surgical instruments and procedures. The present invention is more specifically directed towards intramedullary ankle joint replacements.
Until the early- to mid-1970's, patients with injured or diseased ankle joints commonly resulting from rheumatism, or degenerative or traumatic arthritis, had few options when their ankle joints failed. The most common procedure to help these patients regain some use of their ankle was obliteration of the joint by fusion, a procedure that is still commonly used today. Fusion, however, rendered the ankle stiff and generally immobile relative to the lower leg, resulting in limited use and additional stresses on the knee and hip joints.
Probably the first reported use of a total ankle prosthesis was by Buckholz in 1969. The medical community recognized that such ankle replacement led to largely increased use of the ankle joint because the replacement permitted ankle ranges of motion which generally attempted to mimic the natural human joint. Since that time, ankle replacement prostheses have become increasingly common in use and improved in design.
Ankle fractures are particularly common in people having bone disease, such as osteoporosis. Geriatrics, particularly women, are very susceptible to ankle fractures, and the prognosis after fracture is generally poor, even with the use of a prosthesis. In general, currently used prostheses do not afford the necessary flexibility required for an ankle joint and recovery can be slow and arduous. The fusing together of bones or bone segments required and carried out with prior prostheses limits the ability of the ankle joint to completely heal properly, particularly with those who may have had limited mobility prior to the ankle fracture.
Stability and weight bearing are other issues that are more important when replacing an ankle joint as opposed to other joints. For example, hip, shoulder, or knee joints are not required to bear the load that is supported by an ankle joint. Consequently replacement devices for these other joints do not necessarily translate to possible replacement joints for an ankle joint.
SUMMARY OF THE INVENTIONThe present invention is directed towards a prosthesis and kit for replacing an ankle joint, and methods of applying the devices or systems. The prosthesis is an intramedullary device directed towards replacement of a portion of either a human tibia or fibula bone, wherein the prosthesis is a replacement for the lateral malleolus or the medial malleolus, respectively.
The device has a first end that is inserted into the intramedullary canal of either the fibula or tibia. A second end of the device is shaped and configured to assimilate the shape of the lateral or medial malleolus, respectively. The device will be secured to the respective tibia or fibula. Likewise, a system could comprise two devices, wherein one is directed towards each of the tibia and fibula.
The invention also contemplates methods of installing or inserting the device, wherein the particular malleolus is resected, sufficiently or completely so that the device will replicate the contours of the bone once inserted. The first end of the device is inserted into the intramedullary canal and secured to the bone.
Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
If undue stress is put on the ankle joint, the joint may fracture, with either the fibula or tibia fracturing, or possibly both. Often a fracture will form at the proximal end of respective malleolus, e.g. the lateral or medial malleolus. Such a fracture of the lateral malleolus is shown in
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The prosthesis 100 is also designed to provide protection for the ankle and surrounding tendons once the prosthesis 100 is inserted. For example, a flange or groove 118 is located in the body 112, which is intended to protect the peroneal tendon once the prosthesis is properly positioned. The peroneal tendon will rest within the groove 118, thereby allowing the groove to act as a shield for the tendon. The body 112 may have a groove 118 on either the right side or the left side of the body 112, or both sides of the body 112, which will allow the prosthesis to be used for a right or left ankle repair.
Once properly inserted, the prosthesis will mimic the shape and contour of a portion of the fibula, particularly the lateral malleolus, as shown in
As noted above, a fracture may also occur in the tibia as opposed to, or in addition to, the fibula. Such a fracture is depicted in
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The prosthesis 200 is also designed to provide protection for the ankle and surrounding tendons, e.g. posterior tibial tendon, once the prosthesis 200 is inserted. For example, a flange or groove 218 is located on the body 212, which is intended to protect the posterior tibial tendon once the prosthesis is properly positioned. The posterior tibial tendon will rest within the groove 218, thereby allowing the groove to act as a shield for the tendon. The body 112 may have a groove 218 on either the right side or the left side of the body 212, or both sides of the body 212, which will allow the prosthesis to be used for a right or left ankle repair.
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The prosthesis 200 will be inserted so that it is properly affixed to the tibia, but also to protect the posterior tibial tendon with the use of the posterior groove 218 (see
As such, the present invention is directed towards a prosthesis generally comprising a proximal portion, that will be inserted into the intramedullary canal of a specific bone of the ankle joint, and a distal portion that is shaped and designed to replicate the malleolus section of the particular bone that the prosthesis is used in connection with. By using the prostheses to replicate the shape and form of the bone prior to fracture, these prostheses increase the stability of the ankle joint and also decrease the recovery time, as the ankle joint is capable of bearing weight sooner than prior art devices. Similarly, the intramedullary design also promotes healing and recovery, in that it fosters grafting of the prosthesis to the bone.
The prostheses of the present invention may be made of any suitable biocompatible material. Preferably the prostheses are made of a material that will help with in bone growth. A porous material, e.g. sintered titanium, is one preferred material. For example, the prosthesis 100, 200 may have a titanium porous coating, which assists in bone growth.
It should also be understood that, if necessary, the present invention contemplates a kit that will include both a prosthesis 100 for use with the fibula and a prosthesis 200 for use with the tibia. However, one of the advantages of the present invention over the prior art is that it is not necessary that both the fibula and tibia be resected if one of the bones is not fractured. The prostheses are inserted and attached independently from one another, which also provides for a more efficient reconstruction process for the ankle joint, since alignment of separate prostheses for the fibula and tibia during surgery is not necessary. Likewise, it should be understood that the use of screws 110, 210 refers generally to attachment means for the ankle, e.g. pins, bolts, screws, clamps, etc., that are commonly used in surgical procedures. It is also understood that the length of the screws 210, 110 is determinative on the needs of a particular fracture, including such factors as age of the person requiring the prosthesis. For example, a screw may be sufficiently long so that the screw will intersect syndesmotic ligament, or it may be determined that a shorter screw will be sufficient. Any length of screw 210 or other fastening device will fall within the scope of the present invention.
The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
Claims
1. An ankle prosthesis comprising:
- a proximal portion adapted for insertion into an intramedullary canal of one of a human tibia and a human fibula; and
- a distal portion coupled to the proximal portion, the distal portion shaped similarly to a malleolus of the one of a human tibia and a human fibula, wherein said distal portion further includes a groove configured to receive a tendon associated with a human ankle.
2. The ankle prosthesis of claim 1 further comprising at least one hole located in said distal portion, said at least one hole capable of receiving means for attaching the prosthesis to the ankle.
3. The ankle prosthesis of claim 2 further comprising a plurality of holes located in said distal portion, said holes capable of receiving means for attaching the prosthesis to the ankle.
4. The ankle prosthesis of claim 1 further comprising at least one hole located in said proximal portion, said at least one hole capable of receiving means for attaching the prosthesis to the one of a human tibia and a human fibula.
5. The ankle prosthesis of claim 4, further comprising a plurality of holes located in said proximal portion, said holes capable of receiving means for attaching the prosthesis to the one of a human tibia and a human fibula.
6. The ankle prosthesis of claim 1 wherein the distal portion has a larger cross-sectional diameter than said proximal portion.
7. The ankle prosthesis of claim 6, wherein the proximal portion comprises an insert that defines a distance that the proximal end may be inserted into the intramedullary canal.
8. The ankle prosthesis of claim 1, wherein the distal portion is coupled to the proximal portion by being integrally formed therewith.
9. The ankle prosthesis of claim 1, wherein the proximal portion is adapted for insertion into the intramedullary canal of the human tibia and the tendon comprises the posterior tibial tendon.
10. The ankle prosthesis of claim 1, wherein the proximal portion is adapted for insertion into the intramedullary canal of the human fibula and the tendon comprises the peroneal tendon.
11. The ankle prosthesis of claim 1, wherein the distal portion comprises a through bore configured to receive a pin for syndesmotic fixation to the ankle.
12. The ankle prosthesis of claim 1, wherein the proximal portion and distal portion comprise a porous material.
13. The ankle prosthesis of claim 12, wherein the porous material comprises titanium.
14. The ankle prosthesis of claim 13, wherein the titanium is sintered titanium.
15. The ankle prosthesis of claim 13, wherein the titanium comprises a titanium porous coating.
Type: Application
Filed: Feb 11, 2014
Publication Date: Jun 12, 2014
Applicant: GLOBAL ORTHOPAEDIC SOLUTIONS LLC (SCOTTS VALLEY, CA)
Inventors: Nicholas A. Abidi (Scotts Valley, CA), Jonathan Borkowski (Scotts Valley, CA)
Application Number: 14/177,732