Open wedge osteotomy system and surgical method
An osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising: a first component for disposition in a posterior portion of the open wedge osteotomy; a second component for disposition in an anterior portion of the open wedge osteotomy; and a connection device for selectively connecting the first component and the second component to one another.
This patent application claims benefit of:
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- (1) pending prior U.S. Provisional Patent Application Ser. No. 60/569,545, filed May 7, 2004 by Vincent P. Novak for OPEN WEDGE OSTEOTOMY SYSTEM AND SURGICAL TECHNIQUE (Attorney's Docket No. NOVAK-1 PROV);
- (2) pending prior U.S. Provisional Patent Application Ser. No. 60/603,899, filed Aug. 24, 2004 by Vincent P. Novak for OPEN WEDGE OSTEOTOMY SYSTEM AND SURGICAL TECHNIQUE (Attorney's Docket No. NOVAK-2 PROV); and
- (3) pending prior U.S. Provisional Patent Application Ser. No. 60/626,305, filed Nov. 9, 2004 by Vincent P. Novak for OPEN WEDGE OSTEOTOMY SYSTEM AND SURGICAL TECHNIQUE (Attorney's Docket No. NOVAK-3 PROV).
The three above-identified patent applications are hereby incorporated herein by reference.
FIELD OF THE INVENTIONThis invention is related to surgical apparatus and methods in general, and more particularly to apparatus and methods for open wedge osteotomy surgery.
BACKGROUND OF THE INVENTIONOsteotomies about the knee have been an important component of the surgical treatment in the management of knee osteoarthritis. The ultimate goal of knee osteotomies has been to relieve pain symptoms, slow disease progression and postpone total knee arthroplasty in younger patients by transferring weight bearing load to the relatively unaffected portions of the knee.
The most commonly performed knee osteotomy has been the proximal tibial osteotomy or “high tibial” osteotomy. The first reported tibial osteotomy was in 1958. Knee osteotomy principles and techniques continued to evolve through the 1960s and 1970s. Today, however, other than at a minority of leading orthopedic centers, proximal tibial osteotomies are generally regarded critically by the general populace of orthopedic surgeons. The overall community holds the opinion that, first and foremost, the surgical technique of osteotomy is challenging and cumbersome, requiring much practice in the “art” in order to effectively perform and reproduce the osteotomy procedure.
More particularly, current techniques generally require the passage of hand-directed guidewires and hand-guided bone resecting tools while requiring continual use of fluoroscopy throughout the procedure. In such a procedure, the failure to properly execute the required precision can lead to a lack of, or postoperative loss of, correction and complications such as delayed union or nonunion, unintended changes to the slope of the tibial plateau, intraarticular fractures, and neurovascular problems. All of these issues pose a direct risk to a successful surgical outcome. In addition, the postoperative rehabilitation period using current techniques may require a conservatively long duration so as to protect the osteotomy from potential nonunion during the long healing period. Also, currently practiced procedures often require a second surgery to remove fixation hardware.
The reported long-term surgical outcomes of high tibial osteotomy procedures vary considerably. Published research of these procedures demonstrates that the relief of pain and restoration of function is generally achieved in approximately 80% to 90% of patients at five years, and 50% to 65% of patients at ten years.
The methods and principles of surgically performing an osteotomy have slowly developed over time. The two common osteotomy methods are: (i) the lateral closing-wedge method; and (ii) the medial opening wedge method (with either an internal fixation device or an external fixation device). Within these two general categories of surgical methods, there are varying nuances to the surgical techniques purported by individual orthopedic surgeons. For example, in discussions with individual surgeons, it is common to hear “this is how I do it” inasmuch as no “gold standard” surgical technique has emerged to date.
The lateral closing wedge method has been the traditional method for osteotomy surgery. This is the most common osteotomy for medial compartment osteoarthritis. Correction of alignment is typically achieved by first removing a laterally-based, angled wedge of bone, and then closing the resultant opening.
The medial opening wedge method with internal fixation has been gaining in popularity in recent years. Correction of alignment is typically achieved by first making a single transverse bone cut into the medial sagittal plane of the knee, and then manually opening the cut under fluoroscopy with a series of osteotomes, or pre-sized wedge osteotomes. This technique generally provides the surgeon with the intraoperative ability to more easily achieve the required correction angle. The wedge opening is then fixated at a given height with a small fixation plate and bone screws that support the opening of the wedge osteotomy. The opened bony void is then filled with bone graft material.
The medial opening wedge method with an external fixation device is most often used when a large correction is needed in order to achieve proper alignment. Correction of alignment is achieved by first making a single bone cut into the medial sagittal plane of the knee. Next, an external fixation device is applied and then regularly adjusted, in small increments, usually on a daily basis, so as to slowly open the wedge to a desired correction angle. The progress of this surgical technique is usually confirmed with weekly radiographs.
The opening wedge technique has been advocated as a faster, simpler surgical procedure that can be more easily learned while providing a better method for achieving the desired corrective angle with minimal risks to surrounding neurovascular structures. However, the various opening wedge surgical techniques, as currently practiced, allow a wide window for the introduction of surgical error.
All of these opening wedge osteotomy techniques, as currently practiced, require the hand-guided placement of guide pins to define the anterior-to-posterior tibial slope, sometimes referred to as the AP tibial slope, and require the use of hand-held and hand-guided osteotomes, which are all used under fluoroscopy. The use of frequent fluoroscopic pictures is critical to determine the work performed to that point in the procedure and the required adjustments still to be made in the remainder of the procedure. Errors by the surgeon in defining the AP tibial slope can result in an inappropriately-placed osteotomy with unintended changes to the tibial slope, which in turn may affect knee stability. Errors in the use of hand-driven osteotomes or hand-guided saw blades in creating the bone cut can lead to tibial slope changes, migration of the osteotomy into the joint, and/or injury to neurovasculature and soft tissue structures.
Recent evolutionary developments in osteotomies have focused on two general components. One of these includes improved wedge-shaped osteotomes which are used to form or open the bony wedge osteotomy. The other includes low profile internal fixation plates used during the nonweight-bearing rehabilitation phase to rigidly maintain the wedge opening, and used during the weight-bearing rehabilitation phase to add support to the entire osteotomy site. While significant, these advances do not address important issues including, but not limited to, the reduction of the surgical learning curve to make the procedures more reproducible, the improvement of the surgical precision of osteotomy procedures, the reduction in the use of fluoroscopy, and the fact that internal fixation devices used in an open wedge osteotomy effectively stress-shield the osteotomy or fracture site. Such stress-shielding is often a factor in complications involving nonunion and loss of correction.
Today, the orthopedic surgeon's requirements are demanding prior to the adoption of a new surgical procedure. The actual demands include a predictive knee osteotomy procedure with accuracy in determining the correction angle before surgery, and precision in carrying out the surgical technique with reproducible results. The ultimate surgical outcome depends upon the ability of the surgeon to precisely execute the corrective angle and to ensure that the correction remains long lasting.
EXAMPLE OF DEFICIENCIES OF THE PRIOR ARTIn current surgical practice, if the surgeon desires to institute a desired change in the AP slope (either a change planned from pre-operative x-rays or a change required from intra-operative bone cuts during a routine knee osteotomy), the surgeon is faced with various options to help re-adjust the slope of the bone.
First, the surgeon can place additional bone graft material or solid pieces of bone graft (i.e., allograft bone or synthetic bone) into the osteotomy void, at a specific location within the void, to help re-adjust the AP slope. However, this practice of “shimming” is frequently difficult to estimate and calculate during surgery.
Second, and referring to
Third, the surgeon may both (i) place solid pieces of bone graft (i.e., allograft bone or synthetic bone) into the osteotomy void, at a specific location within the void, to help re-adjust the AP slope and, in addition, (ii) utilize a fixation plate 5. Again, this combined approach suffers from the aforementioned shimming and fixation plate problems.
There are also other issues with the three above-identified options. First, although the exact measurement of an AP slope change may be determined pre-operatively, the execution of a planned change is generally still carried out with intra-operative adjustments due to offset cutting planes which require subsequent shims and perhaps re-estimation of the desired sloped fixation plate. Second, even if the surgeon's intention is not to affect the AP tibial slope, the current practice of knee osteotomy almost always ensures that it will be affected somewhat. With the antero-medial approach, this is due to the offset cutting plane and the opening of the osteotomy void. The surgeon must then make intra-operative adjustments with shims and a sloped fixation plate, changes that are visually estimated and not pre-determined from superior pre-operative radiographic means. Third, inaccuracies in carrying out adjustments to the AP slope may result in immediate poor results following surgery, or the eventual loss of correction adversely affecting long-term outcomes.
OBJECTS OF THE INVENTIONAccordingly, one object of the present invention is to provide an improved open wedge osteotomy system that is instrument-guided and modular in fashion.
Another object of the present invention is to reduce the overall surgeon learning curve in performing an open wedge osteotomy procedure.
Another object of the present invention is to provide an improved open wedge osteotomy system that allows a more surgically reproducible procedure and reduces surgical error.
A still further object of the present invention is to provide an improved open wedge osteotomy system that allows the procedure to be performed more quickly.
Another object of the present invention is to provide an improved open wedge osteotomy system that reduces or eliminates the need for fluoroscopy during the procedure.
A further object of the present invention is to provide an improved open wedge osteotomy system that defines the anterior-to-posterior tibial slope from visual inspection, and enables marking of the natural anterior-to-posterior joint line without the use of radiographic imaging.
A still further object of the present invention is to provide an improved open wedge osteotomy system that accurately executes pre-operative measurements.
A further object of the present invention is to provide an improved open wedge osteotomy system in which the natural joint line is marked by the positioning and fixation of a guide device on which a system of bone cutting guides is attached, whereby to reliably provide a transverse cut through the bone according to the physician's pre-operative calculations.
A still further object of the present invention is to provide an improved open wedge osteotomy system that accurately defines the cutting plane in relation to the AP tibial slope.
A still further object of the present invention is to provide an improved open wedge osteotomy system that maintains a consistent angled cutting plane from the posterior aspects of the bone to the anterior aspects of the bone, and that passes through the sagittal plane during bone resection.
A still further object of the present invention is to provide an improved open wedge osteotomy system that accurately opens the osteotomy void to the desired angle while decreasing the risks of changing the AP tibial slope and the risk of bone fracture.
Another object of the present invention is to provide an improved open wedge osteotomy system that reduces or eliminates the use of static internal fixation plates and screws.
Another object of the present invention is to provide an improved open wedge osteotomy system that better promotes the physiologic growth of bone across the osteotomy site.
Another object of the present invention is to provide a multi-part implant system that rims the periphery of the osteotomy void, allowing for the containment of various bone graft materials while supporting the reoriented bone segments.
A still further object of the present invention is to provide a multi-part implant system for custom assembly in-situ by a surgeon.
A still further object of the present invention is to provide a method for creating an osteotomy in which a multi-part implant is introduced into the osteotomy void part by part, so as to facilitate a minimally invasive procedure, and wherein the implant parts are subsequently assembled in-situ by the surgeon.
A still further object of the present invention is to provide a multi-part implant system that allows graft materials to be optimally compacted or inserted within the osteotomy void and contained by the multi-part implant system.
A still further object of the present invention is to provide a multi-part implant system in which implant parts of varying measurements are assembled together in order to enable accurate adjustments to the AP tibial slope.
A still further object of the present invention is to provide a multi-part implant system that accurately maintains and supports the tibial plateau at a desired slope from its anterior aspect to its posterior aspect.
A still further object of the present invention is to provide a multi-part implant system in which the implant parts support the periphery of bone and the subsequent passage of screws or fastener devices through the implant parts and into surrounding bone secures the multi-part implant in place.
A still further object of the present invention is to provide a multi-part implant system in which channels lead to the surface interface between the implant and the host bone, whereby to facilitate the directed injection of bone glues, cements, biologic materials or grafting materials.
A still further object of the present invention is to provide a multi-part implant system in which two implant parts comprise different biomaterials, biocomposites or formulations thereof, so as to allow for different rates of selective resorption of the implant parts.
A still further object of the present invention is to provide an osteotomy system in which a positioning guide is positioned on top of the skin and percutaneously fixed to the tibia so as to provide a minimally invasive osteotomy.
SUMMARY OF THE INVENTIONWith the above and other objects in view, in one form of the invention, there is provided an osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
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- a first component for disposition in a posterior portion of the open wedge osteotomy;
- a second component for disposition in an anterior portion of the open wedge osteotomy; and
- a connection device for selectively connecting the first component and the second component to one another.
In another form of the invention, there is provided a multi-part osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
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- a first component for disposition in a posterior portion of the open wedge osteotomy;
- a second component for disposition in an anterior portion of the open wedge osteotomy;
- a third component for disposition in a medial portion of the open wedge osteotomy;
- a first connection mechanism for selectively connecting the first component to the third component; and
- a second connection mechanism for selectively connecting the second component to the third component.
In another form of the invention, there is provided an osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
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- a leading edge having a first height, a first width, and the first height configured for placement into a distal portion of the open wedge osteotomy;
- a base portion in opposition to the leading edge, the base portion having a second height, a second width, and the second height configured to substantially close a proximal end of the open wedge osteotomy; and
- two opposing side walls connecting the leading edge to the base portion, the opposing side walls having a first length equal to the distance from the leading edge to the base portion, and the opposing side walls having a tapered height from the first height of the leading edge to the second height of the base portion.
In another form of the invention, there is provided an osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
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- a base portion having a first height, a first end and a second end, a width between the first end and the second end, the first height configured to substantially close a proximal end of the open wedge osteotomy;
- two opposing side walls extending from the first end and the second end, respectively, the two opposing side walls having a third end and a fourth end, the third end extending from the base portion, a second height equal to the first height of the base portion at the third end, each one of the two opposing side walls at the fourth end having a third height, the third height being less than the second height so as to allow placement of the fourth end of each one of the two opposing side walls into a distal portion of the open wedge osteotomy.
In another form of the invention, there is provided an osteotomy implant for supporting an open wedge osteotomy, the osteotomy wedge implant comprising:
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- two opposing side walls having a first end and a second end in opposition to one another, a pair of frame members extending between the first end and the second end of each of the two opposing side walls, an expandable material disposed between the pair of frame members of each of the two opposing side walls, the pair of frame members in connection with one another at the first end thereof, and the pair of frame members selectively separable from one another to a selected height at the second end thereof;
- a base member having a given height and a given width, wherein the given height is substantially equal to the selected height of the pair of frame member of each of the two opposing side walls, and wherein the given width is substantially equal to a distance between the two opposing side walls when placed in the open wedge osteotomy; and
- a set of connectors for connecting the base member to each of the two opposing side walls.
The above and other features of the invention, including various novel details of construction and combinations of parts and method steps, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular devices and method steps embodying the invention are shown by way of illustration only and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGSThese and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which are to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein:
The present invention comprises surgical apparatus and methods for performing open wedge osteotomies. In one preferred embodiment of the present invention, the system embodies several novel devices and methods that provide for precise bone resection, precise control in opening an osteotomy void in the bone, precise achievement of the corrective angle for the open wedge osteotomy, and precise maintenance of the open wedge osteotomy that provides for the containment of bone graft or filler materials. The present invention provides an instrumentation-guided system with a minimally invasive approach for performing open wedge osteotomy procedures. In addition, the present invention provides an implant fixation system that promotes new bone growth and a strong bone repair.
In one preferred form of the invention, the surgical system comprises four primary components: (i) a positioning guide 20 (
In accordance with the present invention, the surgeon first identifies the proper bone cut to be made in the tibia. Once surgeon has identified the proper attributes of the bone cut, the surgeon then uses the method and apparatus of the present invention to effect the bone resection.
More particularly, the surgeon preferably:
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- (i) attaches positioning guide 20 to the proper location on patient's tibia;
- (ii) selects the proper cutting guide 45 to be attached to positioning guide 20, whereby to define the target slope (or plane) of the cut to be made in the tibia;
- (iii) selects the proper protector members 70, 75 to be attached to the cutting guide 45, whereby to protect the soft tissue and neurovasculature structures surrounding the tibia;
- (iv) secures the cutting guide 45 to positioning guide 20, and then secures protector members 70, 75 to the cutting guide 45;
- (v) selects the proper cutting blade 65 to be used in the procedure, whereby to define the proper depth of the cut to be made in the tibia;
- (vi) passes cutting blade 65 through guide slot 50 formed in cutting guide 45 and through tibia 10, following the pathway 65A established by cutting guide 45, until the cut has been made to the proper depth;
- (vii) withdraws cutting blade 65;
- (viii) uses mechanical jack 90 to open the cut in the bone to the proper angle; and
- (ix) inserts the multi-part implant 125 into the osteotomy void 110 created in the bone, whereby to hold the resected tibia in the proper configuration.
Preferably, bone cement or bone paste, etc. is inserted into interior of the osteotomy void, within multi-part implant 125, whereby to facilitate strong bone regrowth and/or bony ingrowth; and preferably bone cement is injected into the implant/bone interface to help further secure the multi-part implant to the bone.
Significantly, with the present invention, the bone cut is made easily and reliably using an antero-medial approach, while providing excellent protection of the soft tissue and neurovasculature structures surrounding the tibia. Furthermore, osteotomy stabilization is achieved through the use of an implant device that provides stability about the osteotomy site while allowing the direct contact of bone graft material with native bone within the open wedge osteotomy. Significantly, the present invention also allows for the necessary physiologic compression and stimulation required to promote new tissue and bone growth through the bony void. This is in sharp contrast with prior art open wedge osteotomy systems, which use fixation plates and screws to maintain and support the corrective wedge opening; such systems do not allow beneficial physiologic compressive forces to act on the bone/graft interfaces. This can lead to nonunion osteotomies and failed corrections.
Positioning Guide 20 Looking next at
Referring now to
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More particularly, and referring now to
Referring to
Referring next to
Alternatively, and looking now at
Mechanical jack 90 is opened by turning a worm gear end 115 with a screwdriver or other instrument (not shown). See
Once the osteotomy wedge has been opened to a desired position, either (i) the entire mechanical jack 90 is removed, or (ii) just the front portion 105 of the mechanical jack 90 is removed, leaving blades 95, 100 within the bone so as to hold open the osteotomy void 110 in tibia 10.
Multi-Part Implant 125Once mechanical jack 90 has been used to open the osteotomy void 110 in tibia 10, a multi-part implant 125 is deployed in the void so as to support the bone in the desired position during healing.
More particularly, and looking now at
A set of fixation holes 160 (
Anterior part 130 and posterior part 135 of implant 125 preferably include injection ports 165 (
Anterior part 130, posterior part 135 and/or base part 140 may be formed out of one or more resorbable materials, whereby they may be resorbed into the host bone.
In one preferred form of the invention, anterior part 130, posterior part 135 and base part 140 are all formed out of a biomaterial and/or a biocomposite that resorbs into the host bone, with anterior part 130 and posterior part 135 being formed so that they resorb faster than base part 140. By forming base part 140 out of a longer-lasting biomaterial and/or biocomposite, base part 140 can provide lasting strength and support for the osteotomy to ensure optimal bone growth within void 110.
Preferably the area within osteotomy void 110 is filled with bone cement, bone paste, growth enhancers, etc. during the procedure, so that the osteotomy void 110 bounded by multi-part implant 125 will create bone or bony ingrowth over time. This may be done (i) after anterior part 130 and posterior part 135 are deployed in the osteotomy void, and (ii) before base part 140 is secured to parts 130 and 135. Alternatively, additional through holes (not shown) may extend through base part 140, whereby to permit the interior of osteotomy void 110 to be accessed even after the multi-part implant is assembled in the osteotomy void.
Osteotomy ProcedureAn osteotomy procedure may be conducted using a medial-to-lateral approach or an antero-medial approach.
(i) Medial-To-Lateral Approach Looking next at
With prior art systems and methods, using the medial-to-lateral approach may allow the surgeon to more easily obtain the correct AP tibial slope, which is crucial to knee stability. In addition, with prior art systems and methods, the medial-to-lateral approach may allow the surgeon to more easily control the cutting plane from posterior to anterior.
However, in practice, the medial-to-lateral approach can be difficult to execute with prior art systems and methods due to the presence of soft tissue structures such as the medial collateral ligament attachment site. Therefore, with prior art systems and methods, it may be preferred to use an antero-medial approach.
(ii) Antero-Medial Approach Referring next at
If the anatomical AP slope is not maintained or controlled, the patient may experience postoperative knee instability. In addition, several surgeons have begun to address knee instability problems (due to knee ligament laxity or damaged knee ligaments) by making planned adjustments to the patient's AP tibial slope. Such important planned changes to the slope must be accurate and carried out methodically.
When performing an opening wedge osteotomy, and more specifically a high tibial osteotomy, there are a number of important elements that need to be executed by the surgeon in order to achieve a positive surgical outcome.
One important element is to maintain the anterior-to-posterior (AP) tibial slope.
Another important element is to maintain and control the plane in which the bone cut is made.
Still another important element is to provide a fixation system that promotes physiologic healing and regeneration of new bone in order to provide for a long lasting osteotomy.
Yet another important element is to support the osteotomy void during healing in order to maintain the AP tibial slope and protect the bone grafting materials used to enable new bone growth.
In prior art systems and methods for carrying out an antero-medial approach, the above criteria are generally not easily met. As a result, the published literature generally teaches that the best approach for making the bone cut is a direct medial-to-lateral approach.
Significantly, the present invention provides an improved system and method for an opening wedge osteotomy using an antero-medial approach.
(iii) Preferred Method Referring next to
Looking now at
Referring now to
Next, the surgeon must determine the cutting depth of the osteotomy and the properly sized, slotted cutting guide 45 to be used for the procedure.
Referring now to
Next, the surgeon calculates the point of entry for the osteotomy bone cut. A line 265 is drawn from the intersecting point 255, angled inferiorly but remaining above the anterior tibial tubercle 270, to a point 275 which lies on the vertical line dropped from the aforementioned portion 240 of the medial cortex. The initial point of entry 280 (
The oblique resecting angle 290 is calculated from the inside wedge angle formed by points 240, 255 and 275 (
Through such preoperative planning, the surgeon can calculate the required positioning of the bone cut which will be used to form an osteotomy void which, in turn, will be used to effect the corrective angle 230 (
Once the surgeon has identified the proper attributes of the bone cut, the surgeon then uses the method and apparatus of the present invention to effect the bone resection. More particularly, the surgeon preferably:
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- (i) attaches positioning guide 20 to the proper location on patient's tibia;
- (ii) selects the proper cutting guide 45 to be attached to positioning guide 20, whereby to define the target slope (or plane) of the cut to be made in the tibia;
- (iii) selects the proper protector members 70, 75 to be attached to the cutting guide 45, whereby to protect the soft tissue and neurovasculature structures surrounding the tibia;
- (iv) secures the cutting guide 45 to positioning guide 20, and then secures protector members 70, 75 to the cutting guide 45;
- (v) selects the proper cutting blade 65 to be used in the procedure, whereby to define the proper depth of the cut to be made in the tibia;
- (vi) passes cutting blade 65 through guide slot 50 formed in cutting guide 45 and through tibia 10, following the pathway 65A established by cutting guide 45, until the cut has been made to the proper depth;
- (vii) withdraws cutting blade 65;
- (viii) uses mechanical jack 90 to open the cut in the bone to the proper angle; and
- (ix) inserts the multi-part implant 125 into the osteotomy void 110 created in the bone, whereby to hold the resected tibia in the proper configuration.
Preferably, bone cement or bone paste, etc. is inserted into the interior of the osteotomy void, within multi-part implant 125, whereby to facilitate strong bone growth and/or bony ingrowth; and preferably bone cement is injected into the implant/bone interface to help further secure the multi-part implant to the bone.
Significantly, with the present invention, the bone cut is made easily and reliably using an antero-medial approach, while providing excellent protection of the soft tissue and neurovasculature structures surrounding the tibia. Furthermore, osteotomy stabilization is achieved through the use of an implant device that provides stability about the osteotomy site while allowing the direct contact of bone graft material with native bone within the open wedge osteotomy. Significantly, the present invention also allows for the necessary physiologic compression and stimulation required to promote new tissue and bone growth through the bony void. This is in sharp contrast with prior art open wedge osteotomy systems, which use fixation plates and screws to maintain and support the corrective wedge opening; such systems do not allow beneficial physiologic compressive forces to act on the bone/graft interfaces. This can lead to nonunion osteotomies and failed corrections.
As noted above, the bone cut typically penetrates to within a centimeter or so of the lateral side of the tibia. In some circumstances, the subsequent opening of the osteotomy void may result in cracking at the far bone hinge. Therefore, and looking now at
Referring now to
More particularly, mechanical jack 300 preferably comprises two plates 305, 310. Plate 305 is disposed in the tibial bone cut in a superior position, and plate 310 is disposed in the tibial bone cut in an inferior position. As seen in
Plates 305, 310 are coupled with a mechanical device 340 (
In an alternative preferred embodiment (not shown), a circular actuator is configured to drive two sliding members in opposing directions relative to one another so as to open up or close down plates 305, 310 with respect one another.
Referring now to
In alternative embodiments of the present invention, and referring now to
As with multi-part implant 125, the overall design of substitute implant 500 is wedge-shaped (
Implant 500 may utilize a variety of shapes and constructs in addition to those shown in
Referring next to
Referring now to
Referring now to
A distinct advantage of the multi-part implant 565, 570, and/or 575, as well as the multi-part implant 125 described previously, is the ability to effect intended changes to the tibial slope by inserting one wall 520 of a specific height and size, and then inserting an opposing wall 520 of a potentially different height and size. These changes can be calculated preoperatively or may be a result of an intra-operative assessment by the surgeon.
Looking next at
The various wedge shaped implants 500 may be formed out of a metal (e.g., titanium or stainless steel) or any other biocompatible material or polymer, absorbable or non-resorbable, that may or may not be osteoinductive or osteoconductive.
Looking next at
As noted above, base 515 can be made of a metal material, a bioabsorbable material, a biocomposite material that may or may not promote bony integration, or a combination of biocomposite materials and metal in order to add strength to the eventual loading of the osteotomy site. It may be preferable to provide a base member that provides sufficient weight-bearing support and strength through the natural healing period of the osteotomy site and then begin to resorb over time, thereby preventing or reducing the effects of stress shielding of the repair and new bone growth. Such a resorbable base member, in conjunction with a resorbable, solid walled implant, provides active compression across the osteotomy site, thereby promoting faster and stronger healing of the osteotomy site.
Looking now at
When adding nonresorbable cements or glues to secure the implant, it may be advantageous to allow natural cortical bone growth and new bone integration into and through the surfaces of the wedge implant; this may provide for better long-term security and stronger healing of the osteotomy site. As such, these adhesives and/or bone cement materials can be delivered through a narrow tube-like device 605 (
Referring now to
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Once the properly sized anterior side 520 and the properly sized posterior side 520 of implant 500 are inserted, actuator 350 is unlocked and rotated so as to slightly loosen corrective device 340 (
Referring now to
Referring now to
Again, stabilization is achieved with the wedge-shaped implant 545 providing stability about the osteotomy site while maintaining the corrective angle. By allowing the direct contact of bone graft material with the bony cut surface of the osteotomy, within the perimeter of the wedge implant, the necessary physiologic compression and stimulation required to promote new tissue and bone growth through the bony void 110 is provided.
Alternative Resection System 700 Comprising Two Blade Positioning Guide 705 and Resection Guide 710 Referring next to
The osteotomy positioning guide 705 comprises two opposing blades 720, 725 (
A posterior blade 720 (
Osteotomy guide 705 is preferably radiolucent, so as to allow the surgeon to take radiographs or use fluoroscopy with blade members 720, 725 in place.
In one embodiment of the present invention (not shown), osteotomy positioning guide members 720, 725 are expandable once placed through an incision.
Resection guide 710 is shown in more detail in
When bone resection guide 710 is attached to tibia 10 using fixation screws 755, cutting slot 760 is properly located relative to the anterior-posterior slope 765 of tibia 10 (
A routine knee arthroscopy is generally carried out to remove any loose bodies and to perform general joint debridement. During the arthroscopy, other repair procedures may be carried out such as meniscus repair, cartilage repair or tissue regeneration procedures. Following the arthroscopy, an antero-medial skin incision is made over the tibia 3-5 cm below the joint line from the anterior tibial tubercle to the postero-medial border of the tibia.
Referring now to
Next, a proper slotted cutting guide 710 is chosen. Preferably, there is provided a system of cutting guides 710 that correspond to overall sizing (i.e. small tibia, medium tibia, or large tibia) with each cutting guide body having a radius of curvature that allows it to fit closely to the bone surface. Based upon the preoperative planning procedure, the surgeon chooses the appropriately sized cutting guide 710, matching the preoperatively measured distance 285 below the joint line for the point of entry (
Preferably, and following the formation of the osteotomy cut via a bone saw, the surgeon ensures that the bone cortices are cut by using a thin osteotome and probing the cortices inside the bone cut. Once assured that the bone cortices are cut, the surgeon removes the blade members 720, 725. Next, bone cut 715 (
With the desired corrective angle achieved, the surgeon then prepares to stabilize and secure the open wedge osteotomy and insert bone graft material into the osteotomy void. This may be done using an appropriately sized implant such as the multipart implant 125 (
Referring now to
Expandable wedge implant 805 comprises two opposing sides 810 (
The transversely split sides 810 can be continuous in form at leading end 845 (
Base side 820 preferably includes passageways 855 for attachment of base side 820 to the ends 860 of transverse split sides 810 with screws, rods or other fastener (
Expandable material 805 is preferably manufactured from, or comprised of, any expandable biocompatible material. Expandable material 840 is preferably resorbable or osteoinductive or osteoconductive in nature.
Referring now to
The expandable wedge implants may comprise metal (e.g., titanium or stainless steel) or other biocompatible material or polymer. The selected material may be either absorbable or non-resorbable, which may also be either osteoinductive or osteoconductive.
Base member 820 of expandable wedge implant 805 preferably provides secure fixation by insertion of bone screws 875 through the base and into the bone of the femur (not shown) or tibia 10 (
Referring now to
When adding nonresorbable cements or glues to secure implant 805, it may be advantageous to allow natural cortical bone growth and new bone integration into and through the surfaces of the wedge implant; this may provide for better long-term security and stronger healing of the osteotomy site. As such, these adhesives and/or bone cement materials can be delivered through a narrow tube-like device 885 (FIG. 119) that incorporates openings 885A that align with channels 880 running to surface 890 of implant 805. Once the adhesive or cement-like material is delivered through tube device 885 into and through channels 880 to the interface of implant 805 and native bony surface of tibia 10, tube device 885 is withdrawn. Such a delivery approach provides areas of adhesion while allowing native bony contact with portions of surface 890. Also, by delivering material through tube device 885, which preferably runs the length of implant 805, and then withdrawing tube 885, more of implant 805 is allowed to integrate with new bone growth while using an efficient amount of adhesive or cement material to secure implant 805.
When using resorbable adhesives or bone cements, implant 805 is alternatively configured to have the material flow or be delivered within a cavity 900 that follows the entire contact surface between implant 805 and the bone (
Referring now to
Next, the wedge opening plate 805 is assembled. An opening wedge plate device 905 is preferably provided with four attachment points 910 (
Stabilization is achieved with expandable wedge implant device 805 at the osteotomy site while maintaining the corrective angle. By allowing the direct contact of bone graft material with the bony cut surface of the osteotomy, within the perimeter of the expandable wedge implant, the necessary physiologic compression and stimulation required to promote new tissue and bone growth through the bony void is provided.
It is to be understood that the present invention is by no means limited to the particular constructions herein disclosed and/or shown in the drawings, but also comprises any modifications or equivalents within the scope of the invention.
Claims
1. An osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
- a first component for disposition in a posterior portion of the open wedge osteotomy;
- a second component for disposition in an anterior portion of the open wedge osteotomy; and
- a connection device for selectively connecting the first component and the second component to one another.
2. An osteotomy implant according to claim 1 wherein the connection device comprises a base component having a first side and second side in opposition to one another, wherein the first side is configured for selective attachment with the first component, and wherein the second side is configured for selective attachment with the second component.
3. An osteotomy implant according to claim 2 wherein the base component forms a fixation hole therein so as to allow placement of a fixation device therethrough for anchoring the multi-part implant to the tibia.
4. An osteotomy implant according to claim 1 wherein the connection device comprises a slotted fitting between the first component and the second component.
5. A multi-part osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
- a first component for disposition in a posterior portion of the open wedge osteotomy;
- a second component for disposition in an anterior portion of the open wedge osteotomy;
- a third component for disposition in a medial portion of the open wedge osteotomy;
- a first connection mechanism for selectively connecting the first component to the third component; and
- a second connection mechanism for selectively connecting the second component to the third component.
6. A multi-part osteotomy implant according to claim 5 wherein the first connection mechanism comprises a first slotted fitting formed between the first component and the third component, and wherein the second connection mechanism comprises a second slotted fitting formed between the second component and the third component.
7. An osteotomy implant according to claim 6 wherein the first slotted fitting comprising a first male projection and a first female recess configured for attachment to one another, and further wherein the first male projection extends from one of the first component and the third component, and the first female recess is configured in the other one of the first component and the third component.
8. An osteotomy implant according to claim 7 wherein the first male projection extends from the third component, and the first female recess is configured in the first component.
9. A multi-part osteotomy implant according to claim 6, wherein the second slotted fitting comprises a second male projection and a second female recess configured for attachment to one another, and further wherein the second male projection extends from one of the second component and the third component, and the second female recess is configured in the other one of the second component and the third component.
10. A multi-part osteotomy implant according to claim 9 wherein the second male projection extends from the third component, and the second female recess is configured in the second component.
11. A multi-part osteotomy implant according to claim 5 wherein the first component, the second component and the third component form a void therebetween when connected together, and wherein the void corresponds substantially to a center region of the open wedge osteotomy.
12. A multi-part osteotomy implant according to claim 11 wherein the first component, the second component and the third component are configured to allow placement of graft material into the void.
13. A multi-part osteotomy implant according to claim 12 wherein the first component, the second component and the third component are configured to allow compaction of graft material in the void.
14. A multi-part osteotomy implant according to claim 5 wherein the first component comprises a first wall having a first set of dimensions, the second component comprises a second wall having a second set of dimensions, and further wherein the first set of dimensions of the first component and the second set of dimensions of the second component are different from one another so as to enable accurate disposition of the AP tibial slope.
15. A multi-part osteotomy implant according to claim 5 wherein the first component has a first surface and a second surface, the first surface configured for placement in the mouth of the osteotomy void and the second surface configured for placement adjacent to a bone surface of the open wedge osteotomy, and further wherein the first component forms a first channel therein between the first surface and the second surface so as to allow injection of a material through the first channel, from the first surface to the second surface, and provide the material to a bone/implant interface formed between the first component and the bone.
16. A multi-part implant according to claim 15 wherein the first component forms a first injection port at the first surface into the first channel, and further wherein the first injection port is configured to be accessible by a surgeon subsequent to placement of the first component adjacent to the bone.
17. A multi-part implant according to claim 16 wherein the first component forms multiple exit ports at the second surface.
18. An osteotomy implant according to claim 15 wherein the selected material comprises at least one chosen from a group consisting of biocompatible adhesive glue, bone cement, biologic material, growth factor, and grafting material.
19. A multi-part osteotomy implant according to claim 15 wherein the second component has a third surface and a fourth surface, the third surface configured for placement the osteotomy void and the fourth surface configured for placement adjacent to a bone surface of the open wedge osteotomy, and further wherein the second component forms a second channel therein between the third surface and the fourth surface so as to allow injection of a material through the second channel, from the third surface to the fourth surface, and provide the material to the bone/implant interface formed between the second component and the bone.
20. A multi-part implant according to claim 16 wherein the second component forms a second injection port at the third surface into the second channel, and further wherein the second injection port is configured to be accessible by a surgeon subsequent to placement of the second component adjacent to the bone.
21. A multi-part implant according to claim 20 wherein the second component forms multiple exit ports at the fourth surface.
22. A multi-part implant according to claim 19 wherein the second channel is configured to allow injection of one selected from a group consisting of bone glue, cement, biologic material, and grafting material.
23. A multi-part implant according to claim 5 wherein the first component has a first resorption rate into bone, the second component has a second resorption rate into the bone, the third component has a third resorption rate into bone, wherein the first resorption rate and the second resorption rate are substantially the same as one another, and the third resorption rate is substantially different from the first resorption rate and the second resorption rate.
24. A multi-part implant according to claim 23 wherein the third component differs from the first component and the second component by at least one chosen from the group consisting of: different biomaterial composition from one another; different biocomposite composition from one another; and different formulation from one another.
25. A multi-part implant according to claim 5 wherein the third component forms a first fixation hole therein so as to allow placement of a first fixation device therethrough for anchoring the multi-part implant to the tibia.
26. A multi-part implant according to claim 25 wherein the third component forms a second fixation hole therein so as to allow placement of a second fixation device therethrough for anchoring the multi-part implant to the tibia.
27. A multi-part implant according to claim 26 wherein the first fixation hole has an entry portion and an exit portion on the third component, the first fixation hole defines a first longitudinal axis from the entry portion to the exit portion of the third component, the second fixation hole has an entry portion and an exit portion on the third component, the second fixation hole defines a second longitudinal axis from the entry portion to the exit portion of the third component, and the first longitudinal axis and the second longitudinal axis are non-parallel to one another so as to direct the first fixation device into a first portion of the tibia and to direct the second fixation device into a second portion of the tibia, with the first portion of the tibia and the second portion of the tibia being on opposing sides of the third component.
28. A multi-part osteotomy implant according to claim 5 wherein the first component, the second component, and the third component are each configured for assembly together with one another while within a bone cut of the open wedge osteotomy.
29. A multi-part osteotomy implant according to claim 5 wherein the first component, the second component and the third component are each configured for assembly together with one another while outside of a bone cut of the open wedge osteotomy.
30. A multi-part osteotomy implant according to claim 5 wherein the first component, the second component and the third component are configured to support a bone cut of the open wedge osteotomy from an anterior aspect thereof to a posterior aspect thereof.
31. An osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
- a leading edge having a first height, a first width, and the first height configured for placement into a distal portion of the open wedge osteotomy;
- a base portion in opposition to the leading edge, the base portion having a second height, a second width, and the second height configured to substantially close a proximal end of the open wedge osteotomy; and
- two opposing side walls connecting the leading edge to the base portion, the opposing side walls having a first length equal to the distance from the leading edge to the base portion, and the opposing side walls having a tapered height from the first height of the leading edge to the second height of the base portion.
32. An osteotomy implant according to claim 31 further comprising a floor portion extending between the two opposing side walls and from the base portion to the leading edge, and wherein the floor portion has a third height, and the first height of the base portion is greater than the third height of the floor portion so as to form an open portion between the two opposing sides.
33. An osteotomy implant according to claim 31 wherein the base portion forms at least one opening therethrough for insertion of a material therethrough.
34. An osteotomy implant according to claim 33 wherein the material is at least one selected from the group consisting of: allograft bone; autograft bone; demineralized bone substitutes; bone graft material; and bone cement.
35. An osteotomy implant according to claim 31 wherein the two opposing sides are substantially parallel with one another.
36. An osteotomy implant according to claim 31 further comprising a series of projections extending from bone interface surfaces of the two opposing side walls, wherein the projections are configured to allow insertion of the opposing side walls into the open wedge osteotomy and prevent migration of the opposing side walls out of the open wedge osteotomy.
37. An osteotomy implant according to claim 31 wherein the two opposing side walls define channels therein for delivering selected material therethrough.
38. An osteotomy implant according to claim 37 further comprising a delivery device comprising a tube having a length and a diameter, the tube forming a series of openings along the length thereof, the diameter configured for placement in a main portion of the channel, and the series of openings configured to correspond with a series of branch portions of the channel.
39. An osteotomy implant according to claim 31 wherein the two opposing side walls define channels opening on a bone interface surface thereof so as to allow delivery of a selected material therethrough.
40. An osteotomy implant according to claim 39 wherein the selected material comprises at least one chosen from the group consisting of: biocompatible adhesive glue; bone cement; growth factor; and grafting material.
41. An osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
- a base portion having a first height, a first end and a second end, a width between the first end and the second end, the first height configured to substantially close a proximal end of the open wedge osteotomy;
- two opposing side walls extending from the first end and the second end, respectively, the two opposing side walls having a third end and a fourth end, the third end extending from the base portion, a second height equal to the first height of the base portion at the third end, each one of the two opposing side walls at the fourth end having a third height, the third height being less than the second height so as to allow placement of the fourth end of each one of the two opposing side walls into a distal portion of the open wedge osteotomy.
42. An osteotomy implant according to claim 41 wherein the two opposing walls are substantially parallel with one another.
43. An osteotomy implant according to claim 41 wherein the two opposing side walls approach one another in a region between the third end and the fourth end of each one of the opposing side walls, respectively.
44. An osteotomy implant according to claim 41 wherein the base portion forms at least one opening therethrough for insertion of a material therethrough.
45. An osteotomy implant according to claim 41 wherein the material is at least one selected from the group consisting of allograft bone; autograft bone; demineralized bone substitutes; bone graft material; and bone cement.
46. An osteotomy implant according to claim 41 further comprising a connector extending between the two opposing side walls from a location between the third end and the fourth end of each one of the side walls, respectively.
47. An osteotomy implant according to claim 41 wherein the two side walls are selectively separable from one another.
48. An osteotomy implant according to claim 47 wherein the base portion is selectively separable from the two side walls.
49. An osteotomy implant according to claim 48 wherein the selected material comprises at least one chosen from the group consisting of biocompatible adhesive glue; bone cement; growth factor; and grafting material.
50. An osteotomy implant according to claim 47 further comprising a series of projections extending from bone interface surfaces of the two opposing side walls, wherein the projections are configured to allow insertion of the opposing side walls into the open wedge osteotomy and prevent migration of opposing side walls out of the open wedge osteotomy.
51. An osteotomy implant according to claim 41 wherein the two opposing side walls define channels therein for delivering selected material therethrough.
52. An osteotomy implant according to claim 51 wherein the selected material comprises at least one chosen from the group consisting of biocompatible adhesive glue; bone cement; growth factor; and grafting material.
53. An osteotomy implant according to claim 51 further comprising a delivery device comprising a tube having a length and a diameter, the tube forming a series of openings along the length thereof, the diameter configured for placement in a main portion of the channel, and the series of openings configured to correspond with a series of branch portions of the channel.
54. An osteotomy implant according to claim 41 wherein the two opposing side walls define channels on a bone interface surface thereof so as to allow delivery of selected material therein.
55. An osteotomy implant according to claim 54 wherein the selected material comprises at least one chosen from the group consisting of biocompatible adhesive glue; bone cement; growth factor; and grafting material.
56. An osteotomy implant for supporting an open wedge osteotomy, the osteotomy wedge implant comprising:
- two opposing side walls having a first end and a second end in opposition to one another, a pair of frame members extending between the first end and the second end of each of the two opposing side walls, an expandable material disposed between the pair of frame members of each of the two opposing side walls, the pair of frame members in connection with one another at the first end thereof, and the pair of frame members selectively separable from one another to a selected height at the second end thereof;
- a base member having a given height and a given width, wherein the given height is substantially equal to the selected height of the pair of frame member of each of the two opposing side walls, and wherein the given width is substantially equal to a distance between the two opposing side walls when placed in the open wedge osteotomy; and
- a set of connectors for connecting the base member to each of the two opposing side walls.
57. An osteotomy implant according to claim 56 wherein base member defines passageways therein for disposition of the set of connectors therethrough to connect the base member to each of the two opposing sides.
58. An osteotomy implant according to claim 56 wherein at least one chosen from a group consisting of the base portion and the two opposing side walls define an opening therethrough, and the opening is configured for inserting a selected material into the open wedge osteotomy between the two opposing side portions.
59. An osteotomy implant according to claim 58 wherein the selected material comprises at least one chosen from the group consisting of biocompatible adhesive glue; bone cement; growth factor; and grafting material.
60. An osteotomy implant according to claim 56 further comprising a series of projections extending from bone interface surfaces of the two opposing side walls, wherein the projections are configured to allow insertion of the opposing side walls into the open wedge osteotomy and prevent migration of opposing side walls out of the open wedge osteotomy.
61. An osteotomy implant according to claim 56 further comprising an opening wedge plate device for opening each of the two opposing side walls at second end, the opening wedge plate having four attachment points configured for attachment to each ones of the pair of frame members of each of the two opposing side walls, and two connectors for attachment to a jack mechanism, wherein the opening wedge plate device is configured to support the two opposing side walls as the second end of each of the side walls are expanded relative to one another.
62. A multi-part osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
- a first component configured for disposition in a posterior portion of the open wedge osteotomy; and
- a second component configured for disposition in an anterior portion of the open wedge osteotomy;
- wherein the first component and the second component form a U-shaped wall when disposed in the open wedge osteotomy.
63. A multi-part osteotomy implant according to claim 62 wherein the first component and the second component are configured for disposition adjacent to one another in the open wedge osteotomy so as to contact one another.
64. A multi-part osteotomy implant according to claim 63 wherein the first component and the second component are configured for disposition in the open wedge osteotomy unconnected with one another.
65. A multi-part osteotomy implant according to claim 62 wherein the first component and the second component are configured for disposition in the open wedge osteotomy unconnected with one another.
66. A multi-part osteotomy implant according to claim 62 further comprising a third component configured for disposition in a medial portion of the open wedge osteotomy, wherein the first component, the second component and the third component form the U-shaped wall when disposed in the open wedge osteotomy.
67. A multi-part osteotomy implant according to claim 66 wherein the first component and the second component are configured for disposition adjacent to one another in the open wedge osteotomy so as to contact one another, and the second component and the third component are configured for disposition adjacent to one another in the open wedge osteotomy so as to contact one another.
68. A multi-part osteotomy implant according to claim 67 wherein the first component and the second component are configured for disposition in the open wedge osteotomy without being in direct contact with one another.
69. An osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
- a U-shaped wall configured for disposition in the open wedge osteotomy, an interior portion formed on a concave side of the wall, and an exterior portion formed on a convex side of the wall; and
- the U-shaped wall forming an access port therethrough from the exterior portion into the interior portion, wherein the access port allows passage of a material between the exterior portion and the interior portion.
70. An osteotomy implant according to claim 69 wherein the access port is configured in a medial portion of the U-shaped wall when the osteotomy implant is disposed in the open wedge osteotomy.
71. An osteotomy implant according to claim 69 wherein the access port is configured in a posterior portion of the U-shaped wall when the osteotomy implant is disposed in the open wedge osteotomy.
72. An osteotomy implant according to claim 69 wherein the access port is configured in a anterior portion of the U-shaped wall when the osteotomy implant is disposed in the open wedge osteotomy.
73. An osteotomy implant according to claim 69 wherein the U-shaped wall forms an additional access port therethrough from the exterior portion into the interior portion.
74. An osteotomy implant according to claim 73 wherein one of the access port and the additional access port are configured to allow overflow of the material to exit from the interior portion as the material is injected through the other one thereof.
75. A multi-part osteotomy implant for supporting an open wedge osteotomy, the osteotomy implant comprising:
- a first component configured for disposition in a posterior portion of the open wedge osteotomy; and
- a second component configured for disposition in an anterior portion of the open wedge osteotomy;
- wherein the first component comprises a first material, the second component comprises a second material, and the first material and the second material are different from one another.
76. A multi-part implant according to claim 75 wherein the first component and the second component are configured for disposition adjacent to one another in the open wedge osteotomy so as to contact one another.
77. A multi-part implant according to claim 76 wherein the first component and the second component form a U-shaped wall when disposed in the open wedge osteotomy.
78. A multi-part implant according to claim 75 further comprising a third component configured for disposition in a medical portion of the open wedge assembly, wherein the third component comprises a third material, and further wherein the first material, second material, and third material are each different from one another.
79. A multi-part implant for supporting an open wedge osteotomy, the osteotomy comprising:
- a first component configured for disposition in a posterior portion of the open wedge osteotomy;
- a second component configured for disposition in an anterior portion of the open wedge osteotomy;
- a third component configured for disposition in a medial portion of the open wedge osteotomy; and
- wherein the first component comprises a first material, the second component comprises a second material, the third material comprises a third material, and one selected from the group consisting of the first material, the second material, and the third material is different than another one selected from the group consisting of the first material, the second material, and the third material.
80. A multi-part implant according to claim 79 wherein the third material is different than the first material and the second material.
81. A multi-part implant according to claim 79 wherein each of the first material, the second material and the third material are different from one another.
Type: Application
Filed: Jan 31, 2005
Publication Date: Nov 10, 2005
Inventor: Vincent Novak (Groton, MA)
Application Number: 11/047,159