Abstract:
A device for unicompartmental arthroplasty of the knee. The device permits arthroplasty of the medial and/or lateral tibial condyle, and allows for securing of the device without the use of bone cement. Such a device comprises a baseplate, the baseplate comprising a first surface configured to be secured to a surgically prepared medial (or lateral) compartment of a proximal end of a patient&#39;s tibia, and an opposing second surface configured to replicate a medial (or lateral) tibial condyle; a flange adjacent the baseplate, the flange shaped to interface with a surgically prepared anterior surface of the proximal end of the patient&#39;s tibia, the flange comprising an orifice therethrough; and at least one anchor protruding from the first surface, the at least one anchor arranged to coincide with at least one corresponding surgically prepared void in the patient&#39;s tibia.

Description:
RELATED APPLICATIONS 
     The present application is related to, claims the priority benefit of and is a U.S. §371 national stage entry of , International Patent Application Serial No. PCT/US2011/027739, filed Mar. 9, 2011, which is related to and claims the priority benefit of U.S. Provisional Patent Application Ser. No. 61/312,112, filed Mar. 9, 2010. The contents of each of these applications are hereby incorporated by reference in their entirety into this disclosure. 
    
    
     BACKGROUND OF THE INVENTION 
     Arthritic damage to portions of the knee joint can severely limit an individual&#39;s ability to walk or enjoy recreational activities. The extent of arthritic damage may be far reaching, affecting all compartments of the knee joint, or the damage may be limited to a single compartment of the knee (“unicompartmental osteoarthritis”), requiring only resurfacing or replacement of a single surface rather than total knee replacement surgery. In understanding unicompartmental joint reconstruction, practitioners typically refer to three separate areas of joint articulation as if they were separate compartments: the inner part of the joint between femur and tibia (the “medial compartment”), the outer part of the joint between femur and tibia (the “lateral compartment”) and the joint between the patella and the femur (the “patello-femoral compartment”). If osteoarthritis affects a patient only in the lateral or medial compartment of the knee, unicondylar knee arthroplasty often is a preferred method of treatment, as the surgery is far less invasive, and allows for more rapid recovery while maintaining the integrity of unaffected areas of the knee, often allowing the anterior and posterior cruciate ligaments to remain intact. 
     As such, unicondylar knee arthroplasty has gained popularity in the recent years for treating medial compartment osteoarthritis of the knee joint, and has proven to be a successful surgery for people with this degenerative arthritis of the knee. The inside (medial) component (medial tibial plateau and the medial femoral condyle) is most commonly involved and replaced using unicompartmental arthroplasty. However, occasionally, the outside (lateral) compartment (the lateral tibial plateau and the lateral femoral condyle) is involved and must be replaced. 
     While a unicondylar arthroplasty is far less invasive on the patient, it should be appreciated that when only a single condyle of the tibia is resurfaced and replaced with an implant, there is less surface area to attach an implant and receive anchors to secure the implant that will receive stresses in nearly all directions almost immediately after the surgery is performed. Traditionally, bone cement was used to secure such an implant into place, thereby securing the implant and filling any voids between the contoured condyle and the bottom surface of the implant. However, bone cement can weaken and crack over time, causing failure of the implant, and/or creating debris within the knee compartment. The flexing motion of the knee is known to cause an implant on the tibial plateau to lift off anteriorly, which also may cause failure of the implant and/or produce debris within the knee compartment. Further, any excess cement that is not cleared from the compartment during surgery can cause inflammation or result in debris within the compartment. 
     Efforts to improve long term success of tibial implants and reduce the inflammation or failure that can be caused by the use of bone cement include the use of highly porous metal or Trabecular Metal implants to encourage better bone growth into the implant for long term retention of the implant, but securing such an implant through the ingrowth of the patient&#39;s cancellous bone requires a significant amount of time, and proper integration requires that the implant be securely held in place while the integration occurs. Considering the significant forces associated with weight bearing and activity as distributed over the small surface area of the tibia, there is concern that porous implants may not be retained in place during the ingrowth of cancellous bone required to maintain the implant during the healing phase. For example, the flexing motion of the knee is known to cause a tibial baseplate to lift off anteriorly, hindering bone ingrowth in a porous metal implant. As such, an implant having an ability to be secured to the anterior medial condyle of a tibia without the use of bone cement would be advantageous. 
     SUMMARY 
     The present disclosure includes disclosure of a device for unicompartmental arthroplasty of a patient&#39;s knee. 
     In at least one embodiment, such a device comprises a baseplate, the baseplate comprising a first surface configured to be secured to a surgically prepared medial (or lateral) compartment of a proximal end of a patient&#39;s tibia, and an opposing second surface configured to replicate a medial (or lateral) tibial condyle; a flange adjacent the baseplate, the flange shaped to interface with a surgically prepared anterior surface of the proximal end of the patient&#39;s tibia, the flange comprising an orifice therethrough; and at least one anchor protruding from the first surface, the at least one anchor arranged to coincide with at least one corresponding surgically prepared void in the patient&#39;s tibia. 
     In at least one embodiment, a device for unicompartmental arthroplasty of a patient&#39;s knee comprises a baseplate, the baseplate comprising a first surface configured to be secured to a surgically prepared medial (or lateral) compartment of a proximal end of a patient&#39;s tibia, an opposing second surface configured to replicate a medial (or lateral) tibial condyle, and an anterior slot; at least one anchor protruding from the first surface, the at least one anchor arranged to coincide with at least one corresponding surgically prepared void in the patient&#39;s tibia; and a flange, the flange shaped to be secured to a surgically prepared anterior surface of the proximal end of the patient&#39;s tibia, the flange comprising an orifice therethrough and a tab protruding therefrom, wherein when the baseplate is secured to the surgically prepared medial (or lateral) compartment of the proximal end of the patient&#39;s tibia, and the flange is secured to the surgically prepared anterior surface of the proximal end of the patient&#39;s tibia, the tab is inserted into the slot. 
     In an aspect of a device for unicompartmental arthroplasty of a patient&#39;s knee according to the present disclosure, such a device comprises a receptacle in at least one anchor, and a rod-like fastener comprising a first end, where the fastener is installed through the orifice, and the first end of the fastener is received in the receptacle. In an aspect of a device for unicompartmental arthroplasty of a patient&#39;s knee according to the present disclosure, such a device comprises internal threads in the receptacle, and external threads on the first end of the fastener, where the external threads are complementary to the internal threads in the receptacle. 
     In an aspect of a device for unicompartmental arthroplasty of a patient&#39;s knee according to the present disclosure, such a device comprises internal threads in the orifice, a rod-like fastener comprising a first end and a second end, where the fastener installed through the orifice and the second end of the fastener is received in the orifice, and external threads on the second end of the fastener that are complementary to the internal threads in the orifice. 
     In an aspect of a device for unicompartmental arthroplasty of a patient&#39;s knee according to the present disclosure, such a device comprises a receptacle in the first surface, and a rod-like fastener comprising a first end, the fastener installed through the orifice, and the first end of the fastener received in the receptacle. In an aspect of a device for unicompartmental arthroplasty of a patient&#39;s knee according to the present disclosure, such a device comprises internal threads in the receptacle; and external threads on the first end of the fastener, the external threads being complementary to the internal threads in the receptacle. 
     The present disclosure includes disclosure of methods of performing unicompartmental arthroplasty of a patient&#39;s knee. In at least one embodiment, the method comprises the steps of making an incision along an anterior medial (or lateral) aspect of the knee; excising any remnants of the medial (or lateral) meniscus; surgically preparing a medial (or lateral) compartment of the patient&#39;s tibia to receive a medial (or lateral) tibial prosthesis component in a manner so as to preserve the integrity of a anterior and posterior cruciate ligaments, the medial (or lateral) tibial prosthesis component having a baseplate, the baseplate comprising a first surface configured to be secured to a surgically prepared medial (or lateral) compartment of a proximal end of a patient&#39;s tibia, and an opposing second surface configured to replicate a medial (or lateral) tibial condyle, a flange adjacent the baseplate, the flange shaped to interface with a surgically prepared anterior surface of the proximal end of the patient&#39;s tibia, the flange comprising an orifice therethrough, and at least one anchor protruding from the first surface, the at least one anchor arranged to coincide with at least one corresponding surgically prepared void in the patient&#39;s tibia; securing the medial (or lateral) tibial prosthesis component to the tibia; and closing the incision. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and advantages of this disclosure, and the manner of attaining them, will be more apparent and better understood by reference to the following descriptions of the disclosed methods and systems, taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  shows a perspective view of a tibial prosthesis component in accordance with at least one embodiment of the present disclosure; 
         FIG. 2  shows an anterior medial perspective view of a tibial prosthesis component in accordance with at least one embodiment of the present disclosure, as placed upon a patient&#39;s tibia; 
         FIG. 3  shows an anterior medial perspective view of a tibial prosthesis component in accordance with at least one embodiment of the present disclosure, as surgically implanted upon and secured to a patient&#39;s tibia; 
         FIG. 4  shows a side view of a tibial prosthesis component in accordance with at least one embodiment of the present disclosure; 
         FIG. 5A  shows a side view of a tibial prosthesis component in accordance with at least one embodiment of the present disclosure; 
         FIG. 5B  shows a side view of a tibial prosthesis component in accordance with at least one embodiment of the present disclosure; 
         FIG. 6  shows a top view of a tibial prosthesis component in accordance with at least one embodiment of the present disclosure; 
         FIG. 7  shows a front elevation view of a tibial prosthesis component in accordance with at least one embodiment of the present disclosure; and 
         FIG. 8  shows a flow chart illustrating a method for surgically implanting a tibial prosthesis component in accordance with at least one embodiment of the present disclosure. 
     
    
    
     DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of this disclosure is thereby intended. 
     The present disclosure includes disclosure of a device for unicompartmental arthroplasty of a patient&#39;s knee. In at least one embodiment, such a device comprises a baseplate and an anterior flange, with a fastening structure interacting with the anterior flange to deter anterior lift off of the tibial baseplate. 
       FIG. 1  shows a medial tibial prosthesis component  10  according to at least one embodiment of the present disclosure, for use in connection with a medial tibial condyle resurfacing. Prosthesis  10  comprises a baseplate having an upper surface  20  for interfacing with the corresponding femoral condyle and lower surface  30  for interfacing with a surgically prepared portion of the medial condyle of a tibia  100 , as shown in  FIGS. 2-3  and described in more detail below. In at least one embodiment of the present disclosure, prosthesis  10  comprises anterior flange  25  for interfacing with a surgically prepared anterior portion of the medial condyle of tibia  100 . 
     As shown in  FIG. 1 , lower surface  30  comprises a least one anchor  50  protruding therefrom. In at least one embodiment of the present disclosure, such anchors  50  protrude between about 7-9 mm from lower surface  30 . According to at least one embodiment of the present disclosure, anchors  50  interface with cancellous bone of the tibia. In such an embodiment, anchors  50  are sized and shaped to correspond to surgically created voids in the tibia. Anchors  50  are inserted into such surgically created voids in the tibia (as shown in  FIG. 2 ), while the surgically prepared surface of the tibia interfaces with lower surface  30  and posterior surface  26  of anterior flange  25 . Different embodiments of anchors  50  may have different cross-sectional shapes. In at least one embodiment, anchors  50  have a circular cross-section. In at least one embodiment, the cross-section has varying dimensions along the length of at least one anchor  50 . In at least one embodiment of prosthesis  10 , a plurality of anchors  50  having more than one cross-sectional shape are used. 
     Prosthesis  10  may comprise titanium or titanium alloys, tantalum or tantalum alloys (including those materials described as “Trabecular Metal” from Zimmer Inc., Warsaw, Ind.), porous metal, stainless steel, cobalt chrome steel, Zirconia, ceramic material, high-density polymer (such as polyetheretherketone “PEEK” or similar materials), or a combination of any of the foregoing. In at least one embodiment of the present disclosure, prosthesis  10 , including anterior flange  25  and anchors  50 , is constructed substantially of porous metal such as, for example, Trabecular Metal. In at least one embodiment, at least a portion of posterior surface  26  of anterior flange  25 , lower surface  30 , and the exterior of anchors  50  is constructed of an absorbable material. In at least one embodiment of the present disclosure, prosthesis  10 , including anterior flange  25  and anchors  50 , is of monolithic construction. In at least one embodiment of the present disclosure, posterior surface  26  of anterior flange  25 , lower surface  30 , and the exterior of anchors  50  have a rough surface for interfacing with tibial bone, or are coated with a material conducive to improving ingrowth of cancellous bone. In at least one embodiment of the present disclosure, anterior flange  25  comprise a malleable material, permitting anterior flange  25  to be conformed to the contours of the tibial condyle. 
       FIG. 4  shows a side view of prosthesis  10  according to at least one embodiment of the present disclosure. Shown in  FIG. 4  are prosthesis  10  comprising upper surface  20 , flange  25 , lower surface  30 , and anchors  50 . The embodiment of the present disclosure shown in  FIG. 4  also comprises optional intermediate layer  40  and optional polymer layer  45 . As shown in  FIG. 4 , in at least one embodiment of the present disclosure, flange  25  and anchors  50  are not perpendicular to lower surface  30 . Instead, in such an embodiment flange  25  and anchors  50  are angled toward the posterior of the prosthesis  10 . Such a structure aids in installation of the prosthesis  10 . 
     In at least one embodiment of the present disclosure, upper surface  20  of prosthesis  10  comprises a high-density polymer portion  45  that is attached to an intermediate portion  40  through adhesives, fasteners, wedged joints, or other attachment mechanisms.  FIG. 4  shows an example of such an embodiment, with proportions enhanced for purposes of clarity. 
     In at least one embodiment of the present disclosure, flange  25  of prosthesis  10  includes at least one orifice  60 , operable to allow the introduction of a fastening structure  70  through flange  25  of prosthesis  10  and through the patient&#39;s tibia. In at least one embodiment of the present disclosure, flange  25  of prosthesis  10  comprises more than one orifice  60 . 
     In at least one embodiment of the present disclosure, fastening structure  70  may comprise a rod comprising titanium or titanium alloys, tantalum or tantalum alloys (including those materials described as “Trabecular Metal” from Zimmer Inc., Warsaw, Ind.), porous metal, ceramic material, high-density polymer, or a combination thereof, and may be solid and smooth, surfaced to have a rough exterior for interfacing with cancellous bone, coated with a material conducive to improving ingrowth of cancellous bone, or fused, bonded, or otherwise attached to the underlying material. In at least one embodiment, fastening structure  70  is constructed of an absorbable material. 
     In at least one embodiment of the present disclosure, fastening structure  70  may comprise a threaded rod sized and shaped to pass through orifice  60 . In at least one embodiment of the present disclosure, fastening structure  70  is threaded at least at its proximal end. In such an embodiment, orifice  60  is tapped with complementary receiving threads to allow fastening structure  70  to be securely fastened within orifice  60  by the interaction of such threads. 
     According to at least one embodiment of the present disclosure, receptacle  80  is a portion of prosthesis  10  sized and shaped to accept a distal portion  75  of fastening structure  70 . By way of nonlimiting example, distal portion  75  of fastening structure  70  may be a threaded rod having a size and thread complementary to that of receptacle  80 . In such an embodiment, fastening structure  70  may be threaded along its entire length, or threaded only at its proximal and/or distal ends. In at least one exemplary embodiment, receptacle  80  of prosthesis  10  may be located toward the posterior of prosthesis  10 , as shown in  FIGS. 1 and 2 . 
     In at least one embodiment of the present disclosure, a receiving structure  80  is formed in an anchor  50 . In at least one embodiment of the present disclosure, receiving structure  80  is formed in lower surface  30  of prosthesis  10 . Regardless of the location and structure of receptacle  80 , it will be appreciated that the positioning of receptacle  80  with respect to orifice  60  will be such that the interior lumens defined by the respective structures are in line with one another. Optionally, fastening structure  70  may be secured into the patient&#39;s tibia, such as, for example, by threads or other securing methods, in addition to or in lieu of securing fastening structure  70  in orifice  60  and/or receptacle  80 . 
     According to the exemplary embodiment of the present disclosure shown in  FIG. 1 , orifice  60  contains a guide receiving portion  65  that is sized and positioned to accept a surgical drill bit. Guide receiving portion  65  comprises a hollow tubular body sized and shaped to fit within orifice  60 . In operation, guide receiving portion  65  is sized and shaped to accept a surgical drill bit, and guide it through orifice  60  to allow a surgeon to create a void by surgically drilling a hole through the patient&#39;s tibia at a predetermined angle that will allow fastening structure  70  to pass from orifice  60 , through the patient&#39;s tibia, and into receptacle  80 . It will be appreciated that guide receiving portion  65  may be threaded, or may be a friction fit that allows a surgical drill bit to be removably inserted into guide receiving portion  65  such that surgical drill bit may be removed after use, thereby allowing fastening structure  70  to be inserted through orifice  60 , through the void created in the tibia by the surgical drill, and received in receptacle  80 . Line  90  of  FIG. 1  illustrates the path followed by fastening structure  70 . 
     According to at least one embodiment of the present disclosure, prosthesis  10  comprises more than one fastening structure  70 , along with a corresponding more than one orifice  60  and more than one receptacle  80 . 
       FIGS. 5A-7  show a medial tibial prosthesis component  110  according to at least one embodiment of the present disclosure, for use in connection with a medial tibial condyle resurfacing. Prosthesis  110  comprises a baseplate having upper surface  120  for interfacing with the corresponding femoral condyle and lower surface  130  for interfacing with a surgically prepared portion of the medial condyle of a tibia  100 . 
     In at least one embodiment of the present disclosure, prosthesis  110  comprises anterior flange  125  for interfacing with a surgically prepared anterior portion of the medial condyle of tibia  100 . According to such an embodiment, flange  125  comprises posterior surface  126  and tab  127 . According to such an embodiment, prosthesis  110  comprises anterior slot  122 . According to such an embodiment, when prosthesis  110  is surgically implanted tab  127  is inserted into anterior slot  122  in the direction shown by arrow  129  in  FIGS. 5A and 6 . 
     As shown in  FIGS. 5A-B , lower surface  130  comprises at least one anchor  150  protruding therefrom. In at least one embodiment of the present disclosure, anchors  150  protrude between about 7-9 mm from lower surface  130 . According to at least one embodiment of the present disclosure, anchors  150  interface with cancellous bone of the tibia. In such an embodiment, anchors  150  are sized and shaped to correspond to surgically created voids in the tibia. Anchors  150  are inserted into such surgically created voids in the tibia, while the surgically prepared surface of the tibia interfaces with lower surface  130  and posterior surface  126  of anterior flange  125 . Different embodiments of anchors  150  may have different cross-sectional shapes. In at least one embodiment, anchors  150  have a circular cross-section. In at least one embodiment, the cross-section has varying dimensions along the length of at least one anchor  150 . In at least one embodiment of prosthesis  110 , a plurality of anchors  150  having more than one cross-sectional shape are used. 
     Prosthesis  110  may comprise titanium or titanium alloys, tantalum or tantalum alloys (including those materials described as “Trabecular Metal” from Zimmer Inc., Warsaw, Ind.), porous metal, stainless steel, cobalt chrome steel, Zirconia, ceramic material, high-density polymer (such as polyetheretherketone “PEEK” or similar materials), or a combination of any of the foregoing. In at least one embodiment of the present disclosure, prosthesis  110 , including anterior flange  125  and anchors  150 , is constructed substantially of porous metal such as, for example, Trabecular Metal. In at least one embodiment, at least a portion of posterior surface  126  of anterior flange  125 , lower surface  130 , and the exterior of anchors  150  is constructed of an absorbable material. In at least one embodiment of the present disclosure, posterior surface  126  of anterior flange  125 , lower surface  130 , and the exterior of anchors  150  have a rough surface for interfacing with tibial bone, or are coated with a material conducive to improving ingrowth of cancellous bone. In at least one embodiment of the present disclosure, anterior flange  125  comprise a malleable material, permitting anterior flange  125  to be conformed to the contours of the tibial condyle. 
       FIGS. 5A-B  shows a side view of prosthesis  110  according to at least one embodiment of the present disclosure. Shown in  FIGS. 5A-B  are prosthesis  110  comprising upper surface  120 , flange  125 , lower surface  130 , and anchors  150 . As shown in  FIG. 5A , in at least one embodiment of the present disclosure, flange  125  and anchors  150  are not perpendicular to lower surface  130 . Instead, in such an embodiment flange  125  and anchors  150  are angle toward the posterior of the prosthesis  110 . Such a structure aids in installation of the prosthesis  110 . 
     In at least one embodiment of the present disclosure, flange  125  of prosthesis  110  includes at least one orifice  160 , operable to allow the introduction of a fastening structure  170  through flange  125  of prosthesis  110  and through the patient&#39;s tibia. In at least one embodiment of the present disclosure, flange  125  of prosthesis  110  comprises more than one orifice  160 . 
       FIG. 5B  shows such an embodiment, with the patient&#39;s tibia cutaway for purposes of clarity. In at least one embodiment of the present disclosure, upper surface  120  of prosthesis  110  comprises a high-density polymer portion that is attached to an intermediate portion through adhesives, fasteners, wedged joints, or other attachment mechanisms. 
     In at least one embodiment of the present disclosure, fastening structure  170  may comprise a rod comprising titanium or titanium alloys, tantalum or tantalum alloys (including those materials described as “Trabecular Metal” from Zimmer Inc., Warsaw, Ind.), porous metal, ceramic material, high-density polymer, or a combination thereof, and may be solid and smooth, surfaced to have a rough exterior for interfacing with cancellous bone, coated with a material conducive to improving ingrowth of cancellous bone, or fused, bonded, or otherwise attached to the underlying material. In at least one embodiment, fastening structure  170  is constructed of an absorbable material. 
     In at least one embodiment of the present disclosure, fastening structure  170  may comprise a threaded rod sized and shaped to pass through orifice  160 . In at least one embodiment of the present disclosure, fastening structure  170  is threaded at least at its proximal end. In such an embodiment, orifice  160  is tapped with complementary receiving threads to allow fastening structure  170  to be securely fastened within orifice  160  by the interaction of such threads. 
     According to at least one embodiment of the present disclosure, receptacle  180  is a portion of prosthesis  110  sized and shaped to accept a distal portion  175  of fastening structure  170 . By way of nonlimiting example, distal portion  175  of fastening structure  170  may be a threaded rod having a size and thread complementary to that of receptacle  180 . In such an embodiment, fastening structure  170  may be threaded along its entire length, or threaded only at its proximal and/or distal ends. In at least one exemplary embodiment, receptacle  180  of prosthesis  110  may be located toward the posterior of prosthesis  110 , as shown in  FIG. 5B . 
     In at least one embodiment of the present disclosure, receiving structure  180  is formed in an anchor  150 . In at least one embodiment of the present disclosure, receiving structure  180  is formed in lower surface  130  of prosthesis  110 . Regardless of the location and structure of receptacle  180 , it will be appreciated that the positioning of receptacle  180  with respect to orifice  160  will be such that the interior lumens defined by the respective structures are in line with one another. Optionally, fastening structure  170  may be secured into the patient&#39;s tibia, such as, for example, by threads or other securing methods, in addition to or in lieu of securing fastening structure  170  in orifice  160  and/or receptacle  180 . 
     According to the exemplary embodiment of the present disclosure shown in  FIGS. 5A-B , orifice  160  contains a guide receiving portion  165  that is sized and positioned to accept a surgical drill bit. Guide receiving portion  165  comprises a hollow tubular body sized and shaped to fit within orifice  160 . In operation, guide receiving portion  165  is sized and shaped to accept a surgical drill bit, and guide it through orifice  160  to allow a surgeon to create a void by surgically drilling a hole through the patient&#39;s tibia at a predetermined angle that will allow fastening structure  170  to pass from orifice  160 , through the patient&#39;s tibia, and into receptacle  180 . It will be appreciated that guide receiving portion  165  may be threaded, or may be a friction fit that allows a surgical drill bit to be removably inserted into guide receiving portion  165  such that surgical drill bit may be removed after use, thereby allowing fastening structure  170  to be inserted through orifice, through the void created in the tibia by the surgical drill, and received in receptacle  180 . 
     According to at least one embodiment of the present disclosure, prosthesis  110  comprises more than one fastening structure  170 , along with a corresponding more than one orifice  160  and more than one receptacle  180 . 
       FIG. 8  shows a flow chart illustrating the method for implanting a prosthesis  110  according to at least one embodiment of the present disclosure. In step  801  of  FIG. 8 , an incision is made along an anterior medial aspect of a patient&#39;s knee. In step  803  of  FIG. 8 , any remnants of the medial meniscus are excised. In step  805  of  FIG. 8 , a medial compartment of the patient&#39;s tibia is surgically prepared to receive a medial tibial prosthesis component according to present disclosure, with such surgical preparation performed in a manner so as to preserve the integrity of the patient&#39;s anterior and posterior cruciate ligaments. In step  805  of  FIG. 8 , the medial tibial prosthesis component according to present disclosure is secured to the patient&#39;s tibia. In step  807  of  FIG. 8 , the incision is closed. 
     While this disclosure has been described as having a preferred design, the systems and methods according to the present disclosure can be further modified within the scope and spirit of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. For example, although the disclosure herein has discussed unicompartmental arthroplasty for the medial compartment of a patient&#39;s knee, the devices and methods disclosed herein may be readily adapted for the lateral compartment of a patient&#39;s knee, and such adaptations are within the scope of the present disclosure. In addition, the methods disclosed herein and in the appended claims represent one possible sequence of performing the steps thereof. A practitioner may determine in a particular implementation that a plurality of steps of one or more of the disclosed methods may be combinable, or that a different sequence of steps may be employed to accomplish the same results. Each such implementation falls within the scope of the present disclosure as disclosed herein and in the appended claims. Furthermore, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims.