Implants with Transition Surfaces and Related Processes

Abstract

Implants, and processes for installing them, which replace the medial condyle and portions of the patellofemoral channel but preferably not portions of the lateral condyle that articulate relative to the tibia. Processes are provided which allow proper location and orientation of an anterior resection and a distal resection on the femur, which make use of a transition point which can be designated on the bone, for navigating proper positioning of such implants. Proper positioning of the implant relative to the femur for insuring a smooth transition between lateral portions of the implant and the lateral condyle is thus reduced to determining proper medial / lateral location of the implant on the anterior and distal resections. Such implants and processes can allow, among other things, for controlled location and orientation of an implant on the bone which saves lateral compartment bone, which eliminates the need to sacrifice the anterior and posterior cruciate ligaments, and which is adapted for minimally invasive surgery with its attendant benefits.

Description

[0001]This application claims the benefit of the following U.S. Provisional Applications Ser. No. 60 / 828158, filed Oct. 4, 2006, titled Instrumentation for Bicompartmental Knee; Ser. No. 60 / 824696, filed Sep. 6, 2006, titled Instrumentation for Bicompartmental Knee; and Ser. No. 60 / 825533 filed Sep. 13, 2006, titled Variable Transition Referencing Guide, the entire contents of each of which are hereby incorporated by reference.FIELD OF THE INVENTION[0002]The invention relates to implants and processes for use in joint surgery, particularly knee replacement surgery. In certain embodiments, methods are provided for locating and using a transition point on the femur for proper positioning of resections that are intended to receive a femoral component during a surgical procedure. Implants are provided according to certain embodiments that replace the medial condyle and part of the patellofemoral channel of the femur, but preferably do not replace portions of the lateral condyle that art...

AI Technical Summary

Benefits of technology

[0012]In some cases, implants adapted to be installed on such resected femurs feature a transition surface which corresponds to the transition resection that has been controllably located and oriented relative to the femur as mentioned above. Such a transition when properly located aims to create a smooth transition from implant surface to bone surface by, among other things, reducing surface discontinuity such as implant and / or bone overhang. Preferably, the transition between bone and implant in such cases is located so that only anatomical lateral condyle surfaces articulate relative to the tibia in the knee joint in which the implant has been installed.

Problems solved by technology

When joint cartilage is worn away, the bone beneath the cartilage is left exposed, and bone-on-bone contact can be very painful and damaging.

Other types of problems can occur when the bone itself becomes diseased.

Such procedures often require sacrifice of the anterior and posterior cruciate ligaments.

However, many patients who develop knee arthritis experience issues isolated to the medial (inner) compartment and the patellofemoral (knee cap) part of the joint, while the lateral (outer) compartment of the joint remains healthy.

However, there is no known solution or method for marking the boundary for bicompartmental knee replacement.

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