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Newer Designs and Methods Improve Results of Knee Replacement Surgery

Total knee replacement surgery (called total knee arthroplasty, or TKA) is becoming quite common these days. New and improved designs for the implants make the TKA a good choice for many patients with knee pain. The new joint or implant is known as a prosthesis.

There are many different styles of knee prostheses. The basic surgery to remove the damaged or diseased joint and replace it with an implant is the same for all knee prostheses. However, there are some small differences.

One of these important differences has to do with the kneecap, or patella. The patella moves up and down over the front of the knee joint. This is called patellar tracking. Maintaining good patellar tracking after a TKA is the subject of this study.

A single orthopedic doctor used two methods to retain good patellar tracking. All patients got the same prosthesis. In one group, the fibrous tissue alongside the patella was severed (released). This band of tissue is called the lateral retinaculum (LR). Cutting the LR is thought to keep the kneecap from pulling too much to the outside edge of the knee.

A new method was used with the second group. Instead of cutting through the LR, it is instead "peeled" off the patella in a way that keeps the correct tracking pattern. Not cutting into the LR prevents bleeding. It also stops a painful snapping when the cut edge of the retinaculum passes over the bone underneath it.

Keeping the kneecap on track after a TKA may depend on the surgeon's skill. Small changes in how the surgery is done may make a difference in the final result. LR release may be replaced by the peel method with the new prosthetic designs.

References: James A. Shaw, MD. Patellar Retinacular Peel: An Alternative to Lateral Retinacular Release in Total Knee Arthroplasty. In The American Journal of Orthopedics. April 2003. Vol. 32. No. 4. Pp. 189-192.

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