Patello-femoral joint replacement

Abstract

It is well known that the knee can suffer from a unicompartmental osteoarthritis which leaves the rest of the joint relatively normal, It is surgically attractive to conserve normal tissues, especially in younger patients, and consequently there have, over the years, been a number of prostheses developed with the aim of treating the single worn compartment, whether it be medial, lateral or patello-femoral. Although good results have been reported, particularly for medial compartment osteoarthritis, these have mostly been by enthusiastic innovators and have not to date achieved widespread acclaim. Isolated replacement of the patello-femoral joint has in particular met with scepticism. There are several reasons for this: 5. 1. The excellent long-term survival rates for conventional total knee replacement. 2. When problems do occur following a total knee replacement, the patello-femoral mechanism is the commonest site. This naturally raises doubt in the surgeon's mind about the wisdom of isolated patello-femoral replacements. 3. Concern over the extent to which a patellofemoral replacement will interfere mechanically with the tibio-femoral articulation. What, for example, will happen in flexion beyond 90 ° when the patellar component 'runs onto' the intercondylar margins of the femoral condyles? Polyethylene bearing against articular cartilage has not got a good reputation, c.f. 'soft-top' Monk hemiarthroplasty of the hip. ~ 6. 4. Since patello-femoral osteoarthritis is primarily