Anatomic Reconstruction of the Patellofemoral Joint

Overview

The investigators posit that it would be advantageous to reproduce the height of the entire patellofemoral joint in order to maintain the lever arm of the quadriceps mechanism at its preoperative level. Failure to do this may cause the quadriceps mechanism to be inefficient. For example the quadriceps mechanism would have to work harder if the total patellofemoral (PF) height is diminished. Alternatively, diminished motion or increased patellar strain may occur if the overall PF height is increased. The investigators theorize that either of these sizing errors could lead to anterior knee pain. The purpose of this study is to compare the clinical outcomes between two surgical techniques: 1) a technique of reproducing the total PF joint on both sides of the articulation (Group 1) and 2) the traditional technique of reproducing only the patellar thickness on one side of the joint (Group 2).

There is no consensus on the source of the anterior pain or the most efficacious treatment. Multiple etiologies have been theorized concerning the cause of this problem including tibiofemoral instability, patellofemoral (PF) instability, PF maltracking and patella stress fractures. It has been reported that patellofemoral forces are associated with anterior knee pain. Moreover, it has been reported that a correlation exists between the tension of the quadriceps muscle and the forces on the patella. In a biomechanical, cadaver study, Browne et al. found that a longer extensor moment arm reduced the tension on the quadriceps and reduced the patellar forces.

Conditions