Computerized tomography of the patellofemoral joint before and after lateral release or realignment.

Computerized tomography (CT) provides an accurate diagnostic tool for evaluating tilt and subluxation of the patella. Using a previously described technique, this study reviews 62 computerized tomograms, including those of 21 patients before and after lateral release or anteromedial tibial tubercle transfer. One patient was evaluated before and after soft-tissue realignment of the patella. Additional CT studies were evaluated to establish the most appropriate reference line for determining patellar tilt. Results show that lateral retinacular release effectively reduces abnormal patellar tilting as determined by CT. Anteromedial tibial tubercle transfer similarly reduces abnormal tilt. Patellar subluxation may improve substantially following either lateral release or anteromedial tibial tubercle transfer, but this study suggests that correction of subluxation is less consistent than reduction of abnormal tilt with tibial tubercle transfer or lateral release alone. Once articular degeneration has progressed to the point of facet collapse, lateral release fails to restore normal tilt.