Patella infera following arthroscopic anterior cruciate ligament reconstruction

Fifty patients who had an arthroscopic anterior cruciate ligament reconstruction for chronic insufficiency were reviewed at an average of 13.6 months following surgery. Among these patients, 32% complained of anterior knee pain that interfered with daily activities. Radiographic patella infera was present in 12% of patients using the Insall-Salvati ratio and in 16% using the Blackburne-Peel ratio. Radiographic patella infera did not correlate with the clinical problem of postoperative anterior knee pain. However, loss of knee extension of greater than 5 degrees correlated highly with pain (p=0.002).