Magnetic resonance imaging evaluation of patellofemoral malalignment.

PURPOSE: The purpose of this study was to determine the relationship between anterior knee pain secondary to suspected patellofemoral malalignment and tibial tubercle lateralization, patellar tilt, and patellar lateralization on magnetic resonance imaging.

METHODS: We compared the bony relationships of the knee in patients with anterior knee pain and patients with nonspecific internal derangements of the knee. We measured the lateral deviation of the tibial tubercle and the patella from the trochlea, patellar tilt, and patellar and patellar tendon length.

RESULTS: The symptomatic knees of patients with anterior knee pain had significantly (P < or = .01) greater lateralization of the tibial tubercle and lateral patellar tilt than did knees of the control group. Patella alta appears to be more common in subjects with anterior knee pain.

CONCLUSIONS: Magnetic resonance imaging determination of tibial tubercle lateralization and patellar tilt correlates positively with the clinical diagnosis of anterior knee pain, suggesting that patellofemoral pain is caused by subtle malalignment.

LEVEL OF EVIDENCE: Level III, development of diagnostic criteria on basis of nonconsecutive patients.