Is there an association between patella alta and the severity and location of patellofemoral joint deterioration? A cadaveric study

Patella alta (PA) has been shown to be a risk factor for patellar dislocation and anterior knee pain. PA is defined as a condition in which the ratio between the length of the patellar tendon (LT) and the length of the patella (LP) is ≥ 1.2. The purpose of this cadaveric study was to determine if PA is associated with the severity and location of patellofemoral joint deterioration (PFJD). Forty‐six knees of 25 previously dissected and embalmed cadavers were used for this study. Each patella was dissected out of the quadriceps tendon while maintaining the patellar tendon attachment to the tibial tubercle. PFJD was graded on a scale of 0–4 in 6 zones of the patella (proximal, middle, and distal thirds on the medial and lateral halves) and 3 zones of the femoral trochlea (medial, lateral, and middle). LP and LT were measured in all knees. The mean ratio was 1.04 and 13 (28%) knees were considered to have PA. PA was found in 3 males (1 right knee, 1 left knee, and 1 bilateral) and 6 females (3 left knees and 3 bilateral). The middle third and middle lateral zone of the patella demonstrated more severe PFJD in the knees with PA (p<.05). There were no significant differences in femoral trochlea degenerative changes. This study demonstrates that knees with PA demonstrate increased PFJD in certain regions of the patellar articular surface. Future research is warranted to determine conservative treatments aimed at preventing PFJD in this population.