Biomechanical Properties of the Lateral Patellofemoral Ligament: A Cadaveric Analysis

Medial instability of the patellofemoral joint is a rare but known phenomenon; it may result from an incompetent lateral patellofemoral ligament (LPFL). However, biomechanical details of the ligament have not been the subject of scrutiny. The purpose of this study was to describe the biomechanical properties of the LPFL. Ten fresh-frozen human cadaveric knees were dissected to identify the LPFL. The ligament was harvested with a bone plug from the patella and the femoral surface and underwent axial loading to failure. Load to failure and location of failure were recorded. Regression analysis was performed to determine which anatomic variables (midsubstance width, femoral insertion width, patellar insertion width, or percent patellar articular surface of insertion) significantly influenced load to failure. Nine of the 10 specimens failed at the midsubstance of the ligament. The mean load to failure was 90±67 N. Logistical regression showed that midsubstance width was most correlated with load to failure, which approached but did not reach significance (P=.09). Studies are warranted to investigate the clinical consequences of medial patellar instability and the best repair or reconstruction techniques available. [Orthopedics. 2018; 41(2):e797-e801.].