Cadaveric-biomechanical study on medial retinaculum: its stabilising role for the patella against lateral dislocation
Abstract
Background: The aim of this study was to analyse the biomechanical role of medial retinaculum, as a stabilising factor against lateral patellar dislocation.
Materials and methods: This cadaveric-biomechanical study included the patellae of 10 cadaveric knees, which were surgically exposed and the medial retinaculum of each one was located. A stable 24.51 N force was applied to the four parts of the quadriceps, and an increasing lateral displacing force was applied to the patella, up to 5 mm dislocation. The study was repeated for 0o, 45o, and 90o of knee flexion, with the medial retinaculum intact and dissected. The Wilcoxon signed rank test was used for data analysis. A p value < 0.05 was considered as statistical significant.
Results: After the dissection of medial retinaculum, the lateral displacement force was lower at every angle of knee flexion (p = 0.005, p = 0.007, p = 0.005, respectively). The lateral displacement force increased as the flexion angle increased (p = 0.005), regardless of medial retinaculum integrity.
Conclusions: Medial retinaculum acts as a stabilising factor for the patella, against its lateral dislocation in lower flexion angles. Therefore, methods of surgical reinforcement or repair of medial retinaculum could provide protection against
recurrent patellar dislocation.
Keywords: patellar instabilitypatellar retinaculummedial stabiliserslateral displacement forcemedial patellofemoral ligament
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