There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
The medial patellofemoral ligament (MPFL) is a band of retinacular tissue connecting
the femoral medial epicondyle to the medial edge of the patella. The MPFL is approximately
55 mm long, and its width has been reported to range from 3 to 30 mm. The MPFL is
overlaid by the distal part of vastus medialis obliquus to a variable extent, and
fibres of MPFL merge into the deep aspect of the muscle. Despite the MPFL being very
thin, it had a mean tensile strength of 208 N, and has been reported to be the primary
passive restraint to patellar lateral displacement. Lateral patellar displacement
tests in vitro showed that the patella subluxed most easily at 20 degrees knee flexion.
The contribution of the MPFL to resisting patellar lateral subluxation was greatest
in the extended knee. This finding was linked to the retinaculae being tightest in
full knee extension, and slackening with flexion.