Dynamic Valgus Instability of the Knee due to Chronic Medial Collateral Ligament Laxity as a Cause of Recurrent Patella Dislocation
Recurrent patella dislocation can be caused by bony abnormalities, such as patella alta, increased tibial tubercle lateralization, trochlea dysplasia, excessive femoral neck anteversion and external tibial torsion. It can also be caused by soft tissue abnormalities such as a ruptured medial patellofemoral ligament (MPFL) or a weak vastus medialis obliquus. It has been reported in the literature that acute lateral dislocation of the patella can be associated with proximal injury to the medial collateral ligament (MCL).
A 26-year-old male pro footballer presented to our institution with a history of recurrent patella dislocation. He had a previous attempted medial capsular plication and MPFL repair at another institution 3 years prior. His last dislocation was a month prior and occurred as a valgus force was applied to his knee when a player landed on him as he was tackled.