Recurrent Patellar Instabilty Culminating in a Vertically Rotated and a Locked Patellar Dislocation - A Rare Entity

Locked vertical patellar dislocations are rare and pose a therapeutic challenge. This case is more unusual, as the patient was a known case of recurrent patellar dislocation and presented with an atraumatic locked and vertically rotated patellar dislocation. This type of presentation has never been reported in literature to the best of our knowledge.

A 14-year-old healthy male child with previous history of recurrent lateral dislocation of patella presented to accident & emergency department with complaints of inability to walk or bear weight on his left lower limb after he spontaneously dislocated his patella while running on uneven ground. Radiographs revealed a laterally displaced and vertically rotated patella along its long axis with the medial patellar edge locked and dipping into the lateral gutter. Open reduction was performed along with lateral patellar retinacular release with medial patellar retinaculum plication, to achieve satisfactory patellar stability and patellofemoral tracking.

We would recommend that in the settings of patella being vertically dislocated and locked, open reduction would be the management of choice, as these types of dislocations are difficult to relocate by closed reduction. Repeated attempts of closed reduction may cause osteochondral damage. Open reduction not only yields better outcomes but also allows the surgeon to perform patellar realignment procedures in order to prevent further patellar dislocations in cases of prior patellar instability.