Missed Transient Patellar Dislocation in Younger Patients With Traumatic Knee Injuries

Abstract

Background: Acute patellar dislocation is a common injury, with up to 40% of the cases missed due to a high rate of spontaneous reduction. Complications mainly arise due to osteochondral fractures, resulting in patellofemoral osteoarthritis and rupture of medial patellar stabilizers, leading to recurrent patellar instability. Methods: Institutional database was retrospectively reviewed to find patients with missed transient patellar dislocation. From January 2010 to January 2015, ten otherwise healthy patients with a history of indirect trauma to the knee were diagnosed with missed patellar dislocation. They all had persistent pain and effusion, despite conservative treatment. Results: Eight patients eventually underwent arthroscopic debridement of osteochondral fractures and repair of ruptured ligaments, with no case of recurrent instability. Conclusions: Detailed history taking and physical examination of all acute knee injuries, with a standard three dimensional (3D) X-ray imaging and a low threshold to obtain magnetic resonance imaging (MRI) studies, could minimize cases of missed patellar dislocation and possibly severe complications.

Keywords

• Transient Patellar Dislocation
• Patellar Instability
• Osteochondral Fracture