Magnetic Resonance Imaging Features of Traumatic Patellofemoral Dislocation

Acute traumatic patellar dislocations are encountered with relative frequency, making up 3% of all knee injuries. Typically witnessed in younger patients following sporting injuries, this injury can be debilitating, potentially leading to recurrent dislocation, pain, reduction in activity and patellofemoral osteoarthritis. Management of this injury remains controversial, and as such detailed magnetic resonance imaging (MRI) is increasingly recommended to help illustrate the exact nature of osteochondral and soft tissue injury, with a view to assessing the anatomical sequelae of patellar dislocation as well as the potential of recurrence and dictating the need for either conservative or surgical management in the acute setting. As such, awareness of the typical MRI findings in traumatic patellar dislocations may potentially aid in pursuing appropriate intervention for this pathology. This case describes a 33-year-old gentleman presenting to the emergency department following patellar dislocation. After failed departmental closed reduction, this patient progressed on to definitive anatomical MRI assessment followed by acute surgical intervention in the form of medial patellofemoral ligament (MPFL) repair. This case allows for both illustration and discussion of typical radiological features associated with traumatic patellar dislocation.