title: Transient medial patellar dislocation: injury patterns at US and MR imaging.
abstract: Medial dislocation of the patella is an unusual entity. It is usually an iatrogenic complication of surgical lateral retinacular release. We describe the clinical, ultrasound (US), and magnetic resonance (MR) imaging features of a transient medial patellar dislocation in a 19-year-old patient with trochlear groove dysplasia presenting no surgical history. US showed acute injury to the lateral patellar retinaculum with complete avulsion at its patellar insertion. MR imaging confirmed the complete tear of the lateral patellar retinaculum and disclosed contusion of the anteromedial portion of the medial femoral condyle and lateral patella. This case is noteworthy because the injury patterns of patellar soft tissue restraints differ markedly from the classical features of lateral patellar dislocation.
authors.affiliation: Radiology Department, Hôpital Sainte-Marguerite, 270 Boulevard de Sainte-Marguerite, 13009 Marseille, France. Thomas.LeCorroller@ap-hm.fr
authors.forename: Thomas
authors.initials: T
authors.lastname: Le Corroller
authors.forename: Melania
authors.initials: M
authors.lastname: Dediu
authors.forename: Pierre
authors.initials: P
authors.lastname: Champsaur
mesh_terms: D000058:Accidental Falls; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology / Q000534:rehabilitation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010329:Patella / Q000293:injuries*; D014463:Ultrasonography; D055815:Young Adult