An unusual case of traumatic medial eversion-dislocation of the patella: a case report

Medial dislocation of patella has been commonly reported as a complication of the surgical release of the lateral patella-femoral ligament. A traumatic medial eversion-dislocation of the patella has not been earlier reported. We report an unusual case of traumatic medial patellar eversion-dislocation in a young adult patient whose magnetic resonance imaging (MRI) showed a discontinuity in medial and lateral patellar retinacula. However, intraoperatively, the retinacula were found intact, and relocation of the patella was achieved by flipping the patella through a small hole in the patellar tendon. No reconstruction of the ligaments was needed. At 1-year follow-up, the patient achieved full range of movements of the knee, and there were no subjective complaints of instability. In our case, although the patella was medially everted and dislocated, both the retinacula were still intact. Clinicians should be aware that acute traumatic patella medial dislocation and eversion can occur without disruption of the medial or lateral retinaculum. Furthermore, knee MRI may suggest patellar retinacula disruption because of the retinaculum's obscure and tortuous course in patients with these injuries.