Injuries of the posteromedial bundle of the posterior cruciate ligament after knee hyperextension trauma: A new clinical entity based on an original case series.

Purpose: This original case series aims to describe an uncommon triad of clinical signs in patients presenting with persistent pain and inability to resume physical activities after knee hyperextension trauma. Methods: Patient history, clinical examination, arthroscopic findings and investigations of 12 patients who consulted with the senior author are presented. Results: Twelve patients (seven males/five females) presented with persistent pain after knee hyperextension trauma either in sport or a traffic accident. They had a median age of 18.5 and a median body mass index of 23 kg/m Conclusion: Patients displayed an increased hyperextension and posterior laxity close to knee extension which normalised at 90° of knee flexion. In patients with a history of knee hyperextension trauma associated with persistent pain, inability to resume physical activities, inconclusive MRIs and a standard clinical examination, clinicians should consider extending their investigations with the knee close to extension to identify this clinical triad consistent with a lesion to the posteromedial bundle of the posterior cruciate ligament. Level of evidence: Level IV.