Case report: unusual posteromedial capsular lesion with posterior lateral meniscus root tear in two patients with constitutional genu recurvatum presenting after an acute ACL injury

Ramp lesions of the medial meniscus and posterior lateral meniscus root tears (LMPRT) can be present simultaneously in up to 8% of patients undergoing anterior cruciate ligament (ACL) reconstruction. The prevalence of these complex and highly unstable meniscal tears increases exponentially with the severity of the injury. The posteromedial capsule (PMC) has often been disregarded in the past when discussing ligamentous and meniscal injuries, but the recent interest in ramp lesions has drawn surgeons' attention to the posteromedial structures of the ACL injured knee. While the meniscocapsular junction is commonly repaired in unstable ramp lesions, in the current literature there is no report regarding proximal PMC lesions, be they in isolation or associated with complex meniscal injuries.We report here two cases of proximal posteromedial capsular lesions associated with medial meniscus instability and posterior lateral root tears after ACL injury. The first case involves a meniscus ramp lesion associated with a proximal PMC tear and a posteromedial fluid collection in the muscle plane on magnetic resonance in a 22-year-old male soccer player. The second case involves a 21-year-old female soccer player who presented with a PMC lesion after hyperextension/valgus knee injury. The capsular lesions were repaired to restore capsular tension and improve medial meniscus posterior horn stability.

Automated summary

Ramp lesions of the medial meniscus and posterior lateral meniscus root tears can occur simultaneously in up to 8% of patients undergoing ACL reconstruction. The prevalence of these complex meniscal tears increases with the severity of the injury. Surgeons have recently shown interest in the posteromedial structures of the ACL-injured knee, which were previously overlooked. However, there is a lack of literature regarding proximal posteromedial capsular lesions, whether isolated or associated with complex meniscal injuries.