A clinical sign to detect root avulsions of the posterior horn of the medial meniscus

Purpose: The goal of the present report was to describe a new clinical sign to make a clinical diagnosis of meniscal extrusion related to medial meniscal root avulsion. Methods: Description of an easy clinical sign to detect extrusion of the medial meniscus at the anteromedial joint line. A varus stress test was applied in full extension before and after transosseous repair of an isolated traumatic avulsion of the posterior root of the medial meniscus in a 21-year-old patient. The clinical sign was verified by sectioning of the meniscotibial ligament during knee arthroplasty surgery in 3 patients. Results: With a deficient posterior root, the clinical sign was positive, showing anteromedial extrusion under varus stress. After repair and at clinical follow-up, extrusion was normalized. Conclusion: Making the clinical diagnosis of medial meniscus extrusion after knee injury by applying a simple varus stress test to the knee and palpating the anteromedial meniscal extrusion might help physicians to suspect a medial meniscus root tear in the early stages after the injury as well as to evaluate its reduction after repair. A varus stress test in full extension should be performed systematically in patients where a root tear of the medial meniscus is suspected as well as after surgery to evaluate the success of the repair. Level of evidence: IV.