Anatomy Msk · Year 1 · from Anatomy Msk
Case 3: Medial Meniscus Tear
Clinical Image
Source: Wikimedia Commons - Meniscus - CC BY-SA 4.0
Case Presentation
A 45-year-old recreational tennis player presents with 6 weeks of right knee pain and intermittent mechanical symptoms. He recalls a twisting injury to his knee while playing tennis when he pivoted on a planted foot. He has had persistent medial-sided knee pain, worse with squatting and going up and down stairs. He reports episodes where his knee "catches" and occasionally "locks" in a flexed position, requiring him to wiggle the knee to unlock it. Physical examination reveals mild joint effusion. There is tenderness along the medial joint line. McMurray test is positive - rotating the tibia externally while extending the knee from a flexed position produces a painful click at the medial joint line. Thessaly test at 20 degrees of knee flexion reproduces medial pain. There is no ligamentous instability. MRI demonstrates a complex tear of the posterior horn of the medial meniscus extending to the inferior articular surface. Given his age, mechanical symptoms, and failure of conservative management, he undergoes arthroscopic partial meniscectomy with debridement of the unstable fragment.
Key Learning Points
- The menisci are C-shaped fibrocartilage structures that deepen the tibial plateau and improve load distribution
- The medial meniscus is more commonly injured (less mobile, attached to MCL and capsule)
- Meniscal tears often occur with rotational force applied to a flexed, weight-bearing knee
- Mechanical symptoms (catching, locking) suggest a displaced fragment; locking in flexion is classic for bucket-handle tear
- McMurray test: external rotation + extension tests medial meniscus; internal rotation tests lateral meniscus