Pain on the medial or lateral joint line during the Thessaly test indicates a tear of which structure?

• A. Medial or lateral meniscal tear
• B. ACL tear
• C. MCL tear
• D. Osteoarthritis

Answer: (A)

The Thessaly test stresses the menisci by having a patient stand on one leg, bend the knee slightly, and twist the knee internally and externally while weight-bearing. If a meniscal tear is present, the torn edge or fragment catches or irritates the joint during this rotational load, producing pain right at the joint line where the menisci sit. Therefore, pain on the medial joint line indicates a medial meniscal tear, and pain on the lateral joint line indicates a lateral meniscal tear. This maneuver specifically targets meniscal integrity, rather than ligaments like the ACL or MCL, or diffuse osteoarthritic changes which tend to cause broader joint symptoms rather than focal joint-line pain with this test.