Resection of Grade III cranial horn tears of the equine medial meniscus alter the contact forces on medial tibial condyle at full extension: an in-vitro cadaveric study

Objective: To evaluate the magnitude and distribution of joint contact pressure on the medial tibial condyle after grade III cranial horn tears of the medial meniscus.

Study design: Experimental study.

Animals: Cadaveric equine stifles (n = 6).

Methods: Cadaveric stifles were mounted in a materials testing system and electronic pressure sensors were placed between the medial tibial condyle and medial meniscus. Specimens were loaded parallel to the longitudinal axis of the tibia to 1800 N at 130°, 140°, 150°, and 160° stifle angle. Peak pressure and contact area were recorded from the contact maps. Testing was repeated after surgical creation of a grade III cranial horn tear of the medial meniscus, and after resection of the simulated tear.

Results: In the intact specimens, a significantly smaller contact area was observed at 160° compared with the other angles (P < .05). Creation of a grade III cranial horn tear in the medial meniscus did not significantly alter the pressure or contact area measurements at any stifle angle compared with intact specimens (P > .05). Resection of the tear resulted in significantly higher peak pressures in the central region of the medial tibial condyle at a stifle angle of 160° relative to the intact (P = .026) and torn (P = .012) specimens.

Conclusions: Resection of grade III cranial horn tears in the medial meniscus resulted in a central focal region of increased pressure on the medial tibial condyle at 160° stifle angle.