Effect of medial meniscal release on tibial translation after tibial plateau leveling osteotomy

OBJECTIVE: To evaluate the biomechanical effects of medial meniscal release (MMR) and medial, caudal pole hemimeniscectomy (MCH) on joint stability in the cranial cruciate ligament (CCL)-deficient canine stifle before and after tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: Experimental study. ANIMALS: Thirty-one dogs. METHODS: In experiment 1, 16 pairs of normal hindlimbs randomly assigned to an intact or transected CCL group were studied to determine the magnitude of tibial translation after MMR and MCH under 20% body weight load using radiographic imaging of radio-opaque markers. In experiment 2, 15 pairs of CCL-deficient hindlimbs were randomly assigned to a TPLO or sham TPLO group. The remainder of the experiment was performed as described for experiment 1. The effect of CCL transection, MMR, MCH and TPLO were analyzed using 2-way repeated measures ANOVA; P<.05 was considered significant. RESULTS: We found a greater effect of MMR on tibial translation in transected CCL stifles than in intact stifles (P=.0016). We found no further effect of MCH after MMR (P>.05). We found a greater effect of MMR in sham TPLO than TPLO stifles (P=.0013) but no further effect of MCH after MMR (P>.05). CONCLUSIONS: By resisting tibial translation the medial meniscus might be at greater risk of tearing in CCL-deficient stifles. TPLO may spare the medial meniscus by neutralizing the tibial thrust and eliminating the wedge effect of the medial meniscus. CLINICAL RELEVANCE: MMR may not be indicated in the CCL-deficient stifle stabilized by TPLO.