Objectives: To investigate whether a difference exists in incidence of medial meniscal tears between small (≤15 kg) and medium-to-large (>15 kg) dogs with naturally occurring cranial cruciate ligament disease.
Materials and methods: Records were retrospectively reviewed to identify the incidence of medial meniscal tears in dogs undergoing tibial plateau levelling osteotomy. Degree of cruciate insufficiency, method of identification (arthroscopy or arthrotomy), tibial plateau angle, weight and signalment were recorded. A two-proportion z-test with clustering adjustment was used to compare the meniscal tear rate between the two groups. Logistic regression analysis was used to investigate the effects of variables on medial meniscal tears.
Results: Seventy-six stifles in 67 small dogs and 504 stifles in 384 medium-to-large dogs were included. The rate of meniscal injury at index surgery was 38.2% in small dogs and 36.7% in medium-to-large dogs. The subsequent meniscal tear rate was 1.3% in small dogs and 8% in medium-to-large dogs. The difference in meniscal tear rate was not statistically significant at either index surgery or subsequently. Degree of cruciate ligament insufficiency and use of arthroscopy were significantly associated with medial meniscal tears at index surgery. No variables were significantly associated with subsequent medial meniscal tears.
Clinical significance: No significant difference exists in medial meniscal tear rate between small and medium-to-large dogs either at index surgery or subsequently. The index of suspicion of concurrent medial meniscal tears should be higher in dogs with complete tear of the cranial cruciate ligament but a partial tear does not preclude meniscal pathology.