Medial meniscal damage is frequently identified in dogs with cranial cruciate ligament rupture (CCLR); 10% to 70% of dogs with CCLR may have meniscal tears. Risk factors for canine meniscal injury in CCLR have not been definitively identified, although early repair might improve joint function and patient outcomes. The associations of breed, duration of lameness, body weight, and CCLR severity with canine medial meniscal tears were assessed in this study. Dogs that presented for CCLR surgery between 2002 and 2009 were included, and analysis included age, breed, sex, lameness duration, CCLR severity, and condition of the meniscus. Grossly unstable stifles with cranial drawer and tibial thrust were characterized as complete ruptures, while partial ruptures had minimal or absent cranial drawer or tibial thrust. All dogs were treated with medial or lateral stifle arthrotomy procedures with or without meniscal probing. Logistic regression was used to create a multivariate model to define the relationship between the factors and meniscal tears. A total of 443 stifle joints (from 366 dogs) were included in the study. Medial meniscal tears were identified in 36.3% of joints (161 of 443 stifles); 38.1% had partial CCLR (169 stifles), and 61.9% had complete CCLR (274 stifles). Further, medial meniscal injuries were identified in 10.1% (17 of 169) of stifles with partial CCLR and 52.6% (144 of 274) of stifles with complete CCLR. The presence of a complete CCLR increased the risk for a medial meniscal tear by 12.9 times as compared with partial CCLR. Each ongoing week of lameness increased the risk for medial meniscal tears by approximately 2.6%. Increasing body weight increased the risk for a medial meniscal tear by approximately 1.4% per additional kilogram of body weight. Golden retrievers and rottweilers were at higher risk than baseline Labrador retrievers while West Highland white terriers were at lower risk.

Commentary: This study suggested that early CCLR corrective surgery was necessary to regain functional stifle stability and to reduce the incidence of medial meniscal injury. Therefore, clinicians must urge pet owners not to delay surgery in order to improve patient outcomes and delay arthritis, particularly in at-risk breeds. Future studies should characterize this further.—Indu Mani, DVM, DSc

Risk factors for medial meniscal injury in association with cranial cruciate ligament rupture. Hayes GM, Langley- Hobbs SJ, Jeffery NJ. J SMALL ANIM PRACT 51:630-634, 2010.