Caudal Cruciate Ligament Damage in Dogs with Cranial Cruciate Ligament Rupture

Objective To investigate the incidence of caudal cruciate ligament (CaCL) damage in dogs with cranial cruciate ligament rupture (CCLR). Study Design Prospective clinical study. Animals Dogs (n=24) admitted for surgical stabilization of the stifle after CCLR and 8 healthy dogs with intact cranial cruciate ligament (CCL) and CaCL studied as controls. Methods Preoperative radiographs and stifle joint images (arthrotomy, 6; arthroscopy, 18) were collected from dogs with CCLR. Severity of arthritis, synovitis, CCL damage, and CaCL damage were assessed using numerical rating scales. The CaCL was probed to determine whether minor fraying or a full thickness defect in the ligament was present. Data collected from the study population were compared with the control population of dogs. Results The CaCL was damaged in 21/24 (88%) of dogs with CCLR; 6/24 (25%) had a full thickness defect in the CaCL. Severity of stifle synovitis and severity of damage to the CaCL were positively correlated (P <.05). Conclusions The CaCL is damaged in a high percentage of dogs with CCLR. A significant and positive correlation exists between the degree of synovitis present and the extent of CaCL damage. Clinical Relevance In dogs with CCLR, cruciate ligament pathology typically involves both the CCL and CaCL. As the severity of synovitis and the extent of CaCL damage are related, this observation supports the hypothesis that stifle synovitis may contribute to CCL and CaCL degeneration and subsequent damage.