Tibial Plateau Angles in Small- and Large-Breed Dogs with Cranial Cruciate Ligament Rupture: A Retrospective Study of 132 Cases

Abstract Cranial cruciate ligament rupture (CrCLR) is a common orthopaedic condition in dogs, with tibial plateau angle (TPA) considered a potential predisposing factor. This study compared TPA, age and signalment between CrCLR and intact cranial cruciate ligament dogs in small- and large-breed groups. Medical records from 171 client-owned dogs (222 tibiae) diagnosed at the Veterinary Teaching Hospital, Khon Kaen University, between February 2020 and December 2024, were analysed. Dogs in the CrCLR group (132 dogs) had a significantly higher TPA (25.28 ± 4.65 degrees) than those in the intact cranial cruciate ligament group (21.49 ± 4.15 degrees, p < 0.001). Among CrCLR dogs, small-breed dogs exhibited a higher TPA (26.04 ± 4.74 degrees) compared with large-breed dogs (24.25 ± 4.33 degrees, p < 0.05). Receiver operating characteristic analysis indicated a moderate predictive value of TPA in diagnosing CrCLR, with higher accuracy in small-breed dogs (area under the curve: 0.76, optimal cut-point: 21.65 degrees) compared with large-breed dogs (area under the curve: 0.66, optimal cut-point: 23.95 degrees). Although TPA was higher in CrCLR dogs, it is not an individual determinant of the condition. Further research is required to explore additional contributing factors and enhance predictive models.