Cranial cruciate ligament rupture in the dog: Gait analysis with an electronic walkway system and investigation in the role of steroid hormones on collagen homeostasis

Abstract

Canine CCL rupture is one of the leading orthopedic problem in the United States and other parts of the world. It has been suggested that gonadectomy of the male is a risk factor for trauma to the CCL, implying that sex hormones play a role in CCL development and maturation. Understanding how sex hormones affect CCL growth during puberty could provide an informed basis for determining the appropriate age for gonadectomy in young animals. Using prepubertal male rabbits, the present study investigated effects of sex hormones on collagen content of the CCL. The results showed that gonadectomy caused the loss of collagen content, affected steroid hormone receptor (AR and ESR1) protein expression and slightly altered MMP-1, -2 and -9 protein levels in the CCL. In order to investigate gait abnormalities caused by orthopedic issues such as CCLR, a normative database was needed using a pressure walkway system. Normal Labrador Retrievers (n=56) were walked across the walkway system which recorded temporal-spatial variables, including SrL, SrT, ST, ST%, TPI applied by each limb, and NS. This study established a protocol for the collection of temporal-spatial gait analysis variables by use of a portable walkway system and determined reference values for variables and symmetry ratios. Subjective clinical gait analysis has been shown to be unreliable indicating that an objective assessment is needed. A pressure walkway system was used to identify measurements that could distinguish between normal gait and lameness associated with surgical stabilization of a CCLR by TPLO. This study indicates that trend lines for unaffected/affected hind limb ratios for NS and TPI from dogs recovering from TPLO surgery were within 1 SD of normal values at days 80 and 91 for NS and TPI, respectively. The time course of recovery documented provides a baseline for future studies to assess rehabilitation protocols after TPLO surgical repair or to compare alternate treatments of CCL insufficiency. Since this pressure walkway system is considered a new technology in the veterinary field, a comprehensive guide to its use was also produced. The manual outlines use of the system from set up, to data collection, to interpretation of the data.