Variations in composition of cartilage from the shoulder joints of young adult dogs at risk for developing canine hip dysplasia

Abstract

Objective - To determine whether the composition of cartilage from the shoulder joints of dogs varied with the risk of developing canine hip dysplasia (CHD). Design - Observational study. Animals - 12 skeletally mature (approx 1 year old) Labrador Retrievers. Procedure - Dogs were classified as having a low, moderate, or high risk of developing CHD on the basis of distraction indices. Cartilage was harvested from the craniolateral and weight-bearing regions of the humeral heads, and wet weight per unit area and dry, glycosaminoglycan, and fibronectin contents were determined. Results - Glycosaminoglycan and dry contents did not vary among risk groups. For cartilage from the craniolateral region of the humeral head, wet weight per unit area and fibronectin content increased as risk of developing CHD increased. Wet weight and fibronectin content of cartilage from the weight-bearing region of the humeral head did not vary among risk groups. Clinical Implications - Dogs that have a high risk of developing CHD are also more likely to develop osteoarthritis of the shoulder joint. The observed increases in wet weight per unit area and fibronectin content in cartilage from the craniolateral region of the humeral head in dogs at a high risk of developing CHD may be early signs of incipient osteoarthritis.