EVALUATION OF SHELF ARTHROPLASTY AS A TREATMENT FOR HIP-DYSPLASIA IN DOGS

Objective-To evaluate effects of shelf arthroplasty on coxofemoral joi nt laxity and progression of degenerative joint disease in young dogs with hip dysplasia. Design-Prospective, controlled study. Animals-10 d ogs between 10 and 24 months old and weighing between 20 and 27 kg. Ai l dogs had bilateral coxofemoral joint laxity (ie, an Ortolani's sign) . Procedure-In all dogs, shelf arthroplasty was performed on the right coxofemoral joints, and a sham procedure was performed on the left, D ogs were evaluated before and after surgery by means of lameness asses sment, coxofemoral joint palpation and goniometry, thigh circumference measurement,and radiography. Results-There were no significant change s in coxofemoral joint mobility, range of motion, joint laxity, degree of degenerative joint disease, or thigh circumference during the stud y. A greater amount oi periacetabular bone formed on the right side th an on the left side; however, dogs did not develop large bony shelves, and the amount of periarticular bone decreased over lime. The polymer implants remained in their original position and were encapsulated by fibrous tissue. There was no histologic evidence of osteoconduction b y the implants. Clinical Implications-The polymer implants used In thi s procedure do not appear to be osteoconductive. Shelf arthroplasty wa s associated with minimal morbidity and was not associated with seriou s adverse sequelae in this study, but the procedure did not alter the progression of hip dysplasia in these dogs. We cannot advocate shelf a rthroplasty using this polymer as a treatment for dogs with hip dyplas ia.