Degenerative Joint Disease – Osteoarthritis OA is the most common joint disease in the world, and is the leading cause of disability in the developed world. Joints: • DIP, PIP, base of thumb, nodal OA • Spine, hips, knees Hyaline Cartilage • 70% water • Proteoglycan aggregates trapped within an arching framework of type II collagen • Aggregates of chondroitin sulphate/keratan sulphate • No nerves or blood vessels Glycosaminoglycans • Hyaluronan o Repeating glucosamine and glucuronic acid o Cartilage and SF o Viscoelastic • Chondroitin sulphate o Repeating glucuronic acid and galactosamine Factors in OA Development • Genetics o Insulin-like growth factor o Collagen defects and production o Proteoglycan defects and production o Enzymes • Biomechanics o Occupation, trauma, sport o Obesity o Muscle bulk, position sense • Inflammation o Inflammation synovitis: collagenases, stromelysin, hyaluronidase, aggrecanase • Age o Impaired chondrocyte function o Cumulative trauma o Strength and position changes • Trauma o ACL Reducing Damage • Joint protection o Weight loss o Occupation safety o Orthopaedic repair o Splints • Reduce inflammation o Reduce enzyme induction o Increase enzyme inhibition • Viscosupplementation Increasing Repair • Transcriptional inducers • Precursor loading: glucosamine, chondroitin • Viscosupplementation: hyaluronic acid injections to improve synovial fluid and self-stimulate production Enzyme Inhibitors • MMPI3 (collagenase 3) o Chondrocyte produced via IL-1 o Potent hydrolyser of cartilage type II collagen • Specific inhibitors of collagenase  increased cancer risk • Doxycycline inhibits MMPI3 i.e. collagen breakdown Glucosamine • Hexosamine component of KS, HA • Not better than placebo for pain relief >6months Viscosupplementation • High molecular weight hyaluronan • Viscoelastic o Lubrication, chock absorption, liquid congruency • Expensive, mild benefit for moderate OA Goals of OA Therapy • Relieve pain and associated symptoms • Relieve stiffness and swelling • Minimise and improve disability • Maintain joint function and QoL Non-Pharmacological Therapy • Joint protection: weight loss, splints, supports, etc. • Move it or lose it • Physical therapy Joint Replacement Surgery • If pain disrupting sleep and limiting function despite conservative therapy  Contraindications: o Severe neurological or cognitive impairment that will impair rehab o Vascular disease/unstable angina o Chronic sepsis