Chapter 56: Osteoarthritis and Osteoporosis

Osteoarthritis represents a chronic degenerative process where the protective articular cartilage within joints deteriorates over time, leading to progressive joint damage, bone spur formation, and functional limitation. Primary osteoarthritis develops without identifiable cause and increases with age, whereas secondary osteoarthritis emerges following joint trauma, infection, or metabolic disturbance. The condition arises from chondrocyte dysfunction in which the balance between cartilage breakdown and repair shifts toward degradation, resulting in characteristic clinical findings including activity-related pain that resolves with rest, brief morning stiffness under thirty minutes, and physical signs such as limited joint mobility and distinctive bony nodules on finger joints. Diagnosis relies primarily on clinical presentation and patient history rather than imaging findings, which often lag behind symptomatology. Treatment emphasizes conservative approaches including patient education, weight management, and low-impact physical activity, supplemented by topical anti-inflammatory medications and intra-articular injections during acute episodes, with surgical joint replacement reserved for advanced cases unresponsive to medical therapy. Osteoporosis, by contrast, represents a systemic bone density disorder characterized by microarchitectural deterioration and heightened fracture susceptibility resulting from an imbalance in bone remodeling where bone-removing osteoclasts outpace bone-forming osteoblasts. This silent disease typically produces no symptoms until fracture occurrence, though advanced cases manifest as height loss and thoracic spine curvature from vertebral compression. Dual-energy x-ray absorptiometry imaging quantifies bone mineral density and establishes diagnosis through standardized T-score comparisons, distinguishing osteopenia from established osteoporosis. Risk factors include estrogen deficiency following menopause, cigarette smoking, corticosteroid medications, and advanced age. Management combines lifestyle modifications emphasizing weight-bearing exercise and fall prevention with pharmacological interventions, particularly bisphosphonate medications that slow bone resorption, while adequate calcium and vitamin D supplementation supports bone mineral maintenance.