Knee Osteoarthritis

"Bone on bone" describes severe cartilage loss on imaging, but it doesn't tell you how much it limits your life — and many people with striking X-rays have surprisingly manageable symptoms, while others with milder imaging changes are significantly limited. Joint replacement is appropriate when pain and function are substantially affecting quality of life despite a genuine trial of conservative care. The strongest evidence-based treatment available is progressive exercise, and studies show even advanced knee OA responds meaningfully to a structured strengthening program.

The evidence says the opposite. Loading cartilage with appropriate exercise maintains its health; prolonged inactivity causes cartilage to thin and atrophy. A 2022 study in Arthritis & Rheumatology found that people with knee OA who walked regularly were significantly less likely to develop worsening pain over time. The guideline from both the American College of Rheumatology and OARSI is clear: exercise is a core treatment, not something to avoid. Mild discomfort during activity that settles within an hour afterward is generally acceptable.

OA is an active biological process, not simple mechanical wear. The muscles around the knee, your movement patterns, and your body weight all influence how the joint is loaded — which means there are meaningful levers to pull before considering surgery. Quadriceps weakness, for example, directly increases compressive force on the joint and worsens pain; rebuilding it reliably reduces both. X-ray findings and symptom severity correlate poorly, which underscores that the joint itself isn't the whole story.

Cortisone injections can provide useful short-term pain relief — typically 4 to 8 weeks — which can be valuable to break a pain cycle or allow someone to participate in rehabilitation. Evidence for hyaluronic acid (viscosupplementation) injections is more mixed, with modest benefits at best. Neither replaces exercise as the foundation of management, and repeated cortisone injections over time may have negative effects on cartilage. They're most useful as a bridge, not as a long-term strategy.

Strengthen your quadriceps — consistently and progressively. The quad is the primary shock absorber for the knee, and weakness allows greater compressive joint loading with every step. Multiple systematic reviews identify quadriceps strengthening as the strongest evidence-based intervention for reducing pain and improving function in knee OA. Even a 10 to 15% improvement in quad strength produces clinically meaningful pain reduction. Weight management, if relevant, is the other evidence-backed intervention with the broadest impact.