Understanding Knee Replacement Surgery

Total knee replacement (TKR), also called total knee arthroplasty, is a surgical procedure in which a damaged or worn knee joint is replaced with an artificial implant made of metal alloys, high-grade plastics, and polymers. The surgeon removes the damaged cartilage and a small amount of bone from the surface of the femur (thigh bone), tibia (shin bone), and patella (kneecap), then caps these bones with prosthetic components that replicate the smooth, gliding surface of a healthy knee. The procedure is one of the most successful operations in orthopedic medicine, with over four million performed annually worldwide.

Recovery timelines vary by patient, but here is a general guide: Most patients can walk with a walker or cane within 24 hours of surgery. Driving typically resumes within 4–6 weeks. By 6–12 weeks, most patients are managing stairs, performing light household activities, and significantly reducing pain medication. Full functional recovery — where you can walk without an aid and resume most activities — generally occurs within 3–6 months. Continued improvement in strength and comfort is common for up to 12 months post-surgery. Factors such as age, overall health, and commitment to physical therapy all influence the pace of recovery.

Good candidates for knee replacement typically have: significant knee pain that limits everyday activities, knee pain that persists while resting or during sleep, chronic knee inflammation that does not improve with rest or medication, knee stiffness that makes it difficult to bend or straighten the leg, and inadequate pain relief from other treatments such as anti-inflammatory medications, physical therapy, corticosteroid injections, or walking aids. While the procedure is most common in patients between 60 and 80 years old, age alone is not a determining factor — your surgeon will evaluate your overall health, bone quality, and lifestyle to determine candidacy. Only a qualified orthopedic surgeon can make this determination after a thorough examination.

Knee replacement is generally safe, but like all surgical procedures it carries some risks. The most common include: blood clots (deep vein thrombosis), which are prevented with blood thinners and compression stockings; infection, which occurs in approximately 1% of cases and is treated with antibiotics or, rarely, revision surgery; implant loosening over time, particularly in younger or more active patients; nerve or blood vessel injury around the knee; persistent pain or stiffness in a small percentage of patients; and reactions to anesthesia. Your surgical team will take measures to minimize all of these risks. Serious complications are uncommon — the vast majority of patients experience an uneventful recovery and excellent long-term outcomes.

Yes, knee replacement surgery is typically covered by Medicare Part A (hospital insurance) and most private health insurance plans when the procedure is deemed medically necessary. Medicare Part A covers inpatient hospital stays, while Part B may cover outpatient physical therapy during recovery. However, coverage details — including deductibles, co-pays, pre-authorization requirements, and in-network surgeon restrictions — vary significantly by plan. Some insurance plans require documented evidence that conservative treatments (physical therapy, injections, etc.) have been tried and failed before approving surgery. We strongly recommend contacting your insurance provider before proceeding and asking your surgeon's office to assist with the prior authorization process. Our free guide includes a detailed insurance checklist to help you navigate this process.