More than 790,000 total knee replacements are performed in the United States each year, making it one of the most common elective orthopedic procedures, according to the American Academy of Orthopaedic Surgeons. A knee replacement resurfaces a worn-out joint with metal and polyethylene components, and most patients return to walking, gardening, and low-impact recreation within a few months. The decision is rarely urgent, but waiting too long can make recovery slower. This guide walks through how the surgery is done, what realistic recovery looks like, and how to weigh whether total knee arthroplasty fits your situation.
What Knee Replacement Is and Who Needs It
Total knee arthroplasty (TKA) replaces the damaged surfaces of the femur, tibia, and often the patella with prosthetic components. Surgeons may use a partial (unicompartmental) replacement when only one section of the joint is worn, but the total version is far more common. The procedure is almost always performed for end-stage osteoarthritis, although rheumatoid arthritis, post-traumatic arthritis, and avascular necrosis are other indications listed by the Mayo Clinic.
Surgeons usually consider the procedure when conservative measures have failed. That means physical therapy, weight management, NSAIDs, corticosteroid or hyaluronic acid injections, and bracing have stopped controlling pain or preserving function. If you can no longer climb a flight of stairs, sleep through the night, or walk a few blocks without significant pain, the joint may be a candidate. For broader context on degenerative joint disease and its progression, see our Medical Conditions guide.
How the Procedure Is Performed
Most knee replacements take 60 to 120 minutes in the operating room. Anesthesia is typically a spinal or epidural block paired with sedation, although general anesthesia remains an option. Once you are positioned and the leg is prepped, the surgeon makes a 6 to 10 inch incision over the front of the knee, displaces the kneecap, and removes a few millimeters of damaged cartilage and bone from the femur and tibia. Precision cutting guides, sometimes assisted by robotic platforms, shape the bone to fit the implant.
The femoral component is metal, the tibial tray is metal with a polyethylene insert, and the patella is often resurfaced with a plastic button. Components are either cemented in place or designed for biological ingrowth. Surgeons close the joint capsule, place a drain in some cases, and finish with sutures or staples. Many hospitals now perform knee replacement as outpatient or 23-hour surgery, with discharge the same or next day, per Cleveland Clinic.
Preparation and What to Expect on the Day
Pre-surgery preparation usually starts four to six weeks out. Expect a medical clearance visit, blood work, an EKG if you are over 50 or have cardiac risk factors, and dental clearance to reduce infection risk. Many surgeons prescribe a “prehab” program of quadriceps and hip strengthening, since stronger muscles before surgery shorten recovery. You will also be asked to stop blood thinners, NSAIDs, and certain supplements one to two weeks before the operation.
On surgery day, plan for several hours at the hospital or surgery center even if you are going home that day. After the operation, a physical therapist will get you out of bed within a few hours, walking with a walker. Pain control combines a multimodal approach: acetaminophen, short-course opioids, NSAIDs if appropriate, and sometimes a peripheral nerve block. Most patients are surprised by how soon they bear weight.
Recovery Timeline and Rehab
The first two weeks focus on swelling control, walking with an assistive device, and regaining range of motion. Outpatient or home physical therapy typically starts within a week. By four to six weeks, most patients walk without a cane indoors and have driven a car if the operated leg is the right side and they are off opioids. Sleep often remains disrupted for the first month because of position-dependent discomfort.
By three months, most patients are back to nearly all daily activities, and many are golfing, biking, or walking longer distances. Final recovery, including the resolution of stiffness and occasional warmth around the joint, can take 9 to 12 months. Range of motion gains taper after the first three months, so consistent rehab in those early weeks matters. AAOS guidance recommends avoiding high-impact activities like running and singles tennis to extend implant life.
Risks, Complications, and Outcomes
Serious complications are uncommon but real. Mayo Clinic cites infection in 1 to 2 percent of cases, deep vein thrombosis in roughly 1 to 3 percent despite prophylaxis, and stiffness requiring manipulation in about 2 to 5 percent. Other risks include nerve or vessel injury, periprosthetic fracture, and ongoing pain of unclear origin. Implant loosening or wear can require revision surgery, although AAOS data suggest 90 to 95 percent of modern knee replacements last at least 15 years.
When to seek emergency care: Call 911 or go to the nearest emergency room if you experience sudden severe shortness of breath or chest pain (signs of pulmonary embolism), calf swelling and pain (DVT), heavy bleeding from the incision, increasing redness with fever above 101 F, or a fall with a sudden inability to bear weight on the operated leg.
Alternatives and When Surgery May Not Be Needed
Knee replacement is rarely an urgent decision, and several alternatives can buy years of function. Weight loss alone reduces joint loading by roughly four pounds for every one pound shed, per NIAMS. Physical therapy targeting hip and core strength offloads the medial knee compartment. Corticosteroid injections offer weeks to months of relief, while hyaluronic acid injections have more variable evidence. For younger patients with isolated medial wear, a unicompartmental replacement or a high tibial osteotomy may be considered before a full TKA.
If your imaging shows arthritis but your function is still good, watchful waiting is reasonable. Some patients also benefit from a meniscus surgery or diagnostic knee arthroscopy when a mechanical symptom such as locking is present alongside arthritis, although arthroscopy is no longer recommended as a treatment for arthritis itself.
Cost Considerations
The total billed cost of a knee replacement in the United States typically ranges from about $30,000 to $70,000 without insurance, depending on geography, hospital system, and implant choice. Medicare’s average payment is closer to $11,000 to $14,000 because of negotiated rates. Out-of-pocket costs for insured patients commonly fall between $1,500 and $5,000 after deductible and coinsurance. Bundled payment programs, ambulatory surgery centers, and direct-to-employer contracts have lowered prices significantly in some markets. Our healthcare costs guide covers strategies for shopping surgical pricing and using HSA dollars effectively.
Frequently Asked Questions
How long does a knee replacement last?
Modern total knee replacements last 15 to 20 years in 80 to 90 percent of patients, according to AAOS registry data. Younger and heavier patients tend to wear implants faster. Revision surgery is more complex than the primary procedure, which is one reason surgeons often delay TKA in patients under 60.
How painful is recovery from knee replacement?
Pain peaks in the first one to two weeks and then steadily improves. Multimodal pain control, including nerve blocks and non-opioid medications, has cut opioid use in half compared with a decade ago. Most patients are off prescription pain medication by four to six weeks.
Can I kneel after a knee replacement?
Kneeling is safe but often uncomfortable because the soft tissue over the implant is thinner. About half of patients can kneel without issue at one year, while others find it permanently awkward. Kneeling does not damage the implant.
How soon can I drive after surgery?
Most patients drive again two to six weeks after a right knee replacement once they are off opioids and can perform an emergency stop. Left knee replacement patients with automatic transmissions often drive at one to two weeks.
The Bottom Line
A knee replacement is one of the most successful operations in modern medicine, but it is also a planned commitment that requires honest self-assessment. The right time to discuss surgery with an orthopedic surgeon is when knee pain has narrowed your life, conservative care has plateaued, and imaging matches your symptoms. Ask about implant choice, discharge plans, expected hospital stay, and the surgeon’s annual volume. If you are also evaluating a hip replacement or comparing approaches with a shoulder replacement, the same questions apply: surgeon experience, infection rates, and a clear rehab plan are what consistently predict good outcomes.