A total knee replacement (TKR) is a common and highly effective surgical procedure to alleviate pain and restore function in a severely damaged knee joint, typically due to advanced arthritis. When people ask, “How long is a knee replacement?” the answer spans several distinct time frames. The total duration includes the time spent in the operating room, the immediate hospital recovery, the extended period of rehabilitation, and the ultimate lifespan of the artificial joint itself. Understanding these separate phases helps set realistic expectations for the entire journey back to mobility.
Duration of the Procedure
The actual time spent performing the total knee replacement surgery, measured from the initial incision to the final closing of the skin, is relatively short. Most total knee arthroplasty procedures take between one and two hours to complete, with an average operative time of around 90 minutes. This period is dedicated to removing the damaged bone and cartilage, preparing the bone surfaces, and implanting the metal and plastic prosthetic components.
The overall time a patient spends in the operating suite is longer, as it includes the administration of anesthesia and the careful setup of the sterile field. The complexity of the case, such as the severity of the joint deformity or the patient’s anatomy, can influence the duration of the operation.
Hospital Stay and Initial Recovery
Following the surgery, the focus immediately shifts to pain management and early mobilization, which dictates the length of the hospital stay. Recent advancements in surgical techniques and pain protocols, often referred to as “fast-track” recovery, have reduced the typical stay to between one and three days, with some healthy, well-prepared patients even being considered for same-day discharge.
The first attempts at movement are a major recovery milestone and often occur within 24 hours of the procedure. Patients are encouraged to walk short distances with the aid of a walker or crutches to prevent complications, such as blood clots, and to initiate physical rehabilitation. Discharge criteria involve demonstrating the ability to safely move with an assistive device, manage pain using oral medication, and perform basic self-care tasks.
Milestones of Long-Term Rehabilitation
The longest and most variable phase of the process is the long-term rehabilitation period following discharge from the hospital. Full recovery is measured in a series of functional milestones reached over several months. The initial phase, covering the first four to six weeks, is focused on intensive physical therapy to regain a functional range of motion and reduce post-operative swelling. From one to three months post-surgery, patients work on strengthening the muscles surrounding the new joint and gradually transitioning away from assistive devices like canes.
During this time, many people can resume light daily activities, such as driving, once they are off narcotic pain medication. The period between three and six months is characterized by continued strength training and the resumption of most low-impact recreational activities, including swimming or cycling. By the six-month mark, most patients experience a substantial reduction in pain and a significant increase in functional mobility. The final phase of recovery lasts from six months up to a full year, during which the joint’s function stabilizes and the patient reaches their maximum possible improvement.
Longevity of the Replacement Joint
While the recovery timeline lasts up to a year, the artificial knee joint itself is designed to function for decades. Modern total knee replacement implants demonstrate excellent long-term survival rates, offering a durable solution for patients. Data from national joint registries indicate that 90% to 95% of total knee implants are still functioning well 10 years after surgery.
This impressive durability extends further, with approximately 82% of total knee replacements continuing to perform successfully 25 years after the initial procedure. The longevity of the implant is influenced by factors such as the patient’s weight, their level of activity, and the quality of the surgical technique and materials used. Younger patients who undergo the procedure face a higher lifetime risk of needing a revision surgery simply because their longer life expectancy increases the time the implant is subjected to wear and tear.