Knee replacement surgery typically takes 1 to 2 hours from the first incision to closing. That’s the time you’re actually on the operating table, but your full day at the hospital will be considerably longer once you factor in pre-operative preparation, anesthesia, and post-surgical monitoring. Here’s what to expect for every phase of the process.
Time in the Operating Room
The surgical procedure itself runs between 60 and 120 minutes for a standard total knee replacement. Most cases fall right around the middle of that range. During the operation, the surgeon removes damaged cartilage and bone from the knee joint and fits metal and plastic components in their place. A partial (unicompartmental) replacement, which resurfaces only one side of the knee, can sometimes be completed in under an hour since less bone needs to be removed and the incision is smaller.
Robot-assisted knee replacements have become increasingly common, though they do add a few minutes. Cleveland Clinic data shows manual surgery averages about 105 minutes of operative time compared to 113 minutes for robot-assisted procedures. That 8-minute difference is measurable but unlikely to affect your experience in any meaningful way. The choice between the two approaches is better made based on precision and outcomes than on time saved.
Your Full Day at the Hospital
Plan for 4 to 6 hours at the surgical facility on the day of your procedure. Before surgery, you’ll spend roughly 1 to 2 hours getting checked in, changing into a gown, having an IV placed, and meeting with your anesthesiologist. After surgery, you’ll be in a recovery room for another 1 to 2 hours while the anesthesia wears off and nursing staff monitor your vital signs, pain levels, and initial movement.
Most people stay in the hospital for 1 to 2 days after knee replacement surgery. During that time, a physical therapist will visit your room, often within hours of the procedure, to help you stand and take your first steps with a walker. In some cases, patients go home the same day as surgery. Same-day discharge is more common for younger, healthier patients undergoing partial replacements, and it requires having a solid support system at home.
What Affects How Long Surgery Takes
Several factors can push your procedure toward the shorter or longer end of the range:
- Severity of joint damage. A knee with significant bone loss, prior fractures, or severe deformity requires more careful preparation of the bone surfaces, which adds time.
- Body weight. Higher body weight can make it harder for the surgeon to access the joint, extending the procedure.
- Type of replacement. A partial replacement is faster than a total replacement. A revision surgery, where an old implant is removed and replaced, takes longer than a first-time procedure, sometimes 2 to 3 hours.
- Surgeon experience. High-volume surgeons who perform hundreds of knee replacements per year tend to operate more efficiently.
Recovery Timeline After Surgery
The surgery itself is the shortest part of the entire process. Recovery unfolds over weeks and months, and knowing the general timeline helps you plan your life around it.
In the first 2 weeks, your focus is on wound healing, managing swelling, and performing basic exercises at home. Most people use a walker or crutches during this period. By weeks 3 to 6, you’ll typically transition to a cane and notice significant improvements in mobility. Physical therapy, usually two to three sessions per week, is the single most important factor in how well your knee recovers.
If you have a desk job, you can generally return to work within 2 to 4 weeks. Physically demanding jobs that involve lifting, climbing, or prolonged standing require 3 to 6 months before a safe return, and sometimes longer. Driving is usually possible again at 4 to 6 weeks, depending on which knee was replaced and whether your car is an automatic.
Most people feel noticeably better than before surgery by the 3-month mark, though continued improvement is common up to a full year. The stiffness and soreness that linger in the early months gradually fade as the tissues around the new joint heal and strengthen.
How Long a Knee Replacement Lasts
Modern knee implants are remarkably durable. Registry data tracking tens of thousands of patients shows that 93% of total knee replacements are still functioning well at 15 years. At 20 years, that number is 90%. Even at 25 years, over 82% of total knee replacements have not needed revision surgery. Partial replacements don’t last quite as long, with about 70% still intact at 25 years, partly because younger, more active patients tend to receive them.
For most people getting a knee replacement in their 60s or 70s, the implant will likely last the rest of their life. If you’re younger when you have the surgery, there’s a higher chance you may eventually need a revision, but advances in implant materials continue to extend their lifespan.