The surgery itself takes 1 to 2 hours, but you'll spend 3 to 4 hours at the surgical facility

The actual cutting and implanting takes about 60 to 90 minutes. Your surgeon removes the damaged cartilage and bone from your knee, then positions the metal and plastic implant pieces. The time varies based on your anatomy, how much bone needs to be removed, and whether your surgeon encounters unexpected damage inside the joint.

The full surgical day is much longer. You arrive 1 to 2 hours before surgery for check-in and anesthesia preparation. After the operation ends, you spend 1 to 2 hours in the recovery room waking up from anesthesia and being monitored for bleeding or other when ready problems. Most people go home the same day or stay one night; if you stay overnight, discharge happens the next morning.

Key Takeaways

  • The surgery itself lasts 60 to 90 minutes, but plan for 3 to 4 hours total at the surgical facility including prep and recovery.
  • Most knee replacements are same-day procedures, meaning you go home the same afternoon or evening, though some patients stay one night.
  • Recovery at home takes 3 to 6 weeks before you can walk without a walker or crutches, and 3 to 6 months before you return to normal activities.
  • Physical therapy starts within days of surgery and continues for 6 to 12 weeks to restore strength and range of motion.
  • Full healing of the bone and soft tissue around the implant takes 12 months, even though you feel much better after 3 months.

What happens in the operating room minute by minute

Once you're asleep, the surgeon cleans your knee with antiseptic and drapes it with sterile cloth. They make an 8 to 10 inch cut down the front of your knee, moving the kneecap to the side to reach the joint underneath. This takes about 10 to 15 minutes.

Next comes bone removal. The surgeon uses a saw to cut away the damaged cartilage and bone from the end of your thighbone and the top of your shinbone. They measure and align these cuts carefully so the implant pieces sit at the correct angle. This step takes 20 to 30 minutes and is where most of the variation happens—if your bone is very damaged or your anatomy is unusual, it takes longer.

Once the bone is prepared, the surgeon tests the fit of the implant pieces without cementing them. They check that your knee bends and straightens smoothly and that the alignment is correct. If adjustments are needed, they make them now. Then they cement the metal pieces to your bone, position the plastic spacer between them, and attach the kneecap component. Cementing and final positioning takes 15 to 20 minutes.

The surgeon then closes the wound with stitches or staples, applies a sterile bandage, and you're moved to recovery. Total operating room time is usually 60 to 90 minutes from the first incision to the last stitch.

Recovery room and going home the same day

In the recovery room, a nurse monitors your heart rate, blood pressure, oxygen level, and pain. You wake up gradually from anesthesia over 30 to 60 minutes. Your leg will feel numb from the anesthesia block (if one was used) for 4 to 8 hours, which actually helps with pain control early on.

Before you leave, you need to pass several checks: your vital signs must be stable, your pain must be controlled with oral medication, you must be able to move your toes and ankle, and you must be alert enough to understand discharge instructions. Most people meet these requirements within 1 to 2 hours of waking up.

You'll go home with a walker or crutches, a compression bandage, ice packs, and pain medication. You cannot drive for at least 24 hours because of the anesthesia, so you must have someone pick you up. If you live alone or cannot manage stairs and bathroom access at home, your surgeon may recommend one night in the hospital instead.

The first 6 weeks at home: walking and physical therapy

Your goal in the first 2 weeks is to reduce swelling and start moving your knee gently. You'll ice your knee 3 to 4 times a day for 15 to 20 minutes, keep it elevated when sitting or lying down, and wear a compression stocking. You take pain medication as prescribed, usually every 4 to 6 hours for the first week, then less frequently as pain decreases.

Physical therapy starts within 3 to 5 days of surgery, either at a clinic or at home. A therapist teaches you exercises to bend and straighten your knee, strengthen your thigh muscles, and improve your balance. You do these exercises 2 to 3 times a day at home. By week 2, most people can walk 100 to 200 feet with a walker or crutches. By week 4, many can walk without an assistive device, though they tire easily.

Swelling peaks around day 3 to 5 after surgery, then gradually decreases. Some swelling remains for 3 to 6 months. Your incision heals on the surface within 2 to 3 weeks, but the deeper layers of tissue continue healing for months. You can shower once the incision is fully closed and dry, usually around day 10 to 14.

Months 2 through 6: returning to normal activities

By 6 weeks, most people walk normally without pain and can climb stairs step-over-step (rather than one step at a time). You can drive again once you're off strong pain medication and can move your knee enough to operate the pedals—usually around week 4 to 6. Check with your surgeon before driving.

Physical therapy continues 2 to 3 times a week through week 12. The focus shifts from basic movement to strength, balance, and endurance. You gradually increase walking distance, add light resistance exercises, and work on activities you want to return to—gardening, golf, hiking, or whatever matters to you.

By 3 months, most people feel nearly normal. Pain is minimal, swelling is mostly gone, and you can do most daily activities without thinking about your knee. However, your knee is still healing internally. The bone is still bonding to the implant, and scar tissue is still remodeling. This is why surgeons recommend avoiding high-impact activities like running or jumping for at least 6 months, even though you feel ready.

Full healing: what happens after 6 months

At 6 months, the bone-to-implant bond is solid, and you can return to most activities. Low-impact exercise like walking, swimming, cycling, and golf is safe. High-impact activities like running, basketball, or tennis are generally not recommended because they stress the implant and may shorten its lifespan.

Healing continues for a full 12 months. Scar tissue continues to remodel, strength continues to improve, and swelling may not fully resolve until month 9 or 10. Some people notice their knee feels slightly different or stiff on cold days even after a year—this is normal and usually improves with time.

Your surgeon will see you for follow-up visits at 2 weeks, 6 weeks, 3 months, and 1 year. X-rays at these visits check that the implant is positioned correctly and the bone is healing well. After 1 year, most people see their surgeon only if a problem develops.

Factors that make surgery take longer or shorter

A straightforward knee replacement in a person with normal anatomy and no previous knee surgery takes closer to 60 minutes. If you've had previous knee surgery, arthritis is severe, your bone is very soft or very hard, or you have unusual anatomy, surgery may take 90 minutes or longer.

Your age and overall health affect recovery speed more than surgery time. Younger people and those in good cardiovascular health often regain strength and range of motion faster. People with diabetes, heart disease, or obesity may progress more slowly through physical therapy and have more swelling.

The type of anesthesia also matters slightly. General anesthesia (you're fully asleep) and regional anesthesia (your leg is numb but you're sedated) both take about the same time in the operating room. However, regional anesthesia may allow you to wake up faster and have less nausea, which can speed up your discharge.

Frequently Asked Questions

Can I watch the surgery or have someone in the operating room with me?

No. Operating rooms are sterile environments, and only surgical staff are allowed inside. Your family can wait in a waiting area and will be updated by a nurse during surgery. Some surgeons record the procedure and can show you video afterward if you're interested.

What if something goes wrong during surgery and it takes much longer?

If the surgeon finds unexpected bone damage, infection, or other problems, surgery may take 2 to 3 hours or longer. They will contact your family to let them know. Longer surgery means more time under anesthesia and potentially more swelling afterward, but it doesn't change the basic recovery timeline significantly.

Do I have to do physical therapy, or can I just rest and let it heal?

Physical therapy is essential. Without it, your knee will become stiff and weak, and you may not regain full function. Even gentle movement in the first week prevents blood clots and stiffness. Most insurance covers physical therapy for knee replacement, and your surgeon will refer you before you leave the hospital.

How long until I can sleep normally and stop taking pain medication?

Most people stop strong pain medication by week 2 to 3 and switch to over-the-counter pain relievers as needed. Sleep improves once swelling decreases and pain is controlled—usually by week 3 to 4. Some people need a pillow under their knee for comfort for several weeks.

Will my knee ever feel completely normal again?

Most people say their knee feels 90 to 95 percent normal by 6 months. You may notice a slight difference in how it feels compared to your other knee, or mild stiffness in cold weather. These sensations usually fade over time. The implant itself has no feeling, so some people describe a subtle difference in sensation, but this doesn't affect function.