The surgery itself usually takes 1 to 3 hours

A total knee replacement surgery typically lasts between 60 and 180 minutes, with most procedures finishing in the 90-minute range. The exact time depends on your anatomy, the complexity of your knee damage, whether you have had previous knee surgery, and how quickly your surgeon works. A straightforward replacement on a first-time patient often takes closer to 90 minutes. A revision surgery — replacing a knee that was already replaced — or a knee with severe bone loss or deformity can stretch to 2.5 or 3 hours.

The surgeon removes the damaged cartilage and bone from your femur, tibia, and kneecap, then cements or presses metal and plastic components into place. Alignment and balance matter enormously, so your surgeon will spend time getting the positioning exact. Once the implant is find, the surgical team closes the incision in layers — muscle, tissue, and skin — which adds another 20 to 30 minutes to the total time in the operating room.

Key Takeaways

  • The actual surgery runs 1 to 3 hours, with 90 minutes being typical for a first-time knee replacement.
  • You will spend 2 to 4 hours in the recovery room after surgery while anesthesia wears off and nurses monitor your vital signs.
  • Most people go home the same day or stay one night; hospital stays longer than 48 hours are now uncommon unless you have other health conditions.
  • Physical therapy begins within 24 hours and continues for weeks or months, which is where the real time investment happens.
  • Full recovery and return to normal activity typically takes 3 to 6 months, though some improvement continues for up to a year.

Recovery room time adds another 2 to 4 hours

After the surgeon closes the incision, you move to the recovery room (also called post-anesthesia care unit, or PACU) while the anesthesia wears off. This phase usually takes 2 to 4 hours. Nurses monitor your heart rate, blood pressure, oxygen level, and pain. They will wake you gradually, check that you can move your toes and ankle, and start you on pain medication if needed.

During this time, a physical therapist may visit you to begin gentle movement — often just bending and straightening your knee a few degrees. This early motion reduces stiffness and blood clots. You will also receive compression stockings or a sequential compression device (a sleeve that inflates and deflates around your leg) to prevent clots from forming.

Hospital stay: same day or one night

Most total knee replacements are now done as outpatient procedures, meaning you go home the same day. You will need someone to drive you home and stay with you for at least the first 24 hours because anesthesia impairs judgment and coordination. Some surgeons keep patients overnight for observation, particularly if you live far away, have other medical conditions, or had complications during surgery.

If you do stay overnight, discharge usually happens the morning after surgery. Before you leave, the surgical team will confirm you can get in and out of a chair, walk a few steps with a walker or crutches, and manage stairs if needed. They will also give you written instructions for wound care, medication, activity restrictions, and when to call the surgeon.

Physical therapy starts within 24 hours and continues for months

The time in the operating room is short compared to the rehabilitation that follows. Physical therapy typically begins within 24 hours of surgery — sometimes while you are still in the hospital or at home the next day. A therapist will visit your home or you will travel to an outpatient clinic, usually 2 to 3 times per week for the first 4 to 6 weeks.

Early sessions focus on reducing swelling, restoring range of motion (bending and straightening), and building strength in the muscles around your knee. You will do exercises at home on the days you do not see the therapist. As weeks pass, therapy becomes more challenging — walking longer distances, climbing stairs, and eventually returning to activities like light gardening or golf. Most people continue some form of therapy or home exercise for 3 to 6 months.

Pain and swelling peak in the first 2 weeks

The first two weeks after surgery are the most uncomfortable. Pain is usually worst on days 2 through 5, then gradually improves. Swelling peaks around day 3 to 5 and can last 6 to 8 weeks. You will take pain medication as prescribed — typically opioids for the first week or two, then over-the-counter pain relievers as you improve. Ice, elevation, and compression all help reduce swelling.

Most people can walk with a walker or crutches within a few days and transition to a cane by week 2 or 3. Driving is usually safe after 4 to 6 weeks, once you can bend your knee enough to sit comfortably and your reflexes are sharp. Return to work depends on your job — desk work may be possible in 2 to 3 weeks, while jobs requiring standing or walking take longer.

Full recovery takes 3 to 6 months for most activities

By 6 weeks, most people are walking without a cane and have regained a good range of motion. By 3 months, strength is improving noticeably and you can do most daily tasks without thinking about your knee. However, the knee continues to improve for up to a year. Swelling may linger, and some people notice their knee feels stiff in the morning or after sitting for a long time.

Return to sports or high-impact activities — running, tennis, skiing — is typically cleared around 4 to 6 months, though some surgeons recommend waiting longer. Low-impact activities like swimming, cycling, and walking are usually safe by 8 to 12 weeks. Your surgeon will give you specific clearance based on your progress in therapy and your individual healing.

What slows down recovery

Some factors make recovery take longer. Age over 75, obesity, diabetes, heart or lung disease, and previous knee surgery all slow healing. If you develop an infection, blood clot, or stiffness, you may need additional treatment and longer therapy. Smoking delays wound healing and increases infection risk. Poor physical therapy compliance — skipping sessions or not doing home exercises — is one of the most common reasons people recover slowly.

Mental readiness also matters. People who expect a quick return to normal often become frustrated and stop therapy early, which leads to stiffness and weakness. Those who understand recovery takes months and commit to therapy tend to have better outcomes and return to activities sooner.

Frequently Asked Questions

Can I have both knees replaced at the same time?

Yes, bilateral knee replacement is possible and some surgeons perform both in one session, which takes 3 to 4 hours total. Others prefer to do them separately, a few weeks apart. Same-day bilateral surgery reduces total anesthesia exposure and recovery time but is more physically demanding. Your surgeon will recommend based on your age, health, and bone quality.

When can I go back to work?

Desk work is often possible in 2 to 3 weeks. Jobs requiring standing, walking, or manual labor typically take 6 to 12 weeks. Your surgeon will clear you based on your pain level, range of motion, and strength — not on a calendar. Many people return part-time before going full-time.

Will my knee ever feel completely normal?

Most people report their replaced knee feels nearly normal by 6 to 12 months. You may notice occasional stiffness, swelling after activity, or a slight awareness of the implant. A small number of people experience persistent swelling or stiffness, which may require additional therapy or, rarely, a second surgery to improve motion.

How long do I need to use a walker or crutches?

Most people use a walker for 1 to 2 weeks, then switch to a cane for another 2 to 4 weeks. Some people are off all assistive devices by week 4 or 5. Your physical therapist will tell you when it is safe to stop based on your strength and balance, not on a fixed timeline.

What happens if I do not do physical therapy?

Skipping therapy significantly increases the risk of stiffness, weakness, and a poor outcome. Without active motion and strengthening, your knee may not bend far enough to climb stairs or walk normally. Some people develop permanent stiffness that requires a second procedure to improve. Therapy is not optional — it is the most important part of recovery.