The surgery itself takes one to three hours
Knee replacement surgery usually lasts between 60 and 120 minutes once you are in the operating room. The exact time depends on whether you are having a total knee replacement (both sides of the joint) or a partial one (one side only), how complex your anatomy is, and whether the surgeon finds unexpected damage once they open the knee.
Total knee replacements typically run longer than partial ones. A partial replacement might take 45 minutes to an hour, while a total replacement usually takes 90 minutes to two hours. If you have had previous knee surgery, arthritis in multiple areas, or bone that is harder to work with, your surgery may take closer to the upper end or slightly beyond.
The time in the operating room does not include the time you spend in pre-op getting anesthesia and being prepped, or the time in recovery afterward. Plan to be at the hospital or surgery center for four to six hours total on surgery day.
Key Takeaways
- The surgery itself takes one to three hours depending on whether it is partial or total and how straightforward your anatomy is.
- You will spend four to six hours at the facility on surgery day when you add pre-op, the procedure, and recovery time.
- Most people go home the same day or stay one night, though some facilities keep patients overnight as standard practice.
- Physical therapy starts within days and continues for three to six months before you reach maximum improvement.
- Return to normal activities like driving and work takes four to six weeks; full recovery can take six months to a year.
Hospital stay: same day or overnight
Many knee replacements are done as outpatient surgery, meaning you go home the same day. This is standard at most surgery centers and increasingly common at hospitals. You will need someone to drive you home because anesthesia affects your judgment and reflexes for the rest of the day.
Some hospitals keep patients overnight as routine practice, and your surgeon may recommend an overnight stay if you live alone, have other health conditions, or had complications during surgery. If you are staying overnight, you will begin physical therapy the next morning before discharge.
Whether you go home the same day or stay overnight, you will leave with pain medication, instructions for wound care, and a schedule for physical therapy. Your surgeon will see you in the office one to two weeks after surgery to check the incision and review your progress.
The first two weeks: managing pain and swelling
The first 14 days after surgery are focused on controlling pain and swelling so you can start moving the knee. You will ice the knee, keep it elevated, and take pain medication as prescribed. Most people need prescription-strength pain relief for the first week or two, then switch to over-the-counter options.
Swelling peaks around day three to five and gradually decreases over the next two weeks. Your physical therapist will visit you at home or you will go to a clinic to begin gentle range-of-motion exercises. These sessions are short — usually 20 to 30 minutes — but happen several times a week.
You will not be able to put full weight on the leg when ready. Most people use crutches or a walker for the first one to two weeks, then transition to a cane as swelling decreases and strength returns. Your therapist will tell you when it is safe to stop using assistive devices.
Physical therapy: three to six months of active work
Physical therapy is the largest factor in how quickly you recover. You will attend sessions two to three times per week for the first four to six weeks, then one to two times per week for another two to three months. Some people continue therapy longer if they are not meeting their goals.
Early therapy focuses on bending and straightening the knee. Later sessions add strengthening exercises for the muscles around the knee and hip, balance work, and functional activities like stairs and walking. By three months, most people have regained enough strength and range of motion to return to light activities.
How hard you work in therapy directly affects your timeline. People who do their home exercises between sessions and push themselves in therapy recover faster than those who attend sessions passively. Your therapist will give you exercises to do at home on days you do not have a scheduled session.
Returning to driving, work, and daily activities
You can usually return to driving four to six weeks after surgery, once you have stopped taking prescription pain medication and have enough strength and range of motion to operate the pedals safely. Check with your surgeon before you drive — some recommend waiting until you can bend the knee to 90 degrees and have good control.
Returning to work depends on your job. Desk work can often resume four to six weeks after surgery. Jobs that require standing, walking, or physical labor may take eight weeks or longer. Your surgeon can write a note describing your restrictions so you can discuss a return-to-work timeline with your employer.
Light activities like walking, swimming, and stationary cycling can usually resume six to eight weeks after surgery. High-impact activities like running, jumping, or contact sports typically take four to six months or longer. Some people never return to high-impact activities, and your surgeon can discuss what is realistic for your situation.
Full recovery: six months to one year
Most people reach maximum improvement between six months and one year after surgery. At six months, you should have good strength, full or near-full range of motion, and be able to do most daily activities without limitation. Pain should be minimal or gone.
Some swelling and stiffness can persist for several months, especially if you are on your feet a lot. Wearing compression socks or an elastic sleeve can help manage swelling. If swelling or stiffness is not improving by three months, tell your surgeon — sometimes additional therapy or other interventions can help.
A small number of people experience ongoing stiffness or limited range of motion even after a year. This is more common if you had limited motion before surgery or if you did not do physical therapy consistently. Your surgeon can discuss options if this happens.
Factors that speed up or slow down recovery
Your age, overall health, and strength before surgery affect how quickly you recover. Younger, healthier people with good muscle tone tend to recover faster. People with other conditions like diabetes, heart disease, or obesity may recover more slowly.
How much you move and exercise matters enormously. People who do physical therapy consistently and push themselves appropriately recover faster and with better outcomes. People who avoid movement because of fear or pain tend to develop stiffness and take longer to regain function.
Complications like infection, blood clots, or excessive swelling can extend recovery by weeks or months. These are uncommon, but your surgeon will give you warning signs to watch for and instructions on when to call. Following post-op instructions about wound care, compression, and elevation reduces the risk of complications.
Frequently Asked Questions
Can I have both knees replaced at the same time?
Yes, some surgeons perform bilateral knee replacements in a single surgery session, though this is less common than doing one knee at a time. Bilateral surgery takes longer overall and requires more recovery time, but some people prefer it to avoid two separate surgeries and recovery periods. Discuss this option with your surgeon based on your health and preferences.
When can I shower or bathe after surgery?
Most surgeons allow showering once the incision has closed, usually around two weeks after surgery. Your surgeon will tell you when it is safe. Until then, you can wash around the incision with a damp cloth. Avoid soaking the incision in a bath or hot tub until your surgeon clears it, usually four to six weeks after surgery.
What if I am not improving as fast as expected?
Tell your surgeon if you are not meeting the milestones your therapist outlined — for example, if you cannot bend the knee to 90 degrees by six weeks or if swelling is not decreasing. Sometimes additional therapy, manual techniques, or other interventions can help. Waiting and hoping usually does not improve slow progress.
Can I fly after knee replacement surgery?
Most surgeons clear patients to fly four to six weeks after surgery, once swelling has decreased and you can walk without crutches. Long flights increase the risk of blood clots, so ask your surgeon about compression socks and whether you should take blood thinners. Get up and walk every hour or two during the flight.
Will my new knee set off airport security?
Metal implants can trigger metal detectors. Tell security you have a knee replacement and they will usually hand-scan you instead. You can also ask your surgeon for a card documenting the implant to carry with you, though it is not required.