The surgery itself usually lasts between one and two hours

The actual time your surgeon spends operating on your knee—from the first incision to the final stitch—typically falls between 60 and 120 minutes. Most procedures land closer to 90 minutes. The exact length depends on your anatomy, whether you have arthritis damage in multiple compartments of the knee, and how straightforward your bone structure is for the surgeon to work with.

What matters more than the surgery time alone is the total time you spend in the operating room. You'll arrive 30 to 60 minutes before the surgeon begins, during which nurses position you, insert a catheter, and the anesthesiologist administers anesthesia. After the surgeon finishes, another 15 to 30 minutes goes to closing the incision and moving you to recovery. Plan on being in the operating room for roughly three to four hours total.

Key Takeaways

  • The actual surgical procedure takes between one and two hours, with most knee replacements completed in about 90 minutes.
  • You will spend three to four hours in the operating room when you include preparation, surgery, and initial recovery time.
  • Your surgeon's experience and your individual anatomy affect how long the procedure takes, but this does not necessarily change the outcome.
  • Recovery from anesthesia takes one to two hours after surgery ends, and you will not go home the same day unless your hospital offers same-day discharge.
  • Full physical recovery takes three to six months, though most people walk without information within four to six weeks.

What happens before the surgeon makes the first cut

You arrive at the surgical center or hospital one to two hours before your scheduled surgery time. A nurse will check your vital signs, review your medical history one more time, and have you change into a surgical gown. An IV line goes into your arm so the anesthesiologist can administer fluids and medications.

The anesthesiologist will meet with you to discuss which type of anesthesia you'll receive—usually general anesthesia (you're fully asleep) or regional anesthesia (your leg is numb but you're sedated). This conversation and the actual administration of anesthesia can take 20 to 30 minutes. Once you're under, the surgical team positions your leg, cleans the surgical site with antiseptic solution, and drapes the area with sterile sheets. This setup takes another 10 to 15 minutes.

The steps the surgeon performs during the operation

Your surgeon makes an incision down the front of your knee, usually 8 to 10 inches long. They then remove the damaged cartilage and bone from the end of your femur (thighbone) and tibia (shinbone). This part of the procedure takes roughly 20 to 30 minutes and involves using specialized cutting guides to shape the bone surfaces to exact measurements.

Next, the surgeon cements the metal components of the artificial knee onto the prepared bone surfaces. These components include a metal cap for the femur, a metal and plastic spacer for the tibia, and sometimes a plastic button for the kneecap. Cementing and positioning these pieces takes another 20 to 30 minutes. The surgeon then tests the knee's range of motion and stability before closing the incision with sutures or staples, a process that takes 10 to 15 minutes.

If you're having a more complex procedure—such as a revision (replacing a previous artificial knee) or a knee replacement combined with other joint work—expect the total time to stretch toward the upper end or beyond the typical range. Your surgeon will tell you before the operation if your case is likely to take longer.

Recovery time in the operating room and when ready after

Once the surgeon finishes, you move to the post-anesthesia care unit (PACU), sometimes called the recovery room. You'll spend one to two hours here while anesthesia wears off. Nurses monitor your heart rate, blood pressure, oxygen level, and pain. You may feel groggy, cold, or nauseous—all normal responses to anesthesia. Most people are alert enough to speak and move their toes within 30 to 45 minutes.

During this time, a nurse will help you do gentle ankle pumps and knee bends to prevent blood clots. You'll receive pain medication if needed. If you're having same-day discharge (which some hospitals now offer for knee replacement), you'll move to a discharge area after PACU. If you're staying overnight, you'll be moved to a hospital room once you're stable and alert enough to move safely.

Hospital stay length varies by your situation and facility

Most people stay in the hospital for one to three days after knee replacement. Some facilities discharge patients the same day if they meet certain criteria: stable vital signs, adequate pain control with oral medication, ability to walk with a walker or crutches, and a caregiver at home for the first 24 hours. Same-day discharge is becoming more common but is not available everywhere.

If you stay overnight, you'll work with a physical therapist on the day of surgery or the next morning. They'll have you sit up in bed, dangle your legs, and practice standing and walking short distances. This early movement reduces the risk of blood clots and stiffness. You'll also receive blood-thinner medication (either injected or oral) to prevent clots, and compression stockings to wear on your legs.

Before you leave the hospital, you'll receive instructions on wound care, medication schedules, activity restrictions, and when to schedule your first outpatient physical therapy session. Most people begin outpatient therapy within one to two weeks of surgery.

The weeks and months after you go home

The first two weeks at home focus on managing swelling and pain, keeping your incision clean and dry, and doing prescribed exercises. You'll likely use crutches or a walker and ice your knee several times a day. Your surgeon will want to see you for a follow-up visit around two weeks after surgery to check your incision and range of motion.

Physical therapy continues for three to six months. Most people can walk without information by four to six weeks and return to light activities like driving (once off pain medication) by six to eight weeks. Returning to higher-impact activities like hiking or recreational sports typically takes four to six months, and some people continue improving for up to a year.

Pain and swelling usually peak around day three to five after surgery, then gradually improve. Expect some swelling to persist for several months, especially if you overdo activity. This is normal and does not mean something went wrong.

Factors that can make surgery take longer than average

Revision surgery—replacing an artificial knee that has worn out or failed—takes longer than a first replacement, often 90 minutes to two hours or more. Your surgeon must remove the old components, which may be cemented firmly to your bone, and prepare the bone surface for new implants.

Severe arthritis that has damaged multiple compartments of your knee, significant bone loss, or unusual bone anatomy can also extend surgical time. If you have had previous knee surgery, scar tissue may need to be removed, adding time. Obesity and certain medical conditions that affect bone quality may also lengthen the procedure.

Your surgeon will discuss your individual situation before surgery and let you know if they expect your operation to take longer than the standard timeframe. A longer surgery time does not automatically mean a worse outcome—it straightforward reflects the complexity of your particular knee.

Frequently Asked Questions

Can I eat or drink before knee replacement surgery?

No. You'll receive instructions to stop eating solid food at midnight the night before surgery and stop drinking clear liquids a few hours before your procedure. This prevents complications from anesthesia. Your surgical team will tell you the exact cutoff times when they call you the day before surgery.

Will I be awake during the surgery?

Not if you receive general anesthesia, which is most common. You'll be fully asleep and won't remember anything. Some people receive regional anesthesia (spinal or epidural) combined with sedation, meaning your leg is numb but you're drowsy. Your anesthesiologist will discuss which option is best for you.

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

Your surgical team will adjust the procedure as needed to keep you safe. If unexpected complications arise—such as severe bone loss or an infection discovered during surgery—your surgeon may need additional time. They will discuss any changes with you after you wake up.

How soon after surgery can I drive?

Most surgeons recommend waiting four to six weeks before driving, and only once you've stopped taking prescription pain medication and can bend your knee enough to operate the pedals safely. Check with your surgeon, as the timeline depends on your healing and which pain medications you're taking.

Is it normal to feel tired for weeks after knee replacement?

Yes. Anesthesia, surgery, and the physical work of healing all drain your energy. Most people feel fatigued for two to four weeks after surgery. Rest, good nutrition, and gradual increases in activity help. Contact your surgeon if fatigue persists beyond six weeks or worsens suddenly.