Orthopedic and movement
Recovery After Knee Replacement
Expert-reviewed guidance on recovery after knee replacement — why the first few weeks are the hardest, and why full recovery can take up to a year.
- Expert Reviewed
- Evidence Based
- Patient Focused
Recovery after knee replacement is front-loaded: the first few weeks are usually the hardest, and most of the difficult work happens early. Walking typically begins within a day of surgery, and regaining knee bend is a priority from the start because scarring can limit how far a new knee bends. Most people manage daily activities independently within about six weeks, but full recovery can take up to a year as strength, confidence, and comfort improve. Some swelling for three to six months and some awareness of the joint are normal, and on their own neither indicates a problem.1,2,3
Looking for ACL reconstruction? That's a different operation for a different population, with a different recovery. → ACL reconstruction
Your surgeon's protocol comes first
This page describes what recovery after knee replacement generally involves. It is not a protocol.
Where anything here conflicts with your surgical team's instructions, follow your surgical team.
Key takeaways
- More than 700,000 total knee replacements are performed each year in the U.S., most in people aged 50 to 80.1
- Physical therapy should start within 24 hours of surgery. Most people resume most daily activities within 3 to 6 weeks, and full recovery takes 4 months to a year.1,3,4
- Exercise before surgery improves strength, function and pain in the first weeks afterward, though the advantage fades over time.4
- Progressive strength training and balance and walking retraining carry the strongest recommendations in the physical therapy guideline; continuous passive motion machines are not recommended after an uncomplicated knee replacement.4
- Tell your doctor right away about calf pain or swelling, a fever above 100°F, or a draining wound. Sudden shortness of breath or chest pain can mean a clot has reached the lungs.1,2
- With Medicare Part B, you pay 20% of the approved amount for outpatient physical therapy after the deductible, and there is no yearly limit when the therapy is medically necessary.14
What is a knee replacement, and how common is it?
A total knee replacement, also called total knee arthroplasty, is closer to a resurfacing. The surgeon removes the damaged cartilage and a small amount of bone from the ends of the thighbone and shinbone, replaces them with metal components, often resurfaces the underside of the kneecap with plastic, and fits a plastic spacer between the metal parts so they glide.1
The knee is the most replaced joint in the body.10 More than 700,000 total knee replacements are performed each year in the U.S. Most people who have one are aged 50 to 80, but the decision rests on pain and disability rather than age.1
Arthritis is the most common reason: osteoarthritis, rheumatoid arthritis, or arthritis that follows a serious knee injury. A surgeon may recommend the operation for knee pain or stiffness that limits walking, stairs and getting out of a chair, pain while resting, a knee that bows in or out, or pain that has not improved with medicines, injections, physical therapy or other surgery.1
Working with a physical therapist may delay the need for surgery, and in some cases help avoid it.10 Most people who have the operation get a dramatic reduction in knee pain, but a new knee does not let you do more than you could before the arthritis. More than 90% of modern total knee replacements are still working well 15 years after surgery.1
Partial or total knee replacement: how does recovery differ?
A partial (unicompartmental) knee replacement resurfaces only one of the knee's three compartments, the inside, the outside or the front between the kneecap and thighbone, and keeps the healthy cartilage, bone and all the ligaments. It suits arthritis limited to one compartment; inflammatory arthritis, significant stiffness or ligament damage can rule it out.6 When the arthritis is only on the back of the kneecap, the operation is a patellofemoral replacement.10
| Partial | Total | |
|---|---|---|
| What is replaced | One compartment of the knee6 | The ends of the thighbone and shinbone, and often the underside of the kneecap1 |
| Hospital stay | Usually little or none6 | Home the same day, or typically 1 to 3 days2 |
| Recovery | Quicker, with less pain and blood loss; regular daily activities usually by 6 weeks6 | Most daily activities within 3 to 6 weeks; full recovery 4 months to a year1,3 |
| Main trade-off | A total knee replacement may be needed later if arthritis develops in the rest of the knee6 | The plastic spacer wears with use, so most surgeons advise against high-impact activity for life1 |
After a partial replacement you begin putting weight on the knee immediately, with a walker, cane or crutches for the first days or weeks.6 After a total replacement, your surgeon or physical therapist tells you when you can put weight on the leg and how much.8 The guide to weight-bearing status explains the terms on discharge papers, from weight bearing as tolerated to non-weight bearing.
Is a knee replacement the same as ACL reconstruction?
No. A tear of the anterior cruciate ligament (ACL), one of the two ligaments that cross inside the knee, affects more than 200,000 people a year in the U.S. It most often happens when pivoting, cutting or jumping, in sports such as soccer, basketball, football and volleyball.12 An ACL reconstruction replaces the torn ligament with tissue from your own kneecap, quadriceps or hamstring tendon, or from a donor, usually through small arthroscopic incisions.11
The recoveries differ too. After ACL reconstruction most people go home the same day, may need a brace and crutches for 1 to 6 weeks, and have physical therapy for up to 4 to 6 months; sports with quick changes of direction may take 9 to 12 months of rehabilitation.11 A knee replacement resurfaces a joint worn down by arthritis, and most people who have one are 50 to 80.1 The guide to ACL reconstruction and return to sport covers that operation's rehabilitation.
Who does what on your knee replacement team?
- Primary care doctor
May refer you to an orthopedic surgeon, and several weeks before surgery may give you a complete physical exam to make sure you are healthy enough for the operation and the recovery.1
- Orthopedic surgeon
Takes your medical history, examines the knee and orders X-rays, sometimes blood tests or an MRI, then talks through other options and the risks before deciding with you.1
- Anesthesia team
Chooses with you between general anesthesia and a spinal, epidural or regional nerve block.1
- Physical therapist
Before surgery, teaches exercises and how to use a walker. Afterward, teaches safe moving, getting in and out of bed, chairs and the car, and ice, elevation and compression, then builds strength, balance and the activities you want back.10
- Rehabilitation or skilled nursing staff
If going straight home is not yet safe, a short stay in a rehabilitation center teaches you to do your daily activities safely on your own.2,3 Medicare-covered skilled nursing care includes physical and occupational therapy.15
- Social worker or discharge planner
If you live alone, can arrange help at home or a short stay in an extended care facility.1
Does physical therapy before a knee replacement help?
For the first weeks after surgery, yes. The American Physical Therapy Association guideline recommends a preoperative exercise program (a moderate-strength recommendation): it improves strength, function and pain in roughly the first six weeks after surgery, though the benefit tends to fade over time, and no single type of exercise, setting or level of supervision has been shown to be best.4
A program before surgery can include:
- Strength and flexibility for the knee joint, the surrounding muscles and the upper body.10
- Learning to use a walker, cane or crutches before you need them.3,10
- Changes at home, such as clearing walkways and placing a chair so you can sit rather than squat to reach a low cabinet.10
- Weight and smoking. Losing excess weight can help you recover more quickly, and smoking slows wound and bone healing.3,10
Ask whether visits before surgery count toward your plan's limit on covered therapy visits; the guideline asks therapists to weigh out-of-pocket costs and visit limits with you.4
What happens in the hospital, and when can you go home?
The operation usually takes 1 to 2 hours.1 You may go home the same day, or stay typically 1 to 3 days.2 Physical therapy, including getting up and moving, should start within 24 hours of surgery; in the studies, people who started within 24 hours had less pain and better knee motion.4 To prevent blood clots, your surgeon may prescribe support stockings, inflatable compression boots or blood thinners, and foot and ankle movement is encouraged right away.1
Before you leave the hospital, the goals are to:
- Get in and out of bed by yourself, with acceptable pain control.2
- Eat, drink and use the bathroom.2
- Walk on a level surface with a cane, walker or crutches, and climb up and down two or three stairs.2
- Do your home exercises and understand any knee precautions.2
If you cannot do these yet, or no one can help you at home, a short stay in a rehabilitation or skilled nursing center may be safer than going straight home.2
What recovery generally involves
Subject to your surgeon's protocol.
- The first days. Walking usually begins within a day, with a walker or crutches. Pain management, swelling control, and starting knee movement all begin immediately; therapy started within 24 hours of surgery has meant less pain and better movement. The early emphasis on bending the knee is deliberate — scarring can limit how far a new knee bends, and if therapy does not restore it, a surgeon may need to bend the knee under anesthesia.1,3,4
- The first weeks. Progressive walking, reducing reliance on walking aids, and steady work on bend and straightening. Getting the knee fully straight matters too, and is easier to overlook: resting the knee bent to control swelling can cost some straightening, so therapists add exercises for it.4
- Weeks to months. Independence in daily activities, stairs, driving where your surgeon permits, and rebuilding the strength lost before and after surgery. Most people resume daily activities within three to six weeks.1
- Months to a year. Continued strength, endurance, and confidence. Improvement continues well past the point most people expect it to stop: full recovery takes four months to a year.3
How long does knee replacement recovery take?
Most people resume most normal daily activities within 3 to 6 weeks and drive again at about 4 to 6 weeks; full recovery takes 4 months to a year.1,3 Keep doing the exercises your physical therapist prescribes for at least 2 months after surgery.2
Those are averages, and your surgeon's protocol sets your own dates. For the phase-by-phase plan, with the knee-bend targets and starter exercises for each stage, read the week-by-week knee replacement physical therapy timeline.
What physical therapy does
- Before surgery, where time allows — a preoperative exercise program improves strength, function, and pain in the first weeks after surgery, though the advantage tends to fade over time.4
- Early — walking, knee bend and extension, swelling management, and safe transfers.4
- Middle — progressive strengthening, gait quality, stairs, and reducing walking aids.4
- Later — endurance, balance, and returning to the activities you want back.4
Which knee replacement rehab treatments have the best evidence?
The 2026 American Physical Therapy Association guideline grades each recommendation from strong (two or more high-quality studies agreeing) through moderate and weak down to consensus (a single low-quality study or none).4
| Treatment | Recommendation | What it means for you |
|---|---|---|
| Physical therapy within 24 hours of surgery, including getting up and moving | Moderate | Less pain and better knee motion than starting later.4 |
| Exercise before surgery | Moderate | Better strength, function and pain in the first weeks; the benefit fades over time.4 |
| Progressive strength training | Strong | From the early weeks after surgery, to improve function, strength and range of motion.4 |
| Balance and walking retraining | Strong | Dynamic balance training, gait retraining and movement training with feedback.4 |
| Range-of-motion exercises | Moderate | Passive, assisted and active bending and straightening.4 |
| Electrical stimulation of the quadriceps | Moderate | At least daily, started early, to improve quadriceps strength and walking.4 |
| A plan to increase physical activity | Moderate | Early activity, increased step by step with goals you set together.4 |
| Ice and elevation | Moderate | Cold therapy for early pain and swelling, with the leg raised.4 |
| Therapy supervised by a physical therapist | Moderate | In the setting that suits your safety, mobility and home.4 |
| Telehealth and other digital tools | Moderate | Alongside or instead of clinic visits.4 |
| TENS, taping, manual therapy and psychologically informed care for pain | Weak | Small decreases in pain; the psychological approaches suit people with a high fear of movement.4 |
| Continuous passive motion (CPM) machine | Not recommended | Strong recommendation against it after a routine knee replacement.4 |
| Bracing or splinting to gain motion | Not routinely | No clinically meaningful gain in range of motion.4 |
| Lymphatic drainage or compression dressings for swelling | Not routinely | Not proven effective (the work group's consensus).4 |
Devices such as an exercise bike or slide board can still be options for knee motion, and the guideline asks therapists to tell you about the lack of evidence for continuous passive motion.4
What happens at your first physical therapy visit, and how is progress measured?
Most people can begin exercising the knee hours after surgery, so the first session is often in the hospital.1 Early on, a physical therapist shows you how to move safely at home, get in and out of bed, chairs and the car, use a walker or crutches, and control swelling with ice, elevation and compression.10
In the first two weeks the focus is bending and straightening the knee, managing pain, reducing swelling and restoring normal walking. After that the program is tailored to you, with more range-of-motion work, progressive strengthening, balance training, functional training and training for your own activities.10
The guideline recommends therapy supervised by a physical therapist, in the setting that suits your safety and mobility, and says video visits and other digital tools can be used alongside clinic visits or instead of them.4
Progress is tracked in the measures the guideline's studies used: how far the knee bends and straightens, quadriceps strength, walking distance and speed, stair climbing, the Timed Up and Go test, and your own ratings of pain and function.4 Exercise and activity should keep improving your strength and mobility; if they do not, contact your surgeon or physical therapist.7
Knee replacement exercises, step by step
These are from the exercise guide of the AAOS, the academy of orthopedic surgeons. Your surgeon and physical therapist may recommend 20 to 30 minutes of exercise 2 to 3 times a day, and walking for 30 minutes 2 to 3 times a day, early in recovery. Check with them before you try any of these.7 Ankle pumps, quad sets, heel slides and straight leg raises are set out in the knee surgery physical therapy timeline.
Knee straightening
For getting the knee fully straight. Lie in bed with a small rolled towel just above your heel, so the heel is off the bed. Tighten your thigh and try to straighten the knee until the back of it touches the bed. Hold 5 to 10 seconds, and repeat until your thigh feels tired, about 3 minutes.7
Sitting supported knee bend
For bending. Sit at the bedside or in a chair with your thigh supported. Put your other foot behind the heel of the operated leg for support, slowly bend the knee as far as you can and hold 5 to 10 seconds. Repeat until the leg feels tired or the knee bends fully, about 2 minutes.7
Sitting unsupported knee bend
For more bend. Sitting with your thigh supported, bend the knee until your foot rests on the floor. Keeping the foot lightly on the floor, slide your upper body forward in the chair to bend the knee further, hold 5 to 10 seconds, then straighten fully. About 3 minutes.7
Standing knee bend
Once you can manage short distances. Stand upright holding a walker or crutches, lift your thigh and bend the knee as far as you can, and hold 5 to 10 seconds. Straighten, touching the floor heel first. Repeat until tired, about 2 minutes.7
Exercise bike
Set the seat so your foot just touches the pedal with the knee almost straight. Pedal backward first, and forward only once backward is comfortable. At about 4 to 6 weeks, slowly add tension: 10 to 15 minutes twice a day, building to 20 to 30 minutes 3 to 4 times a week.7
Stairs
Use a handrail and go one step at a time: lead up with the good knee and down with the operated knee, “up with the good, down with the bad.” Avoid steps higher than a standard 7 inches, and climb foot over foot once you are stronger.7
Light ankle weights of 1 to 2 pounds can usually be added 4 to 6 weeks after surgery. If the knee aches or swells after exercise, raise the leg and ice it for 20 minutes on and 20 minutes off, for about 2 hours.7
How far should a new knee bend, and what if it stays stiff?
An average of about 115 degrees of bend is generally expected after a total knee replacement, but full motion is uncommon, and how far the knee moves afterward can be predicted by how far it moved before surgery. Most people can almost fully straighten the new knee and bend it enough to climb stairs and get in and out of a car.1
Straightening needs work too. Resting the knee bent to control swelling can cost some straightening, and discharge instructions say to keep a pillow under your heel or ankle, not under your knee.4,8
If scarring limits motion, more physical therapy and range-of-motion exercise usually helps. If it does not, your surgeon may recommend a manipulation under anesthesia: while you are asleep, the surgeon gently bends and straightens the knee to break up the scar tissue.1
The guideline recommends against continuous passive motion machines after a routine knee replacement and against routine bracing or splinting to gain motion.4
How do you manage pain, swelling and sleep after knee replacement?
Pain. Doctors often combine opioids, anti-inflammatory drugs, acetaminophen and local anesthetics so that less opioid is needed. Use opioids only as directed, stop as soon as the pain starts to improve, and tell your doctor if it has not begun to improve within a few days.1 Early on, taking pain medicine about 30 minutes before therapy or more activity can help.8
Swelling. Moderate to severe swelling in the first days or weeks, and mild to moderate swelling for about 3 to 6 months, are expected. Raise the leg and use ice; compression stockings may also help.2 The physical therapy guideline recommends cold therapy for early pain and swelling, which may bring short-term reductions in pain, swelling and opioid use.4
Sleep. Pain at night is common for several weeks.1 You can safely sleep on your back, on either side or on your stomach.2
Fear of moving. For people with a high fear of movement, approaches such as cognitive behavioral therapy may ease that fear and improve quality of life.4
When can you stop using a walker or cane?
Your surgeon and physical therapist decide when each walking aid can go.1,8 The AAOS exercise guide suggests moving to a single crutch or cane once you can walk and stand for more than 10 minutes and no longer lean on the walker or crutches, often about 2 to 3 weeks after surgery. Hold it in the hand opposite the new knee.7 Some people use walking aids for up to 3 months.8
Walk heel first, then flatten the foot, then lift the toes, as evenly as you can, without limping or leaning away from the new knee.7 Wear well-fitting shoes with nonskid soles rather than slippers or high heels, and do not twist or pivot while using a walker.8
Driving, stairs, work, kneeling and travel after knee replacement
- Driving
When the knee bends enough to sit comfortably in the car and your muscle control gives you the reaction time to brake and accelerate; most people drive again at about 4 to 6 weeks.1 Wait until you no longer take opioid pain medicine.2
- Stairs
Early on, set up a living space on one floor if you can.1 Use a handrail, lead up with the good knee and down with the operated one, and have someone help until you are stronger.7
- Work
Several days to several weeks, depending on the work you do and how fast you recover; your doctor advises when.2
- Kneeling
Sometimes uncomfortable, but not harmful.1 Difficulty kneeling remains common after knee replacement.5 In the first weeks, do not kneel to pick things up.8
- Sex
Often within several weeks, depending on your condition; ask your doctor.2
- Sports
Walk as much as you like, swim once the wound has healed, and choose golf, cycling or pickleball over jumping, jogging and skiing.2
- Flying
Ask your doctor first: pressure changes and sitting still can swell the leg while it heals. The implant may set off airport metal detectors, so tell the screener.2
- Dentist and MRI
Tell your dentist about the new knee and ask your surgeon whether you need antibiotics before dental work.1 Tell your doctor before an MRI, since the metal can blur the images.2
How should you set up your home before knee replacement?
Plan for help with cooking, shopping, bathing and laundry for several weeks.1 If no one can help for the first 1 or 2 weeks, ask your surgeon about a trained caregiver coming to your home.9 A physical therapist may visit to make sure your home is set up safely.8
- One floor. A bed low enough that your feet touch the floor when you sit on its edge, with a bathroom or commode on the same floor.9
- A firm chair 18 to 20 inches high, with two arms, a firm back and a footstool for raising the leg.1
- The bathroom. Grab bars (not towel racks), a raised toilet seat, a shower chair and nonslip mats.9
- Floors. No throw rugs or loose cords, and night lights in hallways.2,9
- Reaching tools. A reacher, long-handled shoehorn and long-handled sponge, so you do not bend too far.2
- Within reach. Everyday items between waist and shoulder height, and a bag or basket on the walker.9
The home safety checklist after hip or knee replacement goes room by room, and the gap between discharge and recovery covers the help at home that often runs out first.
What are the warning signs of a blood clot or infection after knee replacement?
Serious complications such as a joint infection occur in fewer than 2% of people. Blood clots in the leg veins are one of the most common complications.1
- Blood clot in the leg
Increasing pain in the calf unrelated to the incision, tenderness or redness above or below the knee, or new or increasing swelling of the calf, ankle or foot.1,2
- Clot in the lungs
Sudden shortness of breath, sudden chest pain, or chest pain in one spot when you cough. A clot that reaches the lungs can be life-threatening.1,2
- Infection
A fever above 100°F that persists, shaking chills, increasing redness, tenderness or swelling of the wound, drainage from it, or increasing pain at rest and with activity.1,2
- Also call your surgeon
For bleeding that soaks through the dressing and does not stop with pressure, pain your medicine does not relieve, or a foot or toes that are darker than normal or cool.8
To lower the risk of a clot you may wear compression stockings for about 6 weeks and take blood thinners for 2 to 4 weeks; get up and move after 45 minutes of sitting.8
Does Medicare cover physical therapy after knee replacement?
Yes, when it is medically necessary. Medicare is the main payer for about two-thirds of knee replacements in the U.S.4
| Where or how | What applies |
|---|---|
| Outpatient physical therapy | Part B. After the deductible you pay 20% of the Medicare-approved amount, and there is no yearly limit on medically necessary outpatient therapy. A doctor, nurse practitioner or physician assistant must certify that you need it.14 |
| The 2026 KX threshold | Once your therapy costs pass $2,480 for physical therapy and speech-language pathology combined, or a separate $2,480 for occupational therapy, the clinic adds the KX modifier to confirm the therapy is medically necessary; claims above the threshold without it are denied. Targeted medical review applies from $3,000, and not every claim above it is reviewed.13 |
| Home health | You pay nothing for covered services. You must need part-time skilled care and be homebound: leaving home is not recommended or needs help, such as a walker or crutches, and normally takes a lot of effort. A provider must see you in person and order the care.16 |
| Skilled nursing facility | Part A, after a qualifying inpatient hospital stay of at least 3 days in a row; time under observation does not count. Ask your doctor or the hospital staff whether Medicare covers the stay.15 |
| Medicare Advantage | Plans must cover all medically necessary services Original Medicare covers, but may require prior authorization, a referral or in-network providers.17 |
| Private insurance | Marketplace plans must cover rehabilitative services as an essential health benefit; what is covered varies by state, and self-insured large employer plans do not have to include it.18 |
The guide to Medicare coverage for PT, OT and speech therapy explains each part in full, physical therapy cost and insurance covers private plans, and adult therapy without insurance lists the options when cost limits your visits.
Knee replacement recovery myths
- “Kneeling damages the new knee.” Kneeling is sometimes uncomfortable, but it is not harmful.1
- “Rest is best for the first weeks.” Therapy, including getting up and moving, should start within 24 hours of surgery, with activity increased step by step after that.4
- “A motion machine gets the bend back.” The guideline recommends against continuous passive motion after a routine knee replacement; active exercise is what it supports.4
- “Recovery is over at three months.” Full recovery takes 4 months to a year.3
- “Swelling months later means something is wrong.” Mild to moderate swelling for about 3 to 6 months is expected; new or severe swelling is what to report.2
- “Walking is all the exercise I need.” Walk as much as you like, but walking does not replace the exercises your physical therapist prescribes.2
- “A new knee means I can run again.” Most surgeons advise against running, jogging, jumping and other high-impact sports for life; walking, swimming, golf and cycling are realistic.1
What to expect along the way
- The first few weeks are usually the hardest, and knowing that helps. Swelling is at its worst in the first days and weeks, and pain with activity and at night is common for several weeks.1,2
- Swelling persists. Mild to moderate swelling for three to six months is normal, and it often fluctuates with activity.2
- The knee will feel different. Awareness of the joint, some numbness around the scar, and occasional clicking are common and generally not concerning.1
- Sleep is frequently disrupted early. Pain at night is common for several weeks. This settles.1
- Kneeling is often difficult afterward, though it does not harm the new knee. Worth knowing in advance.1,5
- Full recovery can take up to a year, which surprises people who expect to be finished at three months.3
Goals worth setting
Walk to the end of the street and back · Climb stairs one foot per step · Get in and out of the car unaided · Return to driving · Sleep through the night · Return to golf or gardening
Improve knee flexion · Increase quadriceps strength
How do you find a physical therapist for knee replacement rehab?
Every physical therapist is prepared by education and experience to treat people before and after knee replacement. You may prefer one with experience in orthopedic problems, or one who is a board-certified clinical specialist or has completed a residency or fellowship in orthopedic or geriatric physical therapy. Ask about their experience with knee replacements, and come ready to describe your symptoms and goals.10
Find a physical therapist near you in the DrSensory directory. If you are not sure where to begin, start here for adults; physical therapy for adults covers what adult physical therapists treat, occupational therapy for adults covers daily tasks such as dressing and bathing, and adult orthopedic therapy covers the other joint and bone conditions. If balance worries you after surgery, read the guide to falls and balance in older adults.
Frequently Asked Questions
When can I drive?
Your surgeon decides. Most people drive again about four to six weeks after surgery, once the knee bends enough to sit comfortably in the car and the leg can brake and accelerate quickly enough.1
When will I walk again?
Usually within a day of surgery, with a walker or crutches.3 Reducing to a cane and then to nothing happens over the following weeks, as your surgeon and physical therapist advise.1
Will I be able to kneel?
Often with some difficulty. Trouble kneeling is common after knee replacement, though kneeling does not harm the new knee.1,5 It's worth knowing before surgery rather than after.
Is swelling normal months later?
Yes. Mild to moderate swelling for three to six months is common and often fluctuates with activity. New, sudden, or severe swelling, or swelling in one calf, is different and warrants a call, because it can be a sign of a blood clot.2
Why is bending the knee such a focus early on?
Because scarring can limit how far a new knee bends, and if therapy does not restore it, a surgeon may need to bend the knee under anesthesia.1 Getting the knee fully straight matters too and is easier to overlook.
How long does recovery from knee replacement take?
Most people manage daily activities independently within about six weeks, but full recovery can take up to a year as strength and confidence build.1,3
Should I do physical therapy before a knee replacement?
Where time allows, yes — a preoperative exercise program improves strength, function, and pain in the first weeks after surgery, though the advantage tends to fade over time.4 Ask your surgical team whether it is appropriate for you and when to start.
Why does getting the knee fully straight matter as much as bending it?
Because it is easier to overlook. Resting the knee bent, which helps control early swelling, can cost some straightening, so the physical therapy guideline asks therapists to add exercises for straightening alongside the work on bending.4 Steady work on both is part of the first weeks.
Is a partial knee replacement easier to recover from?
Usually. A partial replacement means a quicker recovery with less pain, less blood loss and a lower risk of infection and blood clots. The trade-off is that a total knee replacement may be needed later if arthritis develops in the rest of the knee.6
Is a knee replacement the same as ACL surgery?
No. ACL reconstruction replaces a torn ligament with a tendon graft, usually after a sports injury, and rehabilitation runs 4 to 6 months or longer for pivoting sports.11 A knee replacement resurfaces a joint damaged by arthritis.1
Do I need a CPM machine after knee replacement?
Not after a routine knee replacement. The physical therapy guideline makes a strong recommendation against continuous passive motion after primary, uncomplicated knee replacement, and supports active range-of-motion exercise instead.4
Does Medicare pay for physical therapy after knee replacement?
Yes, when it is medically necessary. Under Part B you pay 20% of the approved amount after the deductible, with no yearly limit.14 In 2026, once costs pass $2,480 for physical and speech therapy combined, the clinic confirms medical necessity with the KX modifier.13
When can I go back to work after knee replacement?
Anywhere from several days to several weeks, depending on the work you do and how quickly you recover. Your doctor advises when it is safe.2
Can I fly after knee replacement?
Ask your doctor first. Pressure changes and sitting still can make the operated leg swell while it is healing, and the implant may set off airport metal detectors, so tell the screener.2
Related conditions
Conditions and pages that commonly come up alongside knee replacement recovery.
ACL reconstruction
A different knee operation for a different population, with a different recovery.
Learn more →Recovery after hip replacement
What recovery after a hip replacement involves, and how it differs.
Learn more →Tendinopathy
Persistent tendon pain around the knee, and why loading is part of the treatment.
Learn more →Low back pain
What helps with back pain, and what treatment can realistically offer.
Learn more →Knee replacement physical therapy timeline
The week-by-week phases, knee-bend targets and starter exercises.
Learn more →Home safety after knee replacement
A room-by-room checklist for the first weeks at home.
Learn more →Find a physical therapist · Find an occupational therapist · Adult orthopedic therapy · All adult therapy
Sources
- American Academy of Orthopaedic Surgeons, OrthoInfo. Total Knee Replacement. Checked October 29, 2026.
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Most people resume daily activities “within 3 to 6 weeks” and driving at about 4 to 6 weeks; pain at night is common for several weeks; scarring can limit motion, which usually improves with therapy, otherwise manipulation under anesthesia may be recommended; numbness and clicking are normal; “Kneeling is sometimes uncomfortable, but it is not harmful.” Also: “more than 700,000 total knee replacements are performed annually in the U.S.”; “Most patients who undergo total knee replacement are aged 50 to 80”; arthritis as the most common cause and the reasons surgery is recommended; the evaluation (history, examination, X-rays); “Serious complications, such as a knee joint infection, occur in fewer than 2% of patients”; blood clots are “one of the most common complications”; “an average of 115° of motion is generally anticipated”; “restoration of full motion is uncommon”; “more than 90% of modern total knee replacements are still functioning well 15 years after the surgery”; most surgeons advise against high-impact activities; the procedure “usually takes 1 to 2 hours”; combined pain medicines to minimize opioids; clot prevention measures; help needed “for several weeks”; the chair “height of 18 to 20 inches”; the warning signs of a blood clot, pulmonary embolism and infection (“Persistent fever (higher than 100°F orally)”). - American Academy of Orthopaedic Surgeons, OrthoInfo. Activities After Total Knee Replacement. Checked October 29, 2026.
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Swelling is moderate to severe in the first days or weeks and mild to moderate “for about 3 to 6 months after surgery”; new or severe swelling may be a warning sign of a blood clot; lists the warning signs of infection, blood clot and a clot in the lungs. Also: a hospital stay that “will typically last 1 to 3 days” or same-day discharge, and the goals before discharge; a rehabilitation or skilled nursing center if going home is not yet safe; elevation, ice and compression stockings; reaching tools and home preparation; driving “when you are no longer taking opioid pain medication”; sleeping positions; return to work in “several days to several weeks”; exercises “for at least 2 months after surgery”; “walking is not a substitute for the exercises”; lower-impact sports; air travel; MRI scans. - MedlinePlus, National Library of Medicine. Knee joint replacement. Checked October 29, 2026.
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“You will be asked to start moving and walking as soon as the day of surgery”; “Full recovery will take 4 months to a year”; a rehabilitation center teaches “how to safely do your daily activities on your own”; practice using a cane, walker or crutches before surgery; smoking “will slow down wound and bone healing.” - Bove AM, Carroll LA, Cone S, et al. Clinical practice guideline for physical therapist management of total knee arthroplasty: revision 2026. Physical Therapy. 2026;106(7):pzag058. doi:10.1093/ptj/pzag058 (PMID 42506877).
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The American Physical Therapy Association guideline: therapy including early mobilization should start within 24 hours of surgery; preoperative exercise improves early outcomes, though “these early benefits tend to diminish over time”; range-of-motion work should include knee extension, since resting the knee bent “may increase the risk of postoperative knee extension loss”; progressive strengthening, gait and balance training and progressive physical activity are recommended. Strength grades run from strong (“2 or more high-quality studies with consistent findings”) to consensus; strong recommendations for progressive strength training and motor function training (balance, gait retraining) and against continuous passive motion after primary, uncomplicated knee replacement; moderate for prehabilitation (benefits at “0-1.5 months”), range-of-motion exercise, quadriceps NMES, physical activity, cryotherapy and elevation, supervised therapy and digital health tools; against routine bracing, splinting, manual lymphatic drainage and compression dressings; weak for TENS, taping, manual therapy and psychologically informed techniques; Medicare “is the primary payer for approximately two-thirds of TKAs”; outcomes studied include range of motion, strength, walking distance and speed, stair climbing, the Timed Up and Go Test and patient-reported outcomes. - Shah OA, Spence C, Kader D, Clement ND, Asopa V, Sochart DH. Patellar resurfacing and kneeling ability after total knee arthroplasty: a systematic review. Arthroplasty. 2023;5(1):32. doi:10.1186/s42836-023-00184-5 (PMID 37268994). Across eight studies and 24,342 patients, “difficulty kneeling following total knee arthroplasty (TKA) remains highly prevalent.”
- American Academy of Orthopaedic Surgeons, OrthoInfo. Unicompartmental (Partial) Knee Replacement. Checked October 29, 2026.
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“only a portion of the knee is resurfaced”; advantages over total knee replacement include “Quicker recovery,” “Less pain after surgery,” “Less blood loss” and “Lower risk of infection and blood clots”; “a total knee replacement may be necessary in the future if arthritis develops in the parts of the knee that have not been replaced”; inflammatory arthritis, significant stiffness or ligament damage may rule it out; patients “usually spend little or no time in the hospital”; “You will begin putting weight on your knee immediately after surgery”; most resume “all of your regular activities of daily living by 6 weeks.” - American Academy of Orthopaedic Surgeons, OrthoInfo. Total Knee Replacement Exercise Guide. Checked October 29, 2026.
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Exercise “20 to 30 minutes daily, or even 2 to 3 times daily; and walk for 30 minutes, 2 to 3 times daily during your early recovery”; knee straightening, sitting supported and unsupported knee bends, standing knee bends, stairs (“up with the good” and “down with the bad”; no steps higher than 7 inches), exercise bike (tension at about 4 to 6 weeks; 10 to 15 minutes twice a day building to 20 to 30 minutes 3 to 4 times a week), 1- to 2-pound weights from 4 to 6 weeks; a single crutch or cane “when you can walk and stand for more than 10 minutes” and are not carrying weight on the walker, “often about 2 to 3 weeks after your surgery”; ice 20 minutes on and 20 off for about 2 hours; “Exercise and activity should consistently improve your strength and mobility.” - MedlinePlus, National Library of Medicine. Knee joint replacement – discharge. Checked October 29, 2026.
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Walking aids “for up to 3 months”; “A physical therapist may visit you at home to make sure your home is set up safely”; shoes with nonskid soles, no twisting or pivoting on a walker, no kneeling to pick things up, “keep a pillow under your heel or ankle, not your knee”; when to bear weight is decided by the surgeon or physical therapist; pain medicine “about 30 minutes before” therapy; compression stockings “for about 6 weeks” and blood thinners “for 2 to 4 weeks”; move after 45 minutes of sitting; the list of reasons to call the surgeon. - MedlinePlus, National Library of Medicine. Getting your home ready – knee or hip surgery. Checked October 29, 2026.
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A bed low enough that your feet touch the floor, a bathroom or commode on the same floor, items between waist and shoulder level, a bag or basket on the walker, grab bars (“Do not use towel racks as grab bars”), a raised toilet seat, a shower chair, non-slip mats, night lights; “If you do not have someone to help you at home for the first 1 or 2 weeks after surgery, ask your surgeon about having a trained caregiver come to your home.” - American Physical Therapy Association, ChoosePT. Physical Therapy Guide to Total Knee Replacement (Arthroplasty). Checked October 29, 2026.
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“The knee is the most replaced joint in the body”; a patellofemoral replacement when arthritis is only on the back of the kneecap; prehab exercises for the knee joint, upper body and surrounding muscles, walker practice and home changes; losing excess weight and stopping smoking; after surgery, safe movement, bed, chair and car transfers, ice, elevation and compression; the first two weeks focus on bending, straightening, pain, swelling and walking, then a tailored program; working with a physical therapist may delay or avoid surgery; what to look for in a physical therapist. - MedlinePlus, National Library of Medicine. ACL reconstruction. Checked October 29, 2026.
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The graft comes from the kneecap, quadriceps or hamstring tendon or from a donor, usually placed with knee arthroscopy; most go home the same day; a brace and crutches for 1 to 6 weeks; “Therapy can last up to 4 to 6 months”; quick-direction sports “may require up to 9 to 12 months of rehabilitation.” - American Academy of Orthopaedic Surgeons, OrthoInfo. Anterior Cruciate Ligament (ACL) Injuries. An ACL tear “affects more than 200,000 people annually in the U.S.”; it most often occurs “when a person is pivoting, cutting, or jumping,” in activities like volleyball, soccer, football and basketball; the cruciate ligaments cross inside the knee. Checked October 29, 2026.
- Centers for Medicare & Medicaid Services. Therapy Services. Checked October 29, 2026.
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“For CY 2026 this KX modifier threshold amount is: $2,480 for PT and SLP services combined, and $2,480 for OT services”; “Claims for services over the KX modifier threshold amounts without the KX modifier are denied”; the targeted medical review threshold is $3,000, and “not all claims exceeding the MR threshold amount are subject to review.” - Medicare.gov. Physical therapy services. “After the Part B deductible, you pay 20% of the Medicare-approved amount”; “There's no limit on how much Medicare pays for your medically necessary outpatient therapy services in one calendar year”; a doctor, nurse practitioner, clinical nurse specialist or physician assistant must certify the need. Checked October 29, 2026.
- Medicare.gov. Skilled nursing facility care. Covered services include physical and occupational therapy; coverage needs a qualifying inpatient stay “of at least 3 days in a row”; time under observation does not count; “Always ask your doctor or hospital staff if Medicare will cover your SNF stay.” Checked October 29, 2026.
- Medicare.gov. Home health services. “You pay nothing for covered home health services”; you must need part-time or intermittent skilled services and be homebound, including having trouble leaving home without help “like using a cane, wheelchair, walker, or crutches”; a provider must see you in person and order the care. Checked October 29, 2026.
- Medicare.gov. Compare Original Medicare & Medicare Advantage. “Plans must cover all medically necessary services that Original Medicare covers”; “You may need to get approval (prior authorization) from your plan before it covers certain services or supplies”; plans may require in-network providers and referrals. Checked October 29, 2026.
- HealthCare.gov. What Marketplace health insurance plans cover. All Marketplace plans cover “Rehabilitative and habilitative services and devices” as an essential health benefit; specific services “can vary based on your state’s requirements”; large employers who self-insure “don’t have to provide essential health benefits.” Checked October 29, 2026.
Medical disclaimer. This page is for general educational purposes and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your individual situation. This page is not a rehabilitation protocol. Follow the instructions given by your surgical team.