A knee replacement removes the arthritis, but it is the next 12 weeks of exercise that decide how well your new knee bends, straightens and carries you up stairs. This guide walks you through what to expect and what to do, week by week, after total knee replacement (TKR) – based on current trials and the American Physical Therapy Association (APTA) clinical practice guideline, not on habit or hearsay.

Key takeaways

Start moving within 24 hours. Early walking and physiotherapy from day one are recommended by the APTA guideline and lower the risk of blood clots and stiffness.
Getting the knee fully straight matters as much as bending it. Aim for a straight knee (0°) early and about 90° of bend within the first few weeks, and 110–120° by about 3 months.
Where you do physio matters less than doing it. Trials show a well-taught home programme gives results similar to outpatient physiotherapy or inpatient rehab for straightforward cases.
The bending machine (CPM) is not needed routinely. A Cochrane review of 24 trials found no meaningful benefit for bend, pain or function.
Strengthen the quadriceps early and progressively – they lose a large share of their strength in the first month, and strength training started in the first week is recommended.
If bend is stuck well short of 90° at 6 weeks, tell your surgeon early. Treatment for stiffness works best within the first 12 weeks.
Most people return to everyday activities by 3 months, but improvement continues up to a year.

Knee replacement recovery at a glance

Every recovery is different, and your surgeon's protocol comes first. These are typical milestones for an uncomplicated primary TKR.

Time after surgery	Walking	Knee bend (flexion)	Daily life
Day 0–1	Standing and first steps with a walker	Gentle bending begins	Physiotherapy starts in hospital
Days 2–5	Walker; stairs practised before discharge	70–90°	Home once safe on stairs and toilet
Weeks 1–2	Walker or two sticks; short walks at home	80–90°; knee straightening fully	Stitches/clips checked around day 10–14
Weeks 2–6	One stick, then none indoors	100–110°	Desk work from about 4–6 weeks; driving (automatic, left knee) once off strong painkillers
Weeks 6–12	Walking without aid; longer distances	110–120° or more	Right-knee driving usually 4–6 weeks or later; stairs step-over-step
3–6 months	Normal walking; low-impact sport	Final bend usually reached	Most activities back; swelling settling
6–12 months	–	–	Strength and comfort keep improving; mild warmth and swelling can persist

Two numbers to remember: a fully straight knee (0°) as early as possible, and about 90° of bend by 6 weeks at the latest. A knee that will not straighten, or that is stuck well short of 90° at 6 weeks, is the commonest early warning sign of stiffness.

What the evidence says about rehab after knee replacement

A lot of TKR advice online is tradition. Here is what has actually been tested.

Question	What the research shows	What it means for you
When should physio start?	The APTA guideline (Jette et al., Physical Therapy 2020) recommends starting within 24 hours of surgery and before discharge.	Expect to stand and walk on day 0 or 1.
Home programme or outpatient physio?	A meta-analysis of 11 trials (Florez-García et al., KSSTA 2017) found no difference in bend or function at 3, 6 or 12 months. A JAMA trial of 165 patients (Buhagiar et al., 2017) found 10 days of inpatient rehab did not improve walking at 26 weeks over a monitored home programme.	A well-taught, checked home programme works for most people. Supervised sessions help if you are not progressing, live alone or lack confidence.
Do I need a CPM (bending) machine?	A Cochrane review of 24 trials and 1,445 patients (Harvey et al., 2014) found only about 2° more bend and no meaningful effect on pain or function. The APTA guideline advises against routine CPM.	Your own active exercises do the job; CPM is not needed after a routine TKR.
Does ice help?	The APTA guideline recommends cryotherapy for early post-operative pain (moderate evidence).	Ice or a cold-compression device for 15–20 minutes after exercise is worthwhile.
Should I strengthen early?	APTA recommends progressive, high-intensity strength training starting within the first 7 days. In a randomised trial of 66 patients (Stevens-Lapsley et al., Physical Therapy 2012), adding quadriceps electrical stimulation (NMES) from 48 hours gave better strength and function, with benefit still present at one year.	Quadriceps work is not optional. NMES is a useful add-on if your thigh muscle is slow to switch on.
What matters most?	Balance, walking and movement-symmetry training received the guideline's only strong recommendation.	Walking evenly, without a limp, is a goal in itself – not just walking further.
Does pre-surgery exercise (prehab) help?	APTA recommends a pre-operative exercise programme. A recent meta-analysis of randomised trials found prehab eased post-operative pain but had little effect on hospital stay or knee function.	Worth doing if you have time before surgery – but do not delay a needed operation for it.

Phase 1: Hospital and weeks 0–2 – wake the muscles, straighten the knee

Goals: control pain and swelling, prevent clots, get the knee fully straight, reach roughly 80–90° of bend, walk safely with a walker.

Most patients stand and take their first steps on the day of surgery or the next morning. Before going home you will practise getting in and out of bed, using the toilet, and climbing a few stairs ("up with the good, down with the bad").

Exercises (2–3 sessions a day)

Exercise	How to do it	Dose
Ankle pumps	Lying or sitting, pull your toes up towards you, then point them away.	20–30 every hour while awake
Quadriceps sets	Leg straight, tighten the thigh and press the back of the knee down into the bed. Hold 5–10 seconds.	10–15 reps, 3 times a day
Heel slides	Lying on your back, slide your heel towards your buttock, bending the knee as far as you comfortably can. A towel or strap around the foot helps. Hold 5 seconds.	10–15 reps, 2–3 times a day
Straight leg raise	Other knee bent, tighten the thigh of the operated leg first, then lift it straight about 30 cm. Lower slowly. If the knee bends as you lift ("extensor lag"), go back to quad sets for a few more days.	10 reps, 2–3 times a day
Heel prop (extension stretch)	Lie or sit with a rolled towel under the heel – never under the knee – and let the knee sag straight.	5–10 minutes, 3–4 times a day
Sitting knee bend	Sit on a firm chair and slide the foot back under the chair as far as you can. Hold 10 seconds.	10 reps, several times a day
Walking	Short, frequent walks with the walker around the house.	Every 1–2 hours during the day

Do not rest with a pillow under the knee. It feels comfortable but is the quickest way to lose the ability to straighten the knee. Elevate the whole leg on pillows under the calf and heel instead.

Phase 2: Weeks 2–6 – build bend, strength and a normal walk

Goals: knee fully straight, 100–110° of bend, walking with one stick then none indoors, no limp, swelling settling.

Keep doing the Phase 1 exercises and add these as your physiotherapist allows:

Exercise	How to do it	Dose
Stationary cycling	Seat high. Rock back and forth until you can complete a full turn (backwards first is often easier), then pedal with little or no resistance. Lower the seat gradually as bend improves.	5–10 minutes, building to 20
Standing hamstring curl	Holding a counter, bend the knee to bring the heel towards the buttock, keeping thighs side by side.	10–15 reps, 2 sets
Mini squats	Holding a counter, feet hip-width apart, bend both knees about 30–45°, weight even on both legs.	10–15 reps, 2 sets
Step-ups	Step up onto a low step (10–15 cm) with the operated leg, then down. Progress the height as strength allows.	10 reps, 2 sets
Sit-to-stand	Stand up from a firm chair without using your hands if possible, and sit down slowly. A higher chair makes it easier.	10 reps, 2–3 sets
Heel raises	Holding a counter, rise onto your toes and lower slowly.	10–15 reps, 2 sets
Weight shifting and single-leg stance	Shift weight side to side, then stand on the operated leg holding the counter.	30 seconds, 3–5 times

Walking well beats walking far. Practise heel-strike, a straight knee as the leg swings through, and equal step lengths. Move from walker to stick (held in the hand opposite the operated knee) when you can walk without a limp, then drop the stick indoors.

Getting back to normal life: most people with desk jobs return to work at about 4–6 weeks. A systematic review of braking studies (Hartman et al., J Arthroplasty 2017) found brake reaction time returns to pre-surgery levels by about 4 weeks after a right TKR and as early as 2 weeks after a left TKR (in an automatic car) – but only drive once you are off strong painkillers, can bend the knee comfortably and can do an emergency stop. Check with your insurer.

Phase 3: Weeks 6–12 and beyond – strength, balance and stamina

Goals: 110–120° of bend or more, stairs step-over-step, walking 30 minutes or more, confident balance, a return to the activities you had the operation for.

The quadriceps are usually still noticeably weaker than the other side at this stage, and that weakness – not the implant – is the main thing that limits stairs, getting up from the floor and walking distance. This is when strength training should become genuinely challenging.

Area	Examples	Progression
Strength	Leg press, deeper squats to a chair, step-ups on a higher step, forward step-downs, resistance-band knee extension, bridges, side-lying hip abduction	Add load when you can do 3 sets of 10–12 with good form and no swelling the next day
Balance	Single-leg stance, tandem (heel-to-toe) walking, standing on a cushion, reaching while balancing	Reduce hand support, then close your eyes briefly
Stamina	Stationary or outdoor cycling, brisk walking, pool walking and swimming (once the wound is fully healed and your surgeon agrees)	Increase time before intensity; about 10% a week
Function	Getting up from the floor, carrying shopping, stairs without the rail, getting in and out of a car or auto-rickshaw	Practise the real task, not just the exercise

Formal physiotherapy often ends between 6 and 12 weeks, but the gains do not have to. A short home programme two or three times a week – strength, balance and cycling or walking – keeps improving the knee for up to a year and protects the other joints.

How much should my knee bend – and what if it is stiff?

You need roughly 65° of bend to walk, 90° to climb stairs and get up from a chair comfortably, and 105–110° to get out of a low seat or tie your shoes. Most people end up with about 110–125°. Sitting cross-legged or squatting on the floor needs far more bend than most knee replacements allow, so plan to use a chair and a western toilet.

A fully straight knee matters just as much: a knee that stays even 5–10° bent makes the thigh work harder with every step and causes a limp and front-of-knee ache.

If your bend is not progressing

Stiffness after knee replacement affects roughly 5–7% of patients. Common reasons are pain limiting the exercises, too much resting with the knee bent, and some people's natural tendency to form tight scar tissue.

Tell your surgeon early if you are stuck well short of 90° at 6 weeks or cannot straighten fully.
Better pain control around exercise sessions, more frequent short sessions and supervised physiotherapy are the first steps.
If that fails, manipulation under anaesthesia (MUA) – gently bending the knee while you are asleep – is the usual next step. It works best early: in one series reviewed by Mamarelis et al. (2015), MUA within 12 weeks gained an average of 36° (final bend 119°) compared with 17° (final 95°) when done later.
Rarely, keyhole or open release of scar tissue, or revision surgery, is needed for persistent stiffness. Stiffness that comes on late, or after a period of good movement, should also be checked for infection or a problem with the implant.

Pain, swelling, sleep and diet

Pain. Some pain during exercise is expected. A simple guide: pain up to about 4 out of 10 that settles within an hour or two, with no extra swelling the next morning, is acceptable. Sharper pain, or swelling that is worse the next day, means you did too much – ease back for a day rather than stopping. Take your prescribed painkillers about 30–45 minutes before your main exercise session.

Swelling and warmth. The knee stays warmer and more swollen than the other side for 3–6 months, and mild warmth can last up to a year. Ice for 15–20 minutes after exercise, raise the whole leg (not just the knee) above heart level, and keep walking in short, frequent bouts rather than one long one.

Sleep. Night pain and poor sleep are very common for the first 6–8 weeks. Sleep on your back with the knee straight, or on your side with a pillow between the knees. Discuss sleep medication with your doctor rather than self-medicating.

Diet. Eat enough protein (dal, pulses, paneer, curd, eggs, fish, chicken) to rebuild muscle, keep up fluids, and control blood sugar if you are diabetic – high sugar slows healing and raises infection risk. Losing excess weight reduces load on the new knee over the long term. Supplements such as glucosamine or collagen have no proven role in recovery after knee replacement.

Common mistakes – and what you can do long term

Mistakes that slow recovery

A pillow under the knee – the main cause of a knee that will not straighten.
Doing everything in one long session – short sessions several times a day work better and cause less swelling.
Skipping exercises on painful days – reduce the dose, but keep the knee moving.
Overdoing it on a good day – the knee often swells the next day; build up by about 10% a week.
Stopping once the walker is gone – the quadriceps keep getting stronger for months if you keep working them.
Copying generic online videos – your programme should fit your stage, your bend and your other joints.

Activities after knee replacement

Usually fine	Usually fine with experience and care	Generally discouraged
Walking, cycling, swimming, aqua-aerobics, yoga (avoiding deep knee bends), golf, ballroom dancing	Doubles tennis, badminton, hiking, light gym weights, cricket (non-competitive)	Running, jumping, football, kabaddi, basketball, squash, heavy squats and lunges

A systematic review of 18 studies (Witjes et al., Sports Medicine 2016) found 36–89% of people returned to sport after TKR, mostly low-impact sports, at an average of about 13 weeks.

Can I kneel?

Kneeling does not harm a knee replacement, but most people find it uncomfortable. Across cohort studies 56–82% report difficulty kneeling after TKR, and this often does not improve with time. Kneeling on a soft cushion, on one knee at a time, after the wound is fully healed, is reasonable to try. For prayer or floor-sitting, a low stool is often more comfortable.

Warning signs: when to call us

Go to the nearest emergency department or call 108 if you have:

Sudden breathlessness, chest pain or coughing up blood (possible clot in the lung)

Call your surgeon the same day if you notice:

Calf pain, tenderness or swelling in one leg (possible deep vein thrombosis)
Fever above 38°C, or redness, increasing warmth or discharge from the wound
A wound that opens or keeps oozing after the first few days
Pain that is getting steadily worse rather than better
A sudden loss of bend or ability to straighten, or the knee giving way
Not being able to take weight on the leg

Book a review if: the knee is stuck well short of 90° of bend at 6 weeks, will not straighten fully, or swelling and pain are not steadily improving.

Knee replacement rehabilitation at Sports Orthopedics Institute, Bengaluru

At Sports Orthopedics Institute in HSR Layout, Dr Naveen Kumar L.V. and our physiotherapy team plan your rehab before surgery and follow it through to full recovery:

Pre-operative teaching and a home exercise programme
Walking and physiotherapy from the day of surgery
Range-of-motion and quadriceps-strength checks at every review, so stiffness or weakness is picked up early
Supervised physiotherapy where you need it, and a clear home programme where you do not
Early action for stiffness, including manipulation under anaesthesia within the window when it works best

Book a consultation: 📞 +91 6364538660 | +91 9008520831 📍 1084, 2nd Floor, Shirish Foundation, 14th Main, 18th Cross, Sector 3, HSR Layout, Bengaluru 560102 🌐 sportsorthopedics.in

Frequently asked questions

How soon can I walk after a knee replacement?

Most people stand and walk a few steps with a walker on the day of surgery or the next day. Many move to a single stick by 2–4 weeks and walk without an aid indoors by about 4–6 weeks.

How long does full recovery take after total knee replacement?

Most people are back to everyday activities by about 3 months. Strength, stamina and comfort keep improving for up to a year, and some warmth and swelling can last that long.

Do I need a CPM machine at home?

Not for a routine knee replacement. A Cochrane review of 24 trials found CPM adds only about 2° of bend and makes no meaningful difference to pain or function. Your own active exercises are more useful.

Is home physiotherapy as good as going to a clinic?

For most straightforward cases, yes – trials show similar results, provided the programme is well taught and someone checks your progress. Supervised sessions are worthwhile if your bend or walking is not improving.

How much should my knee bend after a knee replacement?

Aim for a fully straight knee and about 110–120° of bend by 3 months. Around 90° is needed for stairs and chairs and 105–110° for low seats and putting on shoes.

When can I drive after knee replacement?

Braking studies suggest reaction time returns by about 4 weeks after a right knee replacement and as early as 2 weeks after a left one in an automatic car. Only drive once you are off strong painkillers and can perform an emergency stop safely.

Can I sit cross-legged or squat after a knee replacement?

Most knee replacements do not bend enough for comfortable squatting or cross-legged sitting, and repeated deep bending under load is best avoided. Use a chair, a western toilet and a low stool for floor-level tasks.

Is cycling good after knee replacement?

Yes. Stationary cycling is one of the best exercises from about 2 weeks onwards for both bend and stamina. Start with the seat high and no resistance.

Why is my knee still swollen and warm months later?

This is normal for 3–6 months and sometimes up to a year. Swelling that suddenly increases, with fever, redness or new pain, needs checking for infection.

References

Jette DU, Hunter SJ, Burkett L, et al. Physical therapist management of total knee arthroplasty (APTA clinical practice guideline). Physical Therapy. 2020;100(9):1603–1631. Link
Harvey LA, Brosseau L, Herbert RD. Continuous passive motion following total knee arthroplasty in people with arthritis. Cochrane Database Syst Rev. 2014;CD004260. Link
Buhagiar MA, Naylor JM, Harris IA, et al. Effect of inpatient rehabilitation vs a monitored home-based program on mobility after knee arthroplasty. JAMA. 2017;317(10):1037–1046. Link
Florez-García M, García-Pérez F, Curbelo R, et al. Efficacy and safety of home-based exercises versus individualized supervised outpatient physical therapy after total knee arthroplasty: systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc. 2017;25(11):3340–3353. Link
Stevens-Lapsley JE, Balter JE, Wolfe P, et al. Early neuromuscular electrical stimulation to improve quadriceps muscle strength after total knee arthroplasty: a randomized controlled trial. Physical Therapy. 2012;92(2):210–226. Link
Prehabilitation is effective in relieving pain after knee arthroplasty, but has little effect on length of stay and knee function: a meta-analysis of randomized controlled trials. Link
Hartman J, Thornley P, Oreskovich S, et al. Braking time following total knee arthroplasty: a systematic review. J Arthroplasty. 2017;33(1). Link
Mamarelis G, Sunil-Kumar KH, Khanduja V. Timing of manipulation under anaesthesia for stiffness after total knee arthroplasty. Ann Transl Med. 2015. Link
Witjes S, Gouttebarge V, Kuijer PP, et al. Return to sports and physical activity after total and unicondylar knee arthroplasty: a systematic review and meta-analysis. Sports Medicine. 2016. Link
Kneeling difficulty after total knee replacement – overview of cohort studies. EFORT Open Reviews. 2019;4(7):460–467. Link

Medical disclaimer: This article is for general information and patient education only. It does not replace advice from your own surgeon or physiotherapist, whose protocol should always take priority. If you have symptoms after surgery, contact your treating doctor.

Knee Replacement Recovery: Week-by-Week Exercises and Timeline