What knee replacement rehabilitation is
A total knee replacement resurfaces the ends of the thigh bone and shin bone, and usually the back of the kneecap, with metal and polyethylene components. It is one of the most successful operations in orthopaedics, with around 90 per cent of implants still in place at fifteen years.
Rehabilitation runs alongside the surgery rather than after it. The soft tissues respond to surgery by tightening, and the window in which range of motion is most readily gained is the first six to twelve weeks.
Nothing here replaces the protocol from your own surgical team. Where their instructions differ from anything on this page, follow theirs, because implant type and surgical approach change the specifics.
What causes it
The two things that most often limit the long-term result are loss of full extension and failure to regain flexion in the early window. Both are avoidable with consistent work in the first weeks.
Swelling drives both. A swollen knee inhibits the quadriceps reflexively, which makes straightening harder, which reduces walking quality, which keeps the swelling up.
What determines the result
- Achieving full extension early, which matters more for walking than flexion does
- Regaining flexion within the first six to twelve weeks
- Controlling swelling consistently through elevation, movement and compression
- Restoring quadriceps activation, which is inhibited after surgery
- Pre-operative strength and range, which predict the post-operative result
- Sticking with the programme past the point where daily tasks feel manageable
Full extension is worth prioritising above flexion, because a knee that cannot fully straighten changes gait permanently and loads the other joints. A practical target is being able to press the back of the knee flat against the bed. Many people focus on bending because that is the number the physiotherapist measures out loud, and lose the last few degrees of straightening without noticing until it is difficult to recover.
What the evidence says
Supervised rehabilitation improves outcomes compared with a home programme alone, particularly in the first three months, with better range and function scores.
Prehabilitation, meaning strengthening in the weeks before surgery, is associated with better early post-operative function and a shorter hospital stay.
Achieving around 90 degrees of flexion by six weeks is a commonly used marker. Struggling to reach it by then is the point at which surgical teams start considering manipulation under anaesthetic, which makes early work time-sensitive.
Strength deficits in the operated leg commonly persist for a year or more without deliberate strength training, which is why rehab that stops at three months tends to leave function on the table.
Cryotherapy and compression help manage swelling in the early weeks and improve comfort, without changing the eventual range.
Recovery timeline
Typical milestones: walking with aids within days, off crutches around four to six weeks, driving at around six weeks for a right knee if you can perform an emergency stop, and a return to most daily activities by three months.
Swelling and warmth around the knee for three to six months is normal, and some people notice it for a year. Continued improvement out to twelve months is the usual pattern, so a plateau at four months is rarely the end point.
| Stage | ✓ Do this | ✗ Avoid this |
|---|---|---|
| Weeks 0–2 | Extension work several times daily, ankle pumps, quads setting, gentle flexion. Elevate and ice. | Resting with a pillow under the knee, which sets up a flexion contracture |
| Weeks 2–6 | Progress flexion steadily toward 90–110 degrees. Begin closed-chain strength. Walk regularly. | Letting extension slip while chasing the flexion number |
| Weeks 6–12 | Strength work: leg press, step-ups, sit-to-stand progressions. Balance training. Stationary bike. | Stopping the programme because walking has become comfortable |
| 3–12 months | Continue progressive strengthening. Return to cycling, swimming, golf, walking distance. | Assuming the result at three months is the final result |
How we treat it at Kingsway
Post-operative rehab here
We work alongside your surgical team's protocol, adding hands-on treatment and progressive strength work that a hospital pathway rarely has the time for.
- Range of motion measured and tracked at every session, extension and flexion recorded separately
- Manual lymphatic drainage and soft tissue work for persistent post-operative swelling
- Joint mobilisation and patellar mobilisation, which is often overlooked and limits flexion
- Soft tissue release for the quadriceps, hamstrings and calf compensations that develop
- Progressive strength programme through the six week to twelve month window
- Gait retraining, since limping habits outlast the reason for them
Rehab here usually starts once the surgical team is happy for hands-on work to begin, often around two to six weeks. A course through to the three-month mark, then periodic reviews out to a year, matches how the recovery actually runs. The ten or twenty session packages fit this timeline.
When to get it checked
Follow your surgical team's follow-up schedule. Book additional rehab if your flexion is behind the target your team set, if you are struggling to fully straighten the knee, or if you have reached three months and want the strength work that gets you back to cycling, golf or hill walking.
See a doctor or go to A&E if
- Calf pain, swelling, warmth or redness, which needs a blood clot excluded urgently
- Fever, wound discharge, spreading redness or increasing wound pain, which can indicate infection
- Sudden severe pain, or a knee that gives way completely
- Chest pain or shortness of breath, which requires emergency assessment
- A sudden loss of range you had previously achieved
Common questions
How much bend should I have by six weeks?
Around 90 degrees is a commonly used marker, with 110 to 120 as a longer-term target. Your surgical team will have set specific goals for your implant and approach, and those take precedence.
Being significantly behind at six weeks is worth raising promptly, since manipulation under anaesthetic is a time-limited option.
Is it normal for the knee to still be swollen at three months?
Yes. Swelling and warmth for three to six months is typical, and some people notice it for a full year.
What is worth reporting is a sudden increase in swelling, or swelling with fever, redness or wound changes.
When can I get back to sport?
Walking, cycling, swimming and golf are usually encouraged and most people return between three and six months. Doubles tennis and similar are often possible later in the first year.
High-impact running and jumping sports are generally advised against, since they shorten implant life.
Why is the pain worse at night?
Night pain is common in the first two to three months, related to inflammation and to the absence of daytime distraction and movement.
It usually eases considerably by three months. Persistent severe night pain beyond that is worth reporting to your surgical team.