Total knee arthroplasty — rehabilitation protocol

Adults following primary elective total knee arthroplasty, most often for osteoarthritis, with an uncomplicated recovery. The programme does not automatically apply to partial replacement, revision surgery, an acute fracture or additional ligament or extensor mechanism reconstruction.¹

Before starting, establish permitted weight-bearing, movement restrictions, any additional repairs, wound condition and limb control after anaesthesia. Record preoperative range of motion, the condition of the other leg and the home environment.

Surgical approach and fixation

A standard medial parapatellar, midvastus or subvastus approach does not require a separate weekly schedule in this protocol. Tailor the programme to function and the documented restrictions. Closure of a standard arthrotomy is not equivalent to repair of a torn tendon. An additional extensor mechanism or ligament repair, or an osteotomy, may require separate protection.

With stable fixation, weight-bearing as tolerated with crutches or a walking frame is often permitted. A cementless implant does not automatically prohibit full weight-bearing. In a randomised trial of a particular TKA model, rehabilitation in both cemented and cementless groups included full weight-bearing from the day of surgery. Do not generalise this to unstable fixation, fracture or every implant model.⁴

Weight-bearing as tolerated allows loading of the operated leg to increase up to the level permitted by the orthopaedic surgeon. Absence of pain does not authorise exceeding a prescribed limit. Permission to walk does not authorise heavy resistance, sudden twisting or deep squats.

Pain management enables movement

The patient takes regular medicines according to the prescribed schedule and rescue medicines as needed. Selection accounts for contraindications, other illnesses and anticoagulant treatment. Do not delay baseline treatment until pain prevents exercise, or increase doses to force movement. Report inadequate analgesia to the team.⁵

Cooling may reduce symptoms and swelling. Protect the skin and monitor sensation and tissue response. Elevation and breaks in activity complement the programme. Positioning method and duration are individualised.¹

Do not keep a pillow permanently under the knee, encouraging persistent flexion. This does not prohibit brief support during exercise or deliberate positioning to reduce swelling. During extension exercises, support the distal lower leg, protect the heel skin and do not force the knee down.

Walking and ankle pumps do not replace prescribed thromboprophylaxis. Do not independently change its duration or dose.²

The numbers are indicative end-of-phase goals, rather than maximum permitted ranges or requirements for the first session. Uncomplicated TKA does not routinely require a six-week 90° flexion limit. Regain range without forcing and while protecting the healing wound.

The poster uses five phases: 0–2 weeks, 2–6 weeks, 6–12 weeks, 3–6 months and beyond 6 months. Phase II aims for full extension and gradual progression beyond 90–100° flexion; in phase III, functional flexion is often approximately 110–120°. This neither prohibits achieving a greater range earlier nor requires these values despite pain.

More detailed reference points can also help monitor the early weeks: approaching full extension and more than 70° flexion by the end of the first week, more than 90° around week four, and approximately 110° or more around week eight, if achievable without forcing. These are checkpoints, not separate treatment phases. Preoperative status and the actual trend of improvement matter.

Extension of 0° means neutral alignment, not hyperextension. Measure passive range, active range and active extension lag separately. If the knee can be straightened passively but the patient cannot maintain that position, regaining muscle control is also a goal. If passive extension is restricted too, work on mobility and assess the cause. Repeat measurements in a comparable position.³

The following exercises are examples, not a list to complete in full from day one. Following instruction, the patient may perform a selected set independently. The physiotherapist records the range, repetitions, frequency and rules for increasing difficulty.

Initial exercises

Quadriceps sets: support the leg, gently straighten the knee and tighten the front of the thigh. For example, hold for 5–10 seconds, then rest, without holding the breath. Heel slides: slide the foot towards the buttock, then return. The other leg or a strap may assist, without jerking.

Extension with lower-leg support: place support near the ankle, with no pillow under the bent knee; allow the relaxed leg to straighten gradually. Straight-leg raise: first tighten the quadriceps, then lift slightly; if extension is lost, make the task easier. Do not add an ankle weight for this test.

Functional exercises

Sit-to-stand: use a stable chair, higher and with armrests if needed. Low step: step up and lower slowly with a handrail. Mini-squat: use a worktop for support without letting the knee collapse inwards. Increase height, depth and resistance only with good control.¹

A daily programme does not mean heavy training every day

Practise mobility, short walking distances and the activation exercises learned regularly at home. Resistance training has a separately selected frequency and recovery schedule. There is no need to delay every strengthening exercise until week six, but intensity must not exceed muscle control and tissue tolerance.⁶

In a trial comparing early higher- and lower-intensity training, both programmes improved function, with no demonstrated advantage of higher intensity in the main outcomes. Greater resistance is therefore not an end in itself. Adjust the dose according to pain, swelling, range and movement quality.⁶

After a session, also check the following day’s response. Clearly increased effusion, poorer gait or loss of gained range call for a lower dose and assessment. Mild, transient stretching discomfort does not necessarily mean damage; sharp or increasing pain is a reason to stop the task.

NMES — neuromuscular electrical stimulation: introduce early to supplement quadriceps activation. The 2026 guideline recommends at least daily use, at the highest tolerated intensity that produces an effective contraction. The physiotherapist assesses parameters, electrode placement and contraindications. Activation inhibition and active extension lag are particularly relevant.¹

Passive, assisted and active movement are parts of the programme; they do not replace strengthening or gait training. Patellar and tissue mobilisation may support exercise, with attention to the wound. Do not routinely use a CPM machine or a brace solely to increase range after uncomplicated primary TKA. An exception following an additional repair or treatment of stiffness requires a separate prescription.¹

Record pain at rest and during movement, swelling, wound condition, active and passive range, quadriceps activation, gait and need for assistance. Later, compare strength and task performance: chair rises, Timed Up and Go, walking and stairs. The other affected knee is not always a suitable reference for percentage symmetry.^{1, 6}

Lack of progress is not an indication to force through resistance. If range fails to increase or decreases across successive reviews, investigate why. Practical reasons for earlier discussion with the surgeon include flexion still below approximately 90° at weeks 4–6 without an improving trend, or a persistent significant extension deficit. These do not automatically diagnose adhesions or indicate surgery.

Consider pain, effusion, wound problems, infection and mechanical causes, among others. When manipulation under anaesthesia is considered, timing matters — outcomes are often better within the first three months.⁷ This does not mean waiting three months to seek advice. The surgeon decides further treatment.

From first standing to basic independence

Rehabilitation starts on the day of surgery if the clinical condition allows, generally within 24 hours.¹ Standing requires supervision, recovered limb control and tolerance of position changes. Absence of pain after a nerve block does not mean the patient is ready to walk independently.

Teach transfers, walking with aids and turning with small steps. Exercises include ankle pumps, quadriceps sets, heel slides and gentle extension. Perform straight-leg raises when the patient can maintain knee extension; if the knee drops into flexion, provide assistance and rebuild activation.

Before discharge: safe basic activities, stair competence if needed, an understandable home programme, controlled pain and an agreed route of contact with the team. A flexion measurement alone does not replace safety assessment.²

After returning home, continue short, regular movement sessions and walking distances with the necessary assistance. Work on extension and flexion while monitoring the wound, pain and swelling. End-of-phase goal: basic independence, safe walking with aids and gradual improvement in knee control.

Improve active extension, chair rises and even weight transfer. Tailor permitted seated exercises, supported mini-squats and hip movements to limb control. Gradually introduce resistance and balance tasks without increasing effusion or losing technique.¹

A stationary bicycle can provide gentle movement once mounting it and sitting on the saddle are safe. If flexion is insufficient, start with part-revolutions; do not force the pedal round. Smooth movement matters more than resistance initially.

Reduce walking assistance when the knee does not buckle under body weight and gait does not deteriorate after several passes. The indicative 2–6 weeks of crutch use shown on the poster is not a compulsory deadline for stopping them.

End-of-phase goal: work towards 0° extension, gradually improve flexion beyond 90–100°, reduce effusion and walk more confidently. Goals must not be achieved at the expense of healing.

Increase exercise difficulty: seated knee extension with selected resistance, chair rises, low step-ups, mini-squats, and hip and calf exercises. Initially practise balance with stable support. Add load gradually without increasing effusion or losing technique.¹

Also practise controlled lowering when stepping down. If the knee buckles suddenly, reduce step height or resistance, or use a handrail. Do not substitute excessive trunk lean for knee function.

Develop longer walks, cycling and safe single-leg tasks.¹ Tailor exercises to planned work and living conditions. Greater fatigue should not cause limping, knee buckling or loss of control when turning. Pool exercises may be introduced once the wound has healed and clearance is given.

End-of-phase goal: maintained extension, functional flexion — often approximately 110–120° — improved strength, more efficient stairs and walking with the least necessary assistance. Twelve weeks elapsed does not automatically authorise running, jumping or full sports training.

Continue strengthening, endurance and movement-control exercises. Gradually increase the difficulty of tasks needed for daily life and work. Prefer low-impact activities⁸: walking, cycling, swimming after wound healing and suitable recreation.

Return to a more demanding sport depends on previous skills, the course of treatment, function and a shared risk assessment. There is no single return month for everyone. Persistent limping, effusion or difficulty controlling the knee call for reassessment, rather than simply more exercises.⁸

End-of-phase goal: independence and tolerance of agreed activities without increasing symptoms or reinforcing compensatory movement patterns.

Maintain strength, endurance, balance and regular activity. Cycling on the poster is an example of recreation, not an exercise reserved until this phase.

Sports involving running, jumping or a high injury risk are not routinely recommended after TKA. Participation is assessed individually, according to preoperative function, the course of treatment and rehabilitation, and the type of activity. Individual clearance does not guarantee implant safety.⁸

Goal: lasting function that meets the patient’s needs. Rehabilitation does not automatically end on reaching a particular flexion measurement; continue developing strength and endurance.