Knee rehabilitation is the programme of exercises and stretches undertaken in order to return the knee to as full a function as possible.

Page updated June 2023 by Dr Sheila Strover (Clinical Editor)

step-up rehab exercises
Rehabilitation is divided into stages. It is important to understand both the objectives and the stages, so that you don't progress too fast and inflame the knee, or go too slow and end up with adhesions and arthrofibrosis limiting your eventual range of motion. If you are just looking for exercises, see the page on early knee exercises.


Early - Protect the joint and limit swelling

Immediately after an injury or surgery, the knee must be protected from infection with dressings, and movement contained with an immobiliser brace or a splint. The leg should be elevated to limit internal bleeding or prevent excess fluid being secreted in the joint, which will cause swelling and be painful. However, this immobile stage must not be longer than a few days or the quads muscles may become inhibited and not 'fire' properly when you get going again.

A key step very early on is P.R.I.C.E., which is a nemonic for 'protect', 'rest', 'ice', 'compression' and 'elevation'.

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Early - Reduce inflammation

Intermittent cryotherapy and anti-inflammatory medication will both help to reduce irritation of the joint lining and accumulation of fluid inside the joint cavity. The iced water will help with the swelling, and bulky dressings can be removed for the treatment session and then replaced afterwards. A helper may intermittently take the knee through a gentle passive range of motion. If continuous passive motion (CPM) is available, then this will help to keep swelling down.

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Early - Identify early infection

Usually any knee infection is just superficial - perhaps from a graze or surgical wound. But any infection should be brought under control, because a deep infection of the knee is considered an emergency situation. Superficial infection may show some skin redness and localised swelling, and perhaps some minor creamy discharge, but with deep infection the whole joint may be hot, swollen and red. Superficial infection may be managed with a topical antiseptic and frequent dressing changes, but deep internal infection (septic arthritis) may require joint aspiration and lavage (washing out) and serious antibiotics, perhaps even intravenously. This is to prevent later serious joint stiffness.

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Early - Limit muscle inhibition

After injury or surgery, the quadriceps (quads) muscle of the lap frequently becomes inhibited. The muscle is there but just won't work! - the patient simply finds it almost impossible to make the leg straughten without help. Passive range of motion exercises will keep the joint mobile (eg facilitated heel slides and passive extension), but the mainstay of active exercise to get the quads working again is quads sets (or static quads).

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Early - Free adhesions

Adhesions are sticky strands that can form in the soft tissue layers from residual blood or joint fluid. They lock up the joint and make it stiff. Appropriate massage and stretching can break up the strands before they mature into scar tissue. Most important are adhesions around the kneecap, because they can lock up any movement of the patella and create painful stiffness of the joint. So patellar mobilisation exercises are critical at this stage.

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Later - Restore range of motion

After injury or surgery, quads muscle inhibition may continue to make full active extension difficult, but it is important to prevent the development of an extension lag. Passive extension exercises should be continued, as well as prone hangs. Special extension devices may be available at the gym. Flexion can be improved with active assisted flexions and facilitated wall slide exercises. Regaining full extension is more critical than regaining full flexion, because full extension enables 'lock back' when one stands unsupported.

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Later - Regain proprioception

Proprioception is the joint's own awareness of where it is in space. Loss of proprioception can lead to stumbling or falling, with further injury. A wobble board is very useful as well as a mini trampoline..

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Advanced - Restore normal gait patterns

Continued limping leads to imbalance in the muscle groups. Normal gait must be restored to prevent strain in the back or hip or the other leg. Side-stepping, carioca and figure-of-eight exercises will help.

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Advanced - Rebuild muscle strength

Eventually muscle strength will stabilise the joint and protect it from further injury, but all the preceding issues must be addressed before trying to rebuild muscle strength. Appropriate exercises are leg curls, rowing machine, cross trainer, static bicycle and treadmill.

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