Dr Sheila Strover highlights those important clinical things that need to evaluated immediately after knee injury or surgery.
First published in 2016, and reviewed August 2023 by Dr Sheila Strover (Clinical Editor)
This phase is immediately after injury or surgery. Focus is on:
- wound management
- protecting the limb
- minimising inflammation and swelling
- ensuring that nerves and blood vessels are functioning
Circulation Evaluation
After an injury or knee surgery, it is helpful to know a little bit about assessing blood circulation in the lower limb. These features suggest poor blood flow to the limb:
- Injured lower leg is quite a lot paler than the good leg.
- It is colder to the touch.
- The pulse, which is usually felt on the top of the foot, in the region between the big and second toe, but about an inch away from them, is less than the other leg.
If a bandage is too tight the circulation away from the limb can be obstructed and the toes might become swollen and darker in colour. Loosening the dressing should improve blood flow.
A serious problem of circulation after knee injury, and sometimes after surgery, is 'compartment syndrome'. The calf muscles and vessels are contained within fibrous compartments, and any bleeding within a compartment may cause an increase in pressure there, causing pressure damage to the blood supply and the nerves. Compartment syndrome is rare but is a clinical emergency - the calf will be tense, pain will be severe and constant, the limb pale and the patient will experience pins and needles.
Wound Evaluation
Most people have a reasonable idea of assessing a wound, so I will just make a few points here.
- The knee can suffer serious internal damage without there needing to be an obvious wound.
- High-speed gravel wounds (motorcycling) need particular attention, and if there is a deep gash be mindful that gravel can penetrate into the joint cavity.
- If any bone has penetrated the skin from an underlying fracture, this is always an emergency and one must go to hospital.
- Occasionally someone kneels on the carpet and has the impression of having knelt upon a sewing needle. A needle can penetrate a knee and apparently 'disappear' - do not be fooled and get an X-ray as soon as possible.
Neurological Evaluation
Nerve damage may occur during surgery, so it is important to be mindful of areas of numbness or any tendency to 'foot drop' where it is difficult to lift up the foot.
Let your doctor know early if these occur.
The peroneal nerve is quite commonly damaged where injury or surgery affects the area around the top of the fibula on the outer side of the knee. Foot drop is the usual consequence, with numbness or pins-and-needles of the skin on the outer calf and top of the foot (but not the little toe).
To test for numbness, an examiner can prick the area gently with a pin, sometimes turning the pin to 'prick' with the blunt end. the patient needs to identify when the skin has been 'pricked' and whether it is sharp or blunt.
PRICE/RICE Regime
This is one of the most important rehab concepts. When you have a knee injury, or after surgery, and you cannot decide the way forward the PRICE or RICE regime is good to remember. This stands for:
PRICE/RICE Regime
- P = Protection - Clean and protect the wound. Splint it if there is any suspected bone break or the joint feels wobbly.
- R = Rest - Rest the joint
- I = Ice - Ice the joint to decrease swelling and inflammation (cryotherapy).
- C = Compression - Use a compression bandage (but be careful not to put it so tight it upsets the blood flow.
- E = Elevation - Put the leg up on a chair or the sofa or bed. This helps to minimise swelling.
Managing Pain
Knee pain is normal after injury or surgery, but extreme pain and swelling may indicate that there is tense bleeding within the knee that may need draining.
Acute pain may respond well to the PRICE/RICE regime as this regime reduces the swelling and inflammation that leads to pain. Simple painkillers may be used for pain and anti-inflammatory tablets for inflammation.
Pain in the knee can also be triggered when the knee is under stress by 'knots' in the muscles around the knee - so-called trigger points. Massage of these trigger points may offer considerable pain relief.
Maintaining Circulation
It is important in this phase to maintain circulation. The lower leg is very dependent upon a 'muscle pump' in the calf. As one walks the muscle contraction and relaxation helps to keep the venous blood going back to the heart. If one is confined to bed or the sofa and the leg is immobilised this muscle pump is not working.
A useful exercise to stimulate the muscle pump is 'foot pumps.
Elevating the leg is also useful in keeping the venous blood flowing.
After surgery the surgeon may order tight 'TED' stockings which help to prevent the blood flow slowing down and forming clots in the veins (deep vein thrombosis). Anti-coagulant (anti-clotting) medication is also normal during and immediately after knee surgery.
Maintaining Quads Tone
When the knee is injured the quads muscles rapidly become inhibited.
An important exercise in this phase, and which can be done in bed or on the sofa, is 'static quads' (also called 'quad sets' or 'isometric quads'.
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