When are knee braces useful? I get asked this question frequently especially by people with arthritic knees, ligament injuries and those trying to prevent deterioration of an already troublesome knee.
Lets consider how a brace helps the knee. It can be broken down into to 4 main functions.
- The brace aims to change the alignment or angle of the knee.
- It is designed to control or guide movement
- The brace is enhancing proprioception. Proprioception is the brain’s unconscious “awareness” of where the knee is in space, the loads going through it and how it is moving.
- A tightly fitted brace will compress the knee reducing the tendency for it to swell. A tight fitting knee sleeve will also cause friction on the skin when the knee moves which boosts proprioception. Good proprioception will enhance the control and timing of muscle contraction.
Let’s look at some examples of these 4 functions.
If you have a knee cap (patella) that dislocates or just tracks off line then a patella stabilisation brace helps physically guide the knee cap reducing the tendency for it to come out of joint. If the maltracking is causing the kneecap to be painful the improved tracking from using a brace will also reduce pain. There is also a proprioceptive effect from the tightly fitted knee sleeve.
If the knee has instability as a result of a ligament injury e.g Anterior Cruciate Ligament rupture a brace may help reduce the tendency to give way. How? The brace restricts the abnormal movement allowed by the damaged ligament. This in turn prevents the knee getting into a position where it will give way. Again there is a proprioceptive component that is related to the friction from the snug fit.
Osteoarthritis of the knee is a common condition that can be helped by bracing. There are two main reasons.
The first is that some braces are designed to try and gap open the worn side of the knee. This can be effective as the knee tends to wear down on either the inner or outer side. When an unloader type brace is put on the knee and done up correctly the painful worn side is literally unloaded by often reducing pain from the knee. There are some limitations of these braces in how much force they can offload. They probably won’t help if you want to run or do high impact sports but they can be very good for walks, gentle tennis and golf.
Osteoarthritic knees tend to swell up. Compression of the knee can reduce the tendency to swell. Swelling in the knee reduces proprioception so preventing swelling can help improve muscles control. In addition the friction of the tight knee sleeve on the skin enhances proprioception. Some people like a simple metal hinge in the knee sleeve but the majority of the benefit is likely to be from the tight knee sleeve alone.
A brace can be a helpful psychological support. This is frequently the case after a ligament reconstruction where putting a brace on the knee is felt to protect the knee. Its fine to use a brace in this way but it may be difficult to stop using it once you have started.
Prevention of injury.
If a brace prevents an unstable knee from giving way then this can potentially reduce the risk of further damage. Episodes of the knee giving way are not good for the knee.
Wearing a brace during sport when the ligaments are healthy has not been shown to reduce ligament injury in fact some studies have shown the opposite with an increased risk of injury in those who wore a brace.
There are some studies that suggest that wearing a brace after Anterior Cruciate reconstruction can reduce the risk of further injury to the reconstructed ligament. It should be noted that some studies have been sponsored by the brace manufacturer which does question whether the conclusions are free from bias.
For many situations a simple tightly fitting knee sleeve is all that is required. These cost about £30 to 40. A small modification of the knee sleeve to help control the patella results in an effective patella stabilisation brace. These cost about £80. There are some highly specialised braces like unloader braces and ACL braces that can specifically help over come abnormnal loads , pain and instability of the knee. These are the braces that tend to cost £400 plus.
My thoughts are that you are probably better off either sticking with a simple device that is under £100 for most situations or get one of the very specialised braces but prepared to pay in excess of £400. In most situations there is little to be gained from buying a brace that falls in between these two prices.
Remember that the brace is only as good as the way it has been fitted. It is advisable to have an orthotist to assess your needs, recommend a brace and fit it.
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