Ligaments are tough, inelastic tissues that hold joints in place. When a joint is forced beyond its normal range of movement, this almost always involves ligament damage. This is commonly known as a sprain, such as a sprained ankle.

Most sprains can be treated at home or with the advice of a GP. It is only rarely that a minor sprain will need to be seen by a sports injury expert or orthopaedic consultant. Surgery is used only in very severe cases, or where the speed of recovery is paramount, as it might be in someone who competes in a sport at professional level.

What are ligaments and what do they do?

The function of a ligament is to limit the degree of movement at a joint and to make sure that the joint remains stable. Commonly sprained joints include knees, ankles and wrists.

The anatomy of a ligament

Some ligaments are long and thin, like string. Others are more like flat sheets. The great strength of ligaments is due to a tough protein called collagen.

A normal ligament consists of:

  • Type 1 collagen – 90%: this is mature collagen in which the fibres are aligned. They have great tensile strength.
  • Type 3 collagen – 9%: this is immature collagen, which doesn’t have anything like the strength of type 1 but is needed to renew type 1 collagen over time.
  • Fibroblasts – 1%: specialised cells that produce collagen.

Different types of sprain

Various physical activities put undue strain on our ligaments which can then tear, either partially or completely. Sprains are classified into 3 different grades depending on how severe they are:

  • A grade 1 sprain is painful but the injury has torn only a few collagen fibres and the inflammation present is local and fairly low key.
  • A grade 2 sprain causes the joint to be intensely painful and there will be a lot of swelling because of more extensive damage to collagen fibres in the ligaments.
  • A grade 3 sprain is the most severe: the ligament has ruptured completely. The pain is excruciating, there is a lot of swelling and the joint is very unstable. In some cases of grade 3 sprains, surgical treatment will be necessary.

How long do sprains take to heal?

There are three distinct phases to the repair process:

  1. The inflammation phase: inflammation is a response to tissue damage. The joint is typically swollen, red, tender and painful. There is usually some internal bleeding.
  2. The repair phase: a blood clot forms over the damaged area. Blood platelets attach to the damaged tissue which results in a blood clot forming over the damaged area. Fibroblast cells multiply and begin to lay down immature (type 3) collagen fibres. This takes from three days to three weeks.
  3. The remodelling phase: regaining full strength ligaments can take months and sometimes up to a year. Initially, the collagen fibres are all type 3 and arranged at random, so the repair has little strength. In time, the fibres all mature into type 1, which are much more orderly and possess greater strength.

The ligaments are weaker during the recovery phase so the risk of injury is reduced by providing additional stability by strapping and/or by increasing the strength of muscles that also provide support to the joint.

The ligament gradually becomes stronger as the joint is used. A normal range of movement should be attempted without too much force, because this helps to align the fibres. This is the basic idea behind any exercise that the physiotherapist will prescribe for you.