ACL Tear Treatment

The anterior cruciate ligament runs diagonally through the centre of the knee, from the back of the thigh bone to the front of the shin, and it stops the shin sliding forwards and rotating out from under the thigh. It is the restraint the knee relies on whenever you plant a foot and turn.

Most tears happen without contact. A landing, a sidestep or a sudden change of direction loads the ligament beyond what it can hold, and the fibres part in one moment. Sports that involve pivoting on a fixed foot account for the great majority, and women tear it several times more often than men for reasons of alignment, hormones and landing mechanics.

The ligament sits inside the joint, bathed in joint fluid, which washes away the clot that healing would normally begin from. That is the reason the two ends almost never knit back together on their own, and the reason treatment is about restoring the restraint some other way.

The examination is what makes the diagnosis in experienced hands. Your surgeon holds the shin and draws it forwards with the knee slightly bent, comparing how far it travels against your other leg, and performs a second test that reproduces the shift of the joint as it rotates. A clear difference between the two knees is a more reliable finding than any single image.

A knee that filled with fluid within a couple of hours of the injury points strongly to this ligament, since blood inside the joint means something with a blood supply has torn, and this ligament is the commonest source.

MRI confirms it and, more usefully, maps what went with it. The meniscus, the collateral ligaments and the bruise pattern in the bone are all assessed, and that combination is what determines whether the knee needs one procedure or several. X-rays are taken to exclude a fragment pulled off the bone, particularly in teenagers.

The first phase happens before any surgery. A knee that is still swollen and will not fully straighten does badly if it is operated on, so several weeks are usually spent getting the swelling down, the range back and the thigh muscle working. Going into surgery with a quiet knee is one of the better predictors of the final result.

Afterwards the graft goes through a biological process that takes the best part of a year. It loses strength over the first weeks as the body remodels it, and only regains it slowly, so the programme is deliberately staged: crutches and range of movement first, strengthening from six weeks, running at three to four months, and change of direction later again.

Return to pivoting sport is rarely before nine months and often later. The decision is made on strength testing and hop tests against the other leg, and going back early is the single clearest risk factor for tearing it again.