Anterior Cruciate Ligament Injury
This is quite a common injury especially in sports which involve a lot of pivoting and turning such as football, netball and skiing. The injury often follows a non contact pivoting type manoeuvre. Occasionally a ‘pop’ may be heard as the ligament ruptures and this is followed by pain and swelling. The injury may initially seem to settle (perhaps with physiotherapy) but the knee often feels weak and unstable. There may be further episodes of giving way and swelling particularly on attempted return to sport although this can also occur during normal daily activities.
It is usually fairly easy to diagnose this injury by a careful history and physical examination by an experienced physiotherapist or doctor. There can sometimes be associated injuries to other important structures of the knee such as meniscus (cartilage) tears, other ligament tears or sprains or joint surface damage. An MRI scan may be requested to assess the knee for these associated injuries.
Initial management should comprise rest, ice, and a knee support to allow the initial pain and swelling to settle. Physiotherapy is then often helpful to help regain full range of movement and strengthen the thigh muscles (quadriceps and hamstrings). It would then be appropriate to see a knee specialist to discuss the relative pros and cons of ongoing conservative management or whether it would be more appropriate to undergo ACL reconstruction. This would depend on a number of factors including the degree of instability of the knee, the level of activity the individual wishes to undertake and the relative risks of secondary damage occurring in the presence of an unstable knee.
Surgical reconstruction of the ACL can now be done as a day-case or a single overnight stay in hospital. A successful reconstruction should not require the use of a brace and allow immediate full weight bearing mobilisation which is optimal for healing tissue and joint nutrition.
There are two main reliable modern methods of reconstruction using either patella tendon or hamstring tendons as grafts to replace the ruptured anterior cruciate ligament. Both techniques have been shown to be effective.
This is essential after anterior cruciate ligament reconstruction. This should be supervised by an experienced sports physiotherapist and access to a gym is essential. Full strengthening and maturing of the graft for a safe return to sport will take a minimum of 9 – 12 months. There is evidence that a return to football before this time is associated with a higher re-injury rate.
The success rate of reconstructions is high and in the 90% category if measured in terms of a successful and safe return to sport with a stable knee. There is evidence that those people who have already sustained an ACL rupture fall into a slightly higher risk category for re-injury although this may equally affect the other knee. This emphasises the importance of a properly supervised rehabilitation program as these have been demonstrated to reduce these risks.