ACL and PCL Injury
The anterior and posterior cruciate ligaments are tough bands of tissue in the central portion of the knee that connect the tibia and the femur. They are the main stabilisers of the knee and are important to control everyday knee movements especially during sport and recreation.
Either (or both) cruciate ligament(s) can be ruptured or torn by sudden twisting movements of the knee (e.g. when changing direction while running) or by a very heavy blow to the front or sides of the knee. When more than one ligament is injured, this is often a severe knee injury with the significance increasing according to how many ligaments are injured. It is possible to injure the cruciate and collateral (side) ligaments at the same time leading to a dislocation of the knee joint itself.
At the time of the injury, a pop or snap may be heard with immediate pain and swelling developing. Usually there is the inability to continue playing sport or bearing weight. These symptoms mostly resolve over the subsequent weeks, however longer term symptoms may eventuate. These include a sense of instability within the knee, where it may collapse, buckle or give way, or the feeling that you can’t trust your knee when walking on uneven surfaces or attempting to run up or down stairs. Frequently there is a sense of instability or even true giving way when trying to change direction (pivoting). Frequently one or both of the menisci (shock absorbers within the knee) are injured at the same time as the cruciate injury. These meniscal injuries may be a source of knee pain and further instability for the knee. Fortunately, meniscal injuries can frequently be addressed at the same time as surgery for the ACL or PCL injury.
The first line of treatment for an ACL, PCL or any other ligament injury is first aid. Rest, Ice, Compression (or bracing if multiple ligaments are injured) and Elevation are the mainstays of immediate management. Use of crutches and limited weight bearing may be required to assist with pain relief along with simple oral analgesia (tablet medication) such as anti-infammatories plus paracetamol. Once first aid has been completed, it is important to obtain imaging of the knee (x-ray and MRI) and assessment by an orthopaedic surgeon. Depending on the nature of your injury, physiotherapy is usually recommended to regain movement and reduced swelling in and around the knee.
Not all patients with a ruptured ACL or PCL need to have surgery to reconstruct it. Some patients are able to retrain the muscles of their knee with physiotherapy to make them strong and co-ordinated enough to compensate for the lack of function of the injured cruciate ligament. In these cases, surgery may not be necessary.
It is possible to play sport without a functioning ACL, however this can be very difficult in sports that rely on changing direction or pivoting. If you wish to play sports such as football, basketball, netball, rugby and others where pivoting is common, a functional ACL is very important. If there is an associated meniscal injury as well as cruciate injury, and meniscal repair is considered, there is a higher chance of the meniscal repair healing if the cruciate ligament is reconstructed at the same time. Longer term, there is an association with arthritis developing within the knee in people who have a deficient ACL or PCL. The risk of arthritis increases with continued playing of sport in the absence of a stable knee as well as any associated meniscus or cartilage damage present.