Conditions and treatments
PCL INJURIES
The posterior cruciate ligament is responsible for controlling rotation and translation between the thigh (femur) and leg (tibia), being a core stabiliser of the knee.
In movements such as twisting and turning it is a core structure in controlling motion. Thus, when injured the biomechanics of the lower limb may change dramatically.
What causes a PCL injury?
Fortunately, PCL injuries are rare events, usually caused by severe knee trauma, where other ligaments are also torn. There are several ways the PCL may tear, but the most frequent mechanisms are bad landing (hyperextension, knee moving backwards) or direct impact on the front of the leg (tibia) forcing it to move backwards.
What are the symptoms and how is it diagnosed?
Many people hear a “pop” or a “snap”, and feel the knee giving way. This is followed by intense pain, swelling, and difficulty bending/straightening the knee or weight-bearing on the affected limb.
Over time, the symptoms subside, but the person reports “I can’t trust my knee”, particularly while rotating, quickly changing directions or walking downhill. If left untreated, this instability leads to difficulty practising some sports or in heavy labour, as instability and further articular cartilage or meniscus injuries may develop. When a PCL tear occurs along with other ligament ruptures (multi-ligament injury) the instability is so significant that the clinical set up is much more dramatic. In the long term, the joint maybe prone to develop symptomatic osteoarthritis since there are abnormal mechanical loads in the joint.
Diagnosis of PCL tear is made by a physician through careful medical examination, where symptoms are interpreted, and a systematic gait and joint analysis is performed. When an injury is suspected, a MRI scan may identify the tear, as well as assess other joint structures.
How is it treated?
Fortunately, where there is an isolated PCL tear healing is possible. On the other hand, in multi-ligament injuries surgery is mostly needed due to a significant degree of instability.
Either way, the first step is to control pain, swelling and reestablishing as much range of movement of the knee as possible. Ice, pain killers, crutches are the first aid during initial assessment. After correct observation, diagnosis and understanding the pattern of your injury (isolated PCL vs. multi-ligament) the physician will advice you on what is the best treatment. For isolated PCL injury, conservative treatment is usually indicated. The use of a special knee brace is almost mandatory to increase the chances of healing. In parallel, a stepwise (and demanding) rehabilitation programme is initiated. First, pain and swelling management, controlled joint mobilisation, and early activation of the muscles around the knee is promoted as they are impaired by pain. Secondly, the focus will be on normalising your gait, training your balance, reestablishing your muscle activation patterns and their responses to external stimulus. Thirdly, strengthening, conditioning and proprioception training will help you dealing with the “new knee”. Finally, you will start all the activities you are keen on doing, testing your ability to cope with them. Unfortunately, when conservative treatment doesn’t work surgery is needed.
In multi-ligament injuries surgery is mostly indicated. The goal is to reconstruct the PCL and other torn ligaments to provide stability to the joint, thereby minimise further damage of the knee and improving your quality of life. The reconstructions are made with tendons (one that belongs to you or one from a cadaver) that will replace the torn native ligaments, being these called “grafts”. There are different grafts options, being the choice individualised. During surgery, the inside of the joint is visualised through key holes in a procedure called arthroscopy. With the aid of a camera and tolls, the knee is inspected, all damaged structures are fixed, and the grafts are placed and fixed. What follows is a staged rehabilitation programme similar to the one described. It will be explained to you, and progression between stages will not be only guided by a timeframe that respects the biological healing, but also by the state of your condition. Thus, your progression is closely monitored and tested to ensure the knee is ready for the future demands it will face. At the end, you will be given a set of prevention programmes to lower the risk of reinjury, optimise your performance, and keep you moving.
