At our Galway-based physiotherapy clinic, we commonly treat ligament injuries of the knee. There are four main ligaments in the knee complex that can be injured: 1) Anterior cruciate ligament (ACL); 2) Medial collateral ligament (MCL); 3) Lateral collateral ligament (LCL); and 4) Posterior cruciate ligament (PCL).

ACL 

ACL injuries are relatively common knee injuries among athletes. They occur most frequently in those who play sports involving pivoting (e.g. football, basketball, netball, soccer, European team handball, gymnastics, downhill skiing). They can range from mild (such as small tears/sprain) to severe (when the ligament is completely torn). Both contact and non-contact injuries can occur, although non-contact tears and ruptures are most common. It appears that females tend to have a higher incidence rate of ACL injury than males, that being between 2.4 and 9.7 times higher in female athletes competing in similar activities.

Interestingly the ACL is most commonly injured in non-contact situations. This is caused by forces generated within the athlete’s body whilst most other sport injuries involve a transfer of energy from an external source. Approximately 75% of ruptures are sustained with minimal or no contact at the time of injury. A cut-and-plant movement is the typical mechanism that causes the ACL to tear, being a sudden change in direction or speed with the foot firmly planted. Rapid deceleration moments, including those that also involve planting the affected leg to cut and change direction, have also been linked to ACL injuries as well as landing from a jump, pivoting, twisting, and direct impact to the front of the tibia.

MCL

MCL is a big ligament on the medial (inside) side of the knee joint. MCL injuries describe a stretch, partial tear, or complete tear of the ligament on the inside of the knee. It is one of the most common knee injuries and results mostly from a valgus force on the knee such as an impact on the outside of the knee, lower thigh or upper leg, when the foot is in contact with the ground and unable to move.

The MCL on the inside of the knee will become stressed due to the impact, and a combined movement of flexion/valgus/external rotation will lead to tears in the fibres. The athlete might feel immediate pain and feel or hear a popping or tearing sound. Mostly the deep part of the ligament gets damaged first, and this may lead to medial meniscal damage or anterior cruciate ligament damage.

As with all the ligament injuries, the MCL injury is graded I, II or III (this grade is given depending on the degree of sustained tear). A grade I tear consists of less than 10% of the collagen fibres being torn, with some tenderness but no instability.

Grade II tears vary in symptoms and therefore they are broken down further to grades II- (closer to grade I) and II+ closer to grade III, but both of them count as having tenderness but no instability. The pain and swelling are more significant than with grade I injuries. When the knee is stressed (as for grade I), patients complain about pain and significant tenderness on the inside of the knee, and moderate laxity in the joint is observed.

Obviously, this means that a grade III tear is a complete rupture of the MCL resulting in instability. Patients have significant pain and swelling over the MCL. Most of the time they have difficulty bending the knee.

LCL

The lateral collateral ligament (LCL), or fibular collateral ligament, is one of the major stabilizers of the knee joint with a primary purpose of preventing excess varus and posterior-lateral rotation of the knee. Although less frequent than other ligament injuries, an injury to the LCL of the knee is most commonly seen after a high-energy blow to the anteromedial knee, combining hyperextension and extreme varus force.

The LCL can also be injured with a non-contact varus stress or non-contact hyperextension. The LCL most commonly occurs in sports (40%) with high velocity pivoting and jumping such as soccer basketball, skiing, football or hockey. Tennis and gymnastics have been shown to have the highest likelihood of an isolated LCL injury.

The LCL is rarely injured alone and therefore additional damage of the ACL, PCL, and posterior-lateral corner (PLC) is common along with the LCL when the lateral knee structures are injured.

PCL

The PCL is one of the two cruciate ligaments of the knee. It acts as the major stabilising ligament of the knee. It prevents the tibia from excessive posterior displacement in relation to the femur. It also functions to prevent hyper-extension and limits internal rotation, adduction and abduction at the knee joint. The PCL is twice as thick as the ACL which results in less injuries than the ACL due to its stronger nature. As a result, PCL injuries are less common than ACL injuries.

Here at West Coast Physio, our physios are experts at assessing and diagnosing your knee injury. We are able to lead you on the right path in managing and rehabilitating your knee injury.