The Medial Collateral Ligament (MCL) is on the inner region of your knee joint and connects the thigh bone (femur) to the shin (tibia). Its function – along with the Lateral Collateral Ligament, is to provide stability to the knee joint, by preventing excessive sideways movement. It is also a source of ‘proprioception’ for the knee joint (providing feedback about joint positioning to the brain and helping with balance).
The MCL is commonly injured in sports such as football and rugby, and is the most commonly injured ligament of the knee. Injury typically occurs due to excessive force applied to the outside of the knee whilst the foot is planted, and particularly whilst the knee is slightly bent. This can lead to straining or rupturing fibres of the MCL on the inside of the knee (what is known as “valgus” stress). This injury can also occur via any mechanism which can ‘open up’ the inside of the knee joint such as blocking a pass/tackle in football with the side of your foot, or twisting motions during activities such as skiing.
In more severe/traumatic cases, injury to the MCL can sometimes be accompanied by injury to the meniscus of the knee, and the Anterior Cruciate Ligament.
The MCL can also be damaged by cumulative/repetitive use, but this tends to be less common.
If you have injured your MCL, you may present with some of the following:
Grade of MCL sprains, as any other ligament injury, are divided into 3 categories:
Grade 1: The least severe. A mild sprain involving less than 10% of the ligament fibres. You are likely to feel discomfort and possibly mild swelling, but will not have laxity/instability of the joint, and may even feel able to continue most normal activities. Typically return to full sport is within 4-6 weeks.
Grade 2: An increased portion of the ligament fibres will be ruptured compared to grade 2, and you will have pain, with possible swelling, and some instability. Typically return to sport is around 8-12 weeks.
Grade 3: Most severe. Full rupture (tear) of the ligament. Severe pain. Likely to involve instability of the knee joint. Difficulty bending the knee. Return to sports can be 3 months +.
Physiotherapist examination can help ascertain the degree of injury, and therefore the next suitable course of action.
Initial treatment for this type of injury will depend of the extent of damage. Initially ice and rest are used to control the swelling and help pain management. Some lesser injuries may simply require a short period of relative rest, and phased return to activity with some exercises, with little more concern. A more extensively damaged ligament may require bracing, and the use of crutches in the beginning, to help healing.
Physiotherapy treatment is then essential for the rehabilitation of more severe MCL injuries. It is important to regain full movement of the knee joint via stretching exercises, regaining power around the knee, particularly the quadriceps muscles, and improving stability/proprioception at the knee joint; all to help to return to full function, and help prevent future issues.
Surgery is rarely required for MCL injuries, may can be an option particularly if more than one ligament of the knee is affected, and if the knee joint is still particularly unstable after a period of physiotherapy. It will also be dependent on the desired level of function/sport.