A Medial collateral knee ligament sprain or MCL sprain is a tear of the ligament on the inside of the knee. It is usually caused by twisting or direct impact, but may develop gradually over time through overuse. Here we explain the symptoms, causes, treatment and rehabilitation of an MCL sprain.
MCL sprain symptoms
Medial knee ligament sprains are graded 1, 2 or 3 depending on the severity of the injury. It is important to know how bad your injury is as this determines where you start from and how you progress on the MCL rehabilitation program.
- Grade 1 injuries are regarded as a mild sprain. You may have some tenderness but no swelling and you will probably be able to continue running, although your knee may feel uncomfortable or weak.
- Grade 2 MCL sprains are considered moderate with significant pain and tenderness on the inside of the knee with some swelling.
- Grade 3 injuries are severe, often involving a complete tear of the ligament. Pain may range from moderate to severe. However, you will have significant swelling and your knee will feel unstable.
- The valgus stress test is used to help diagnose an MCL sprain.
More on MCL sprain diagnosis
What is an MCL sprain?
The medial collateral ligament (or MCL for short) connects the thigh bone (or femur) to the shin bone (or tibia) on the inside of the knee and prevents the knee joint from moving sideways, particularly from forces on the outside of the knee.
The MCL itself has two parts to it; a deep section which attaches to the cartilage and capsule in the knee, and a superficial band that starts higher up on the femur to an area lower down on the inner surface of the tibia and is much more near the surface.
What causes an MCL sprain?
MCL sprains usually occur suddenly but can develop gradually over time.
Sudden onset/acute injuries
Medial ligament injuries are common in contact sports such as football, rugby, and martial arts but they can also occur in activities of daily living as a result of falls that include a twisting action of the knee joint.
Injury to the MCL often occurs after an impact to the outside of the knee when the knee is slightly bent. The ligament on the inside of the knee becomes stretched and if the force is great enough, some or even all of the fibres will tear.
The deep part of the ligament is prone to becoming damaged first which may lead to a medial cartilage meniscus injury. Twisting the knee can also cause a medial ligament sprain as well as the possibility of an ACL tear.
If the foot is planted and the player tries to turn quickly this can also lead to stressing the joint causing the inside of the joint to open and tear the ligament.
Gradual onset MCL sprains
Repetitive sideways forces on the knee (known as valgus forces) can gradually over time lead to an MCL sprain. For example, from kicking a football with the inside of the foot or from kicking in martial arts. However, pain on the inside of the knee which does not occur after a sudden injury should also be considered for pes anserine tendinopathy or bursitis.
Treatment for medial ligament sprains
Treatment can be considered in terms of immediate first aid during the acute stage and longer-term rehabilitation which will depend on the severity of the injury.
Cold therapy & compression
Immediate first aid is to apply the PRICE principles (Rest, Ice, Compression, Elevation) as soon as possible. Apply ice or cold therapy wrap as soon as possible for 10 to 15 minutes and repeat every hour, reducing the frequency as symptoms allow.
Ice should not be applied directly to the skin but use a wet tea towel or similar. Commercially available cold therapy knee wraps are convenient to use and will apply compression as well.
Rest from training or any activities or movements which are painful to allow healing to take place. Continuing to train or do any activity which causes pain will only prevent healing and prolong recovery.
Wear a knee brace
Wear a compression bandage or knee support to help reduce any swelling and protect the joint. A hinged knee brace is best particularly for grade 2 and 3 injuries. It has solid metal supports down the sides to prevent sideways movement of the joint.
More severe grade 2 and full grade 3 injuries may require a limited motion hinged knee brace which also restricts the amount of movement or knee bend in the joint.
When pain allows a full rehabilitation program of mobility, strengthening and finally functional exercises should be done to return to full fitness and prevent the injury returning.
Initially, mobility exercises are done to restore full, pain-free range of movement. In the early stages, isometric strengthening exercises (static muscle contractions) can be done to help maintain muscle strength and prevent muscle wasting whilst the ligament heals.
As your ligament heals, strengthening exercises such as mini squats, leg press, and step-ups can be done. But movements involving a change of direction or sideways stresses should be avoided until much later in the rehabilitation program.
A hinged knee brace should be worn to protect the ligament whilst exercising.
View MCL sprain exercises
A professional therapist may use electrotherapy treatments such as Ultrasound to help control swelling and pain. Ultrasound transmits high frequency sound waves into the tissues applying a mico massage effect and helping to reduce swelling.
MCL sprain taping
Taping your knee joint can also provide a high level of support and protection. It can be done in the early stages as well as later on when returning to full training.
Manual therapy techniques including massage may be used as part of a rehabilitation program. Massage to the injured tissues should be avoided in the early acute stages.
Later as the ligament starts to heel then light cross friction massage may be used and in particular, if there is persistent pain in the later stages of rehabilitation then cross friction massage may be beneficial.
Do I need surgery?
Most medial ligament injuries do not require surgical treatment. If there is additional damage to the joint for example an ACL tear as well then surgery may be considered. However, it is thought there is no advantage even with grade 3 injuries to treating them surgically as opposed to bracing and rehabilitation exercises.
How long will it take to recover?
- A mild MCL injury or grade one sprain should take 3 to 6 weeks to make a full recovery.
- A more severe grade 2 or grade 3 injury may take 8 to 12 weeks.
Elite Football Physiotherapist Neal Reynolds explains MCL sprain treatment
- Indelicato PA. Isolated medial collateral injuries in the knee. J Am Acad Orthop Surg 1995;3(1):9–14.