A medial ligament sprain or MCL injury is a tear of the ligament on the inside of the knee, usually a result of twisting or direct impact. Medial ligament injuries are common in contact sports such as football and rugby, as well as martial arts. They can also occur in daily life through falls and twists of the knee joint.
Symptoms are graded 1, 2 or 3 depend on the severity of the injury.
Grade 1 symptoms
For a grade 1 MCL injury, there may be mild tenderness on the inside of the knee over the ligament. There is usually no swelling. When the knee is bent to 30 degrees and an outward force applied to the lower leg to stress the medial ligament, pain is felt but there is no joint laxity (play valgus stress test video). A grade one tear consists of fewer than 10% of the fibres being torn.
Grade 2 symptoms
Significant tenderness will be felt on the inside of the knee along the medial ligament. Some swelling may be seen over the ligament. When the valgus stress test is applied there is a pain with mild to moderate laxity in the joint, although there is a definite end point (the knee cannot be bent sideways completely).
Grade 3 symptoms
This is a complete tear of the ligament. Pain can vary and is sometimes not as bad as that of a grade 2 MCL sprain. The valgus stress test will reveal significant joint laxity and the patient may complain of having a very wobbly or unstable knee.
Causes & anatomy
What is the MCL?
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 medial knee ligament itself has two parts to it; a deep inner section which attaches to the cartilage meniscus at the top of the shin bone, and a superficial band that originates higher up on the femur to an area lower down on the inner surface of the tibia.
What causes a medial knee ligament sprain?
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 and this 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.
Can an MCL injury occur gradually?
Repetitive sideways forces on the knee (known as valgus forces) can gradually over time lead to an MCL sprain. 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 divided into immediate first aid during the acute stage and longer-term rehabilitation.
Immediate first aid
- Apply P.R.I.C.E. principles (Rest, Ice, Compression, Elevation) to the injured knee.
- Rest from training or any activities or movements which are painful to allow healing to take place
- Apply ice or cold therapy wrap for 10 to 15 minutes every hour initially reducing the frequency as symptoms allow. Ice should not be applied directly to the skin but use a wet tea towel or similar. Specialist cold therapy knee wraps are convenient to use and will apply compression as well.
- 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.
Read more on PRICE principles.
Download grade 1 MCL rehab program overview (PDF)
Wear a hinged knee brace
A hinged knee brace is a strong knee support which has solid metal supports down the sides to prevent sideways movement of the joint and protect the knee ligaments while healing. More severe grade 2 and full grade 3 injuries may require a limited motion hinged knee brace which restricts the amount of movement or knee bend in the joint whilst healing.
Ultrasound treatment involves applying high-frequency sound waves to the injured tissues. A professional therapist may do this in the early more acute stages to help control swelling and pain. Interferential or tens involves applying electric currents to the tissue around the injury which can also help with pain and swelling.
Taping the 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. A good taping technique can provide excellent support and often more support than some of the cheaper hinged knee braces, but the effectiveness of tape will reduce over time as the tape stretches slightly. It will need to be re-applied to maintain good support for the joint, particularly during competitive sport.
Play knee taping video
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 a persistent pain in the later stages of rehabilitation then cross friction massage may be beneficial.
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.
A full rehabilitation program consisting of mobility and strengthening exercises should begin as soon as pain allows. Initially, the range of motion mobility exercises is 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 the 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.
Read more on MCL exercises