Diagnosis and assessment of a medial knee ligament sprain (MCL sprain) should include questions to understand the background of the injury, how it occured as well as a series of physical tests.
The therapist will do an initial consultation and ask questions about how the injury occured the symptoms the patient is experiencing. For an MCL sprain these will include:
Grade 1 - there may be mild tenderness on the inside of the knee but usually no swelling. The patient is likely to be able to walk or even run but they will likely be in some discomfort.
Grade 2 - significant tenderness will be felt on the inside of the knee and there is likely to be some swelling seen over the ligament.
Grade 3 - is a complete tear of the ligament, pain can vary and is sometimes not as bad as that of a grade 2 sprain. There is likely to be swelling although again this can vary. The patient may complain of having a very wobbly or unstable knee.
Observation & palpation
The therapist will observe the joint for swelling, bruising and deformity and then proceed to 'palpate' or feel around the joint for areas of tenderness, warmth, swelling and pain. In cases of medial collateral ligament (MCL) injury palpating over the ligament will range from mild tenderness in grade one sprains, to acute pain in more serious injuries.
Range of motion
The therapist will check the range of motion at the knee. They will usually ask you to bend and straighten the knee yourself (active) and will then ask you to relax as they do it for you (passive). In MCL injuries range of motion is often affected in more severe injuries and is usually only limited by pain or swelling.
Resisted muscle tests
The therapist will usually ask you to try to bend and straighten your knee against resistance. Doing this causes the muscles to contract. Pain on contraction suggests a muscular injury.
Specific MCL assessment tests
Valgus stress test
This test is used in cases of suspected MCL injuries. The therapist takes hold of the limb, ensuring the knee is slightly bent (approx 30 degrees). They stabilise the thigh whilst applying an outward pressure on the lower leg. This stretches the medial ligament. Pain on the inside of the knee indicates a positive test. The degree of damage can be determined by how much movement/stability is present.