Medial collateral ligament (MCL) injury is the most common ligament injury to the knee and often occurs in sports activities though can be injured through non-contact forces as well. Injuries occur when there is valgus stress at 20 degrees of knee flexion and usually with simultaneous trauma of external rotation of the tibia, causing the MCL to stretch and tear. In addition to this, the ACL ligament and medial meniscus is often injured at the same time as the MCL.
The three grades of an MCL injury are:
- Grade 1: no valgus laxity, some pain on the inside of the knee but no swelling, and no instability of the knee.
- Grade 2: valgus laxity at 30o of flexion, much pain on the inside of the knee with some swelling, and some knee instability.
Grade 3: valgus laxity at 0o and 30o of flexion, much pain on the inside of the knee with large swelling, and gross instability of the knee.
Frequently Asked Questions
How is an MCL injury diagnosed?
Your physiotherapist will take a patient history including how the injury occurred and what your symptoms are. A physical examination including observation and palpation, knee range of motion and special tests such as valgus stress test and MCL grading are necessary to determine the extent of the injury. If deemed necessary, you may be referred for medical imaging. An X-ray or MRI can rule out other diagnoses and confirm the degree of injury to the MCL and supporting structures.
How does an MCL injury present?
If you have an MCL injury, you may present with the following impairments. Pain on the medial or inner side of the knee, varying in intensity is common and swelling may occur in the first 24 hours and will again vary based on the grade of injury. You may describe a feeling of ‘giving way’ or an instability and limited range of motion as a result of the pain and swelling. Due to inflammation, your injured knee may feel tender on palpation and some bruising may appear for more serious grades.
What is the treatment for an MCL injury?
For grades 1 and 2 MCL injury, a conservative approach can be taken. This includes rest and protection of the affected knee joint. Ice and TENS can be used to reduce pain and control any swelling. Manual therapy including joint mobilisations of the knee can reduce stiffness and improve range of motion. Following the acute phase of recovery, your physiotherapist will prescribe active range of motion exercises and begin strengthening the knee joint with resistance exercises. There is a gradual return to activity through graded exposure and progressive overload of the knee joint and surrounding muscles.
For a grade 3 MCL injury, conservative management may be an option and this will follow a similar regime as a grade 1 or 2 MCL injury. If there is extensive damage to the knee joint, surgery may be required. Following any surgery, there is a period of post-surgical rehabilitation to return your knee to its pre-injury function.