MCL sprain not as glamorous as an ACL injury
In the world of knee injuries, the anterior cruciate ligament (ACL) gets all the attention. Because of this, we don’t give medial collateral ligament (MCL) sprains the attention they deserve. An MCL sprain is a common knee injury – particularly in team sports. They occur often in sports that require agility, cutting and turning.
Some basic physio knee anatomyThe knee joint is formed by the femur (thigh bone) articulating with the top of the tibia (shin bone). It is completed by the patella (kneecap) sitting over the top of these at the front – connecting the muscles of the thigh to the top of the tibia. The femur is connected to the tibia by ligaments. Ligaments are rope-like bands of tissue that connect one bone to another. There are many large and small ligaments in the knee. The main four are as follows:
- Anterior cruciate ligament (ACL)
- Posterior cruciate ligament (PCL)
- Medial collateral ligament (MCL)
- Lateral collateral ligament (LCL)
The role of the MCLThe MCL’s primary role is to stabilise the medial aspect of the knee. This is required to protect the knee from forces trying to bend the knee inwards. Think of the inward bowing of the knee when side-stepping, or when being tackled from the side. In protecting from these forces, the MCL often works in unison with ACL to protect knee stability. The MCL is a broad and strong ligament. However, it has very little direct support from muscles crossing the medial knee joint line. It relies on muscles of the knee and hip to keep it in safe positions.
How is the MCL injured?Injuries to the MCL occur when the knee is forced into valgus position. This is when the knee is forced inwards, and can happen to a straight or bent leg. The position (straight or bent) that the knee is in can determine which position of the MCL is injured, and can also impact whether the ACL or other structures are involved.
Initial signs and symptoms of an MCL sprainInitial signs of MCL sprain are localised pain around the medial knee, and laxity on valgus stress testing. There can be a wide range of symptoms depending on other structures injured. The knee may feel locked, or be unable to be fully straightened or bent past a certain point.
Grading of an MCL sprainThe most common grading system for MCL injuries is the standard ligament grade 1-3 system.
- Grade 1 – stretching and injury to a small portion of the fibers, but generally intact and with an end feel present
- Grade 2 – more extensive stretching and injury to the ligament, with greater pain and instability
- Grade 3 – complete tear of the fibers of the ligament, resulting in gross laxity. Grade 3 ligament tears will often involve other ligament damage or bone bruising.
Early injury management for any knee MCL sprainEarly management once an MCL injury is identified involves protecting the ligament and the joint from further damage. This may require a period of non-weight bearing and bracing the knee to prevent side-to-side movement, and sometimes prevent bend as well. In grade 1 injuries, the period of immobilisation may be quite short – from 24 hrs to a week, to allow for pain to settle. In grade 2-3 tears, the knee may be immobilised in a brace for between 4-8 weeks. Again, this can involve a period of non-weight bearing. Time in the brace depends on many factors. These include but are not limited to: the degree of damage, other injured structures, bony bruising, muscle control and overall joint laxity. A decision to come out of the brace is often made based on how the joint feels clinically – whether it has a stable end feel when tested by the physio.
Surgery for the MCL injury?In cases of extreme laxity, recurrent injury, or where other structures are significantly impacted, then surgery can be the best answer. In our experience, this is rare for isolated MCL sprains. However we consider all appropriate options and discuss them with our patients and their doctor or surgeon.
Knee physio rehab for MCL while in the braceAny exercise program in the first 6 weeks needs to be heavily individualised. The primary focus during this period is on healing the injured ligament, with secondary focus on maintaining strength and range of motion as possible. We will often try to craft an exercise regimen for our patients involving as much strength work as possible while protecting the healing ligament. Returning to exercise is key for mental health, as well as to preserve muscle and joint function for when the brace is removed. Knee physio rehab exercises that we try to incorporate while still in the brace include:
- Use of the pilates reformer for early strength work – particularly leg press, calf work and some abdominal work
- Squats through available range of motion – often quite shallow, but important to be weightbearing as early as safe to do so
- Shallow step-ups
- Stiff Leg deadlifts
- Calf raises
- Crab walks
- Glute bridging
- All available upper body exercise
Rehab progressions after the initial bracing periodProgression involves strength through a deeper range of motion. We then add medial and lateral forces to the knee – generally in positions of control. This often involves band work and ball work for isometric holds, and forces to the knee while squatting, stepping, planking and lunging. We then increase the speed and complexity of the movement as strength and coordination allows. This process can take several weeks, and is as dependent on application of exercise as it is on healing time frames. There are some very important knee physio rehab exercises that patients should move through for a safe return to sport. In our programs, these include:
- Jumping and soft landing
- Jogging with acceleration and deceleration
- Running through arc / curves
- Side-stepping in a planned and repetitive manner
- Side-stepping and stop-start movement reacting to an external stimulus
- Simulated game play
- Return to training drills
- Adding the above to conditions of fatigue and competition