If we asked you to name the most common knee ligament injury, how would you answer?
Most people would plump for the Anterior Cruciate Ligament. Which is understandable, because the ACL crops up so often in headlines involving famous sport stars, particularly footballers.
The actual answer, though, is the Medial Collateral Ligament (MCL), a less well-known but equally vital band of tissue that runs through the knee joint. In fact nearly eight percent of all knee injuries are thought to involve a tear to the MCL. That’s quite high!
So, given how common MCL tears are, how easily can they be fixed? Let’s look at the question in more detail.
What does the MCL do?
The main job of the MCL, which runs down the inner side of your knee joint, is to keep your knee stable and control sideways movement. It does this in tandem with the Lateral Collateral Ligament (LCL), which runs down the outer side of the knee.
How do people injure MCLs?
Being on the inner edge, the MCL is vulnerable to blows from the opposite side of the body. Typical examples are a side-tackle in rugby, or a low-impact injury from a car bumper, or even a collision with a dog (something we’ve seen several times in clinic). But it can involve sudden stops or twists. However it happens, the force of the impact overstretches the ligament fibres until they break.
What does tearing an MCL feel like?
Like many knee injuries, this varies. Some people hear a “pop” on impact. Most people feel pain along the inner side of the knee. That’s often followed by swelling. In more serious cases, there can be instability too – the knee feels too vulnerable to place weight on, or it pulls to the side when you try to walk.
So… could it heal on its own?
The short answer is yes, it may do. The good news about MCL tears is that many can self-heal without surgery. But there are a couple of ways we can determine whether this is likely to happen.
1: Surrounding damage
MCL tears can occur in isolation: a big impact, a single point of damage. But if you think about it, any force that’s strong enough to rip the fibres in a ligament has the potential to hurt other structures too. This is often the case with bigger MCL injuries. When we take an MRI scan, we might find that the ACL has been torn as well. A combined MCL/ACL injury is much less likely to heal by itself.
2: The type of tear
Doctors use a grading system to determine the severity of MCL tears. A Grade 1 tear is a mild sprain, where just a few fibres have been damaged. Grade 2 is a partial tear, where the ligament has frayed, and there may be looseness in the knee, but many of the fibres are still intact. And a Grade 3 injury is a complete rupture of the MCL, most likely causing significant looseness and instability, and often accompanied by an ACL tear.
What does treatment for an MCL tear involve?
If it’s a severe, Grade 3-style tear – particularly when there’s instability too – we may need to consider surgery. One option is a reconstruction operation, where we replace the ruptured ligament with a graft (usually taken from the hamstring). But MCL surgery is quite rare. And that’s because – with a little care and attention – the collateral ligaments have a good capacity for healing within a few weeks or months. By care and attention, we mean:
- R.I.C.E. – rest, ice, compression and elevation: resting your knee properly gives the joint time to settle down and begin the healing process. Ice, compression and elevation help to reduce pain and swelling
- Painkillers – if you’re able to take them, a short course of NSAIDS (non-steroidal anti-inflammatories) can provide short-term relief of inflammation as well as pain
- Knee brace – a brace can sometimes help to keep the joint stable and prevent it from moving from side to side while the MCL regains strength
- Physio – physiotherapy helps to maintain range of motion in your knee while the ligament heals. This is important because some MCLs can get quite stiff as they heal, preventing the knee from extending properly. The therapist can also show you exercises that will help to rebuild strength in the surrounding muscles. As with many other knee injuries, this can have a big impact on the overall healing process – not to mention the time it takes to fully recover.
For further reading…
Website section: collateral ligament injuries
Joint 101: a beginner’s guide to the knee
The top 5 causes of knee pain
