If you google the phrase MPFL, you’ll find it often pops up alongside the words “dislocation” and “kneecap”.
That’s because the MPFL (medial patellofemoral ligament) plays a critical role in protecting the kneecap from becoming dislocated. And when things go wrong with this particular ligament, recurrent dislocations often follow.
If this does happen to your knee, one of the potential solutions is MPFL reconstruction – a type of surgery that doctors generally turn to when other treatments haven’t worked. Let’s explore this operation in a bit more detail, why you might have it, and what it entails…
Where and what is the MPFL?
The medial patellofemoral ligament is the key ligament on the inside of your kneecap (the patella). You can think of it as a “guy rope” between your thighbone and kneecap, pulling the two bones together and keeping everything taut and strong. (The other guy rope is the lateral patellofemoral ligament, which does a similar job on the outer side of the knee.) Without the MPFL, your kneecap wouldn’t sit firmly in place within your joint.
How do dislocations happen?
There are several reasons why MPFL-related dislocations happen. Two important causes are:
- Trauma – if you damage (tear) the ligament during an accident, usually a sporting injury or a bad fall
- Hyperlaxity – when your joints are more flexible than most people’s, making them less supportive of your kneecap
Hyperlaxity – also known as joint hypermobility or double-jointedness – can run in families and is most common in children and teenagers. Although it usually gets better with age, some patients experience ongoing problems with dislocation or subluxation (partial dislocation): the kneecap keeps popping out of the joint, causing pain and considerable distress.
What’s the treatment for kneecap dislocation?
In most cases – especially if it’s a first-time dislocation – your doctor will recommend non-surgical treatment. That means relieving the immediate pain with painkillers or NSAIDs, using the RICE protocol (rest, ice, compression, elevation), possibly immobilising your knee with a brace or splint, and potentially working on exercises with a physiotherapist. One issue with kneecap dislocations, however, is that once they’ve happened once, they are prone to recur. In over 90% of first-time dislocations, the MPFL suffers damage or gets stretched in the process – which, unfortunately, increases the risk of further dislocations. The good news is that many MPFL tears can heal naturally over time. But this doesn’t always happen.
When would you recommend MPFL reconstruction?
MPFL reconstruction is what we call an operation of last resort. It’s a very effective procedure, but really only one to consider when other avenues haven’t worked, if you have severe MPFL damage, or your kneecap keeps on dislocating (“recurrent patella dislocation”). The aim of the operation is to restore stability to your kneecap and stop it from popping out of the joint. We would normally assess your knee with an x-ray, CT scan and / or MRI to determine this.
What happens in an MPFL reconstruction?
Reconstruction basically involves replacing the damaged ligament with a new one. The traditional way to do this is with a piece of your hamstring (known as an autograft, since it comes from your own body). But we use a synthetic version made from a highly durable polyester material. This synthetic tape, about 1cm wide, is passed through an incision in your kneecap, looped back on itself to create a kind of sling for the knee joint, and secured into place on your thighbone. We do this with a modern technique called interference screw fixation, which creates a smoother fixation than traditional titanium staples. (You can read more about how it works in this blog: A new technique for dislocated kneecaps.)
How long does it take to recover from MPFL reconstruction?
For most young people – who make up the bulk of our cases – the recovery journey is fairly straightforward. It takes about six weeks get back to everyday activities, and a few months to resume sport if you feel able to. It’s important to keep up with rehabilitation exercises to give yourself the best opportunity for a strong recovery. This is something you’ll work on with a physiotherapist in the weeks following your operation. It’s worth adding that a reconstructed MPFL can feel unusual at first and may take some getting used to. But, overall, as a solution for the pain and frustration of recurring dislocations, we find most patients are very happy with the results and are able to get back to a good level of activity.
Are you or a family member thinking about surgery for repeated dislocation? We would be happy to have a look at your knee and discuss the potential options. Please call the team on 01962 826107, or fill out a quick form online, and we’ll book you an appointment with Mr Bailey.
