You’ve probably heard of the ACL. It’s a ligament that often pops up in football-related headlines, most recently with a nasty, season-ending injury to the Barcelona prodigy Gavi.
The ACL is a “workhorse” ligament that provides crucial stability and backwards-forwards control within the knee joint. But it couldn’t do this without the help of another, less well-known ligament that sits just behind it: the Posterior Cruciate Ligament (or PCL).
The PCL is less commonly injured than the ACL. But a tear here still has the capacity to cause significant problems to the knee. In some cases, it can lead to an operation called PCL reconstruction. Let’s explore how that works.
How do people injure their PCLs?
A PCL injury usually happens when the knee takes a major blow from the front – often to the top of the shinbone (the proximal tibia) while the knee is flexed. That might happen because of a bad fall. Or a tackle in sport. Or a heavy object swinging into the knee unexpectedly. We also commonly see them in car accidents, when the knee strikes the underside of the dashboard.
What happens to the ligament in a PCL injury?
The fibrous tissue in the ligament literally overstretches to breaking point. That’s usually accompanied by pain and swelling soon after the injury, and stiffness or instability if the damage is fairly severe. Doctors tend to think about PCL damage on a scale of severity, from 1-3:
Grade I – where there’s mild damage to the ligament, but with a stable knee joint
Grade II – where there’s a partial tear of the ligament
Grade III – where there’s a complete rupture of the ligament, with an unstable joint
Having said that, PCL tears can be subtle injuries. As a result, they often go undetected or are sometimes misdiagnosed as knee sprains. They also often happen in conjunction with other injuries, such as an ACL tear, a damaged meniscus or a posterolateral corner injury.
Does everyone with a significant PCL tear need a reconstruction?
No. If it’s an isolated injury, you can often manage the rupture conservatively. The ligament tissues have the capacity to heal by themselves. So, with rest and physio-led exercises, the problem may resolve over the coming weeks. But if it doesn’t – or if you’ve suffered multiple ligament damage, a dislocation, or significant instability – then it may be time to consider surgery.
How does a PCL reconstruction work?
PCL reconstruction works by removing the damaged ligament and replacing it with a natural graft (usually a piece of tendon taken from your hamstring). It’s normally done by keyhole surgery, under a general anaesthetic, and takes one to two hours to complete. The surgeon makes several small incisions, to allow access for the instruments and a miniature camera. They wash out any loose material and remove the torn pieces of ligament. They then create tunnels in the tibia and femur. The graft is threaded through these tunnels and carefully secured to the bone, giving the right tension to the new ligament.
How long does it take to recover from a PCL reconstruction?
PCL reconstruction is a fairly significant operation, so it can take some time to get your knee back to full strength afterwards. In the early days, you’ll need to take painkillers and keep your knee iced and elevated to help control any swelling. You’ll probably also be fitted with a knee brace for the first two months or so, to support the graft and keep your tibia pushed forward. In the first few weeks, the focus will be on gradually building up strength and flexibility in your knee and the surrounding muscles. A physiotherapist will work with you to find the right exercises to help you do this.