The PCL – A neglected injury in the back of the knee

Written by Simon Parsons

A lot of athletes know of teammates, or have so themselves, sustained a traumatic knee injury – maybe an ACL, MCL, PCL or meniscus injury.

But have you ever heard of a PLC injury?

What is the Posterolateral Corner in the knee?

An often neglected area of the knee is the posterolateral corner (PLC).

  • Posterior = behind
  • Lateral = outwards from the middle

The PLC is a very complex compartment in the knee, with 28 separate structures running through it…there’s lots of ‘stuff’ in this part of the knee.

What’s so important about the PLC?

The PLC’s primary role is to prevent knee hyperextension, twisting of the upper and lower leg, and blows to the inside of the knee. These are all important on overall knee stability, especially in change of direction sports.

Why haven’t we heard more about this?

Injuries to this area occur in 16% of all knee ligament injuries, not common…but not incredibly uncommon either. (LaPrade et al. 2007).

Unfortunately, a 2011 study by Pacheco et al. showed that 72% of individuals with a PLC injury were incorrectly diagnosed and they took an average of 1 year to be correctly diagnosed.

So, ensuring you go to a Physiotherapist who knows about these injuries can be vital.

How do I know if I have a PLC injury?

A detailed assessment from a Physiotherapist or other qualified health professional is integral before putting a diagnosis on a PLC injury, and based on this assessment, your Physio may suggest and refer you for magnetic resonance imaging (MRI).

Often PLC injuries can occur from falling, sports trauma or motor vehicle accidents – with knee hyperextension or blows to the inside of the knee being a common mechanism of injury.

Often include pain in the back and outermost part of the knee and sometimes numbness and weakness in the foot or toes.

What do I do for rehab if I have injured the PLC?

It varies case by case, and is often very individualised, with lower severity injuries to the PLC benefiting from physiotherapy management.

If surgery is not indicated, often a hinged knee brace is worn for a period of 3-4 weeks and then gradual return to activity under physiotherapy guidance is recommended.


Consulting a physiotherapist is advised for any knee injury, especially traumatic injuries in a specific episode. This blog is to highlight that some knee injuries can be worth getting a second opinion if something just “isn’t quite right.”


  1. Covey, D. C. (2001). Injuries of the posterolateral corner of the knee. The Journal of Bone & Joint Surgery, 83(1), 106-106.
  2. Davies, H., Unwin, A., & Aichroth, P. (2004). The posterolateral corner of the knee: anatomy, biomechanics and management of injuries. Injury, 35(1), 68-75.
  3. LaPrade, R. F., Griffith, C. J., Coobs, B. R., Geeslin, A. G., Johansen, S., & Engebretsen, L. (2014). Improving outcomes for posterolateral knee injuries. Journal of Orthopaedic Research, 32(4), 485-491.