Anterior and posterior cruciate ligament injury (ACL & PCL)

The ACL and PCL are vital for stabilising the forward and backwards movement of the knee and when either is ruptured the knees' stability is severe compromised.

Torn ACL is a relatively common injury amongst sports people and is more common in female athletes. It usually occurs as a result of a twisting injury when the foot is firmly planted on the floor, resulting in the knee having to deal with all of the rotational force rather than the foot moving.  It can be caused by a direct blow to the knee often on the outside aspect of the knee e.g. a football or ruby tackle. 

Such injuries may be combined with MCL injuries; although, the majority of ACL injuries do not involve any form of contact with another sports person.

What are the symptoms of a torn ACL?

  • There may be an audible popping or cracking at the time of the injury
  • Sudden pain at  the time of the injury
  • Immediate extensive swelling (this can be delayed in some cases)
  • An immediate feeling of instability but later swelling may mask or reduce this sensation
  • Inability to continue to exercise

How do I manage / treat my ACL injury?

  • Stop any sport or activity immediately
  • Contact your doctor or attend A&E


  • Protect the knee by not exposing it to the same activity
  • Rest. This should be relative not absolute, and maintain your range of movement and do not confine yourself to bed
  • Ice – use ice packs for up to 20 minutes every 2 – 3 hours that you are awake
  • Compression – if you have access to some tubi-grip of the correct size use it
  • Elevation – when resting try elevating the knee slightly up on a pillow length ways so it is above the height of the hip
  • Drugs – painkillers such as paracetamol provide good relief, debate remains on the use of anti-inflammatory drugs in the first 48 hours, as although all these steps are designed to control swelling/inflammation some swelling is still required as this is the body's injury response mechanism so it may delay the overall healing process in the longer term

How will I be treated once an ACL rupture diagnosed?

  • A full assessment of the knee is required to ascertain if and what other structures have been injured
  • You will need to be seen by an Orthopaedic consultant to explore surgical and nonsurgical options
  • MRI scans are commonly used but not always, and so is the use of arthroscopic surgical procedures as the symptoms are so obvious that the need for surgical repair is highly likely to be the outcome
  • Non-surgical treatment is likely to include physiotherapy (including strengthening and proprioception, isokinetic assessment) rehabilitation and bracing

Surgery – the techniques and approaches used will vary depending upon the severity of the injury and surgery is performed more often than not following an ACL injury.  The decision to operate will be based on a number of factors;

  • Age
  • Lifestyle
  • Sporting activities
  • Occupation
  • Degree of knee instability
  • Ability to comply with the extensive and complex post operative rehabilitation

PCL injuries are less common than ACL but the advice remains the same.