A ligament is a strong band of tissue that joins bone to bone. The posterior cruciate ligament (PCL) is one of two ligaments within the knee joint. It attaches from the thigh bone (femur) to the shin bone (tibia). The (PCL) with the anterior cruciate ligament provides support to the knee joint. In addition the (PCL) prevents the shin bone moving backwards on the thigh bone.
When a ligament is sprained it is stretched or torn. The sprain can be graded depending on the severity of the injury:
• grade I sprain: pain with minimal damage to the ligaments
• grade II sprain: more ligament damage and mild looseness of the joint
• grade III sprain: complete tearing of the ligament and the joint is very loose or unstable.
The (PCL) is usually damaged when a strong force is put through the knee (eg. a footballer falling onto a bent knee, the dashboard of a car hitting the front of the knee in a car accident). It can also be damaged when excessive tension is placed on the knee (eg. when a knee is dislocated).
Symptoms of Posterior Cruciate Ligament Sprain/Tear
• Marked, immediate swelling (within three hours of the injury)
• Difficulty walking after the injury
• Painful to move the knee
• Occasionally, a feeling of instability, or the knee “giving way”
Diagnosis and treatment
Your physiotherapist will be able to diagnose and treat this condition according to the severity of the sprains. At times an x-ray may be done to rule out any bony damage. A scan may also be done to see the damage to the ligament especially in the case of severe sprains as often other ligaments and tissues (nerves, bones, blood vessels) of the knee joint can be involved.
If a complete tear of the (PCL) has occurred with damage to other soft tissue structures then surgery is often required followed by a physiotherapy rehabilitation program.
If the tear/sprain is isolated to the PCL only, then a conservative management plan of physiotherapy would be appropriate. In the management of a (PCL) sprain initial physiotherapy would involve reducing pain and swelling. This may involve electrotherapeutic modalities, ice, rest, wearing of a brace, the use of crutches and gentle massage. Following this treatment would move onto rehabilitation and return to sport. This may involve strengthening of knee stability muscles, stretching and decreasing activity of tight/overactive muscles, proprioceptive (balance) exercises and correction of any abnormal lower limb biomechanics. Your physiotherapist would also guide you in a gradual progression to sport.