The posterior cruciate ligament is one of the four important ligaments. It stabilizes the knee and preventing backward translation of tibia on femur. This movement is known as posterior drawer.
The posterior cruciate ligament also helps to prevent the tibia from twisting outwards. Knee Instability and tendency of tibia to sag backwards is the common problem with injury to PCL in more severe cases.
The incidence of PCL injury is less than that of the anterior cruciate ligament. This is mainly due to the greater strength of the ligament and other supportive structures backwards.
PCL is injured can occur through–
- Blow to the knee while the foot is fixed in flexed position,
- Landing wrong from a jump,
- Hyperextension injury
- A blunt force hit to the knee, such as in football tackle or
- Motor vehicle accidents
The injury is commonly associated with injuries to other structures of the knee. In addition the articular cartilage may also be damaged.
The incident is usually sudden and occurs at high speed. Muscular weakness or incoordination predisposes the ligament to sprains or tear.
Grades of PCL injury:
The severity and symptoms of a knee ligament sprain depend on the degree of stretching or tearing of the knee ligament. An audible snap or tearing sound at the time of ligament injury might be patient’s complaint.
In a grade I sprain, the ligament is mainly stretched with minimal tear. There is a little pain, mild swelling and slight discomfort in weight bearing activities. A mild ligament sprain can increase the risk of a repeat injury.
In a grade II sprain, there is moderate tear (50-70% fibers torn). Severe pain in weight bearing activities, Swelling and bruising can be seen around the joint. The feeling of instability i.e. knee giving way from undersurface backwards may or may not be the complaint of the patient
In grade III sprain, there is complete tear of the ligament. Swelling and under skin bleed can be seen at times. As a result, the joint is unstable and unable to bear weight. Often there is no pain following a grade 3 tear (but pain can be due to injuries to other structures) as all of the pain fibers are torn at the time of injury. With these more severe tears, other structures are at risk of injury including the meniscus and/or ACL.
On examination, the physiotherapist looks for signs of ligament injury and instability, tenderness over the ligament site, possible swelling and pain with stress tests. Positive posterior drawer test and reverse Lashman’s test. Pain can be felt in calf region at times.
POSTERIOR DRAWER TEST
MRI may be used to confirm the diagnosis and look for any concurrent injuries to surrounding structures.
Treatment of a PCL injury depends on the severity and whether there are other concurrent injuries.
Grade I sprains may heal by itself in a few weeks time. It may take 6-8 weeks to develop maximum strength in the ligaments (time for collagen fibers to mature). Initial treatment as always in sports injury will be relative rest, icing, compression/ supporting the joint, protection (avoid painful weight bearing activities). Some NSAIDS can be prescribed by a physician to reduce pain.
Physiotherapy is recommended to increase the healing process. This comprises of electrical modalities, soft tissue techniques, strengthening exercises to guide the direction that the ligament fibers heal. This helps to prevent a future tear.
With a grade II sprain, weight-bearing braces/ supportive taping is must in early treatment days to relieve pain and avoid stretching of the healing ligament. After a grade II injury, usually returning to activity is possible only once the joint is stable and there is no longer pain. This usually takes six weeks.
Physiotherapy is recommended to hasten the healing process. A physiotherapist uses some modalities, soft tissue techniques, strengthening exercises and later on focus in on complete rehabilitation so to avoid any factor that may contribute to reoccurrence.
With a grade III injury, the patient usually wears a hinged knee brace to protect the injury from weight-bearing stresses. The aim is to allow ligament healing and gradually return to normal activities. It may take 3-4 month to completely return to sporting activity. This is again only possible with intensive post operative physiotherapy rehabilitation.
The aims of physiotherapy treatment are:
- Reduce pain and inflammation.
- Normalise joint range of motion.
- Strengthen the knee muscles.
- Strengthen lower limb muscles
- Improve patellofemoral (kneecap) alignment
- Normalise muscle lengths/ stretches
- Improve proprioception and balance
- Improve functionality e.g. walking, running, squatting, hopping and landing.
- Guide return to sport activities and exercises
- Minimize re-injury.
However, we strongly suggest that one should discuss his/her knee injury after a thorough examination with a physiotherapist or knee surgeon. PAIN FREE PHYSIOTHERAPY CLINIC provides appropriate diagnosis and best possible treatment for pains with ligament strain/ tear.
Knee Ligament Surgery
Most PCL injuries resolve well with conservative management, however, surgery may be considered if there is significant ligament disruption e.g. Grade III. Knee surgery may also be required if there is a significant combination of injuries involving the ACL, postero-lateral corner and/or meniscus injury.
Risks of knee surgery include infection, persistent instability and pain, stiffness, and difficulty returning to your previous level of activity though not many cases report of any complication.
For successful and quick outcomes results, post-operative knee rehabilitation is one of the most important and often neglected aspects of knee surgery.
The physiotherapy rehabilitation focuses on restoring full knee motion, strength, power and endurance, balance and proprioception and agility training that is individualized to specific sporting or functional needs.
A knee strengthening, agility and proprioceptive training program is the best way to reduce the chance of a knee ligament sprain. Premature return to high-risk sports increases the chance of reoccurrence.