What is PCL?
PCL stands for posterior cruciate ligament. It is a band of tissue that bridges across the center to the back of the knee. It prevents backward slippage of the leg bone (tibia) over the thigh bone (femur).
The PCL is one of two cruciate ligaments of the knee, which is the counterpart to the anterior cruciate ligament (ACL).
It comprises of 2 functional bundles: the larger anterolateral bundle (ALB) and the smaller posteromedial bundle (PMB).
What causes PCL tear?
It is relatively rare injury compared to ACL tears. Most common mechanisms of PCL tears include the following:
- Dashboard injury- when a driver/passenger’s bent knee hits against the dashboard, pushing in the shinbone just below the knee & causes the PCL to tear.
- Sports injury- Soccer players with fall on a bent knee with foot pointed down. The shinbone hits the ground first and moves backward.
- Being tackled when your knee is bent also can cause this injury.
Mechanism of PCL Injury
What are the symptoms of PCL tear?
- Pain & swelling around knee
- Difficulty in weight bearing on affected leg
- Restricted movement at knee
- Instability/lax knee
- Difficulty in sitting cross-legged, using stairs
- Walking restricted to a few meters.
How can it be diagnosed?
MRI scan is the investigation of choice.
MRI showing normal PCL
MRI of PCL tear
Do all PCL tears require surgery?
If you strain or slightly tear your PCL, it may heal over time with your doctor’s help and physical therapy. But if it’s completely torn, you may need to have it replaced -- especially if you’re young and active or an athlete who wants to keep playing sports. If you’re older or less active, your doctor might recommend treatments that don’t require surgery.
What is the treatment?
- According to the age, arthritic/non-arthritic knee, activity of patient and severity of the tear, individuals may require an arthroscopic PCL reconstruction to get back to pre-injury levels. This is again a minimally invasive procedure like ACL reconstruction. Self tissue(Auto-graft) is harvested from the same leg for the new ligament.
- Minor grades of sprain are treated non-operatively.
- Patients with higher grades of pre-existing arthritis with PCL tear may be given an option of joint replacement.
The first step is to harvest the graft from the back of your knee-hamstring graft harvesting. This is done via a 2-3 cm incision taken below the knee on the inner aspect using special instrument called tendon stripper. Then, your doctor will drill two holes, called “tunnels.” One tunnel will be drilled across thigh bone (above the knee) and another in the tibia (below the knee). They’ll use endobutton and screws in the tunnels to hold the graft in place. It serves as a sort of bridge that a new ligament will grow on as you heal. These are bio-degradable screws- meaning they will self absorb over a period of time-around 2-3 years, requiring no removal of implant in future . It can take months for a new PCL to grow in fully- this process is called ligamentisation.
Completed PCL Reconstruction
Completed PCL reconstruction
Femur side fixation – endobutton made of titanium
Tibia side fixation- bio-absorbable screw
How long will the recovery take after surgery? What will be the hospital stay?
Patients are made to walk using crutches/walker the very next day. Usually, 2-3 days of hospital stay is required.
They can walk independently by the end of 3 weeks.
Knee is given due protection by keeping the calf/leg supported underneath in the hinged brace when patient is in supine/sleeping position.
Office jobs can be resumed after a month.
Rest recovery protocol is similar to ACL reconstruction.