Overview
The posterior cruciate ligament (PCL) is the stronger of the two cruciate ligaments inside the knee. Its job is to keep the tibia (tibia) from sliding backward under the femur (femur). It usually tears from a direct blow to the front of a bent knee. The classic causes are a dashboard injury in a car crash or a fall onto a bent knee in sport. Unlike the ACL, the PCL has some ability to heal on its own. Many isolated, low-grade tears improve with bracing and rehab alone.
The picture changes when the PCL tears completely, or tears along with other structures. Those can include the ACL, the inner collateral ligament, or the posterolateral corner (a group of ligaments at the back-outer knee that control rotation). The tibia then settles backward at rest, which surgeons call posterior sag. Patients notice a dead or give-way feeling on stairs, on downhill slopes, and with changes of direction. Left untreated, the poor alignment concentrates force on the inner and front parts of the knee. Cartilage there wears out faster over the years. PCL reconstruction replaces the torn ligament with a tendon graft threaded through bone tunnels. That restores the normal position of tibia under femur and protects the cartilage from chronic overload.
How the Procedure Works
PCL reconstruction is more demanding than ACL reconstruction, mostly because of the tunnel drilled in the tibia. That tunnel must exit at the back of the tibia, near the large blood vessels behind the knee. So drill direction and depth are planned precisely and confirmed on live X-ray (fluoroscopy). We pass the graft through the tunnel and anchor it to the femur at the ligament's natural attachment point. We then set the graft's tension with the knee nearly straight, while pushing the tibia forward to correct the sag. PCL tears often come with other ligament injuries, and there the order of repair matters. We restore the PCL first, so the rest of the reconstruction has a stable reference point.
When to Consider PCL Reconstruction
We generally offer PCL reconstruction when your symptoms, your imaging, and a full course of non-surgical care all point the same way. The typical picture includes:
High-grade PCL tear with instability
A complete tear that leaves the knee unstable. It feels loose or gives way on stairs and downhill slopes.
Multi-ligament knee injury
A PCL tear combined with ACL, MCL, or posterolateral corner injury. Here, reconstruction is one part of a larger repair plan.
Symptoms despite rehab
You finished a supervised rehab program and the knee is still unstable or painful.
Treats: PCL Tear
Risks & Why We Still Recommend It
Every operation carries risk. This procedure is offered because the condition, when left untreated, can cause a lasting backward sag of the tibia, pain behind the knee on stairs and downhill walking, and faster cartilage wear at the front and inner knee. The decision to proceed weighs the risks of surgery against the limitations the condition places on daily function. Surgery does not remove risk; it addresses a problem that is otherwise progressive. Whether it is appropriate is determined for each patient in consultation with the surgeon.
The risks we discuss with you before PCL reconstruction include:
- bleeding and infection
- anesthesia risk
- stiffness
- graft stretch-out or re-tear
- residual posterior laxity
- blood clot in the leg or lung
- rarely, injury to the nerves and blood vessels that run close behind the knee
The reason to proceed is a PCL-deficient knee that is painful and unstable in daily life, often alongside other ligament injuries. If the operation is not right for you, we will say so.
Frequently Asked
questions we hear in clinicCan a PCL tear heal without surgery?
Sometimes. Unlike the ACL, the PCL has some ability to heal on its own, and many isolated, low-grade tears improve with bracing and rehab alone. Reconstruction is considered for complete tears that leave the knee unstable, tears combined with other ligament injuries, or a knee that is still unstable or painful after a supervised rehab program.
How does a PCL tear usually happen?
From a direct blow to the front of a bent knee. The classic causes are a dashboard injury in a car crash or a fall onto a bent knee in sport.
What does an unstable PCL-deficient knee feel like?
The tibia settles backward at rest, which surgeons call posterior sag. Patients notice a dead or give-way feeling on stairs, on downhill slopes, and with changes of direction.
What happens if I leave a high-grade tear untreated?
The lasting backward sag of the tibia concentrates force on the inner and front parts of the knee, so the cartilage there wears out faster over the years, along with pain behind the knee on stairs and downhill walking.
Why is PCL reconstruction more demanding than ACL reconstruction?
Mostly because of the tunnel drilled in the tibia. That tunnel must exit at the back of the tibia, near the large blood vessels behind the knee, so drill direction and depth are planned precisely and confirmed on live X-ray during surgery.
What if I tore more than just the PCL?
PCL tears often come with other ligament injuries, and the order of repair matters. We restore the PCL first, so the rest of the reconstruction has a stable reference point.
Further Reading
Outside reading we trust, plus related OSI pages:
