Definition and Overview
The posterior cruciate ligament, or PCL, is an internal ligament of the knee joint that connects the femur (thigh bone) with the tibia (one of the bones of the leg). It is found in the center of the knee joint and crosses the anterior cruciate ligament (ACL), forming the shape of an “X”. Both function to stabilize the knee joint and prevent displacement.
The knee joint is mobile and weight bearing, making it prone to injuries that can result in PCL tears and injuries. PCL reconstruction is considered in severe cases or when multiple ligaments have been damaged.
Who Should Undergo and Expected Results
Since the PCL is a strong ligament, PCL injuries are not as common as injuries to other ligaments of the knee. This injury is frequently encountered in athletes, and typically occurs when a force is applied to the flexed knee, such as in basketball or football. This can also occur in car accidents and head-on collisions, especially when the knee joint hits the dashboard. PCL injuries and tears usually occur alongside other injuries of the bones and other ligaments of the knee, resulting in knee pain, swelling, and a feeling of instability when walking. Some level of discomfort may also be experienced when performing certain activities, such as running or walking up the stairs.
Not all patients with PCL injuries need to undergo PCL reconstruction. For minor cases, conservative management with aggressive rehabilitation may be satisfactory. Control of pain and swelling is of primary importance and is accomplished with rest, ice, compression, and elevation (RICE technique). Weight bearing has to be limited and patients may have to wear a leg brace and use crutches until the knee is more stable. Specific muscle strengthening exercises are also necessary to restore normal function.
In patients with more severe knee injuries, especially when multiple ligaments are involved, surgery to reconstruct the PCL may be necessary. This is often recommended for patients with persistent knee instability and who experience chronic pain, despite non-operative management and rehabilitation.
The results of surgery tend to vary, but generally, the laxity of the knee joint improves following the procedure.
How is the Procedure Performed?
The surgery makes use of a graft to rebuild or replace the PCL. There are several options that can be used as graft materials, such as the patellar or Achilles tendon. The ideal type of graft to be used in PCL reconstruction remains to be determined, with various reports showing similar success rates for both autografts and allografts.
PCL reconstruction is performed under general anesthesia, often arthroscopically, which is a less invasive form of surgery. Small incisions are made on the knee, where special instruments are inserted. Initially, the injury is evaluated using the scope, and the damaged ligaments are trimmed. After evaluation, pins are screwed into the femur to serve as tunnels where the catheters are subsequently inserted. The graft is then secured at one end of the catheter and threaded through the tunnels. Once positioned properly, the graft is sutured or screwed in place.
Over time, the graft heals and, together with the remnant of the injured ligament, a new ligament is formed. This process can take as long as one year.
Rehabilitation after knee surgery is very important. Typically, patients are advised to minimize weight bearing on the joint, and a leg brace is usually necessary. Range of motion exercises are performed to make sure that fibrosis does not occur and that the knee joint returns to its normal function. Physical therapy is typically performed once a week after the surgery and full recovery can take six months.
Possible Risks and Complications
Complications that can occur with PCL reconstruction include the following:
- Pain and swelling
- Persistent numbness
- Infection – This is a rare complication and is treated with aggressive antibiotics.
- Stiffness of the knee – This can occur if physical therapy is not sought following the procedure. In some cases, repeat arthroscopic surgery may be necessary to take down the adhesions and facilitate movement.
- Graft failure - In these cases, the knee is noted to give way and instability recurs.
Complications with posterior cruciate ligament reconstruction occur in less than 5% of patients.
Lenschow S, Zantop T, Weimann A, Lemburg T, Raschke M, Strobel M. Joint kinematics and in situ forces after single bundle PCL reconstruction: a graft placed at the center of the femoral attachment does not restore normal posterior laxity. Arch Orthop Trauma Surg. 2006 May. 126(4):253-9.
Kim SJ, Kim TE, Jo SB, et al. Comparison of the clinical results of three posterior cruciate ligament reconstruction techniques. J Bone Joint Surg Am. 2009 Nov. 91(11):2543-9.