Many people are familiar with anterior cruciate ligament (ACL) tears. But inside the knee joint there are two important ligaments. The ACL criss-crosses with the posterior cruciate ligament (PCL). And PCL injuries account for up to one-third of all knee injuries.
The PCLs main job is to keep the tibia (lower leg bone) from sliding backwards under the femur (thigh bone). A second function of the PCL is to restrain the tibia from rotating outward too far.
It is possible to test for PCL injury using clinical exams, stress X-rays, and MRIs. But there are problems with each of these tests. The biggest problem is that there could be a combined PCL tear and damage to the posterolateral corner that goes undetected. If the PCL tear is repaired surgically but the posterolateral corner isn’t reconstructed, then joint laxity (looseness) can lead to another injury later.
Posterior refers to the back side of the knee.Lateral is along the outside edge of the joint. There are five basic structures that make up the posterolateral corner. These include two muscles: the lateral head of the gastrocnemius (calf) and the popliteus. Three ligaments are also involved: the popliteofibular ligament, the lateral collateral ligament (LCL), and the arcuate-fabellofibular ligament complex.
The surgeon’s exam may be limited by patient discomfort and muscle splinting and guarding during the exam. With the patient completely relaxed under anesthesia, an accurate exam can be done. Once the full extent of the damage is determined, then the appropriate surgical repair or reconstruction can be done for the best result.