Question: We hear a lot about ACL injuries. I read an article recently that mentioned a PCL injury. How do the two differ in symptoms, treatment and recovery time?

Answer: Ligaments are strong, cord-like tissues that connect one bone to another and function to stabilize the joint. The knee has four primary ligaments. The anterior and posterior cruciate ligaments (ACL and PCL) are located in the center of the knee joint. Both are attached between the femur (thigh bone) and tibia (leg bone). The ACL attaches on top of the tibia in front of the PCL. The ACL thus prevents the tibia from sliding forward while the PCL prevents it from sliding back. There are also two ligaments on the sides called the medial and lateral collateral ligaments (MCL and LCL). These provide stability with side to side stress to the knee joint.

The reason you hear a lot about ACL injuries is because it is the most common knee ligament tear that requires surgery. The MCL is actually sprained more often than the ACL however it usually heals with use of a brace and rest. A higher amount of trauma is needed for injury to the LCL and PCL and that is why they are less common. While LCL injuries usually require surgery, many PCL tears can be treated without surgery.

PCL tears can occur with severe hyperextension of the knee, a blow to the front of the tibia or other high velocity trauma such as car accidents. In many cases another ligament in addition to the PCL will tear simultaneously. If this occurs the patient will require surgery and recovery can take six to 12 months. If there is an isolated PCL tear, many patients will be able to recover full function with rest, bracing, and therapy without surgery. Depending on the severity, it can take six weeks to three or four months to resume sports activities when isolated PCL sprains are treated non-operatively. If the patient experiences pain and instability after he or she resumes activities, surgery can still be performed.

Regardless of which ligament is sprained, the most important thing is to have a thorough examination by an experienced knee specialist as PCL injuries are frequently missed. Even if surgery is needed for an ACL or PCL tear, advances in the past few years allows more anatomically correct repair with all arthroscopic techniques that avoid incisions.

Vic Goradia, MD
Knee, Shoulder, and Sports Medicine Specialist
Go Orthopedics
GoOrtho.net