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New Insights for Avoiding Early Knee Arthritis after Injury to the Posterior Cruciate Ligament

Chances are you know someone who's had an anterior cruciate ligament (ACL) tear. The ACL is one of two ligaments that cross inside the knee joint. The second ligament is called the posterior cruciate ligament (PCL).

ACL tears are far more common than PCL tears. Both types of tears can cause major problems. Treatment decisions are based on understanding of the injury and what can happen years later. The goal of this study was to find out if a PCL tear increases the risk of cartilage damage in the same ways as damage to other ligaments.

Doctors in Germany studied 181 patients with PCL injury that was not surgically repaired. Two areas of cartilage (inside the knee joint and behind the kneecap) were viewed with an arthroscope. An arthroscope is a tool used by doctors to look and work inside the joint.

X-rays showed that changes in the cartilage are present within a year after a PCL tear. The two injuries together (PCL tear and cartilage damage) also result in early arthritis. Even more problems occur if there is an old injury of the meniscus, the protective cushion between the knee joint. The authors of this study suggest that surgery to repair a torn PCL may be needed to prevent worse damage to the knee.

It appears from this study that two-thirds of all patients with a torn and unrepaired PCL will develop damage to the knee joint cartilage. Half of the changes occur on the inside edge of the knee joint. Another third affect the kneecap or patella. A smaller number cause damage to the outside edge of the knee joint.

The authors of this study hope the new understanding of PCL tears and their effect on knees will help doctors make better treatment decisions. The risk of joint damage increases when the ligament isn't repaired. The outcome is worse if the meniscus was torn previously. For these reasons, early surgery to repair a torn PCL may be necessary.

References: Michael J. Strobel, MD, et al. Arthroscopic Evaluation of Articular Cartilage Lesions in Posterior Cruciate Ligament-Deficient Knees. In Arthroscopy. March 2003. Vol. 19. No. 3. Pp. 262-268.

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