The posterolateral (back and outside) corner of the knee has been called “the dark side of the knee.” Much less is known and understood about its complex structure than about the rest of the knee joint. This author sheds some light on injuries of the posterolateral part of the knee.
Posterolateral knee injuries don’t happen often. When they do occur, they can cause severe disability. Usually they happen along with damage to the central knee ligaments. In many cases, the injured ligaments are treated, but the injury to the posterolateral structures goes undiagnosed. When this happens, surgery for the central ligaments may eventually fail.
Posterolateral knee injuries are difficult for doctors to diagnose. There may be pain in the back and outside part of the knee. Damage to nerves is fairly common, so there may also be tingling or numbness in the leg. The author lists some ways for doctors to examine the knee and suggests imaging tests that can help identify damage to this part of the knee. Arthroscopy may be necessary for accurate diagnosis. This involves inserting a tiny TV camera into the joint.
Mild or moderate tears in the outer portion of the knee may heal without surgery. Complete tears usually require surgery. Surgery is more likely to be successful when it is done soon after a severe injury. Surgery is less successful when posterolateral problems develop over a long period of time. The author concludes that future research should focus on improving ways to repair the posterolateral corner of the knee, now that we are learning more about the knee’s “dark side.”