Orthopedics Hip & Knee Knee Ligament Injuries Posterolateral Rotatory Instability of the Knee By Jonathan Cluett, MD Jonathan Cluett, MD LinkedIn Twitter Jonathan Cluett, MD, is a board-certified orthopedic surgeon with subspecialty training in sports medicine and arthroscopic surgery. Learn about our editorial process Updated on November 12, 2020 Medically reviewed by Miho J. Tanaka, MD Medically reviewed by Miho J. Tanaka, MD on October 23, 2020 Facebook LinkedIn Twitter Miho J. Tanaka, MD, is a board-certified orthopedic surgeon who specializes in the treatment of sports medicine injuries. Learn about our Medical Review Board Print Posterolateral rotatory instability can occur due to damage to the structures that support the outside of the knee joint, described as the posterolateral corner. These structures are critical to preventing symptoms of knee instability. An injury of the knee ligaments can affect the structures of the posterolateral corner. These structures include the lateral collateral ligament, the popliteus tendon, and the knee joint capsule. They can be injured when the knee sustains ligament damage—including ACL tears and PCL tears. If damage to the posterolateral corner is not treated, persistent knee problems can occur, despite treatment of other knee injuries. Westend61 / Getty Images Symptoms of Posterolateral Corner Injuries Posterolateral corner injuries often occur with knee dislocations. About 70% of posterolateral corner injuries occur in the setting of an injury to the ACL and/or PCL—also known as the cruciate ligaments. About 15% of posterolateral corner injuries also involve injuries of the peroneal nerve. An injury to this nerve can cause numbness down the outside of the leg or weakness of the foot. About 20-30% of the time, an injury of the posterolateral corner is isolated. Symptoms of posterolateral corner injuries include: A feeling that the knee is going to give outPain and swelling over the outside of the knee joint, toward the back of the knee Your doctor will perform a Dial test when examining your knee for posterolateral rotatory instability. During this test, your doctor will determine the rotation of your knee (by turning your foot outwards at a specific position) and compare it to the opposite knee. Excessive rotation is indicative of an injury to the posterolateral corner. Your doctor will check the degree of rotation at different levels of knee flexion to determine which structures have been injured. Treatment Treatment of a posterolateral corner injury depends on the degree of instability. This type of injury is considered a contributing reason for why some people might not improve after ACL reconstruction surgery. When posterolateral corner injuries cause significant instability in the knee joint, the structures can be surgically repaired. A surgical repair requires an incision along the outside of the knee joint. If the injuries to the ligament are recent, they can often be repaired without the use of donor tissue, whereas chronic injuries may require donor tissue to reconstruct the damaged structures. Severe injuries also generally require the use of some donor tissue to augment the repair along the outside of the knee. Rehab After Surgery Rehabilitation after posterolateral reconstruction will depend on which knee structures that have been injured and repaired. Was this page helpful? Thanks for your feedback! Dealing with joint pain can cause major disruptions to your day. Sign up and learn how to better take care of your body. Click below and just hit send! Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Covey DC, "Injuries of the Posterolateral Corner of the Knee" J Bone Joint Surg (Am) 83:106 (2001)