Injuries to the posterior cruciate ligament and posterolateral instabilities of the knee.

Unlike anterior cruciate ligament (ACL) injury, disability from isolated posterior cruciate ligament (PCL) injury varies from no interference with life style to severe impairment of daily activities. Therefore, management of isolated PCL injuries remains controversial. High-energy vehicular accidents often cause more-serious PCL injuries, while less-severe injuries result from low-energy trauma including sports. The natural history and prognosis of PCL injury are correlated with the type and extent of instability and the development of degenerative changes in the knee. Indications for surgery include pain and instability of the knee. Arthroscopic single-bundle PCL reconstruction improved the function and stability of the knee with 77.4% satisfactory results in medium-term follow-up. Complete restoration of ligament stability was achieved in only 52% of knees, while 1/3 of the knees showed mild and 9.7% showed moderate residual ligament laxity. The incidence of degenerative changes was 52%, and the rate was correlated with duration of injury and severity of ligament laxity. Therefore, the significance of PCL injury has been overly simplified, and the functional disability of knees with PCL injury underestimated. Early surgical reconstruction of knees with grade III PCL injury is recommended. PCL injury is frequently associated with multiple ligamentous injuries. Combined PCL and posterolateral instabilities are serious knee injuries and frequently result in severe functional disability due to pain, instability, and degenerative changes in the knee. Unlike isolated PCL injury, there is a consensus of opinion that surgical reconstruction is indicated in knees with combined PCL and posterolateral instabilities. Commonly employed methods of reconstruction of the posterolateral corner include popliteus reconstruction, lateral collateral reconstruction or advancement, and a combination of the two. Combined arthroscopic PCL reconstruction and posterolateral reconstruction achieved 64% satisfactory (24% excellent and 40% good) and 36% unsatisfactory (24% fair and 12% poor) results over an average of 32 months of follow-up. Complete restoration of ligament stability was noted in only 44% of knees. The incidence of degenerative changes was 44%, and the rate was correlated with duration from injury to surgery and severity of ligament laxity. Despite the fact that currently employed surgical techniques only achieve modest success in restoration of ligament stability, early surgical reconstruction in knees with combined PCL and posterolateral instabilities achieved the best clinical results and a high rate of patient satisfaction.