This paper reviews the treatment for symptomatic combined Grade III anterior cruciate ligament (ACL) and posterolateral knee injuries. Due to the high failure rate of ACL reconstructions when injuries to the posterolateral corner are neglected, it is recommended that reconstruction of an acute posterolateral knee complex injury be performed at the time of the acute ACL reconstruction to reduce the chance of ACL reconstruction failure. Treatment options for reconstruction of chronic Grade III posterolateral complex and ACL injuries are more complex and are also reviewed here. The results of combined ACL and posterolateral corner reconstructions in chronic cases are still preliminary, and further research is necessary to determine the optimal method of reconstruction in these cases.