Currently, there is no collective consensus on the most effective treatment method for medial collateral ligament injuries with or without associated structural deficiencies. An in-depth understanding of relevant anatomic structures and diagnostic tools is critical to determining an appropriate treatment strategy. This article presents an overview for management of chronic combined posterior cruciate ligament (PCL) and posteromedial instability of the knee, and the results of treatment within the context of the PCL-based multiple ligament injured knee. Recognition and correction of the varying types of posteromedial instability is the key to successful PCL reconstruction in combined PCL posteromedial instability. Reasons for failure of PCL reconstruction include failure to address associated collateral ligament instability, associated limb malalignment, and improper tunnel position. The principles of reconstruction in the combined PCL posteromedial injured knee are to identify and treat all pathology, accurately place tunnels to approximate ligament anatomic insertion sites, utilize strong graft material, employ mechanical graft tensioning, provide secure graft fixation, and perform a deliberate postoperative rehabilitation program. Results of treatment indicate that multiple techniques of posterior ligament reconstruction and posteromedial reconstruction are successful and return patients functional activity with long-term follow-up.