Posterolateral Instability of the Knee

It is a pleasure to introduce this special focus section of the Journal of Knee Surgery presenting topics related to posterolateral instability of the knee. Experts in the field of posterolateral knee instability address interesting and timely topics. A brief summary of these articles is presented in this introductory section. The purpose of this special focus section of the Journal of Knee Surgery is to provide experienced knee surgeons, general orthopedic surgeons, fellows, residents, medical students, and other health care professionals with an interest in posterolateral instability of the knee a useful reference for the management of these complex injuries.

Posterolateral corner (PLC) knee injuries are relatively rare, but can lead to significant instability, dysfunction, and chronic knee pathologies. Recent trends in the literature suggest that the best clinical outcomes are obtained through the early identification and timely management of PLC injuries. Appropriate use of physical examination tests and imaging studies are a crucial part of the initial assessment, allowing identification of all associated injuries and accurate preoperative planning. Drs. Martin, Berdusco, and MacDonald present an evidence-based approach for the initial assessment of PLC injuries by focusing on the physical examination and relevant imaging studies.

Posterolateral instability of the knee combined with varus malalignment of the knee is a complex and challenging clinical condition. Drs. Herman, Litchfield, and Getgood describe high tibial osteotomy (HTO) as a useful and necessary operation in patients with varus malalignment and posterolateral instability, particularly in the chronic setting. The biomechanics, indications, surgical approach, and outcomes of HTO in the setting of PLC injury are reviewed in this article.

Drs. J. P. Stannard, J. T. Stannard, and J. L. Cook discuss the complex topic of repair or reconstruction in acute posterolateral instability of the knee. Several studies have found that reconstruction has better outcomes and lower failure rates. Optimally, if the patient has high-quality tissue available for repair, it is best to combine reconstruction with repair. The authors have developed a new posterolateral reconstruction technique which applies the functional anatomy that has been increasingly defined. The surgical technique is described in this article.

Dr. Fanelli presents his extensive experience with fibular head–based surgical procedures for the treatment of posterolateral instability of the knee. The surgical techniques presented are the biceps tendon transfer procedures and the fibular head–based figure of eight posterolateral reconstruction using free grafts. Each of these techniques is combined with capsular repair and/or posterolateral capsular shift procedures in all cases. The decision points for surgical technique selection, the surgical technique itself, the postoperative rehabilitation, and the outcomes of these surgical procedures are presented, including a comparison of the biceps tendon procedures with the free graft procedure.

Reconstruction of the PLC of the knee using two-tailed techniques involved grafts originating on the femur and inserting on the proximal tibia and fibular head. This method reconstructs the fibular collateral ligament, popliteofibular ligament, and popliteus tendon using anatomically placed grafts. Drs. Prince, Stuart, King, Sousa, and Levy describe the history, anatomy, indications, and authors' preferred technique for a two-tailed PLC reconstruction. Additionally, biomechanical and clinical outcomes of this technique are compared.

Drs. Spitzer, Doyle, and Marx assess the outcomes of surgical treatment of posterolateral instability of the knee in an evidence-based manner. The majority of the existing outcomes literature on posterolateral instability consists of small, level IV case series and level III retrospective studies. Outcomes of surgical treatment of posterolateral instability of the knee are difficult to compare due to the heterogeneous presentation of PLC injuries, the variability of their associated injuries, and their relative rarity. As such, three common types of surgical intervention for posterolateral instability are explored separately in this article, namely, acute repair, acute reconstruction, and chronic reconstruction. In general, the current literature supports early anatomic repair of all soft tissues and concomitant PLC reconstruction; however, due to the variability of posterolateral injury, surgical treatment options should be tailored to the patient depending on the severity and chronicity of the posterolateral instability, as well as the associated injuries present.