Complex Topics in Knee Dislocations

It is a pleasure to introduce this special focus section of the Journal of Knee Surgery presenting complex topics in knee dislocations. Brief summaries of these articles are presented in this introduction. The purpose of this special focus section is to provide experienced knee surgeons, general orthopedic surgeons, fellows, residents, and other health care professionals with an interest in the multiple ligament injured (dislocated) knee, a useful tool for the management of these complex injuries.

Fanelli and Fanelli present the surgical techniques and outcomes of knee dislocations and posterior cruciate ligament—based multiple ligament knee injuries in patients 18 years of age and younger. Their article presents a review of the literature, and the author's experience treating knee dislocations and PCL-based multiple ligament knee injuries in patients 18 years of age and younger. This article discusses patient age at the time of surgery, mechanisms of injury, surgical techniques, considerations in patients with open growth plates, a review of the literature, and the author's surgical outcomes in these complex knee ligament instabilities.

Miller, Carr, Werner, and Gwathmey address the topic of knee dislocations in the morbidly obese patient. These injuries are often referred to as “ultra-low velocity knee dislocations” since they commonly occur after a seemingly trivial injury, such as a ground level fall. As a result, these injuries are often underappreciated and initially misdiagnosed. Knee dislocations in the morbidly obese are associated with a particularly high rate of neurovascular injury. A timely and accurate diagnosis is crucial to avoid serious limb-threatening complications, including the need for amputation. Therefore, evaluating physicians should maintain a high suspicion for a knee dislocation in any morbidly obese patient who presents with knee pain following a seemingly innocuous injury. Associated vascular injuries must be identified promptly and appropriately managed by a vascular surgery team. There is no consensus on the ideal orthopedic treatment of knee dislocations in the morbidly obese patient. Operative treatment can be fraught with complications, including a higher rate of neurovascular injury, increased surgical complications, and poor subjective patient outcome scores compared with nonobese patients sustaining a high-velocity knee dislocation. This article presents a review of the existing literature on knee dislocations in the morbidly obese population, including diagnosis, management, and outcomes.

Levy, O'Malley, Pareek, Reardon, Krych, and Stuart discuss treatment of peroneal nerve injuries in the multiligament injured/dislocated knee. Tibiofemoral knee dislocations are typically a consequence of high-energy mechanisms, causing significant damage to the soft tissue and osseous structures of the knee. Concomitant neurovascular injuries such as popliteal artery and peroneal nerve injuries are also common and can have significant long-term consequences. The mechanism typically involves a traction injury to the peroneal nerve subsequent to an extreme varus moment applied to the knee. Complete nerve injuries typically hold a worse prognosis than incomplete palsies. Rates of functional recovery in the setting of a complete palsy following a knee dislocation event have been dismal. A period of observation and nonoperative treatment is initially performed, utilizing orthotic devices to assist with lower extremity deficits. Surgical treatment options include neurolysis, nerve grafting, tendon transfer, arthrodesis, and direct motor nerve transfers. Motor nerve transfers continue to be explored with initial reports showing promising results.

Stuart, O'Malley, Reardon, Pareek, Krych, and Levy present the topic of extensor mechanism disruption in knee dislocations. This is a challenging injury with no clear consensus on optimal treatment. Acute, complete rupture of either the quadriceps or patellar tendon necessitates primary repair with or without augmentation. Surgical management may also be required in the setting of a partial tear if a significant extensor lag is present or nonoperative treatment has failed. Tendon augmentation is employed during primary repair if the native tissue is inadequate or after a failed primary repair. This article evaluates the extensor mechanism disruption incidence, injury patterns, associated injuries, and surgical options, including a novel tendon augmentation technique.

Stannard addresses the complex topic of fracture dislocations of the knee. These severe injuries are a potentially limb-threatening injury with poor outcomes in the historical literature. This article describes a treatment algorithm for this injury that begins with making the correct diagnosis and continues through a staged treatment protocol. Results of 27 patients who were treated using this protocol are reported, demonstrating that good results can be obtained. There is a high incidence of complications associated with this injury, but patient outcomes are still good if they are recognized and treated appropriately.

The multiple ligament injured (dislocated) knee is an extremely complex pathological entity. Through research, improved surgical techniques, the use of allograft tissue, advancement in surgical equipment, careful documentation, and experience, we are progressively improving our outcomes in treating this devastating knee injury. It is my personal hope that this special focus section will serve to stimulate new ideas to further develop treatment plans and surgical techniques for the dislocated knee.