Knee Dislocation in the Morbidly Obese Patient

Abstract

Though a relatively rare orthopedic injury, knee dislocation in the morbidly obese population has been increasingly reported in the literature. These injuries are often referred to as "ultralow-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. Even though these injuries are low-velocity, they should still be regarded as a high energy injury because of the large amount of mass contributing to the dislocating force. 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. Management of these injuries is controversial. 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. It is paramount that treating physicians are familiar with the unique challenges of treating knee dislocations in the morbidly obese patient when discussing risks and benefits of treatment options. This article presents a review of the existing literature on knee dislocations in the morbidly obese population, including diagnosis, management, and outcomes.