Ultra-low velocity knee dislocation in obese and morbidly obese patients: a current concepts review

As the prevalence of obesity continues to rise, there has been an increase in the number of ultra-low velocity knee dislocations within the obese population reported in the literature. These injuries are often referred to as 'ultra-low velocity knee dislocation' since they commonly occur during activities of daily living (e.g., same-level fall, stepped off curb, tripped on carpet). As a result, these injuries are often underappreciated and initially misdiagnosed. Even though these injuries are regarded as low velocity, a high magnitude of force is still transferred through the knee joint to dislocate the knee. Knee dislocation in obese and morbidly obese patients is associated with a particularly high rate of neurovascular injury. A low velocity knee dislocation is an orthopaedic emergency; therefore, evaluating physicians should maintain a high index of suspicion for a knee dislocation in any obese or morbidly obese patients who present with knee pain following a seemingly innocuous injury. Vascular injuries must be managed by a vascular team. Orthopaedic management of these injuries is still controversial. There is currently no consensus on the ideal orthopaedic treatment of the knee dislocations in the obese and morbidly obese patient. Operative management may be associated with more complications, such as a higher rate of neurovascular injury, increased surgical complications, and poor subjective patient outcome scores compared with non-obese patients sustaining a high velocity knee dislocation.