A Quick Update on Knee Dislocations
You are called over to the examination table by the athletic trainer to evaluate a 19 year old soccer player with knee pain during a game. The player says he was cutting when he felt his knee buckle. On exam, he has an obvious effusion, has laxity with valgus stress at both 0 and 30 degrees as well as an equivocal lachmans. Given these findings, what is your most immediate concern in this player?
A) ACL Injury
B) MCL Injury
C) Vascular injury
D) Bone contusion
Image 1. Spontaneous posterior knee dislocation following total knee arthroplasty.
Image 2. Posterior knee dislocation of native knee with significant pneumarthrosis
Image 3. Angiography of politeal artery with occlusion of flow
Image 4. Sagittal view of MRI following multiligament knee injury with popliteal artery hematoma
Case Conclusion. The answer is C. This athlete has an exam concerning for a multiligament knee injury which likely includes ACL and MCL. A multiligament knee injury should be considered the equivalent of a knee dislocation until proven otherwise. In this athletes case, it would be important to perform a thorough neurovascular exam. At the bare minimum, he will require serial exams over the next 24 hours. If there is any question or concern for a vascular injury, meaning popliteal artery, then he needs to be sent to the emergency department for advanced vascular workup.