A knee sprain is common presentation to the ED or Urgent Care. There are 4 main ligamentous structures (ACL,PCL,MCL,LCL) and the medial and lateral meniscus which are all at risk for injury. The mechanism of injury can often help determine the most likely injured structure. The presence of a large effusion or a “pop” heard by the patient raises the suspicion for a high grade or complete ligamentous tear. Radiographs can obtain but may be normal even with complete tears. If there is concern for a high grade tear the patient should be referred to orthopedics within a week- emergent MRI is not required. If the patient has concern for a bi-cruciate (ACL/PCL) tear these are at high risk for vascular injury and; the provider should consider vascular imaging or emergent consultation if there are signs of vascular compromise.

 

ACL