Use of Dynamic Ultrasound Imaging for Assessment of the Fibular Collateral Ligament of the Knee.

A 25-year-old male college student reported an immediate sharp pain in the lateral aspect of his left knee while playing recreational basketball. He sought a direct-access consultation by a physical therapist. Due to the superficial nature of the fibular (lateral) collateral ligament (FCL), static and dynamic ultrasound imaging was used to visualize the FCL. Complementing the clinical examination findings, use of dynamic imaging strengthened the differential diagnosis of multidirectional laxity and supported the clinical decision of referral. Subsequent follow-up magnetic resonance imaging confirmed tears of the anterior cruciate ligament and FCL.J Orthop Sports Phys Ther 2019;49(3):210. doi:10.2519/jospt.2019.8460.