An Overlooked Cause of Posterior Knee Pain: Ultrasound Imaging and Guided Injection for Proximal Lateral Gastrocnemius Tendon Sprain

Proximal lateral gastrocnemius tendon injury is an overlooked cause of posterior knee pain. As the proximal gastrocnemius tendon attaches on the distal femur; its pain is more deeply located and can also be aggravated by flexion of the affected knee. In the present report, sonopalpation showed that the painful tendon appeared to have lost its fibrillary pattern and become thickened and hypoechoic as well. Under the diagnosis of proximal gastrocnemius tendon sprain, the ultrasound guided dextrose injection was performed and the pain was totally relieved.