Abstract
The infrapatellar branch of the saphenous nerve (IPBSN) is the sensory branch that supplies the anteromedial knee. While iatrogenic injury following knee surgery is well documented, spontaneous or activity-related IPBSN entrapment is under-recognized and can mimic common extensor mechanism disorders. Herein, we present the case of a male physical education teacher in his 20s who developed reproducible anterior knee pain with lunge movements after repeated basketball jumps. The initial clinical suspicion was patellar tendinopathy; however, high-resolution ultrasound (HRUS) revealed IPBSN entrapment at the sartorius penetration site. Manual decompression of the sartorius muscle immediately alleviated the pain. Subsequently, ultrasound-guided soft tissue mobilization was performed, resulting in complete resolution of pain. This case highlights the diagnostic value of HRUS and introduces ultrasound-guided manual therapy as a potentially safe and effective conservative option for treating IPBSN presenting with anterior knee pain.