Ultrasound-Guided Perineural Hydrodissection for the Treatment of Lacertus Fibrosus Syndrome in a Baseball Player: A Case Report.

Lacertus fibrosus Syndrome (LFS) is a rare cause of persistent medial elbow pain in baseball players, often not considered in the initial diagnostic considerations. This case report details a 19-year-old collegiate baseball player who presented with insidious left anterior medial elbow pain, initially diagnosed as biceps tendonitis. The patient did not experience pain relief after six months of conservative management. Sonopalpation during diagnostic ultrasound localized the source of pain to the median nerve at the level of the lacertus fibrosus, and the decision was made to perform ultrasound-guided hydrodissection of the median nerve at this level. The procedure resulted in rapid and sustained symptom relief without the scarring that has been associated with traditional surgical techniques. To date, there has been no study investigating the use of ultrasound-guided hydrodissection targeting lacertus fibrosus. This report highlights the importance of considering LFS in throwing athletes with persistent elbow pain, and advocates for considering ultrasound-guided hydrodissection as a management option for patients with clinical suspicion of LFS.