The combined treatment of entrapped Infrapatellar Branch of the Saphenous Nerve after ACL reconstruction: Ultrasound-guided perineural injection and acupotomy.

BACKGROUND The anterior cruciate ligament (ACL) reconstruction (ACLR) under the arthroscopy is a widespread procedure for ACL rupture, which could stabilize knee and promote recovery. However, one of its complications is the injury of infrapatellar branch of saphenous nerve (IBSN). In traditional Chinese medicine, acupotomy functions via releasing and stripping adhesion tissues. Accordingly, acupotomy is suitable for the treatment of entrapped nerve injury and tissues adhesion. CASE DESCRIPTION A 14-year-old man, who had ACLR before and returned to normal activity, presented with severe pain after a mild strain two weeks ago. The physical and imaging examinations revealed the compression injury of IBSN. METHODS We provided the ultrasound-guided perineural injection of 0.4% lidocaine, while it only alleviates the symptoms temporally and partially. Acupotomy using a small needle knife (0.4*40 mm) was performed. RESULTS The severe pain was immediately resolved. The visual analog pain scale (VAS) decreased from 10 to 1 and return to normal walking. The diameter of IBSN became smaller and the signal of peripheral soft tissue became hypoechoic in ultrasound. CONCLUSION In this case, the combined treatments of ultrasound-guided perineural injection and acupotomy are thought to be innovative procedures for IBSN entrapment with relative long-lasting therapeutic effects.