Million-dollar nerve dysfunction after Dupuytren's contracture surgery.

The thenar muscles are supplied by the median nerve's recurrent motor branch (RMB). Its integrity is crucial for normal thumb motion, despite its small size and frequent neglect. We report a 70-year-old man experienced thumb weakness after Dupuytren's contracture surgery. Sensation was unaffected, but there was noticeable thenar atrophy and decreased strength. Ultrasound and magnetic resonance imaging revealed evidence of local compression, and electromyography verified a partial RMB injury. An uncommon but clinically significant RMB dysfunction is demonstrated in this case. Wide incisions or retraction may jeopardize this branch, even though Dupuytren's surgery typically spares it. Recovery depends on knowledge of RMB anatomy and timely rehabilitation.