Wide-awake Surgery for Congenital Thumb Flexion Anomaly in a Child.

We report a rare case of absent thumb IP joint flexion in bilateral thumbs due to anomalous tendon slips of the flexor pollicis longus. Cutting the anomalous insertions failed to improve active flexion of the IP joints. Successful treatment was achieved by evaluating the musculotendinous units of the original flexor pollicis longus and the anomalous flexor pollicis longus tendon during a wide-awake surgery.