To evaluate the efficacy of dynamic ultrasound to diagnose extensor carpi ulnaris (ECU) subluxation and assess the results of a new technique for anatomic ECU tendon sheath reconstruction.

Dynamic ultrasound was used to confirm the diagnosis of ECU tendon subluxation in patients presenting with painful snapping of the ulnar wrist during supination and pronation. Twenty-one patients with persistent subluxation had reconstruction of the ECU tendon sheath using a new technique. In this procedure, the ECU tendon is elevated within its sheath dorsally and radially. The distal ulnar groove is deepened with a power burr, and 2 or 3 suture anchors are placed along the ulnar margin of the reconstructed groove. The sutures are passed through the ulnar border of the ECU sheath and tied, securing tendon sheath to bone. Preoperative wrist flexion-extension, radial-ulnar deviation, pronation-supination, grip strength, and ratings of pain, satisfaction, and Disabilities of the Arm, Shoulder, and Hand (DASH) scores were recorded and compared with postoperative values in a prospective study. Fourteen male patients and seven female patients were followed from 24 to 45 months postoperatively (mean, 31 mo).

Twenty-one patients presented with symptomatic ECU tendon subluxation confirmed by dynamic ultrasound of the wrist. We noted a statistically significant increase in arc of wrist flexion-extension, radial-ulnar deviation, pronation-supination, and grip strength after reconstruction. There was a statistically significant improvement in pain, satisfaction, and DASH scores after ECU stabilization.

Dynamic ultrasound is an effective and noninvasive method of diagnosing ECU tendon subluxation. Our technique of anatomic ECU tendon sheath reconstruction improved postoperative wrist range of motion, grip strength, pain, satisfaction, and DASH scores.

Therapeutic IV.