Entire flexor carpi radialis tendon harvest for thumb carpometacarpal arthroplasty alters wrist kinetics.

PURPOSE: To investigate the clinical outcome of thumb carpometacarpal arthroplasty with entire-thickness flexor carpi radialis (FCR) ligament reconstruction and tendon interposition and to investigate the isokinetic wrist flexion/extension torque and flexion fatigue strength of the surgically treated wrist compared with the nonsurgically treated wrist.

METHODS: Thirty-nine patients with osteoarthritis who had unilateral thumb carpometacarpal arthroplasty with the entire FCR tendon were studied prospectively with a minimum follow-up period of 24 months. Preoperative Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire score, grip, pinch, and postoperative DASH score, grip, pinch, and Biodex (Shirley, NY) isokinetic wrist flexion/extension torques were recorded. The nonsurgically treated extremity served as the control for each patient with unilateral ligament reconstruction and tendon interposition. Peak torque ratios and fatigue were measured for the control and surgically treated extremities with the Biodex.

RESULTS: Postoperative DASH scores were 12 +/- 4 and were improved significantly from preoperative scores of 43 +/- 4. The surgically treated extremity showed a significantly lower wrist flexion-to-extension peak torque ratio than the control extremity. The control extremity had 2.5 times greater wrist flexion fatigue resistance than the surgically treated side. After surgery the surgically treated extremity had significantly improved grip strength and thumb-index tip pinch compared with the preoperative status.

CONCLUSIONS: Our data show conclusively that wrist flexion extension torque ratio decreases and wrist flexion fatigue resistance decreases when the entire FCR tendon is harvested even though the final outcome is favorable and uniformly based on traditional DASH, grip, and pinch scores.