Thumb Carpometacarpal Suspension Arthroplasty Using Interference Screw Fixation: Surgical Technique and Clinical Results

Abstract

Arthritis of the thumb carpometacarpal (CMC) joint is a common condition, for which reconstruction using the flexor carpi radialis (FCR) is a standard treatment. We describe the technique and clinical results for thumb CMC arthroplasty using interference screw fixation of the FCR to the first metacarpal through a single incision. Over 12 months, 29 consecutive CMC arthroplasties were performed in 29 patients using FCR transfer tenotomized at the level of the scaphoid with an absorbable biotenodesis screw for fixation. There were 24 women and 5 men, with a mean age of 58 years. Patients were evaluated at a minimum of one year with radiographs, standardized outcome instruments, and measurements of motion and strength. The scaphoid to first metacarpal distance was measured at 2 weeks, 3 months, and greater than 1 year to assess settling. A total of 28 patients were available at a mean of 19 months. No arthroplasties required revision. Postoperative scaphoid to first metacarpal distance was 5.9 mm, which had decreased by a mean of 1.4 mm at final follow-up. There were no side-to-side differences in range of motion or strength in the entire cohort except for lateral key pinch, which was lower on the reconstructed side. The mean postoperative Disabilities of the Arm, Shoulder, and Hand score was 15, and the mean visual analog scale score was 1. Correlations were found between age and lateral key pinch strength for the reconstructed and contralateral sides. There were no significant relationships among Disabilities of the Arm, Shoulder, and Hand score, visual analog scale, radiographic settling, side-to-side strength or range of motion versus gender, Eaton stage, or workers' compensation status. Our series demonstrates excellent clinical outcomes with no revisions at an average of 19 months for this technique. Strength, range of motion, and radiographic settling compare favorably with published results of alternative techniques. Except for lateral key pinch, there was no statistically significant difference in strength compared with the contralateral side. Therapeutic IV.