Transosseous tenodesis of the extensor pollicis brevis as treatment for acquired metacarpophalangeal hyperextension deformity of the thumb: a preliminary report

Abstract

Background: Hyperextension deformity of the metacarpophalangeal (MP) joint of the thumb contributes frequently to thumb pain and loss of function. Many treatments have been proposed, but none are universally accepted as ideal. Aims: To describe a new technique of tenodesis of the MP joint of the thumb using the extensor pollicis brevis (EPB) tendon and to analyze the results of a preliminary series with a minimum follow-up of one year. Methods: A descriptive study of a series of 12 symptomatic hyperextension deformities of the MP joint of the thumb in 10 patients who underwent a new method of tenodesis, with a minimum follow-up of 12 months. MP joint hyperextension and range of motion were assessed. Disability changes were evaluated by the QuickDASH score, the pain Visual Analogue Scale, the Kapandji opposition score, and pinch strength. The Wilcoxon test was used for statistical analysis. Results: The mean preoperative MP hyperextension deformity was 50.83+5.57o, which after the operation became a flexion attitude of 17.91+7.82o. The mean perceived pain went from 7.66 to 1.16. The QuickDash score was reduced by 34.4 points and the pinch strength increased by 50.42%. All changes observed after surgery were statistically significant. No major complications after the procedure were recorded. Conclusion: EPB transosseous tenodesis is a safe and mildly invasive option for achieving successful functional and cosmetic MP hyperextension deformity correction in posttraumatic and trapezio-methacarpal osteoarthritis-related cases. The advantage over MP fusion is that the functional range of flexion is maintained, even in deformities greater than 40o.