Opponensplasty using the extensor indicis proprius tendon for severe carpal tunnel syndrome in 40 patients.

The aim of this study was to assess the clinical results after extensor indicis proprius opponensplasty in patients with carpal tunnel syndrome and severe thenar muscle atrophy. Forty patients who underwent this procedure during open carpal tunnel releases. The mean follow-up period was 17 months (range 10 to 36). Kapandji scores significantly improved from 5.5 before surgery to 9.6 at final follow-up. Thumb pronation angle also significantly improved from 111° before surgery to 149°. Side and pulp pinch strength significantly improved postoperatively, as well as DASH scores at final follow-up. In conclusion, the extensor indicis proprius tendon transfer technique represents a reliable opponensplasty procedure to achieve consistent results in patients with severe carpal tunnel syndrome.Level of evidence: IV.