Classification and treatment of congenital central slip hypoplasia.

Objectives: The aim of this study is to make a diagnosis and a classification for congenital central slip hypoplasia. The surgical treatment was determined according to the classification.

Methods: A retrospective study of 25 treated digits in 13 patients with congenital central slip hypoplasia was carried out. The central slip was classified into two types. Type I: The distance between the insertion of central slip and the proximal interphalangeal joint was shorter than or equal to 5 mm. Type II: The distance between the insertion of central slip and the proximal interphalangeal joint was longer than 5 mm. Tendon advancement or tendon graft was used for type I or II, respectively.

Results: The preoperative mean extension lag was 91° (range, 80°-100°), and the mean follow-up duration was 18 months (range, 9-24 months). The postoperative mean extension lag was 19° (range, 0°-50°). No matter whether in type I or II, the postoperative ranges of proximal interphalangeal joint extension had significant improvement compared with the preoperative ones. There was no statistical difference of proximal interphalangeal joint extension lag changes before and after surgery between the two types.

Conclusion: Congenital central slip hypoplasia could be classified into two types. Either tendon advancement or tendon graft might be effective, which depended on the classification.