Congenital fusion of the 4th and 5th metacarpal bones: a new classification and approach to treatment

Abstract

Objective To review the clinical and radiological characteristics of patients with congenital fusion of the 4th and 5th metacarpal bones,and propose a new classification to provide better guidelines for the treatment of the deformity.Methods Based on the experience of 11 cases (16 hands) treated by the authors,the new classification takes into account according to the shape of the deformity and the appropriate treatment methods for each group.Under the new classification scheme,all patients were divided into 3 groups,according to the inter-metacarpal angle between the 4th and 5th metacarpals,and each group was further subdivided into 2 sub-groups according to the length of the fifth finger ray.Results All 16 hands could be classified according to this new classification,including 2 cases of group Ⅰ (both Ⅰ A),9 cases of group Ⅱ (Ⅱ A in 8 cases,ⅡB in 1 case),and 5 cases of group Ⅲ (Ⅲ A in 4 cases,Ⅲ B in 1 case).Patients in different groups received appropriate treatment according to the treatment guidelines proposed by the new classification scheme.It was also possible to classify all the cases illustrated in the literature according to this scheme.Conclusion The new classification could not only classify the deformity according to different morphological characteristics,but also provide general guidelines for deformity correction and a useful scheme for comparison of treatment outcomes among different studies. Key words: Hand deformities,congenital; Metacarpal bones; Synostosis; Classification