Characteristics of patients with hypoplastic thumb: a prospective study of 51 patients with the results of surgical treatment.

The aim of this study was to characterize a group of patients with hypoplasia of the thumb, classifying them, describing the associated anomalies and to evaluate the results of surgical treatment of such cases. Thumb hypoplasia is a complex and heterogeneous congenital disorder that is detrimental to hand functions. The characteristics of patients with these anomalies are not well described in the literature. A prospective study on 51 patients with 82 hypoplastic thumbs was done. All the patients' data regarding their personal, family, pregnancy and developmental histories were recorded. All the patients were exposed to thorough clinical examination with genetic assessment and radiological examination including abdominal ultrasonography and echocardiography when requested by the paediatrician. The cases were classified using the modified Blauth classification into five types and we added the five-fingered hand. Surgical treatment was performed for 26 hands in 18 patients and the postoperative results were recorded with an average duration of follow-up of 38.6 months. Of the 51 patients, there was a positive consanguinity in 23.5%. Eighty-six per cent were found to have associated anomalies. Type V thumb hypoplasia was the most common type followed by type IV, with type I being the least common. All the patients' parents were satisfied with the results of surgical treatment and noticed improvement of the performance of the operated hands in the daily activities. We detected some anomalies that have never been described before or described as case reports only; such as lacunar skull, congenital facial palsy and toe amputation; we also described familial radial side dysplasia with variable presentation of congenital anomalies of the thumb in the families. In addition, we think that the five-fingered hand should be added to the classification of thumb hypoplasia. Our study agrees with the literature regarding the distribution of different types of hypoplasia of the thumb, the incidence of associated anomalies and the results of surgical treatment.