TREATMENT OF FRACTURES OF THE HUMERAL CAPITELLUM USING HERBERT SCREWS M. MAHIROGULLARI, A. KIRAL, C. SOLAKOGLU, O. PEHLIVAN, I. AKMAZ and O. RODOP From the Department of Orthopedics and Traumatology, Gulhane Military Medical Faculty Hospital, Istanbul, Turkey Isolated fractures of the capitellum are rare injuries and account for 1% of all elbow injuries. The purpose of this study is to evaluate the clinical outcomes of 11 Type I capitellum fractures treated by open reduction and internal fixation using at least two standard Herbert screws between 1998 and 2003. The average age of the patients was 27.5 years. The mean follow-up time was 23.4 months. The final postoperative assessment was made at the 12th month. The results were evaluated according to the Mayo Elbow Performance Index. We obtained excellent result in eight patients and good result in three patients. We recommend open reduction and fixation with Herbert screws inserted from the posterior surface of the lateral epicondyle and early mobilization in Type I fractures of the capitellum. Journal of Hand Surgery (British and European Volume, 2006) 31B: 3: 320–325 Keywords: fracture, distal humerus, humeral capitellum, Herbert screw Isolated fractures of the capitellum are rare and account for only 1% of all elbow injuries (Alvarez et al., 1975; Mehdian and McKee, 2000). These fractures are seen mostly in individuals older than 12 years old (De Boeck and Pouliart, 2000; Fowles and Kassab, 1974; Letts et al., 1997). Because of the largely cartilaginous composition of the capitellum in childhood, a similar injury in children usually results in a supracondylar, or lateral condylar, fracture, although there are rare reports published in the literature concerning capitellar fractures in younger children (Letts et al., 1997; Ring et al., 2003; Stricker et al., 1993). These fractures have been classified into three groups (Hardy et al., 2002). Type I, also called a Hahn–Steinthal fracture, is a shear fracture in the coronal plane of the distal humerus involving a large osseous portion of the capitellum. Type II, also called a Kocher–Lorenz fracture, results from a shearing force detaching a cartilaginous frag- ment with its subchondral support from the capitellum. Type III includes comminuted fractures. A fourth type has also been described, viz. a shear fracture of the distal end of the humerus extending across the capitellum in the coronal plane to include most of the lateral trochlear ridge and the lateral half of the trochlea (McKee et al., 1992, 1996). Injuries to the articular surface of the capitellum are usually a result of axial loading of the capitellum by forces transmitted through the radial head (Silveri et al., 1994; Webb, 2001). The combination of radial head and capitellar fractures has been variously reported as 10% and 31% of all capitellar fractures (Collert, 1977; Grantham et al., 1981; Milch, 1931; Palmer, 1961). The incidence of combined medial collateral ligament injuries and capitellar fractures has been variously reported as 5% and 17% of all capitellar fractures (Collert, 1977; Dushuttle et al., 1985). Although Bohler (1956) believed that fractures of the capitellum occur in patients with abnormal degrees of valgus and hyperextension of the elbow joint, this has not been the universal experience (Grantham et al., 1981). Although surgical excision is the preferred treatment for small and unfixable osteochondral and comminuted capitellar fractures, the selection of appropriate treat- ment for displaced large fragments of capitellar fractures is a controversial issue. Options include closed reduc- tion, excision, open reduction, with or without internal fixation, and prosthetic replacement (Mehdian and McKee, 2000). Whatever of these treatments, other than resection and prosthetic replacement, is proposed, anatomic reduction is imperative if normal function is to be restored. The purpose of this study was to evaluate the clinical outcomes of Type I capitellum fractures treated by Herbert screws. PATIENTS AND METHODS Between 1998 and 2003, 11 capitellum fractures of Hahn-Steinthal type (Type I) (Fig 1) were treated by open reduction and internal fixation using Herbert screws. The study group included three female and eight male patients of average age 27.5 (range 17–43) years (Table 1). Three patients were military officers, three were military privates, two were housewives, one was a military student, one was a secretary and one was a farmer. The average time from injury to operation was 2.8 (range 1–7) days. The dominant arm was involved in seven patients. All of the fractures were closed and all occurred as a result of a fall on the outstretched hand. Each fracture was an isolated injury, with no associated neurovascular injury or posterior dislocation. Under general anaesthesia and tourniquet control, pre-operative evaluation of the elbow with valgus stress ARTICLE IN PRESS 320