Capitellar fractures in children are more common among adolescents than other age groups, which is related to the development of the anatomical structure of the elbow joint [8, 13]. In young children, there are anatomical and mechanical weak areas at the junction of the humeral condyle and the humeral shaft [14]. Violence often leads to humeral supracondylar fractures. In addition, nonossified secondary ossification centres in children’s elbow joints,which starts to fuse around the age of 12 years [15]༌provide a cushioning effect against external stress. Therefore, capitulum fractures often occur in older children. The ossification centre of the capitellum has an anterior inclination of approximately 40°, resulting in an angle of approximately 140° between it and the humeral shaft [16]. Capitellar fracture is often considered to be the result of the shear force on the capitellum caused by the direct impact of the radial head on the capitellum [17, 18]. So coronal fractures of the capitellum are the most common type.
There are still controversies about the surgical approach for capitellar fractures. Many researchers have utilized the lateral or posterior approach in their studies [1, 5, 8]. Ravishankar et al [19] suggests that the lateral approach may cause the laxity of the lateral collateral ligament, and the repair of the ligament during the operation will prolong the operation time. Ballesteros et al [10] suggests that due to the lack of operating space when using the lateral approach, the screw cannot be implanted perpendicularly to the fracture surface, which affects the fixation effect. The posterior approach may damage the blood supply to the posterior capitellum [20, 21]. The anterior approach can provide sufficient exposure of the fractured fragments and has gradually become the preferred surgical approach for open reduction of supracondylar fractures of the humerus in children [22]. However, some researchers argue that this approach may damage blood vessels and nerves [23]. In this study, capitellar fractures were reduced and fixed via the anterior approach. There was no vessel or nerve damage during the operation. Since the median nerve, ulnar nerve, and brachial vessels are medial to the elbow joint, damage to the main blood vessels and nerves can be avoided with slight retraction of the superficial elbow vein and cutaneous nerve after incision and protection of the radial nerves between the brachialis and brachioradialis..
Moreover, due to the non-fully developed muscles of the anterior elbow in children, the fracture site can be quickly and clearly exposed by gentle retraction of muscles during the operation, and the fracture can be reduced and fixated under direct vision. In addition, because the incision is made along the cubital crease of the elbow, which was consistent with the skin pattern of the elbow joint, the application of intradermal suture is conductive to incision healing and an aesthetic outcome. Only one patient had an incision scar in this study. The results of this study show that the anterior approach is safe for the surgical operation of capitellar fractures in children. It can sufficiently expose the operative field to allow the surgeon to perform fracture reduction under direct vision.
Choosing an appropriate internal fixator is key to the treatment of capitellar fractures. Kirschner wire is the most commonly used fixator for fractures in children, but it has certain limitations for the treatment of capitellar fractures. The Kirschner wire passes through the articular surface but cannot provide stable fixation of the fractured fragments, and long-term cast immobilization after the operation is needed. This cannot meet the requirements of early elbow movement and is prone to cause elbow stiffness [24]. Some researchers choose absorbable screws to fixate capitellar fractures in children, but their absorbability makes the strength of such screws uncertain. Compared with metal internal fixators, absorbable screws may extend the time needed for external fixation [9]. Capitellar fractures are intra-articular fractures, and long-term external fixation is not conducive to the recovery of elbow function. Moreover, an absorbable material may cause serious complications such as foreign body reactions, and there is a potential risk for stunted development of the epiphysis in children [25].
In this study, Herbert screws were used to fixate capitellar fractures. Elkowitz et al [26] suggest that headless screws provide better stability than cancellous bone screws. For treatment of intra-articular fractures, anatomical reduction and firm fixation of the fracture are key to fracture healing and functional recovery [27]. Since the Herbert screw is completely driven into the articular cartilage, it will not affect the smoothness or integrity of the articular surface and has almost no effect on joint movement. Herbert screws can provide a firm fixation of fracture fragments, and patients can start functional exercise early after surgery. This can effectively prevent postoperative complications such as elbow stiffness.
Three children in this study had elbow dysfunction. One of them had a missed diagnosis in another hospital and was later diagnosed with capitellar fracture by CT examination in our hospital. Due to the long time from injury to surgery, the child still had a certain degree of elbow dysfunction even after functional exercises. The other two children developed postoperative elbow dysfunction due to nonadherence to functional exercises. The function of the elbow joint in the other children had recovered well at the last follow-up. We should be watchful of capitellar fractures in adolescents with elbow joint injuries. CT, MRI, or arthrography can be used to confirm the diagnosis. For those with surgical indications, surgery should be performed as soon as possible, and effective functional exercises should be carried out promptly after the operation. These measures can effectively prevent postoperative elbow dysfunction.
The limitations of this study include that it was a retrospective analysis and that it lacked a randomized controlled design. As capitellar fractures are rare, the sample was small, and long-term follow-up was not performed. Future research should include a multicentre, randomized, controlled study to further investigate the effectiveness (and its correlates) of open reduction through the anterior approach and the use of Herbert screws in the treatment of capitellar fractures in children.