Cutting edge Orthopedics

26 • CUTTING EDGE - ORTHOPEDICS investigated factors associated with loss of fixation in pediatric supracondylar humerus fractures [106]. Loss of fixation was identified in 8 of 279 fractures retrospectively reviewed with all 8 frac- tures being Gartland Type III fractures. Seven of the eight had been treated with two lateral-entry pins and one with two crossed pins. The authors concluded that a technical error was present in each of these cases. The technical errors that they identified were: (1) less than two pins engaging both fragments, (2) less than two bicortical pins, and (3) insufficient pin separation at the fracture site (<2 mm) [106] (Fig. 17). However, it should also be noted that three lateral-entry pins are typically recommended for Type III fractures. Cubitus Varus Cubitus varus, or “gun-stock” deformity , can occur following supracondylar humerus fractures treated with casting or CRPP (Fig. 18). Pirone and colleagues (1988) reported occurrence of cubitus varus deformity in 8% of patients treated with cast immobilization and approximately 1% in patients treated with CRPP [22]. Traditionally, cubitus varus was considered a cosmetic deform- ity since it was painless. However, cubitus varus deformity has been reported to increase the risk of lateral condyle fractures [107] and snapping medial triceps [108]. Additionally, O’Driscoll and colleagues (2001) investigated 22 limbs with chronic cubitus varus deformity. Each of the adult patients complained of lateral elbow pain and recurrent instability at presentation, and some of the patients also complained of medial snapping. All of the patients were diagnosed with late posterolateral elbow instability, and the authors postulated that it was due to the cubitus varus deformity. The varus angulation of the distal humerus shifts the mechanical axis of the elbow medially, which alters the line of pull of the triceps. Over time, the asymmetric triceps force may promote slow attenuation of the lateral collateral ligament. The patients were primarily treated with a corrective osteotomy with the addition of ligamentous reconstruction in some cases. One patient who had degenerative changes underwent a total elbow arthroplasty. Nineteen patients had good or excellent outcomes, and three had fair or poor outcomes [109]. Tardy ulnar nerve palsy is also associated with cubitus varus deformity [19]. Osteotomies to correct the varus deformity may be performed for children with substantial cubitus varus deformity following a supracondylar humerus fracture. For pure coronal plane defor- mities, an oblique, lateral closing wedge osteotomy is preferred and can be performed through either a lateral or posterior approach to the elbow (Fig. 19). When sagittal plane deformity is present, a biplanar osteotomy may be performed. For example, with residual varus and extension deformities (Fig. 20), a small wedge of the bone may be removed anteriorly so that when the lateral osteoto- my is closed, the distal humerus is also brought into some flexion (Figs. 21 and 22). Following the same principles, a dome osteotomy may be performed to obtain multi-planar deformity correction (Fig. 23). Regardless of the type of osteotomy, a pin or plate and screw construct may be utilized for fixation [9, 14]. Solfelt and colleagues (2014) performed a meta-analysis investigating four treatment options for cubitus varus: lateral closing wedge osteotomy, dome osteotomy, multi-planar osteotomy, and osteotomy with distraction osteogenesis [110]. No significant differences were found between treatments for correction achieved and incidence of complications [110].