Cutting edge Orthopedics

Supracondylar Humerus Fractures • 27  Fig. 18: Clinical appearance of cubitus varus deformity of the left elbow (Courtesy of Shriners Hospital for Children, Philadelphia, PA). 57 Cubitus Varus Cubitus varus, or “gun-stock” deformity, can occur following supracondylar humerus frac- tures treated with casting or CRPP (Fig. 4.18 ). Pirone and colleagues (1988) reported occur- rence 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 deformity 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 col- lateral 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 out- comes, and three had fair or poor outcomes [ 109 ]. Tardy ulnar nerve palsy is also associ- ated with cubitus varus deformity [ 19 ]. Osteotomies to correct the varus deformity may be performed for children with substan- tial cubitus varus deformity following a supra- condylar humerus fracture. For pure coronal plane deformities, an oblique, lateral closing wedge osteotomy is preferred and can be per- formed through either a lateral or posterior approach to the elbow (Fig. 4.19 ). When sagit- tal plane deformity is present, a biplanar oste- otomy may be performed. For example, with residual varus and extension deformities (Fig. 4.20 ), a sma l edge of the bone may be removed anteriorly so that when the lateral osteotomy is closed, the distal humerus is also brought into some flexion (Figs. 4.21 and 4.22 ). Following the same principles, a dome osteotomy may be performed to obtain multi- planar deformity correction (Fig. 4.23 ). 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 compli- cations [ 110 ]. Fig. 4.18 Clinical appearance of cubitus varus deformity of the left elbow (Courtesy of Shriners Hospital for Children, Philadelphia, PA) 4 Supracondylar Humerus Fractures Fig. 17: These figures depict potential errors in percutaneous pinning technique for supracondylar humerus fractures. ( a ) Lateral and anteroposterior views demonstr ting less than two pins engaging both fragments due to one pin exiting through the fracture site. ( b ) Lateral and anteroposterior views showing less than two pins with bicortical fixation. ( c ) Lateral and anteroposterior views illustrating inadequate separation of pins (<2 mm) at the level of the fracture in both planes (Courtesy of Dan A. Zlotolow, MD). factors have been identified as the primary rea- son for loss of reduction. Sankar and colleagues (2007) investigated factors associated with loss of fixation in pediatric supracondylar humerus fractures [ 106 ]. Loss of fixation was identified in bicortical pins, and (3) insufficient pin separa- tion at the fracture site (<2 mm) [ 106 ] (Fig. 4.17 ). However, it should also be noted that three lat- eral-entry pins are typically recommended for Type III fractures. a b c Fig.4.17 These figures depict potential errors in percuta- neous pinning technique for supracondylar humerus frac- tures. ( a ) Lateral and nteropos rior views demonstra ing less than two pins e gagi g b th fragments due to one p exiting thr ugh the fracture site. ( b ) Lateral and antero- posterior vi ws showing less than two pins with bicortical fixation. ( c ) Lat ral and anteroposterior views illustrating inadequate separatio of pins (<2 mm) at the level of the fracture in both planes (Courtesy of Dan A. Zloto w, MD)