Supracondylar Humerus Fractures J. Benjamin St. Clair, MD, PhD,* and Verena M. Schreiber, MD† Supracondylar humerus fractures are common elbow injuries in children that occur in a vul- nerable anatomical location with risk for sequelae ranging from neurovascular compromise to residual deformity. While nondisplaced fractures can be managed nonoperatively, both closed and open surgical reduction techniques are indicated when fractures are displaced or associated with neurovascular injury. This paper describes the techniques employed in the surgical treatment of pediatric supracondylar humerus fractures. Oper Tech Orthop 29:11-16 © 2019 Elsevier Inc. All rights reserved. KEYWORDS humerus fracture, pediatric elbow fracture, supracondylar Introduction Mechanism of Injury upracondylar humerus fractures are one of the most The supracondylar distal humerus contains a thin region of S common fractures in children and account for 60% of bone connecting the medial and lateral columns of the all pediatric elbow fractures with an incidence of 177.3 per humerus between the olecranon fossa and coronoid fossa 100,000 children per year.1-4 The majority (95%) of these that is particularly vulnerable to the linear force exerted dur- fractures are extension-type injuries and predominantly ing hyperextension of the elbow which, in conjunction with occur in children between 5 and 7 years who suffer trauma the force from the olecranon pressing into the olecranon to the elbow during a fall from height onto an outstretched fossa, creates the anterior tension that leads to anterior supra- hand or during other recreational activities with the elbow condylar failure in the common extension-type fractures. The in full extension.5,6 Flexion-type fractures account for force continues to propagate posteriorly with increasing dis- approximately 3% and a small subset can have multidirec- placement of the posterior cortex and disruption of the peri- tional instability, which can be caused by the injury itself or osteum with subsequent instability during reduction.3,9 during reduction. Closed reduction and percutaneous pin- Flexion-type fractures represent 5% of pediatric supracondy- ning have become the standard of care for displaced frac- lar injuries and occur when there is a direct blow to the pos- tures; however, open reduction is sometimes required with terior aspect of the flexed elbow. Vigilance for neurovascular irreducible fractures and open exploration of the antecubi- injury given the density of these structures at the elbow is of tal fossa indicated in patients with pulseless, poorly per- critical importance in the initial evaluation of all injuries; the fused hands. The presence of the rarer flexion-type fracture flexion-type injury is particularly associated with a high rate pattern may signify a lower threshold for open reduction in of initial or subsequent injury to the ulnar nerve. difficult cases because of concern about involvement of the 3,7,8 ulnar nerve. Clinical Presentation and Exam A pediatric patient with elbow pain or refusing to use an upper *Department of Orthopaedic Surgery and Rehabilitation Medicine, Medicine extremity after a fall should be evaluated with high suspicion Division of Biological Sciences, University of Chicago, Chicago, IL. for elbow fractures. Patients will present with varying degrees y Department of Orthopaedic Surgery, Division of Pediatric Orthopaedic of swelling and tenderness to palpation about the distal Surgery, NorthShore University HealthSystem, Evanston, IL. humerusaswellrestrictionofelbow range of motion, most Address reprint requests to Verena M. Schreiber, MD, Department of commonly extension given the prevalence of extension-type Orthopaedic Surgery, Division of Pediatric Orthopaedic Surgery, NorthShore University HealthSystem, Clinician Educator University of injuries. Depending on the severity of the injury, there may be Chicago, Pritzker School of Medicine, 2650 Ridge Ave, Walgreen Building, visible deformity about the elbow and even skin tenting or Suite 2505, Evanston, IL 60201. E-mail: [email protected] anterior arm ecchymosis signifying penetration of the brachialis https://doi.org/10.1053/j.oto.2018.12.003 11 1048-6666/© 2019 Elsevier Inc. All rights reserved. 12 J.B. St. Clair and V.M. Schreiber muscle by the spike of the proximal fracture fragment.10 Evalu- ation for compartment syndrome must be performed and accurately documented, as this can be a devastating sequela of the injury; this evaluation should include tenseness of the fore- arm compartments as well as passive extension and flexion of the fingers. It is also critical to perform a careful distal neuro- vascular exam to evaluate for neurapraxia or vascular injury, as these may guide operative or postoperative decision-making. Vascular status, to include distal pulse and perfusion exam, has ramifications for decision-making in regards to possible open exploration of the brachial artery in pulseless, poorly per- fused upper extremities.7 Motor and sensory examination of the radial, ulnar, and median nerve, to include the anterior interosseous nerve (AIN), should be performed to the extent to which the child will allow as neurapraxia will commonly occur with both extension-type (AIN, radial) and flexion-type (ulnar) injuries and can also be affected by iatrogenic injury, Figure 2 Anteroposterior elbow radiograph demonstrating Bau- particularly during medial percutaneous pinning (ulnar).3,11 mann's angle which is formed by the intersection of a line drawn down the humeral shaft axis and a line drawn along the physeal line Radiographic Evaluation of the lateral condyle. Dedicated anteroposterior (AP) and lateral radiographs are obtained to assess for displacement, rotation, translation, children less than 2 years of age, the AHL was found to be in degree of comminution, and intra-articular extension. It is the anterior third in 30% of the cases.15,16 also important to keep in mind that the presence of a poste- Baumann angle is useful to assess coronal plane deformity rior fat pad sign without obvious fracture can represent an on an AP radiograph and is formed by the intersection of a occult elbow fracture and it is recommended to obtain repeat line drawn down the humeral shaft axis and a line drawn imaging several weeks later, as 76% of children with initial along the physeal line of the lateral condyle (Fig. 2). negative radiographs were found to have a fracture later.12,13 A normal angle ranges from 70° to 75° and a study by Silva The anterior humeral line (AHL) has been widely used for et al confirmed excellent intraobserver reliability.6,17-19 assessment of sagittal plane displacement and is formed by a line, which lies along the anterior humeral cortex and should intersect the middle third of the capitellum (Fig. 1). Herman Classification et al have shown that the AHL intersects the middle third of the capitellum in most healthy children older than 4 years of Gartland first introduced a simple yet easy to apply classifica- age but may lie in the anterior one-third of the capitellum in tion system in 1959 based on the degree of displacement, those aged <4 years.14 A more recent study by Ryan et al has and although it has been modified over the years, current shown that the AHL touches the ossific nucleus of the capi- treatment recommendations by the American Academy of tellum in 100% of patients; however, in children less than Orthopaedic Surgeons (AAOS) continue to be based on this 5 years of age, the AHL fell outside the middle third, and in classification system.20,21 The Gartland classification system identifies the degree of posterior displacement in the sagittal plane, although coronal displacement is also common and can lead to malunion and residual deformity17,20,22 (Fig. 3). A modified Gartland classification was introduced by Table 1 Modified Gartland Classification of Supracondylar Humerus Fractures Type I Nondisplaced, fat pad elevation can be only radiographic finding Type II Displaced with intact posterior cortex and poste- rior periosteal hinge, anterior humeral line is anterior to capitellum. IIA (with rotation) and IIB (without rotation) Type III Displaced, often in 2 or 3 planes Type IV Displaced with complete periosteal disruption. Figure 1 Lateral elbow radiograph demonstrating placement of the These fractures are unstable in flexion and anterior humeral line, which lies along the anterior humeral cortex extension24 and should intersect the middle third of the capitellum but may lie Flexion type in the anterior one-third of the capitellum in younger children. Supracondylar Humerus 13 medication is kept to a minimum so that a potentially evolving compartment syndrome is not masked. On the other hand, open fractures, fractures in the setting of a pink pulseless, or dysvascular limb, evolving compartment syndrome, floating elbow, and median nerve compromise are considered emergent and require immediate surgical intervention.13 The management of the pulseless but per- fused supracondylar fractures remains controversial but there is consensus that timely reduction is required. Weller et al29 concluded that the lack of a radial pulse after closed reduction and percutaneous pinning did not pose an abso- lute indication for vascular exploration as long as the limb was perfused; however, these patients require close postop- Figure 3 (A) AP radiograph of a type II supracondylar humerus frac- erative monitoring in case of late-developing vascular com- ture. (B) Lateral radiograph of a type II supracondylar humerus frac- promise.