[Radial external fixator for closed treatment of type III and IV supracondylar humerus fractures in children. A new surgical technique].

OBJECTIVE: Closed, anatomical reduction and reliable fixation of type III and IV supracondylar fractures that are either difficult or impossible to treat with conventional methods. INDICATIONS: According the Pediatric Comprehensive AO Classification for long bones this technique is preferred for type III and IV supracondylar fractures that cannot be reduced using closed standard manipulative techniques, where stable fixation using standard percutaneous wire configurations cannot be achieved, when severe swelling, open fracture, primary neurological or vascular problems ("pulseless pink hand") or multiple injuries indicate that optimal management of the injured limb should be free from cast. In patients with comorbidities (e.g., seizures or spasticity) requiring more stable fixation. CONTRAINDICATIONS: In principle there are no contraindications. SURGICAL TECHNIQUE: Prior to reduction of the fracture, fluoroscopically controlled insertion of a single Schanz screw into the lateral (radial) aspect of the distal fragment, which is defined by bulls eyeing the capitellum in the perfect lateral radiographic projection of the epiphysis, parallel to the physis. For very distal fractures this screw may be intra-epiphyseal, although usual placement is in the metaphysis just distal to the fracture line. After obtaining perfect lateral radiographic projection of the distal humeral metaphyseal-diaphyseal junction, a second Schanz screw is inserted independently into the proximal fracture fragment at the proximal end of the lateral supracondylar ridge in the sagittal plane perpendicular to the long axis of the humeral diaphysis. By bringing the screws parallel to each other in the coronal and transverse planes direct manipulations of the fragments and anatomical reduction using the so-called joystick technique is achieved. Fracture reduction can then be adjusted anatomically under fluoroscopic control and through clinical assessment. Once reduction is achieved the fragments have to be secured with a so-called "anti-rotation" K-wire. This wire significantly enhances stability and prevents pivoting of the fracture fragments around the Schanz screws in the sagittal plane and assists in prevention of medial collapse of the reduced fracture. POSTOPERATIVE MANAGEMENT: No additional plaster cast fixation required; mobilization of the upper limb as comfort allows.
RESULTS: The majority of children have a normal range of motion at the time of external fixator removal. At follow-up (40 months), 30 of 31 children had normal function and a normal, anatomical axis as judged against the contralateral upper limb.