Cutting edge Orthopedics

Supracondylar Humerus Fractures • 21  mately 5 [84] and 6% [85]. If the medial pin is placed with the elbow in hyperflexion, the reported risk of iatrogenic injury to the ulnar nerve is as high as 15% [84]. The ulnar nerve was found to shift over or anterior to the medial epicondyle with elbow flexion greater than 90° in 32 out of 52 (61.5%) children under 5 years of age [86]. Additionally, Wind and colleagues (2002) determined that surgeons were unable to accurately predict the loca- tion of the ulnar nerve by palpation [87]. This suggests that medial pins should not be blindly placed. However, even making an incision in an attempt to improve visualization during medial pin placement and decrease the risk to the ulnar nerve does not guarantee its protection [84], although a series with no iatrogenic ulnar nerve injuries using a small medial incision has been reported [88]. Conversely, another series observed ulnar nerve injuries in 2 of 33 patients (6%) in whom a small incision was made, which was greater than the overall rate of nerve injuries in the full cohort (17 out of 345, 5%) [84]. Although most of these injuries resolve [85], sustained ulnar nerve palsy has been reported [84, 89]. Along with the benefit of lower risk of iatrogenic ulnar nerve injury [31, 61, 83, 84, 90], later- al-entry pin constructs have been shown to have equivalent radiographic outcomes compared to cross pin constructs in two randomized [91, 92] and one retrospective study [84]. This is despite reports that a lateral-entry construct may not be as strong as a cross pin construct [80–82]. A recent meta-analysis of the stiffness of pin configurations found no significant differences between two crossed pins and two divergent, lateral-entry pins [79]. The same review noted that the addi- tion of a third, medial pin may improve stabilization of fractures with medial comminution [79] based on two previous studies [93, 94]. Silva and colleagues (2013) found a statistically significant increase in torsional stiffness and a nonsignificant trend toward increased bending stiffness with a third, medial pin [94], while Larson and colleagues (2006) demonstrated significantly increased torsional stability with a third, medial pin compared to two lateral pins, but no significant differ- ence between a third, medial pin (two lateral-entry pins and one medial-entry pin) and three lateral-entry pin constructs [93]. Previous authors have recommended two lateral-entry pins for Type II fractures, three lateral-entry pins for Type III fractures and Type II fractures that were still unstable with two pins, and consideration of a medial pin under direct visualization with elbow extension when medial comminution is present or there is no space for an additional lateral pin [8, 9, 14, 19]. Type IV Fractures Type IV fractures are characterized by multidirectional instability [17]. This presents an additional challenge to the surgeon during CRPP procedures. Leitch and colleagues (2007) described a vari- ation of the standard CRPP technique to assist in dealing with Type IV fractures. Intraoperative examination with live fluoroscopy demonstrating displacement of the distal fragment into both extension and flexion deformities with manipulation confirms a Type IV fracture. The authors recommended utilizing a hand table so that the C-arm may be rotated, rather than the patient’s limb, to obtain orthogonal radiographs due to the high degree of instability and ease of loss of