Utility of Follow-up Radiographs After Pin Removal in Supracondylar Humerus Fractures: A Retrospective Cohort Study

Introduction: Displaced supracondylar humerus fractures (SCFs) are common pediatric injuries, typically treated by closed reduction and percutaneous pinning (CRPP). Radiographs are obtained at pin removal and subsequently to evaluate fracture healing. We evaluated the utility of radiographs obtained after pin removal in pediatric SCF management. Methods: A retrospective cohort study of children aged 2 to 11 years with SCF requiring CRPP at a single institution from January 2007 to July 2017 was conducted. Radiographs were taken at pin removal and minimum 3 weeks later. Demographic and treatment data were collected via chart review. Radiographic measures were Baumann and lateral humeral-capitellar angles, anterior humeral line alignment, and number of cortices with callus. The McNemar-Bowker test analyzed anterior humeral line alignment and cortices with callus. The paired t-test analyzed Baumann and lateral humeral-capitellar angles. Results: One hundred patients were included (47 males and 53 females, mean 5.7 years). The mean time to pin removal was 23.8 days, and the median clinical and radiographic follow-up periods were 109.0 and 52.2 days, respectively. Fracture patterns were extension type II (21%), III (73%), IV (1%), flexion (4%), and varus (1%). No patients’ fracture management changed in the acute or long-term postoperative period because of findings on post-pin removal (PPR) radiographs. Fewer cortices with callus were seen at pin removal versus PPR (,0.001). At pin removal, no differences were found in the Baumann angle (75.8 6 5.0 versus 74.6 6 5.9; P = 0.053), lateral humeral-capitellar angles (30.7 6 12.5 versus 31.6 6 1.3; P = 0.165), or anterior humeral line alignment (P = 0.261). Discussion: No patients’ fracture management was modified because of findings evident on PPR radiographs. The number of cortices with callus was the only radiographic measure to differ over time, as is anticipated with routine healing. Elbow radiographic alignment measures did not differ in the interval between radiographs. Therefore, PPR radiographs may not provide clinical utility in the absence of other clinical findings.