Nonunion is a known and much-dreaded complication of paediatric lateral condyle fractures. This systematic review aims to pool together individual studies to find out if the timing of fixation and method of fixation impacts surgical outcomes (postoperative union and elbow ROM) in paediatric lateral condyle nonunion.

A systematic review and individual patient data meta-analysis was conducted according to PRISMA guidelines. All surgical studies with original data on pediatric lateral humeral condyle nonunion were included. Patients who did not undergo surgical fixation were excluded.

A total of 12 studies with 177 patients were included. 159 patients (89.8 %) achieved bony union postoperatively while 18 patients (10.2 %) did not. Mixed-effects logistic regression showed that percutaneous fixation (p-value=0.020) was associated with lower rates of postoperative union compared to open fixation, whereas the age at surgery did not have a significant impact (p-value=0.401). For elbow ROM, mixed-effects linear regression showed that increased age at surgery (p-value=0.007) and reduction of the fracture fragment (vs in-situ fixation) (p-value=0.041) were associated with reduced postoperative ROM whereas female sex (p-value=0.009) and corrective osteotomy (p-value=0.045) were associated with increased postoperative ROM.

While the timing of surgical fixation did not significantly impact postoperative bony union, undergoing fixation at an older age was associated with reduced postoperative elbow ROM. In addition, percutaneous fixation may be associated with poorer postoperative union compared to open fixation while anatomical reduction may be associated with reduced postoperative elbow ROM compared to in-situ fixation.

IV.