Incidence of nonunion after surgery of distal femoral fractures using contemporary fixation device: a meta-analysis.

PURPOSE: Nonunion is the most frequent cause of reoperation and is associated with high morbidity after distal femur fracture (DFF). We examined the rates of nonunion requiring reoperation after fixation for DFF using a locking compression plate (LCP) or retrograde intramedullary nail (RIMN). METHODS: We included four studies comparing LCP and RIMN and 38 single-cohort studies reporting LCP or RIMN. In total, 2156 femurs were included and 166 non-unions were detected. We conducted a pair-wise meta-analysis (with a fixed-effects model) on the four comparative studies and a proportional meta-analysis on the 38 articles to estimate the nonunion rate. We performed sensitivity analysis by comparing studies using LCP with less invasive surgical systems (LISS) with those that used RIMN. RESULTS: The pairwise meta-analysis showed a similar nonunion rate between the groups [odds ratio: 1.02; 95% confidence interval (CI) 0.94-1.11, p = 0.633]. According to proportional meta-analysis, the pooled prevalence of nonunion was 5% (95% CI 4-7) totally, 6% (95% CI 4-8) in the LCP group, and 4% (95% CI 2-6) in the RIMN group (heterogeneity: p = 0.105). According to the sensitivity analysis, there was no difference in the union rate. The pooled prevalence of nonunion from sensitivity analysis was 4 % (95% CI, 3-5); it was 4% (95% CI, 3-6) in LCP with LISS and was 4% (95% CI, 2-6) in RIMN group (heterogeneity: p = 0.941). CONCLUSION: Approximately 5% of patients who underwent LCP or RIMN fixation developed nonunion. Therefore, LCP and RIMN are effective DFF techniques and mastering one of them is essential.