Postoperative outcomes of initial varus versus initial valgus proximal humerus fracture: A systematic review and meta-analysis

ObjectivesOur objective was to perform a systematic review of the literature and conduct a meta-analysis to investigate the effect of initial varus or valgus displacement of proximal humerus on the outcomes of patients with proximal humerus fractures treated with open reduction and internal fixation.MethodsIn accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement standards, we performed a systematic review. Electronic databases MEDLINE, EMBASE, CINAHL and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched to identify randomised and non-randomised studies comparing postoperative outcomes associated with initial varus versus initial valgus displacement of proximal humerus fracture. The Newcastle-Ottawa scale was used to assess the methodological quality and risk of bias of the selected studies. Fixed-effect or random-effects models were applied to calculate pooled outcome data.ResultsWe identified two retrospective cohort studies and one retrospective analysis of a prospective database, enrolling a total of 243 patients with proximal humerus fractures. Our analysis showed that initial varus displacement was associated with a higher risk of overall complication (RR 2.28, 95% CI 1.12-4.64, P = 0.02), screw penetration (RR 2.30, 95% CI 1.06-5.02, P = 0.04), varus displacement (RR 4.38, 95% CI 2.22-8.65, P < 0.0001), and reoperation (RR 3.01, 95% CI 1.80-5.03, P < 0.0001) compared to valgus displacement. There was no significant difference in avascular necrosis (RR 1.43, 95% CI 0.62-3.27, P = 0.40), infection (RR 1.49, 95% CI 0.46-4.84, P = 0.51), and non-union or malunion (RR 1.37, 95% CI 0.37-5.04, P = 0.64).ConclusionsThe best available evidence demonstrates that initial varus displacement of proximal humerus fractures is associated with higher risk of overall complication, screw penetration, varus displacement, and reoperation compared to initial valgus displacement. The best available evidence is not adequately robust to make definitive conclusions. Further high quality studies, that are adequately powered, are required to investigate the outcomes of initial varus and valgus displacement in specific fracture types.Level of evidenceLevel II.