Evaluation of the Posterior Tilt Angle in Predicting Failure of Nondisplaced Femoral Neck Fractures After Internal Fixation: A Systematic Review.

OBJECTIVE: To evaluate the posterior tilt angle (PTA) in predicting treatment failure after internal fixation of nondisplaced femoral neck fractures as graded by the Garden classification, which is based solely on anterior-posterior radiographic evaluation. DATA SOURCES: A search was conducted of all published literature in the following databases from inception to December 20, 2021: PubMed, Embase, Cochrane Library, Web of Science, Scopus, and ClinicalTrials.gov . STUDY SELECTION: We included English-language randomized controlled trials, prospective and retrospective cohort studies that reported malunion/nonunion, avascular necrosis, fixation failure, or reoperations in patients with nondisplaced femoral neck fractures treated with internal fixation who were evaluated for PTA using either lateral radiograph or computed tomography. DATA EXTRACTION: All abstract, screening, and quality appraisal was conducted independently by 2 authors. Data from included studies were extracted manually and summarized. The Methodological Index for Non-Randomized Studies criteria was used for quality appraisal. DATA SYNTHESIS: Odds ratios with 95% confidence intervals were calculated for treatment failure, defined as nonunion/malunion, avascular necrosis, fixation failure, or reoperation, in cases involving preoperative PTA ≥20-degrees and <20-degrees. Statistical significance was set at P < 0.05. RESULTS: Nondisplaced femoral neck fractures with PTA >20-degrees had a 24% rate of treatment failure compared with 12% for those <20-degrees [odds ratios, 3.21 (95% confidence intervals, 1.95-5.28); P < 0.001]. CONCLUSION: PTA is a predictor of treatment failure in nondisplaced femoral neck fractures treated with internal fixation. Nondisplaced femoral neck fractures with a PTA >20-degrees may warrant alternative treatment modalities. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.