Comparison of the aperture and midportion femoral tunnel widening after anterior cruciate ligament reconstruction: A systematic review and meta-analyses

BACKGROUND: To identify whether the aperture or the midportion of the femoral tunnel had a larger tunnel widening in patients who undergo ACL reconstruction. METHODS: PubMed, EMBASE and Cochrane Library were searched for relative studies that evaluated tunnel widening in patients underwent arthroscopic ACL reconstruction. Two reviewers independently recorded data from each study, including the sample size and magnitude of tunnel widening. Random-effects meta-analyses were performed to pool the outcomes of tunnel widening by estimating the standardized mean differences in tunnel widening and their 95% confidence intervals (CIs), Publication bias was assessed using funnel plots and Egger test when the number of included studies was >10. RESULTS: Eleven included studies compared tunnel widening between the aperture and the midportion. In these studies, 372 and 92 patients underwent single- and double-bundle ACL reconstructions, respectively. Subgroup analyses in terms of evaluation imaging tool for tunnel widening showed no significant differences in tunnel widening between the aperture and the midportion of the femoral tunnel regardless of plain radiograph (mean difference, 0.02 mm; P = .97), computed tomography (mean difference 0.08 mm; P = .55), and magnetic resonance imaging (mean difference, 0.13 mm; P = .78). Likewise, no significant difference in femoral tunnel widening was found between the aperture and the midportion, irrespective of transtibial (mean difference, 0.18 mm; P = .57), anteromedial (mean difference, 0.02 mm; P = .90), and outside-in techniques (mean difference, 0.01 mm; P = .98). CONCLUSION: No significant difference in femoral tunnel widening was found between the aperture and the midportion in the patients who underwent ACL reconstruction.