The effect of cortical button location on its post-operative migration in anatomical double-bundle anterior cruciate ligament reconstruction.

PURPOSE: To investigate the effect of EndoButton (Smith & Nephew Endoscopy, Andover, MA, USA) location on post-operative migration in anterior cruciate ligament (ACL) reconstruction.
METHODS: Seventy-seven patients underwent anatomical double-bundle ACL reconstruction using EndoButtons. Comparing patient radiographs immediately post-operatively with those at 1 year, migration was defined when EndoButtons moved more than 1 mm or rotated over 5°. Initial location of EndoButtons was evaluated on radiographs immediately post-operatively. We measured distances from the EndoButton to the posterior and distal edge of the femur (D1, D2) on lateral radiographs and distances from the EndoButton to the lateral and distal edge of the femur (D3, D4) on anteroposterior radiographs. The relationship between supracondylar line and the ratio of migration was also investigated.
RESULTS: D1 in the migrated group were significantly lower than those in the non-migrated group (11.8 ± 12.7 vs. 16.0 ± 10.2 mm). D2, D3 and D4 were not of significant difference in the two groups. The ratio of migration in the area posterior to the supracondylar line was significantly higher than that in the anterior area (54.3 vs. 15.1%).
CONCLUSION: EndoButtons, which was located distally and posteriorly, especially in the area posterior to the lateral supracondylar line, migrated more frequently, although migration of the button had no effect on the clinical parameters evaluated in this study. CLINICAL RELEVANCE: It is preferable to settle EndoButton anteriorly to the lateral supracondylar line in order to avoid its migration for the graft tension due to our findings about the relationship between initial location of EndoButton and the rate of migration. LEVEL OF EVIDENCE: Prognostic case series, Level IV.