Background: Compared with a patellar tendon autograft (PT), a hamstring tendon autograft (HT) has an increased risk of revision after anterior cruciate ligament reconstruction (ACLR). There are no studies analyzing whether this can be explained by inferior fixation devices used in HT reconstruction or whether the revision risk of ACLR with an HT or a PT is influenced by the graft fixation.
Purpose: To compare the risk of revision and the revision rates between the most commonly used combinations of fixation for HTs with PTs.
Study design: Cohort study; Level of evidence, 2.
Methods: This study included all patients registered in the Norwegian Knee Ligament Registry from 2004 through 2013 who underwent primary PT or HT ACLR with no concomitant ligament injury and known graft fixation. The 2-year revision rates were calculated using the Kaplan-Meier analysis. Hazard ratios (HRs) for revision at 2 years were calculated using multivariate Cox regression models.
Results: A total of 14,034 patients with primary ACLR were identified: 3806 patients with PTs and 10,228 patients with HTs; the mean follow-up time was 4.5 years. In the HT group, 5 different combinations of fixation in the femur/tibia were used in more than 500 patients: Endobutton/RCI screw (n = 2339), EZLoc/WasherLoc (n = 1352), Endobutton/Biosure HA (n = 1209), Endobutton/Intrafix (n = 687), and TransFix II/metal interference screw (MIS) (n = 620). The crude 2-year revision rate for patients with PTs was 0.7% (95% CI, 0.4%-1.0%), and for patients with HTs, it ranged between the groups from 1.5% (95% CI, 0.5%-2.4%) for TransFix II/MIS to 5.5% (95% CI, 4.0%-7.0%) for Endobutton/Biosure HA. When adjusted for detected confounding factors and compared with patients with PTs, the HR for revision at 2 years was increased for all HT combinations used in more than 500 patients, and the combinations Endobutton/Biosure HA and Endobutton/Intrafix had the highest HRs of 7.3 (95% CI, 4.4-12.1) and 5.5 (95% CI, 3.1-9.9), respectively.
Conclusion: The choice of fixation after ACLR with an HT has a significant effect on a patient's risk of revision. In this study population, none of the examined combinations of HT fixation had a revision rate as low as that for a PT.
Keywords: ACL; Endobutton; fixation; reconstruction; revision.
© 2015 The Author(s).