The Influence of Graft Fixation Methods on Revision Rates After Primary Anterior Cruciate Ligament Reconstruction
Authors: Eysturoy Niclas H. , Nissen Kåre Amtoft , Nielsen Torsten , Lind Martin 
Published: January 2018

Background:

The method of graft fixation in primary anterior cruciate ligament (ACL) reconstruction is important for initial stability of the graft. Poor graft fixation can result in failure of the reconstruction. The effect of ACL graft fixation principles and fixation implant combinations on the risk of revision after ACL reconstruction is not well understood.

Purpose:

The study aimed to compare the risk of revision among 4 categories of femoral fixation divided by their principle of function using a hamstring tendon (HT) graft only. Furthermore, this study aimed to compare the risk of revision among the most frequently used combinations (tibia and femur) of graft fixation implants in a national patient cohort.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

The authors divided the femoral fixation constructs into 4 categories by their principle of function: cortical suspensory fixation, adjustable cortical suspensory fixation, intratunnel transfixation, and interference screw (aperture) fixation. Data on revision rates and graft fixation methods were extracted from the Danish ACL Reconstruction Registry. The study included patients who underwent primary ACL reconstruction with either an HT or patellar tendon (PT) graft and were followed up at 2 to 10 years. Revision rates at 2-year and full follow-up were extracted for the category of graft fixation in the femur as well as for the most common implant combinations (those involving >175 patients). Patients with infrequently used fixation devices were excluded from this analysis. The HT group included 14 frequently used combinations (n > 175), and there were 2 such combinations in the PT group. A total of 13,200 ACL reconstructions were included in the study. For ACL reconstruction with an HT graft, there were 4680 with cortical suspensory fixation, 577 with adjustable cortical suspensory fixation, 5921 with intratunnel transfixation, and 617 with interference screw fixation. There were 1405 ACL reconstructions with a PT graft.

Results:

When only comparing primary ACL reconstructions using an HT graft, cortical suspensory fixation exhibited a significantly higher risk of revision at 2-year follow-up than the other categories of femoral fixation (hazard ratio [HR], 1.24 [95% CI, 1.07-1.44]; P < .05). Intratunnel transfixation exhibited a significantly lower risk of revision (HR, 0.83 [95% CI, 0.73-0.94]; P < .05). Comparing the most frequently used femoral/tibial fixation implant combinations with the mean risk of revision, Endobutton/Intrafix and Endobutton/Biosure PEEK for HT grafts exhibited an increased risk of revision, with an relative risk (RR) of 1.36 (95% CI, 1.03-1.81; P < .05) and 1.55 (95% CI, 1.15-2.09; P < .05), respectively. The Atlantech metal screw/metal screw and Softsilk/Softsilk combinations (both for PT grafts) exhibited a significantly decreased risk of revision, with an RR of 0.41 (95% CI, 0.18-0.91; P < .05) and 0.36 (95% CI, 0.15-0.87; P < .05), respectively.

Conclusion:

When comparing ACL graft fixation methods in the 4 categories using an HT graft, cortical suspensory fixation was found to have a significantly increased risk of revision, while intratunnel transfixation exhibited a lower risk of revision. Both Endobutton/Intrafix and Endobutton/Biosure PEEK implant combinations exhibited a significantly higher risk of revision. For PT grafts, Atlantech metal screw/metal screw and Softsilk/Softsilk exhibited a significantly lower risk of revision.