Femoral Tunnel Widening After Hamstring Anterior Cruciate Ligament Reconstruction with Bioabsorbable Transfix

Background: Previous reports have shown that bio-Transfix implants (Arthrex, Naples, Florida) have the possibility of fracture during the early postoperative period. However, to date, there exists no study reporting the radiological and clinical significance of broken bio-Transfix implants.

Hypothesis: A broken bio-Transfix results in adverse effects, both radiologically and clinically.

Study Design: Cohort study; Level of evidence, 3.

Methods: Hamstring anterior cruciate ligament (ACL) reconstructions using bio-Transfix in 50 patients with a minimum of 2 years' postoperative follow-up were reviewed. On the anteroposterior (AP) and lateral radiographs, the diameter of the femoral tunnel was measured at the widest diameter and compared with the diameter of the reamer used at surgery. Magnetic resonance imaging (MRI) scans were obtained 6 months postoperatively for all patients to evaluate the condition of bio-Transfix implants. The patients were divided into intact and broken bio-Transfix groups. Postoperative stability evaluations were performed using the Lachman and pivot-shift tests and instrumented laxity testing using the KT-1000 arthrometer. Functional evaluations were performed using the Lysholm score and Tegner activity scale.

Results: Follow-up MRI scans revealed that the bio-Transfix was broken in 11 and intact in 39 patients. Five implants were broken within the femoral tunnel and 6 were broken outside the femoral tunnel. Two bio-Transfix in the intact group were bent. On the AP and lateral radiographs at 24 months postoperatively, the average diameter of the femoral tunnel in the intact group increased by 13.1% and 17.1%, respectively. In the broken group at 24 months postoperatively, the average diameter of the femoral tunnel increased by 33.6% and 26.5%, respectively. There were significant differences between the 2 groups in the average diameters of the femoral tunnel on the AP radiographs at 24 months postoperatively (P = .000). However, on the lateral radiographs, there were no significant differences between the 2 groups. Postoperative knee stability tests and functional evaluations showed no significant differences between the 2 groups.

Conclusion: Broken bio-Transfix implants resulted in significant femoral tunnel widening in the coronal plane, although clinical results were not affected. Surgeons should be aware of this phenomenon when selecting a fixation device for hamstring grafts.