Biodegradable Screw Versus a Press-fit Bone Plug Fixation for Hamstring Anterior Cruciate Ligament Reconstruction: a Prospective Randomized Study

Background: Press-fit fixation of a tendon graft has been advocated to achieve tendon-to-bone healing.

Hypothesis: Fixation of hamstring tendon grafts with a porous bone scaffold limits bone tunnel enlargement compared with a biodegradable interference screw fixation.

Study Design: Randomized controlled trial; Level of evidence, 1. Methods Between 2005 and 2006, 20 patients (17 men, 3 women) with a primary reconstruction of the anterior cruciate ligament (ACL) were enrolled in this study. Patients were randomized to obtain graft fixation in the tibial tunnel either by means of an interference screw (I) or a press-fit fixation with a porous bone cylinder (P). At 3 months after surgery, a computed tomography (CT) scan of the knee was performed, and tunnel enlargement was analyzed in the coronal and sagittal planes for the proximal, middle, and distal thirds of the tunnel. After 6 months and 1 and 2 years, radiographs of the knee in the sagittal and coronal plane were analyzed for bone tunnel widening. The International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores of both groups were compared after 1 and 2 years.

Results: The bone tunnel enlargement determined by CT was 106.9% + or - 10.9% for group P and 121.9% + or - 9.0% for group I (P < .02) in the anteroposterior (AP) plane and 102.8% + or - 15.2% versus 121.5% + or - 10.1% in the coronal plane (P <.01). The IKDC, Tegner, and Lysholm scores improved in both groups from preoperatively to postoperatively without significant differences between the 2 groups. There was a trend to higher knee stability in group P after 3 months (0.6 + or - 1.4 mm vs 1.8 + or - 1.5 mm; P = .08).

Conclusion: Both interference screw and a press-fit fixation lead to a high number of good or very good outcomes after ACL reconstruction. Tibial press-fit fixation decreases the amount of proximal bone tunnel enlargement.