Efficacy of Fibrin Clot Implantation for Reduction of Bone Tunnel Enlargement in Double-Bundle ACL Reconstruction...

Although previous reports have stated that the addition of a fibrin clot to an allograft can effectively inhibit femoral bone tunnel enlargement (BTE) after anterior cruciate ligament reconstruction (ACLR), no relevant study has quantitatively evaluated the chronological changes in the cross-sectional area (CSA) of the bone tunnel on 3-dimensional computed tomography (3D-CT) images in double-bundle ACLR (DB-ACLR) with hamstring tendon autografts.

To evaluate whether adding a fibrin clot to a hamstring autograft would reduce postoperative femoral BTE by means of 3D-CT image analysis.

Cohort study; Level of evidence, 3.

A total of 21 patients with fibrin clot who underwent anatomic DB-ACLR using hamstring tendon autografts and 24 control patients without fibrin clot were included in the study. In preparing the graft, a fibrin clot was placed between the 2 strands of the graft end to be inserted into the femoral bone tunnel. The CSAs of the anteromedial (AM) and posterolateral (PL) femoral bone tunnels at the intra-articular aperture, 5 mm and 10 mm from the tunnel aperture, were measured on 3D-CT images at 1 week and 1 year postoperatively, and the difference between the 2 time points was defined as the BTE.

In the autograft group with fibrin clot, a significantly smaller BTE ratio was observed in the AM tunnel 5 mm (P = .003; with fibrin clot: 29.3% ± 58.1%; autograft alone: 58.8% ± 57.8%) and 10 mm (P < .001; with fibrin clot: -8.0% ± 43.7%; autograft alone: 42.3% ± 39.7%) from the intra-articular tunnel aperture and in the PL tunnel at all levels (P = .048, P < .001, and P < .001; with fibrin clot: 49.1% ± 89.3%, 7.9% ± 28.4%, and -5.1% ± 25.6%; autograft alone: 89.8% ± 57.0%, 28.9% ± 26.8%, and 51.4% ± 38.6%, respectively) compared with controls who received only autograft.

Adding a fibrin clot to the autograft of an anatomic DB-ACLR was associated with a decreased BTE at 1 year. This effect was more evident in the PL tunnel and the midportion of the AM tunnel.