The effects of two different fixation methods on femoral bone tunnel enlargement and clinical results in anterior cruciate ligament reconstruction with hamstring tendon graft

Objectives: We investigated the effects of anatomic and nonanatomic tunnel fixations on femoral tunnel widening and clinical results in anterior cruciate ligament (ACL) reconstructions. Methods: We retrospectively evaluated 35 patients who underwent arthroscopic ACL reconstruction with quadrupled hamstring tendon graft. Fixation was performed in the tunnel using the transcondylar RigidFix pin (group 1) in 18 patients (mean age 32 years), and from outside the tunnel using the EndoButton-CL device (group 2) in 17 patients (mean age 30 years). The patients were assessed using the IKDC (International Knee Documentation Committee) and Lysholm knee scores and tunnel widening was assessed by computed tomography. Ligament laxity was measured bilaterally using the Rolimeter knee tester. The mean follow-up was 24 months (range 21 to 38 months) in group 1, and 24.6 months (range 12 to 36 months) in group 2. Results: The two groups were similar with respect to age and sex distribution, operated side, the size of the tunnel created, and follow-up period (p>0.05). Postoperative knee scores did not show a significant difference (p>0.05). There was marked and excessive tunnel enlargement in 14 patients (77.8%) in group 1, and in 15 patients (88.2%) in group 2, with no significant difference between the two groups (p>0.05). Ligament laxity exceeded 3 mm in eight patients (44.4%) in group 1, and in three patients (17.7%) in group 2 (p<0.001). There was no relationship between tunnel widening and ligament laxity (p>0.05; r=0.175 and r=-0.01 for group I and group 2, respectively). Conclusion: Our results suggest that differences in the localization of the tunnel fixation have no effect on tunnel enlargement and that joint laxity may be affected by biomechanical properties of fixation materials.