Bone tunnel enlargement after ACL reconstruction using autologous hamstring tendons: a CT study

Purpose: To evaluate prospectively the increase in the size of the tibial and femoral bone tunnel following arthroscopic anterior cruciate ligament (ACL) reconstruction with quadrupled-hamstring autograft. Methods: Twenty-five consecutive patients underwent arthroscopic ACL reconstruction with quadrupled-hamstring autograft. Preoperative clinical evaluation was performed using the Lysholm knee score, Tegner activity level, and International Knee Documentation Committee forms and a KT-1000 arthrometer (side to side). Computed tomography (CT) of the femoral and tibial tunnel was performed on the day after operation in all cases and at mean follow-up of 10 months (range 9-11 months).Results: All of the clinical evaluation scales performed showed an overall improvement. The postoperative anterior laxity difference was < 3 mm in 16 patients (70%) and 3-5 mm in seven patients (30%). The mean average femoral tunnel diameter increased significantly (3%) from 9.04 +/- 0.05 mm postoperatively to 9.3 +/- 0.8 mm at 10 months; tibial tunnel increased significantly (11%) from 9.03 +/- 0.04 mm to 10 +/- 0.8 mm. There were no statistically significant differences between tunnel enlargement, clinical results, and arthrometer evaluation. Conclusions: The rate of tunnel widening observed in this study seems to be lower than that reported in previous studies that used different techniques. We conclude that an anatomical surgical technique and a less aggressive rehabilitation process influenced the amount of tunnel enlargement after ACL reconstruction with doubled hamstrings.