Enlargement of bone tunnels after anterior cruciate ligament reconstruction.

We measured the width of tibial bone tunnels after anterior cruciate ligament (ACL) reconstruction, and investigated the correlation between bone tunnel enlargement and clinical results. Thirty-two patients who had undergone ACL reconstruction with patellar tendons augmented by woven polyester underwent physical and radiographic examinations postoperatively. The interval between surgery and examination ranged from 60 to 91 months with a mean of 68.9 months. The clinical results investigated included the total Lysholm score, the injured-to-uninjured difference in anterior knee laxity from KT-1000 arthrometer measurements, and range of motion. The width of the tibial bone tunnels was increased by a mean of 2.6 +/- 1.5 mm in the antero-posterior view, and by a mean of 2.7 +/- 1.4 mm in the lateral view. Eighteen patients had tunnel enlargements of less than 3 mm, and 14 patients had enlargements of 3 mm or more. The clinical results for patients with tunnel enlargements of less than 3 mm were compared with those for patients with tunnel enlargements of 3 mm or more. However, no significant differences were found between the two groups. We conclude that bone tunnel enlargement does not appear to adversely affect clinical results over the long term.