Evaluation of tibial bone tunnel enlargement using MRI scan cross-sectional area measurement after autologous hamstring tendon ACL replacement

The aim of this study was to evaluate tibial bone tunnel enlargement following four-strand hamstring tendon anterior cruciate ligament (ACL) reconstruction, using a new method of magnetic resonance imaging (MRI) assessment. Correlation with clinical outcome was also examined. In a prospective study following ACL reconstruction, 24 patients underwent MRI and clinical assessment, at a mean follow-up of 6.5 months. A four-strand semitendinosus and gracilis (STG) tendon graft with the polyester Soffix (Surgicraft Ltd) fixation device was placed via an instrument guided tibial tunnel and an over-the-top femoral route. Cross-sectional area (CSA) perpendicular to the long axis of the tibial tunnel was calculated digitally at three levels, using MRI. Clinical assessment included physical examination, Lysholm subjective self-evaluation score and KT 2000 arthrometric measurement. A mean CSA tibial tunnel enlargement of 33% was found. The mean side-to-side KT 2000 arthrometric difference was 1.66 mm and the mean Lysholm score was 92. We concluded that this previously unused MRI evaluation using digital direct CSA measurements provides a highly accurate method of tunnel assessment. We found no correlation between tibial tunnel enlargement, knee stability, joint function and patient satisfaction scores in the short term. (C) 2002 Elsevier Science B.V. All rights reserved.