Tibial tunnel enlargement following anterior cruciate ligament reconstruction with patellar tendon autograft

Purpose: The purpose of this study was to prospectively evaluate changes in the tibial bone tunnel following endoscopic anterior cruciate ligament (AC L) reconstruction with patellar tendon autograft. We used computed tomograp hy (CT) sequentially to monitor the time course of these changes over a 2-y ear period and correlated the results to clinical outcome and instrumented laxity measurements. Type of Study: Case series. Methods: Thirty-four patie nts (11 women, 23 men; mean age, 26.4 +/- 4.5 years) who underwent endoscop ic patellar tendon ACL reconstruction, were evaluated clinically according to IKDC, Lysholm, and Tegner scores as well as with respect to changes in t ibial tunnel morphology over a 2-year period. Subsequent CT scans were perf ormed at 1 and 6 weeks and at 3, 6, 12, and 24 months postoperatively. The tibial bone tunnel was measured in the sagittal and coronal planes at 5 dif ferent levels (L1 to L5). Results: The diameters fof the tibial tunnel incr eased an average overall by 30.6% in the sagittal plane and 16.4% in the co ronal plane within 2 years. the enlargement was significantly higher (P < . 05) in the mid portion of the tunnel (L 2/3: 44.0% and 47.9% in the sagitta l and 29.8% and 29.9% in the coronal plane, respectively), which resulted i n a uniform cavity-type appearance. The percentage of change in tunnel size was significantly higher (P < .05) within the first 6 weeks following surg ery compared with all other time intervals. No correlation between the amou nt of tunnel enlargement and the clinical results or between tunnel enlarge ment and KT-1000 measurements could be detected. Conclusions: Endoscopic AC L reconstruction is associated with tibial tunnel enlargement, which is alr eady present within weeks following surgery. However, no negative effects o n the clinical results were found over a 24-month period in our study popul ation.