Do Anterior Laxity and Knee Function Change Between 1 and 7 Years After ACL Reconstruction with a Tibialis Allograft

BACKGROUND: In a previous study we used a non-irradiated and non-chemically processed fresh-frozen tibialis allograft anchored with slippage-resistant fixation devices and determined with RSA that the average increase in anterior laxity was limited to 1.1 mm and that subjective scores indicating knee function (Lysholm), activity level (Tegner), and patient satisfaction (IKDC) were all high 1 year following surgery. Because the healing process extends well beyond 1 year following surgery and the effects on anterior laxity and subjective scores are unknown, the primary objectives of the present study were to determine whether anterior laxity increased between 1 year and 7 years and whether subjective scores were affected.;METHODS: Sixteen of 19 available subjects from our previous study were reexamined 7 years after the surgical procedure. An examiner, different from the treating surgeon, applied 150 N of anterior force to the knee, took biplanar radiographs, and used RSA to compute the increase in anterior laxity between the day of surgery, 1 year after surgery, and 7 years after surgery. Activity level, function, and patient satisfaction were also assessed with patient-reported scoring scales.;RESULTS: Anterior laxity increased an average of 2.7 +/- 2.3 mm between the day of surgery and 7 years after surgery (p = 0.0007) and yet the average increase of 1.5 +/- 2.1 mm between 1 year after surgery and 7 years was not significant (p = 0.08). Activity level (Tegner score) did not change between 1 year after surgery and 7 years (p = 0.58), function (Lysholm score) did not change between 1 year after surgery and 7 years (p = 0.79), and subjective satisfaction (International Knee Documentation Committee score) did not change between 1 year after surgery and 7 years (p = 0.83). Average KOOS (Knee injury and Osteoarthritis Outcome Score) was 90 (out of 100) at 7 years after surgery.;CLINICAL RELEVANCE: Although an ACL reconstruction with a soft tissue allograft trended towards an increase in anterior laxity of 1.5 mm between 1 and 7 years, the result was not statistically significant at the 0.05 level and there was no change in patient-reported activity level, function, and patient satisfaction. Hence ligamentization, which is a long-term healing process, did not result in an increase in anterior laxity for our soft tissue allograft and subjective scores were not affected.