No differences were found between early aggressive and nonaggressive rehabilitation after an isolated ACL-R using STG autografts for the primary outcomes of A-P knee laxity and subjective IKDC score. In addition, no differences were observed for secondary outcomes between groups for differences in ROM and PIF values.

Context: Substantial research has been conducted on anterior cruciate ligament reconstruction (ACLR) to evaluate patient outcomes. However, little attention has been given to outcomes during the early phase of recovery and how early deficits affect both short-and long-term outcomes.Objective: To identify relationships between demographic (age, sex, and body mass index [BMI]) and intraoperative (isolated ACLR versus primary ACLR þ secondary procedures), and postoperative (range-of-motion [ROM] and peak isometric knee-extension force [PIF]) variables during the first 2 months after ACLR using self-reported outcomes.Design: Cohort study. Results: Significant relationships were identified between !12-month IKDC scores and the 1-month (Pearson correlation, r ¼ 0.283, r 2 ¼ 0.08; P ¼ .025) and 2-month (r ¼ 0.301, r 2 ¼ 0.09; P ¼ .017) IKDC scores. After controlling for other variables, we found that the PIF ratio measures at 1 and 2 months were positively associated with 1-and 2-month IKDC scores (P , .001) and BMI was negatively associated with both 1-and 2-month IKDC scores (P , .05). One-month IKDC scores were related to the 1-month difference in knee-flexion ROM (P ¼ .04).Conclusions: The IKDC scores during the first 2 months were positively correlated with patients' perceptions of function on long-term IKDC scores. It also appears that improvements in lower extremity strength and flexion ROM deficits were positively associated with short-term IKDC scores. Higher BMI was negatively associated with patients' perceptions of function on short-term IKDC scores.Key Words: force output, knee, motion, rehabilitation, International Knee Documentation Committee Key PointsAfter anterior cruciate ligament reconstruction, patients' subjective International Knee Documentation Committee (IKDC) scores at both 1-and 2-month follow-ups had fair but significantly positive associations with the !12-month IKDC score. The ratio of surgical-to nonsurgical-limb measures of peak isometric knee-extension force at 1 and 2 months was positively associated with 1-and 2-month IKDC scores. The difference in flexion range of motion between the surgical and nonsurgical limbs had a significant positive relationship with 1-month IKDC score. Body mass index had a significant negative association with both 1-and 2-month IKDC scores. No significant relationships were noted between demographic, intraoperative, or postoperative variables during the first 2 months and IKDC scores at !12 months after anterior cruciate ligament reconstruction.