Prospective study of changes in impairments and disabilities after anterior cruciate ligament reconstruction

Study Design: Single-group, repeated-measures prospective study. Objectives: To analyze changes in impairments and disabilities among patien ts with anterior cruciaie ligament (ACL) reconstruction and to assess the r elationships between the impairment and disability outcome measures from 3 months to 2 years following ACL reconstruction. Background: Outcomes after ACL reconstruction can be categorized as impairm ents or disabilities. The relationship between impairments and disabilities may be crucial to understanding physical therapy interventions and predict ing long-term outcome. Methods and Measures: Sixty patients who had undergone ACL reconstruction p articipated in the study. impairment measures were range of motion, pain, k nee-joint laxity, and muscle performance using isokinetic muscle tests. Dis ability measures were the Cincinnati knee score and lower limb performance using the triple-jump and stair-hop tests. Follow-up times were 3 and 6 mon ths and 1 and 2 years after surgery. Results: The Cincinnati knee score results show significant improvement 1 y ear after surgery (84.2 +/- 13.6) compared with 6 months (76.8 +/- 13.7) an d 3 months (67.4 +/- 16.3) after surgery. Quadriceps total work (percentage of normal leg) significantly improved 2 years after surgery (92.6 +/- 14.1 %) compared with 1 year after surgery (81.6 +/- 16.8%). Between 37 and 75% of the variability in the Cincinnati knee score could be explained by varia tion in the impairment variables, and quadriceps muscle performance and pai n were the most significant predictors of disability. Extension deficit and pain at 3 months were significantly related to the Cincinnati knee score a t the 2-year follow-up. Conclusions: Up to 2 years may be needed to regain normal quadriceps muscle performance following ACL reconstruction. Pain and quadriceps muscle perfo rmance explained most of the variability in the Cincinnati knee score.