To assess the suitability of the Korean KOOS (Knee injury and osteoarthritis outcome score) as a patient-centered clinical measurement of the validity, reliability and responsiveness to the treatment of knee injuries.

One hundred and eight patients who had experienced an arthroscopic ACL reconstruction or a menisectomy between Jan. 2002 and Jun. 2003 were examined immediately after surgery, and 6 and 12 months after surgery. The SF-36 and Lysholm knee scale were administered simultaneously to each case in order to calculate the inter-item correlation.

Measurements of the test-retest reliability showed that all intra-class coefficients (ICC) were measured as r=0.75-0.89 and Cronbach's alpha was 0.73-0.81. Regarding the validity, there was a strong correlation with the SF-36 and the Lysholm, subscales (SF-36 vs KOOS: Physical functioning vs ADL (r=0.67)/Physical functioning vs Sports and recreational activities (r=0.61)/Bodily pain vs Pain (r=0.63)). In terms of the responsiveness, the average score measured preoperatively, and three, six and nine months showed a gradual increase. The effect size of pain, symptoms and ADL at postoperative 6 months was 0.8-1.1. A larger effect size was observed in the QOL (1.5) and sports and recreational function (1.3) at 3 months after surgery (n=25).

The validity, reliability and responsiveness of the Korean KOOS was confirmed and is considered to be a useful clinical metrology for a knee injury.