Introduction: The Lysholm knee score and the Tegner activity scale are frequently used to assess outcome following treatment of meniscus pathology. The purpose of this study was to determine the psychometric properties of the Lysholm knee score and Tegner activity level for meniscus injuries of the knee.
Methods: Test-retest reliability, content validity, criterion validity, construct validity, and responsiveness to change were determined for the Lysholm score and the Tegner activity scale within 3 subsets of patients. Group A contained patients with only meniscus pathology at surgery (no ligament pathology or chondral surface pathology) (n=191). Group B consisted of patients at least 2 years from surgery for meniscus pathology, who completed a follow-up form and then completed a retest with 4 weeks of the primary questionnaire (n=122). Group C consisted of patients with meniscus pathology with other intraarticular pathology (n=477).
Results: There were acceptable (intraclass correlation coefficient >
0.70) test-retest reliability for the overall Lysholm score and the Tegner activity scale. (Group B). There were acceptable floor and ceiling effects for the Tegner scale (floor: 8.1%; ceiling: 2.5%) and the overall Lysholm score (floor: 0%; ceiling: 0.4%) (Group A and C). There were unacceptable (>
30%) ceiling effects for the Lysholm domains of limp, instability, support, and locking. There was acceptable criterion validity, with significant (P<
0.05) correlations between the Tegner activity scale and the physical score of the SF-12 and between the overall Lysholm score and the physical score of the SF-12(Group C). There was acceptable construct validity for the Tegner activity scale and Lysholm score, with all hypotheses demonstrating significance (P<
0.05) (Group A). There was acceptable responsiveness to change for the Tegner activity scale (Group A effect size=0.61; standardized response mean=0.60; Group C effect size=0.84; standardized response mean=0.70) and the Lysholm score(Group A effect size=1.2; standardized response mean=0.97; Group C effect size =1.2; standardized response mean =1.13).
Discussion: The use of outcome instruments whose psychometric properties have been vigorously established is essential. The Lysholm knee score demonstrated overall acceptable psychometric performance for outcomes assessment of meniscus injuries of the knee, although some domains demonstrated suboptimal performance. The Tegner activity scale demonstrated overall acceptable psychometric performance for outcomes assessment of meniscus injuries of the knee, however, it demonstrated only moderate effect size. Psychometric testing of other condition-specific knee instruments in patients with meniscus pathologies of the knee would be helpful to allow for comparison of properties.