A comparison of telephone interview versus on-site completion of Lysholm knee score in patients who underwent arthroscopic ACL reconstruction: are the results equivalent?

Abstract

The purpose of this study was to compare two different modes of administration (telephone versus face to face) for Lysholm knee score (LKS) to test their multi-mode equivalence and reliability. Two LKSs were obtained in 100 patients who underwent ACL reconstruction surgery. First LKS was completed through telephone interview, and second LKS, which was at least 2 weeks later, was completed face-to-face interview at the hospital. To analyze the test-retest reliability, the relative level of agreement between the two modes of administration for LKS was calculated using interclass correlation coefficient (ICC) in 95 % confidence interval. The mean LKS was 93.01 ± 9.12 (range 59-100) at telephone interview and 93.56 ± 7.93 (range 59-100) at face-to-face interview (p = 0.130). Both the total point and the each item's point were statistically similar (p < 0.05 for each item). The total score was same in 66 (66 %) subjects. The mean difference between two scoring was only 1.83 ± 3.14 points (range 0-15). However, eight (8 %) patients were assigned to different grading groups (excellent, good, fair, and poor). The overall LKS and the each item of the LKS had acceptable test-retest reliability [ICC = 0.954 (95 % CI 0.931-0.969)]. LKS can be reliably completed through telephone interview, which would provide accurate data similar to face-to-face interview. Researchers can design studies using telephone interview as a mode of administration for LKS or use mix-mode designs.