Responsiveness of the Various Short-Form Versions of the Knee Injury and Osteoarthritis Outcome Score Between 2 and 5 Years After Anterior Cruciate Ligament Reconstruction

Kate E Webster; Haydn J Klemm; Timothy S Whitehead; Cameron J Norsworthy; Julian A Feller

doi:10.1177/23259671241236513

Responsiveness of the Various Short-Form Versions of the Knee Injury and Osteoarthritis Outcome Score Between 2 and 5 Years After Anterior Cruciate Ligament Reconstruction

Orthop J Sports Med. 2024 Mar 22;12(3):23259671241236513. doi: 10.1177/23259671241236513. eCollection 2024 Mar.

Authors

Kate E Webster¹, Haydn J Klemm^{1

2}, Timothy S Whitehead², Cameron J Norsworthy^{2

3

4}, Julian A Feller^{1

2}

Affiliations

¹ School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Australia.
² OrthoSport Victoria, Epworth HealthCare, Melbourne, Australia.
³ Faculty of Medicine, Monash University, Melbourne, Australia.
⁴ Eastern Health, Box Hill, Australia.

Abstract

Background: Various short-form versions of the Knee injury and Osteoarthritis Outcome Score (KOOS) have been developed in an attempt to minimize responder burden. However, the responsiveness of these short-form measures in patients who have undergone anterior cruciate ligament (ACL) reconstruction has not been compared at midterm follow-up.

Purpose: To determine the responsiveness of 3 short-form versions of the KOOS (KOOS-12, KOOS-Global, and KOOS-ACL) in patients who have undergone ACL reconstruction.

Study design: Cohort study (diagnosis); Level of evidence, 3.

Methods: In 276 patients (149 male, 127 female), we administered the KOOS and a measure of overall knee function at both 2 and 5 years after ACL reconstruction. From the full KOOS, the following short-form versions were calculated: KOOS-12, KOOS-Global, and KOOS-ACL. Responsiveness was assessed using several distribution and anchor-based methods for each of the short-form versions. From distribution statistics the standardized response mean (SRM) and smallest detectable change (SDC) were calculated. Using the anchor-based method, the minimally important change (MIC) that was associated with an improvement in knee function was determined using receiver operating characteristic (ROC) analysis.

Results: High ceiling effects were present for all measures. KOOS-Global scores increased significantly over time, whereas KOOS-12 and KOOS-ACL did not change. The KOOS-Quality of Life (QOL) subscale, which can be derived from both KOOS-Global and KOOS-12, also increased significantly between assessments. Both these increases were associated with a small (0.2-0.3) SRM. The MIC was smallest for KOOS-Global (3.2 points) and largest for KOOS-QOL (9.4 points), and, for all measures, the MIC was larger than the SDC at a group level. KOOS-Global was the only measure for which the mean difference between the 2- and 5-year assessments exceeded both the SDC (group level) and the MIC.

Conclusion: Of the 3 short-form versions of the KOOS currently available, the KOOS-Global had the greatest responsiveness to change between the 2- and 5-year assessments after ACL reconstruction. High ceiling effects were present for all versions.

Keywords: ACL; KOOS; knee; patient-reported outcomes.