Thank you” to a team of Australian researchers who has been the first to fully explore the new Hip disability and Osteoarthritis Outcome Score (HOOS-12) and the Knee injury and Osteoarthritis Outcome Score (KOOS-12). Their work, “Performance of the HOOS-12 and KOOS-12 instruments for evaluating outcomes from joint replacement surgery,” was published in the June 1, 2021, edition of Osteoarthritis and Cartilage.
Co-author Ilana Ackerman, Ph.D. associate professor at the School of Public Health and Preventive Medicine at Monash University in Melbourne, Australia, explained to OTW that her study may well be the first time HOOS, KOOS and Oxford scales have been tested against other large data sets. “Beyond the initial validation study by the instrument developers, this is the first time that the measurement properties of the new 12-item HOOS-12 and KOOS-12 instruments have been examined using data from a large national arthroplasty registry. This study provides new information about the validity, reliability, and responsiveness of these measures for use with people undergoing joint replacement surgery.”
Using longitudinal Australian Orthopaedic Association National Joint Replacement Registry data, the researchers dove into HOOS-12 and KOOS-12 domain (pain, function, quality of life) and summary impact data, comparing them to the Oxford Hip Score, Oxford Knee Score and EQ-5D-5L. Baseline HOOS-12 data were available for 3,023 patients undergoing primary total hip replacement; KOOS-12 data were available for 4,010 patients undergoing primary total knee replacement.
“At baseline,” wrote the authors, “high internal consistency was demonstrated for all domains and summary scores (Cronbach’s alpha: HOOS-12 1⁄4 0.81e0.93; KOOS-12 1⁄4 0.82e0.92). Post-operative ceiling effects (>15% of patients scoring the best possible score) were identified for the HOOS-12 pain (46%), function (39%) and quality of life domains (26%) and summary score (17%), and for the KOOS-12 pain (21%) and function domains (18%). The HOOS-12 and KOOS-12 could differentiate between two known groups (lowest/highest Oxford Hip Scores or Oxford Knee Scores quartiles post-operatively; p < 0.001) and were highly responsive to change (effect sizes for HOOS-12: 2.20e2.83; KOOS-12: 1.82e2.35).”
Big Benefits to HOOS-12, KOOS-12
“The HOOS-12 and KOOS-12 were more responsive than other commonly used measures (for example, the Oxford Hip and Knee Scores and the EQ-5D-5L). The HOOS-12 and KOOS-12 also offer the advantage of generating separate pain, function, and quality of life scores—all important indicators of patient outcome after hip and knee replacement surgery. The shortened format of these instruments (12-items vs 42-items for the original HOOS and KOOS) also reduces the responder burden for patients.”
“The HOOS-12 and KOOS-12 instruments are valid and reliable measures that can detect large improvements in pain, function, and quality of life after joint replacement surgery. As with other similar instruments, we also found some evidence of ceiling effects which may also reflect excellent patient recovery after surgery.”
