Performance of the HOOS-12 and KOOS-12 instruments for evaluating outcomes from joint replacement surgery

Area of Science:

• Orthopedics
• Rheumatology
• Health Outcomes Research

Background:

• Osteoarthritis significantly impacts joint function and quality of life, necessitating reliable outcome measures after joint replacement surgery.
• Patient-reported outcome measures (PROMs) are crucial for evaluating the effectiveness of total hip replacement (THR) and total knee replacement (TKR).

Purpose of the Study:

• To evaluate the psychometric properties of the 12-item Hip disability and Osteoarthritis Outcome Score (HOOS-12) and Knee injury and Osteoarthritis Outcome Score (KOOS-12).
• To determine the suitability of HOOS-12 and KOOS-12 for assessing outcomes following joint replacement surgery for osteoarthritis.

Main Methods:

• Utilized patient-reported outcomes data from the Australian Orthopaedic Association National Joint Replacement Registry.
• Assessed internal consistency reliability, floor/ceiling effects, convergent validity, known groups validity, and responsiveness using standard psychometric techniques.
• Compared HOOS-12 and KOOS-12 with the Oxford Hip Score (OHS), Oxford Knee Score (OKS), and EQ-5D-5L pre- and post-operatively.

Main Results:

• High internal consistency was observed for all HOOS-12 and KOOS-12 domains and summary scores (Cronbach's alpha: 0.81-0.93).
• Significant post-operative ceiling effects were noted in several HOOS-12 and KOOS-12 domains, potentially limiting the assessment of improvement.
• Both HOOS-12 and KOOS-12 demonstrated excellent responsiveness to change and ability to differentiate between known patient groups.

Conclusions:

• The HOOS-12 and KOOS-12 exhibit good psychometric properties, including excellent responsiveness, for evaluating outcomes after hip and knee joint replacement.
• Ceiling effects in the HOOS-12 and KOOS-12 may pose limitations in monitoring post-operative functional improvements in highly satisfied patients.