Adjustments in 2011 KSS increase the clinical suitability

Area of Science:

• Orthopedics
• Medical Statistics
• Patient-Reported Outcome Measures

Background:

• The 2011 Knee Society Score (KSS) is a validated tool for total knee arthroplasty (TKA) but suffers from low patient completion rates (42%).
• Suboptimal scale features and lack of clear administration rules may contribute to low engagement.
• Improvements are needed to enhance the clinical utility and patient adherence to the KSS.

Purpose of the Study:

• To develop and evaluate an adjusted version of the 2011 KSS (2011 KSS-A) to improve completion rates and maintain clinimetric quality.
• To simplify the questionnaire while ensuring its reliability and validity for TKA patients.

Main Methods:

• The 2011 KSS was modified based on identified limitations, creating the 2011 KSS-A.
• A cohort of 499 primary TKA patients completed the 2011 KSS-A pre- and postoperatively via mail.
• Clinimetric properties, including internal consistency, correlations with the Knee injury and Osteoarthritis Outcome Score Physical Function Short Form (KOOS-PS), and responsiveness, were evaluated.

Main Results:

• The adjusted questionnaire achieved a 70% response rate and 90% completion rate, significantly higher than the original KSS.
• Excellent internal consistency (Cronbach's Alpha ≥0.79) and strong correlations with KOOS-PS were observed.
• All subscales demonstrated significant improvement postoperatively, with moderate to large effect sizes, though some ceiling effects were noted.

Conclusions:

• The adjusted 2011 KSS-A is a shortened, simplified, and more clinically useful questionnaire for TKA patients.
• The 2011 KSS-A maintains excellent clinimetric quality and demonstrates improved patient engagement.
• This adjusted tool offers a more efficient and effective method for assessing TKA outcomes.