Knee OA is a chronic and multifactorial disease; self-management needs are complex, which requires a multidimensional management plan. There is a need for healthcare providers to provide patients with knowledge of knee OA and how to effectively manage the disease.

Self-management-needs scales are one means of determining the management requirements of an individual patient. There is no suitable instrument available for assessing self-management needs of adult patients with knee OA in Taiwan. This study developed an instrument that could assess the self-management needs of knee OA patients using Orem's self-care theory as a theoretical framework.

This study developed and psychometrically tested a new instrument for measuring adult patients’ self-management needs of knee OA (SMNKOA).

Development of the instrument involved three phases: item generation and scale development; content and face validity of the initial instrument; and evaluation of validity and reliability of the new instrument. Participants (n=372) were purposively sampled from orthopaedic clinics at medical centres in Taiwan.

The self-care theory guided the development of the 35-item SMNKOA scale. The content validity index was 0.83. Principal components analysis identified a 3-factor solution, accounting for 53.19% of the variance. The divergent validity was –0.67; convergent validity was –0.51. Cronbach's α was 0.95, Pearson correlation coefficient was 0.88, and the intraclass correlation coefficient was 0.95.

The SMNKOA scale can measure and identify the individual self-management needs of knee OA patients. It will help healthcare providers better evaluate strategies that can help these patients cope with this chronic disease.