Although the knee joint is one of the joints most affected by osteoarthritis (OA), research on the economic implications of joint disease has generally focused only on OA. The goal of this study was to identify and quantify knee-related productivity and medical costs in knee OA patients with paid employment. Furthermore, we evaluated associations between productivity loss and relevant patient, health, and work characteristics.
Consecutive knee OA patients with mild to moderate knee OA who were 18-65 years of age, had conservative treatment for ≥6 months, and had paid employment were included. Productivity loss and health care consumption were measured by questionnaires. The associations between productivity loss and patient, health, and work characteristics were explored with regression analyses.
In total, 117 knee OA patients with a mean age of 53.2 years and a mean body mass index of 28.8 kg/m(2)  were included. Total knee-related productivity costs and medical costs were €871 (median €411, interquartile range [IQR] €107-1,200) per patient per month, with total productivity costs of €722 (median €217, IQR €0-1,041) and total medical costs of €149 (median €137, IQR €72-198). More pain during activity and performing physically intensive work were significantly associated with productivity loss.
The total knee-related productivity costs and medical costs of conservatively treated symptomatic knee OA patients with paid employment in The Netherlands are €871 per patient per month, with productivity costs accounting for 83% and medical costs for 17%. Productivity loss is associated with having more pain during activity and performing physically intensive work. Developing adequate treatment strategies for knee OA may be cost beneficial.