Limitations

(i)No provincial-level stratified analysis was conducted in this study. Significant urban-rural disparities in medical resources and OA screening/diagnostic capacity exist nationwide. Rural areas lack sufficient imaging and primary care screening services, leading to underreported OA cases. As a result, the national aggregated burden trend calculated in this paper may underestimate the real OA prevalence and disability burden in remote rural populations. Subnational stratified burden evaluation will be included in our follow-up research.(ii)OA data were extracted from the GBD 2021 database, which includes various data sources such as surveillance system data and individual-level survey data, meaning selection bias may affect the accuracy of OA disease burden estimates.(iii)There are many factors affecting OA, which were not analyzed in detail in this study.(IV)Our univariate ARIMA and Brown prediction models only extrapolate historical OA burden time series and cannot incorporate dynamic future variations in population obesity prevalence, physical activity levels and healthcare policy adjustments. These critical socioeconomic and behavioral determinants will continuously reshape the epidemiological trajectory of OA over the next two decades and may lead to notable forecasting bias. Meanwhile, the wide 95% prediction intervals of 2044 outcomes shown in Table 3 further demonstrate the high inherent uncertainty of 20-year extrapolation; all predicted values should not be regarded as definitive population estimates.(V)This study cannot adopt GBD2023 China-specific detailed data due to restricted open access of country-level stratified indicators.

In conclusion, from 1990 to 2021, the incidence rate and DALY rate of OA in China showed an overall upward trend. The incidence rate and DALY rate were significantly higher in females than in males; the highest incidence rate was in the middle-aged population (55–59 years old), and the DALY rate was mainly concentrated in the elderly population. The huge burden of OA in China and its potential future growth indicate the need to develop a comprehensive OA management strategy. Currently, there are few safe and effective treatments for OA, and the main clinical management goals are to relieve pain and improve function. Therefore, primary prevention of OA may be more effective in reducing the disease burden [23,24]. For example, implementing public health education programs to emphasize the importance of maintaining a healthy lifestyle to reduce obesity risk, prevent knee joint injuries, and avoid strenuous joint-loading activities. Consistent with previous GBD-based burden research focusing on middle-aged and elderly Chinese populations [25], targeted population screening is essential to mitigate rising OA disability burden, especially regular knee OA screening for women aged 55–59 years. At the secondary prevention level, publicity should be strengthened to improve public awareness of OA. In addition, doctors should receive adequate training on OA treatment guidelines, such as exercise therapy to delay functional loss and appropriate use of analgesics to minimize side effects.