Global, regional, and national burden of lower-limb fractures, 1990 to 2021, with health inequalities and projections to 2040: An observational analysis of Global Burden of Disease Study 2021 data.

Lower-limb fractures are important contributors to disability worldwide, but their long-term burden, Sociodemographic Index (SDI)-related inequalities, and future trajectories remain incompletely characterized. This study assessed the global, regional, and national burden of lower-limb fractures from 1990 to 2021 and projected trends to 2040 using data from the Global Burden of Disease Study 2021. Data on years lived with disability due to lower-limb fractures were obtained from the Global Burden of Disease Study 2021 for 204 countries and territories. Four anatomical subtypes were analyzed: fracture of the hip (FH); fracture of the patella, tibia, fibula, or ankle (FPTFA); fracture of the foot bones excluding the ankle (FFB); and fracture of the femur excluding the femoral neck (FF). Age-standardized rates (ASRs) and YLD numbers were assessed by sex, age, year, location, and SDI. Joinpoint regression, decomposition analysis, the Slope Index of Inequality, Concentration Index, and Bayesian age-period-cohort models were used to evaluate temporal trends, drivers of absolute burden, SDI-related inequalities, and projections to 2040. In 2021, FPTFA had the largest global YLD burden, with 16.58 million years lived with disability, followed by FH with 3.10 million, FF with 1.18 million, and FFB with 0.41 million. From 1990 to 2021, global YLD numbers increased for all 4 subtypes, by 75.2% for FH, 43.0% for FPTFA, 35.5% for FFB, and 56.7% for FF. In contrast, global ASRs declined by 19.7%, 23.1%, 26.5%, and 18.2%, respectively. Slope Index of Inequality values decreased across all subtypes, indicating narrowing absolute SDI-related differences, whereas Concentration Index values changed less markedly, suggesting persistent relative distributional inequality. Joinpoint regression showed declining global ASRs, with average annual percentage changes of -0.71 for FH, -0.83 for FPTFA, -0.99 for FFB, and -0.65 for FF. Bayesian age-period-cohort projections suggested broadly stable or slightly declining global ASRs through 2040, with sex-specific patterns differing by subtype. Although global ASRs for lower-limb fracture-related disability declined from 1990 to 2021, the absolute YLD burden increased across all 4 subtypes. These findings support subtype- and context-specific strategies, including osteoporosis management, fall prevention, fracture liaison services, and rehabilitation in aging high-SDI settings, alongside strengthened trauma care, timely orthopedic treatment, rehabilitation, and financial protection in lower-SDI settings.