Epidemiology of cruciate ligament injuries in New Zealand: exploring differences by ethnicity and socioeconomic status.

OBJECTIVES: To investigate the temporal trends and ethnic and socioeconomic disparities in cruciate ligament (CL) injury incidence and associated costs in New Zealand over a 14-year period. METHODS: All CL injury claims lodged between 2007 and 2020 were extracted from the Accident Compensation Corporation (a nationwide no-fault injury compensation scheme) claims dataset. Age-adjusted and sex-adjusted incidence rates, total injury costs and costs per claim were calculated for each year for total population and subgroups. RESULTS: The total number of CL injury claims increased from 6972 in 2007 to 8304 in 2019, then decreased to 7068 in 2020 (likely due to widespread COVID-19 restrictions; analysis is therefore restricted to 2007-2019 hereafter). The (age-adjusted and sex-adjusted) incidence rate remained largely unchanged and was 173 cases per 100 000 people in 2019. There was a 127% increase in total injury claims costs and a 90% increase in costs per claim. Pacific people had the highest incidence rate and costs per 100 000 people, while Asians had the lowest; European, Maori and 'other' ethnicities had similar incidence rates and total costs. Incidence rates and total costs increased with income and decreased with neighbourhood deprivation. Costs per claim differed little by ethnicity, but increased with income level. CONCLUSION: The number and costs of CL injury claims in New Zealand are increasing. There are ethnic and socioeconomic disparities in CL incidence rates and costs, which are important to address when designing CL injury prevention programmes and programmes aimed at improving equity of access to medical care.