Revision is a key negative outcome of joint replacements. The purpose of this abstract is to present revision risk curves for hip and knee replacements based on the most recently available national data sources. Having a better understanding of determinants of revision risk can help inform clinical and health care system improvements.

We explored revision risk of primary joint replacement stratified by key clinical, prosthesis, and surgeon-level factors using data from three databases managed by CIHI: the Canadian Joint Replacement Registry (CJRR), the Discharge Abstract Database, and the National Ambulatory Care Reporting System. To investigate early revisions, we used Kaplan-Meier analysis stratified by demographic factors to determine the risk of revision within up to five years of primary surgery. This analysis identified the primary cohort from the CJRR from April 1, 2012 to March 31, 2017 and was limited to mandatory reporting provinces (British Columbia, Manitoba and Ontario) to ensure maximal coverage of prosthesis information. Bearing surface was obtained from the International Prosthesis Library maintained by the International Consortium of Orthopaedic Registries (ICOR) and the International Society of Arthroplasty Registers (ISAR).

The total revision risk cohort contained 283,620 primary surgeries, of which 5,765 (2%) had at least one revision. For total hip arthroplasties, revision risk at the end of the follow-up period did not differ by age, by sex or across bearing surface (metal on cross-linked polyethylene [XLPE], ceramic on XLPE, ceramic on ceramic, metal on non-cross-linked polyethylene). For hemiarthroplasties in hip fracture patients, cement fixation was significantly associated with decreased revision risk. Surgeon volume had a positive effect on survivorship with cementless fixation (2.7% at one year [95% CI 2.3%, 3.1%] for high-volume vs 3.2% [2.7%, 3.7%] for low-volume). However, surgeon volume did not have an effect on survivorship with cemented fixation (2% at one year [95% CI 1.3%, 2.6%] for high-volume vs. 2% [1.4%, 2.6%] for low-volume). For total knee replacements, revision risk increased with decreasing age and male sex. For patients aged 75 and older, four-year revision risks were 1.5% (95% CI 1.3%, 1.7%) for women and 2.0% (1.7%, 2.3%) for men, but for patients under 55 years old, they were 4.3% (3.7%, 5%) for women and 5.9% (4.9%, 6.9%) for men. Additional results from the upcoming 2019 CJRR annual report, including data up to March 31, 2018, will be presented.

Revisions represent a key failure of the primary replacement, they are costly to the health care system and negatively affect patients' quality of life. CJRR's coverage is currently 72%, increased coverage and follow-up time will allow increasingly comprehensive reporting on hip and knee prostheses in Canada. Future work in this area involves exploring additional prosthesis attributes for stratification of revision risk curves and calculation of hazards ratios adjusted by age and sex.

The Canadian Institute for Health Information (CIHI) and the Organisation for Economic Co-operation and Development (OECD) have partnered to advance international patient-reported outcome measures (PROMs) collection and reporting standards for hip and knee arthroplasty. This project is part of the OECD's Patient-Reported Indicator Survey (PaRIS) initiative, which aims to address the need for internationally comparable patient-reported outcome and experience measures in order to better monitor health system performance and drive continuous improvement. PROMs are in varying stages of implementation across OECD health systems, with differences in collection and reporting practices across existing programs.

CIHI and the OECD are leading an international working group for PROMs in hip and knee replacement surgery in order to build consensus on PROMs data collection standards and develop indicators for international reporting. Working group members include patient representatives, clinicians, national arthroplasty registries, the International Society of Arthroplasty Registries (ISAR), experts in PROMs measurement, and government representatives of several OECD member countries. Activities of the working group focus on two main priorities: 1) Use existing PROMs programs to maximize pilot comparable reporting in OECD's Health at a Glance 2019 report, and 2) Advance new PROMs standards and data collection to maximize comparable reporting beyond Health at a Glance 2019.

An environmental scan of PROMs in hip and knee arthroplasty found that a number of countries are collecting this data, however, there are variations in survey instruments as well as administration and reporting methods within and across countries. As part of priority 1, the working group has achieved consensus on a number of aspects around pilot reporting. The project is compiling data from existing PROMs programs in order to report results in the Health at a Glance 2019 publication.

For priority 2, the most notable challenge is establishing an agreement across countries on common survey tools, as well as a minimum data set that works for all, given the disparities of existing collection across countries. Many international programs lack the flexibility to change PROMs tools or collections methods, and have concerns regarding the break in trend for PROMs data within their own countries if they were to change methods. The project is exploring the use of crosswalks and other opportunities for comparable reporting, such as the use of single-item anchor questions. To date, the working group continues to develop consensus on international standards for PROMs collection and reporting. Results of the international consensus building and work to date will be shared.

PROMs incorporate the patient's perspective into the delivery of treatments and care – such as hip and knee arthroplasty – that aim to improve a patient's quality of life. Alignment of standards in PROMs collection across countries will make comparable data available for reporting, in order to inform quality improvement initiatives within health systems to provide better care for patients. CIHI and the OECD will continue to work with member countries to develop international data collection and reporting standards for PROMs, and encourage the adoption of common approaches across countries.