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.

Introduction

Postoperative nausea and vomiting (PONV) is a common occurrence following total joint arthroplasty, and can result in patient discomfort, delayed discharge, and decreased patient satisfaction. Carbohydrate loading as part of the Enhanced Recovery after Surgery (ERAS) protocol has gained popularity, and has been shown to minimize postoperative nausea, vomiting, pain, and lead to accelerated recovery and better overall outcome following abdominal surgery. This study aims to investigate the effects of preoperative carbohydrate-rich drinks on PONV following primary total knee arthroplasty (TKA).

Objectives: To investigate whether components of MSTS-87 (Pain, ROM, Strength, Stability, Deformity, Acceptance and Function) correlate with function as measured by TESS following endoprosthetic replacement (EPR) for patients with bone sarcoma.

Methods: 255 patients with extremity bone sarcoma treated by resection & EPR were identified from a prospective database. From this group we investigated 111 patients with primary bone sarcoma with > 2 years follow up, evaluated by both MSTS-87 & TESS, no local recurrence, metastasis or major complication for at least 2 years prior to the follow-up. Upper extremity patients were excluded due to small numbers. We examined the influence of patient demographics and tumour characteristics on functional outcome scores. Correlation between MSTS-87 & TESS was performed using linear regression analysis.

Results: Age, gender, tumour size, anatomical site, chemotherapy treatment and presence of pathological fracture did not significantly correlate with TESS. Linear regression analysis of MSTS-87 individual criteria and total score revealed that only pain, ROM and function helped explain the TESS score (p < 0.05) while strength, stability, deformity & acceptance had no significant effect on overall functional outcome.

Conclusions: Of the seven MSTS-87 variables, only pain, ROM and function significantly correlate with overall functional outcome as measured by TESS following EPR for bone sarcoma. This suggests that patients with decreased strength, stability, deformity and acceptance as defined by MSTS-87 scores, may still adapt well with good overall functional outcomes.