Traumatic rotator cuff injuries can be a leading cause of prolonged shoulder pain and disability, and contribute to significant morbidity and healthcare costs. Previous studies have shown evidence of socio-demographic disparities with these injuries. The purpose of this nationwide study was to better understand these disparities based on ethnicity, sex, and socio-economic status, in order to inform future healthcare strategies.

Accident Compensation Corporation (ACC) is a no-fault comprehensive compensation scheme encompassing all of Aotearoa/New Zealand (population in 2018, 4.7 million). Using the ACC database, traumatic rotator cuff injuries were identified between January 2010 and December 2018. Injuries were categorized by sex, ethnicity, age and socioeconomic deprivation index of the claimant.

During the 9-year study period, there were 351,554 claims accepted for traumatic rotator cuff injury, which totalled over $960 million New Zealand Dollars. The greatest proportion of costs was spent on vocational support (49.8%), then surgery (26.3%), rehabilitation (13.1%), radiology (8.1%), general practitioner (1.6%) and “Other” (1.1%). Asian, Māori (Indigenous New Zealanders), and Pacific peoples were under-represented in the age-standardized proportion of total claims and had lower rates of surgery than Europeans. Māori had higher proportion of costs spent on vocational support and lower proportions spent on radiology, rehabilitation and surgery than Europeans. Males had higher number and costs of claims and were more likely to have surgery than females. There were considerably fewer claims from areas of high socio-economic deprivation.

This large nation-wide study demonstrates the important and growing economic burden of rotator cuff injuries. Indirect costs, such as vocational supports, are a major contributor to the cost suggesting improving treatment and rehabilitation protocols would have the greatest economic impact. This study has also identified socio-demographic disparities which need to be addressed in order to achieve equity in health outcomes.

The aim of the New Zealand National Shoulder Arthroplasty Register is to evaluate the provision of shoulder arthroplasty across the entire country by both recording accurate technical information and measuring the clinical outcomes of all shoulder replacements performed in New Zealand.

An initial form is completed at the time of surgery which includes details of the patient, surgical indications, the surgical procedure, the implant and the operating surgeon. Six months following surgery, all registered patients are asked to complete the Oxford Shoulder Score and comment on post-operative complications.

Data from 686 consecutive primary and 44 revision shoulder arthroplasties were prospectively collected from January 2000 until December 2003. 82 surgeons performed shoulder arthroplasty during the study period but only 9 performed on average more than 5 per year. Their results at 6 months were statistically superior to those provided by other surgeons. Amongst all diagnoses, osteoarthritis scored significantly better than the rest and for this condition total shoulder replacement scored higher than hemiarthroplasty. 15 different prostheses were used, many of them too infrequently. There was no difference in outcome amongst the 5 most commonly used prostheses. The number of complications reported by patients and the revision rate within the study period was low. No benefit was observed in the use of laminar flow theatre to prevent infection.

The combination of technical data about the joint implanted and the individual patient assessment has made the New Zealand Shoulder Arthroplasty Register unique in its own kind. Our findings are in general agreement with the current literature and supports the idea that shoulder arthroplasty is better provided by surgeons with a higher yearly case-load.