A key outcome measured by national joint registries are revision events. This informs best practice and identifies poor-performing surgical devices. Although registry data often record reasons for revision arthroplasty, interpretation is limited by lack of standardised definitions of revision reasons and objective assessment of radiologic and laboratory parameters. Our study aim was to compare reasons for unicompartmental knee arthroplasty (UKA) revision reported to the New Zealand Joint Registry (NZJR) with reasons identified by independent clinical review. A total of 2,272 patients undergoing primary medial and lateral UKA at four large tertiary hospitals between 2000 and 2017 were included. A total of 158 patients underwent subsequent revision with mean follow-up of 8 years. A systematic review of clinical findings, radiographs and operative data was performed to identify revision cases and to determine the reasons for revision using a standardised protocol. These were compared to reasons reported to the NZJR using Chi-squared and Fisher exact tests.Introduction
Methods
The NZ Standards of Service Provision for Sarcoma patients were developed by the NZ Sarcoma working group and published by the Ministry of Health (MOH) in 2013. Although not formally enacted by the MOH we aimed to determine the impact of these published standards and referral pathways on disease-specific survival of patients with soft-tissue sarcoma in NZ. The Middlemore Musculoskeletal Tumour Unit database was searched. Patients referred for treatment in our centre with a diagnosis of soft tissue sarcoma in the five-year period before (n=115) and after (n=155) were included. We excluded patients with bone sarcomas and retroperitoneal soft tissue sarcomas. The rate of referral after inappropriate treatment reduced after implementation of the Standards (24% vs 12%, p=0.010). The number of patients referred with tumours larger than 50mm decreased (74.8% vs 72.3%, p=0.021) and fewer had metastases at diagnosis (11.3% vs 3.2%, p=0.017). Mortality was lower in the group after introduction of the Standards (45% vs 30%, p=0.017). The estimated disease-specific survival curve between the two groups shows a trend towards increased survival in the post-standards group, although not reaching statistical significance. Local recurrence rate and metastasis rate after definitive treatment were similar between the two groups. Patients had a shorter duration of symptoms before referral in the post-Standards group although this was not statistically significant. Since implementation of the Standards, patients have been referred more promptly, with fewer inappropriate treatments. The time to mortality curve indicates a trend towards improved disease-specific survival. We conclude that the pathway for investigation and referral for this condition has become clearer, supporting the ongoing use of the Sarcoma Standards, and that these should be formally implemented by the MOH.
