Browsing by Author "Burger, M. C."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Lost to follow-up : challenges to conducting orthopaedic research in South Africa
    (Health & Medical Publishing Group, 2018) Badenhorst, D. H.; Van der Westhuizen, C. A.; Britz, E.; Burger, M. C.; Ferreira, N.
    Loss to follow-up poses a major problem for clinicians and researchers, and several factors that may increase its risk have been postulated. The objective of this study was to describe potential factors that contribute to loss to follow-up as seen in orthopaedic patients participating in a research study and attending the sole public orthopaedic service provider in the Northern Cape Province of South Africa (SA). All patients who underwent ankle fracture surgery at Kimberley Provincial Hospital between January 2012 and July 2013 were included, and the number of follow-up visits attended by each participant was recorded prospectively. Demographic information pertaining to travel distance, social circumstances and comorbid conditions was captured and reviewed. A total of 268 patients (male n=112, 41.8% and female n=156, 58.2%) were included. The mean (standard deviation (SD)) age was 42.3 (13.8) years (95% confidence interval (CI) 40.6 - 43.9, n=266) and the mean body mass index (BMI, kg/m2) was 28.0 (6.5) (95% CI 27.2 - 28.8, n=251), the BMI for females being 30.2 (6.1) (95% CI 29.3 - 31.2, n=152) compared with 24.6 (5.7) (95% CI 23.4 - 25.7, n=99) for males. After excluding local patients living within 5 km of the hospital (n=77), the mean travel distance was 460 km (range 10 - 910). There was a significant association between the number of follow-up visits attended and travel distance (incidence rate ratio (IRR) 0.999, 95% CI 0.999 - 1.000; p=0.030), BMI (IRR 0.980, 95% CI 0.966 - 0.994; p=0.004) and HIV status (IRR 0.841, 95% CI 0.725 - 0.975; p=0.022). The main factors identified in this study that influenced the number of follow-up visits attended were travel distance, BMI and HIV status. BMI was a unique finding in our study. It was identified to be a significant contributing factor to the loss to follow-up. BMI was not a contributing factor in other studies.
  • Thumbnail Image
    Item
    Prevalence of a postoperative troponin leak in patients with cardiac risk factors undergoing knee and hip arthroplasty in a South African population
    (Health & Medical Publishing Group, 2020) Van Zyl, R. D.; Burger, M. C.; Jordaan, J. D.
    Background. Patients undergoing arthroplasty may have comorbidities that put them at risk of myocardial injury after non-cardiac surgery (MINS). MINS, a new clinical concept that has a different pathophysiology from conventional myocardial infarction, is related to a supply-demand mismatch ischaemia in the perioperative setting. MINS is often a silent event, and the diagnosis relies on cardiac biomarker testing such as troponin T. The incidence is estimated at 40%, with a fourfold increase in morbidity and mortality risk 1 year post surgery. Objectives. To determine the prevalence of postoperative troponin leak in a single-centre arthroplasty unit in patients with various cardiac risk factors undergoing hip or knee arthroplasty and investigate the differences in troponin T levels between comorbidities and different types of arthroplasty, i.e. total hip replacement (THR), total knee replacement (TKR) and neck of femur (NoF) fracture hip replacement. Methods. A prospective, cross-sectional study of patients with one or more cardiac risk factors undergoing replacement surgery was conducted from October 2017 to April 2018. Troponin levels of all included patients were recorded on days 1 and 3 post surgery using a high-sensitivity cardiac troponin T assay (Roche hs-cTnT). A level of >15 ng/L is considered abnormal and termed a positive troponin leak, while >100 ng/L is considered suspected acute coronary syndrome (ACS). Results. One hundred and sixty patients (n=66 THR, n=55 NoF hip replacement, n=39 TKR) were included. Sixty-eight patients (42%) had a positive troponin leak, and in 6 of these cases ACS was suspected. The highest prevalence of troponin leak was recorded in patients undergoing NoF hip replacement (62%), followed by TKR (46%) and then THR (24%). Sixty-two patients (38%) had positive troponin levels on day 1 and 53 patients (33%) had positive levels on day 3. Important patient cardiac risk factors were identified in the presence of a positive troponin leak, with ischaemic heart disease, hypertension, diabetes, renal disease, age >65 years and atrial fibrillation being statistically most likely. Conclusions. Postoperative troponin surveillance is an inexpensive and reliable way to identify patients at risk of MINS and subsequently enhance early detection, medical optimisation and referral strategies. Simple interventions may improve outcomes and contribute to lower ACS rates and the timeous prevention of other complications. The prevalence of MINS in orthopaedic-specific patients in South Africa (SA) and other resource-constrained developing countries is unknown. Our finding of 42% positive troponin leaks raises awareness of this issue, and we recommend routine postoperative troponin surveillance for all arthroplasty units in SA.