Surgery (St Vincent's) - Research Publications

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    The immediate post-operative radiograph is an unreliable measure of coronal plane alignment in total knee replacement
    Petterwood, J ; Dowsey, MM ; Rodda, D ; Choong, PFM (FRONTIERS MEDIA SA, 2014)
    BACKGROUND: Restoration of a neutral mechanical axis is a primary goal of total knee replacement (TKR). A mechanical axis within 3° of neutral has been correlated with improved implant longevity, function, and patient satisfaction. We hypothesize that the immediate post-operative radiograph is an unreliable method of measuring alignment following TKR surgery. METHODS: Seventy-five consecutive patients had supine X-rays performed on day two post-operatively followed by standing long-leg radiographs (LLRs) 6 weeks post-operatively. Correlation was sought between the mechanical axis measured on the LLR and surrogate markers of alignment on the post-operative X-ray including component alignment and an estimation of anatomical alignment using the available length of femoral and tibial shafts. Inter- and intra-observer reliabilities were assessed. RESULTS: The mean mechanical axis on the LLR was 180.5 (SD 3.0, range 175.1-187.1). Mean offset between anatomical axis and mechanical axis was 6.4°. The mean anatomical axis measured on the short-leg X-ray was 174.9 (SD 2.4, range 169.5-181.3). Mechanical axis on the LLR was compared to the anatomical axis measured on the short-leg radiograph (SLR) + 6° with an interclass correlation coefficient of 0.588 (p < 0.001). The level of disagreement between the short- and long-leg X-rays was assessed using the Bland-Altman method and demonstrated clinically important discrepancies of 5 or more degrees in 9% of cases. Inter- and intra-observer agreements were high on all measures (p < 0.001). CONCLUSION: The long-leg weight bearing X-ray is an essential tool to accurately assess coronal plane alignment post TKR. While the immediate post-operative X-ray taken supine provides useful information to the surgeon on any immediate complications, our results indicate that it cannot be relied upon to determine correct restoration of the mechanical axis.
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    The effect of mindfulness training prior to total joint arthroplasty on post-operative pain and physical function: study protocol for a randomised controlled trial
    Dowsey, MM ; Castle, DJ ; Knowles, SR ; Monshat, K ; Salzberg, MR ; Choong, PFM (BioMed Central, 2014-06-05)
    BACKGROUND: Osteoarthritis is a leading cause of disability in developed nations. In Australia it afflicts 16.5% of the adult population. Total joint arthroplasty is considered the treatment of choice for end stage osteoarthritis. The number of total joint arthroplasties undertaken in Australia has doubled over the last decade (more than 80,000 procedures in 2011). The incidence of pre-operative psychological distress in this group of patients is reported between 30% and 60% and pre-operative psychological distress is associated with poorer pain and functional outcomes after surgery. This study will use a mindfulness-based psychological intervention to enhance outcomes in people undergoing total joint arthroplasty and, in addition, will test hypotheses about coping with chronic illness in an aged population. This study is the first of its kind and will provide a greater understanding of the role of a mental health enhancement program on the physical recovery of total joint arthroplasty patients. METHODS/DESIGN: One hundred and fifty people with end-stage arthritis on the waiting list for total hip or knee arthroplasty will be recruited and randomly allocated to one of two groups using computer-generated block randomisation. A randomised controlled trial adhering to CONSORT guidelines will evaluate the efficacy of a mindfulness training program (weekly group-based classes in mindfulness practice, 2 ½ hours, for 8 weeks plus a 7-hour Saturday session in Week 6) prior to total joint arthroplasty, compared to a "standard care" group who will undergo routine total joint arthroplasty. Primary outcomes will be evaluated by a blinded examiner at baseline, 3 and 12 months post-surgery, using a validated self-reported pain and physical function scale. Secondary outcomes will include i) a range of validated measures of psychological wellbeing and ii) health economic analysis. All analyses will be conducted on an intention to treat basis using linear regression models. Health economic modelling will be applied to estimate the potential cost-effectiveness of mindfulness training and total joint arthroplasty.
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    Selecting those to refer for joint replacement: Who will likely benefit and who will not?
    Dowsey, MM ; Gunn, J ; Choong, PFM (ELSEVIER SCI LTD, 2014-02)
    Osteoarthritis (OA) is one of the 10 most disabling diseases in developed countries and worldwide estimates are that 10% of men and 18% of women aged over 60 years have symptomatic OA, including moderate and severe forms. Total joint replacement (TJR) is considered the most effective treatment for end-stage OA in those who have exhausted available conservative interventions. The demand for TJR is continually rising due to the ageing population; in the United States, more than 1 million TJRs were performed in 2010 and the number of procedures is projected to exceed 4 million in the US by 2030. It has been estimated that of all hip and knee replacements performed, approximately one quarter of the patients may be considered inappropriate candidates. Predicting who will benefit from TJR and who will not would seem critical in terms of containing the current and projected expenditure as well as improving satisfaction in TJR recipients. Few formal predictive tools are available to aid referring clinicians to determine those likely to be good or poor responders to surgery and current available tools tend to focus on disease severity alone with little consideration of risk factors that may predict a poor outcome or impede an effective response to surgery. This review examines the tools available to assist with assessing appropriateness for TJR; investigates the modifiable risk factors associated with poor outcome; and identifies areas for future research in selecting those appropriate for joint replacement.
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    Outcomes following large joint arthroplasty: does socio-economic status matter?
    Dowsey, MM ; Nikpour, M ; Choong, PFM (BIOMED CENTRAL LTD, 2014-05-06)
    BACKGROUND: We sought to determine whether socio-economic status (SES) is an independent predictor of outcome following total knee (TKR) and hip (THR) replacement in Australians. METHODS: In this prospective cohort study, we included patients undergoing TKR and THR in a public hospital in whom baseline and 12-month follow-up data were available. SES was determined using the Australian Bureau of Statistics 'Index of Relative Advantage and Disadvantage'. Other independent variables included patients' demographics, comorbidities and procedure-related variables. Outcome measures were the International Knee Society Score and Harris Hip Score pain and function subscales, and the Short Form Health Survey (SF-12) physical and mental component scores. RESULTS: Among 1,016 patients undergoing TKR and 835 patients undergoing THR, in multiple regression analysis, SES score was not independently associated with pain and functional outcomes. Female sex, older age, being a non-English speaker, higher body mass index and presence of comorbidities were associated with greater post-operative pain and poorer functional outcomes following arthroplasty. Better baseline function, physical and mental health, and lower baseline level of pain were associated with better outcomes at 12 months. In univariate analysis, for TKR, the improvement in SF-12 mental health score post arthroplasty was greater in patients of lower SES (3.8 ± 12.9 versus 1.5 ± 12.2, p=0.008), with a statistically significant inverse association between SES score and post-operative SF-12 mental health score in linear regression analysis (coefficient-0.28, 95% CI: -0.52 to -0.04, p=0.02). CONCLUSIONS: When adjustments are made for other covariates, SES is not an independent predictor of pain and functional outcome following large joint arthroplasty in Australian patients. However, relative to baseline, patients in lower socioeconomic groups are likely to have greater mental health benefits with TKR than more privileged patients. Large joint arthroplasty should be made accessible to patients of all SES.
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    Alcoholic Chlorhexidine or Alcoholic Iodine Skin Antisepsis (ACAISA): protocol for cluster randomised controlled trial of surgical skin preparation for the prevention of superficial wound complications in prosthetic hip and knee replacement surgery
    Peel, TN ; Cheng, AC ; Buising, KL ; Dowsey, MM ; Choong, PFM (BMJ PUBLISHING GROUP, 2014)
    INTRODUCTION: Wound complications following arthroplasty are associated with significant impact on the patient and healthcare system. Skin cleansing prior to surgical incision is a simple and effective method to prevent wound complications however, the question of which agent is superior for surgical skin antisepsis is unresolved. METHODS AND ANALYSIS: This cluster randomised controlled trial aims to compare the incidence of superficial wound complications in patients undergoing elective prosthetic hip or knee replacement surgery receiving surgical skin antisepsis with either: 0.5% chlorhexidine gluconate (CHG) in 70% alcohol or 10% povidone in 70% alcohol. The trial will be conducted at an Australian tertiary, university affiliated hospital over a 3-year period involving 750 participants. Participants will be drawn from the surgical waiting list. Consent for this study will be 'opt-out' consent. On a given day, all eligible participants will have skin preparation either with 0.5% chlorhexidine in 70% alcohol or 10% povidone iodine in 70% alcohol. The primary outcome is superficial wound complications (comprised of superficial incisional surgical site infections (SSI) and/or prolonged wound ooze) in the first 30 days following prosthetic joint replacement surgery. Secondary outcomes will include the incidence of wound complications according to the joint replaced, assessment of the causative agents of SSI and cost-effectiveness analysis. The primary analysis is an intention-to-treat analysis including all participants who undergo randomisation and will be performed at the individual level taking into account the clustering effect. ETHICS AND DISSEMINATION: The study design and protocol was reviewed and approved by the St Vincent's Hospital Human Research Ethics Committee (HREC-A 016/14 10/3/2014). Study findings will be disseminated in the printed media, and learned forums. A written lay summary will be available to study participants on request. TRIAL REGISTRATION NUMBER: The trial has been registered with the Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12614000177651.
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    The Grand Challenge Managing End-Staged Joint Osteoarthritis
    Choong, PF ; Dowsey, MM (FRONTIERS MEDIA SA, 2014)
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    Gap Balancing Sacrifices Joint-Line Maintenance to Improve Gap Symmetry: A Randomized Controlled Trial Comparing Gap Balancing and Measured Resection
    Babazadeh, S ; Dowsey, MM ; Stoney, JD ; Choong, PFM (CHURCHILL LIVINGSTONE INC MEDICAL PUBLISHERS, 2014-05)
    A total knee arthroplasty can be completed using two techniques; measured resection or gap balancing. A prospective blinded randomized controlled trial was completed with 103 patients randomized to measured resection (n = 52) or gap balancing (n = 51). Primary outcome measure was femoral component rotation. Secondary outcome measures were joint-line change, gap symmetry and function and quality-of-life outcomes. Gap balancing resulted in a significantly raised joint-line compared to measured resection. Gap symmetry was significantly better using gap balancing. Functional outcomes and quality-of-life were not significantly different at 24 months. Using computer navigation, gap balancing significantly raises the joint-line in order to improve gap symmetry. This does not result in a clinical difference in function or quality of life at 24 months.
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    Risk factors for superficial wound complications in hip and knee arthroplasty
    Carroll, K ; Dowsey, M ; Choong, P ; Peel, T (ELSEVIER SCI LTD, 2014-02)
    Superficial wound complications have been consistently implicated in the development of prosthetic joint infection. This cohort study aimed to determine perioperative risk factors associated with superficial wound complications. The study was performed over an 18-month period (January 2011 to June 2012) and included 964 patients undergoing prosthetic hip or knee replacement surgery. The factors associated with superficial wound complication differed according to arthroplasty site. In the combined cohort the following factors were associated with superficial wound complications: the use of 0.5% chlorhexidine in 70% alcohol for surgical skin preparation compared with 1% iodine in 70% alcohol (odds ratio (OR) 4.75; 95% confidence interval (CI) 1.42, 15.92; p = 0.012); increasing age (OR, 1.13; 95% CI, 1.06,1.19; p 0.18); increasing body mass index (BMI) (OR, 1.08; 95% CI, 1.05,1.12; p < 0.001); rheumatoid arthritis (OR, 2.56; 95% CI, 1.17, 5.58; p 0.018); and increasing blood transfusions (OR, 1.26; 95% CI, 1.06,1.49; p 0.008). In the hip arthroplasty cohort, the use of 0.5% chlorhexidine in 70% alcohol for surgical skin preparation (OR, 13.35; 95% CI, 2.11, 84.29; p 0.006), increasing BMI (OR, 1.13; 95% CI, 1.06, 1.19; p < 0.001) and increasing blood transfusions (OR, 1.26; 95% CI, 1.06, 1.49; p 0.008) were associated with superficial wound complications. In the knee arthroplasty cohort rheumatoid arthritis (OR, 2.75; 95% CI, 1.03, 7.33; p 0.043) and increasing tourniquet time (OR, 1.01; 95% CI, 1.00, 1.02; p = 0.029) were independent predictors of superficial wound complications. Further research is warranted to assess the impact of modification of these factors on the subsequent development of wound complications and prosthetic joint infection.