Aims

It is unclear whether mortality outcomes differ for patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) surgery who are readmitted to the index hospital where their surgery was performed, or to another hospital.

Aims

Several different designs of hemiarthroplasty are used to treat intracapsular fractures of the proximal femur, with large variations in costs. No clinical benefit of modular over monoblock designs has been reported in the literature. Long-term data are lacking. The aim of this study was to report the ten-year implant survival of commonly used designs of hemiarthroplasty.

There is an increasing incidence of revision for periprosthetic joint infection. The addition of vancomycin to beta-lactam antimicrobial prophylaxis in joint arthroplasty may reduce surgical site infections, however, the efficacy and safety have not been established.

This was a multicenter, double-blind, superiority, placebo-controlled trial. We randomized 4239 adult patients undergoing joint arthroplasty surgery to receive 1.5g vancomycin or normal saline placebo, in addition to standard cefazolin antimicrobial prophylaxis. The primary outcome was surgical site infection at 90-days from index surgery. Perioperative carriage of Staphylococcus species was also assessed.

In the 4113 patients included in the modified intention-to-treat population, surgical site infections occurred in 72/2069 (3.5%) in the placebo group and 91/2044 (4. 5%) in the vancomycin group (risk ratio 1.28; 95% confidence interval 0.94 to 1.73; p value 0.11). No difference was observed between the two groups for primary hip arthroplasty procedures. A higher proportion of infections occurred in knee arthroplasty patients in the vancomycin group (63/1109 [4.7%]) compared with the placebo group (42/1124 [3.7%]; risk ratio 1.52; 95% confidence interval 1.04 to 2.23; p value 0.031). Hypersensitivity reactions occurred in 11 (0.5%) patients in the placebo group and 24 (1.2%) in the vancomycin group (risk ratio 2.20; 95% confidence interval 1.08, 4.49) and acute kidney injury in 74 (3.7%) patients in the placebo group and 42 (2.1%) in the vancomycin group (risk ratio 0.57; 95% confidence interval 0.39, 0.83). Perioperative Staphylococcus aureus carriage was detected in 1089/3748 (29.1%) of patients.

This is the first randomized controlled trial examining the addition of a glycopeptide antimicrobial to standard beta-lactam surgical antimicrobial prophylaxis in joint arthroplasty. The addition of vancomycin to standard cefazolin prophylaxis was not superior to placebo for the prevention of surgical site infections in hip and knee arthroplasty surgery.

The aim of this study was to examine the incidence of obesity in patients undergoing primary total shoulder replacement (TSR) (stemmed and reverse) for osteoarthritis (OA) in Australia compared to the incidence of obesity in the general population.

A 2017-18 cohort of 2,621 patients from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) who underwent TSR, were compared with matched controls from the Australian Bureau of Statistics (ABS) National Health Survey from the same period. The two groups were analysed according to BMI category, sex and age.

According to the 2017-18 National Health Survey, 35.6% of Australian adults are overweight and 31.3% are obese. Of the primary TSR cases performed, 34.2% were overweight and 28.6% were obese. The relative risk of requiring TSR for OA increased with increasing BMI category. Class-3 obese females, aged 55-64, were 8.9 times more likely to require TSR compared to normal weight counterparts. Males in the same age and BMI category were 2.5 times more likely. Class-3 obese patients underwent TSR 4 years (female) and 7 years (male) sooner than their normal weight counterparts.

Our findings suggest that the obese population is at risk for early and more frequent TSR for OA. Previous studies demonstrate that obese patients undergoing TSR also exhibit increased risks of longer operative times, higher superficial infection rates, higher periprosthetic fracture rates, significantly reduced post-operative forward flexion range and greater revision rates.

Obesity significantly increases the risk of requiring TSR. To our knowledge this is the first study to publish data pertaining to age and BMI stratification of TSR Societal efforts are vital to diminish the prevalence and burden of obesity related TSR.

There may well be reversible pathophysiology in the obese population to address prior to surgery (adipokines, leptin, NMDA receptor upregulation). Surgery occurs due to recalcitrant or increased pain despite non-op Mx.

There is growing interest in the peri-operative management of patients with indications for hip and knee arthroplasty in the setting of modifiable risk factors such as morbid obesity, type 2 diabetes mellitus, and smoking. A recent survey of the American Association of Hip and Knee Surgeons (AAHKS) found that 95% of respondents address modifiable risk factors prior to surgery. The aim of this study was to poll Australian arthroplasty surgeons regarding their approach to patients with modifiable risk factors.

The survey tool used in the AAHKS study was adapted for use in the Australian context and distributed to the membership of the Arthroplasty Society of Australia via Survey Monkey.

Seventy-seven survey responses were received, representing a response rate of 64%. The majority of respondents were experienced, high volume arthroplasty surgeons. Overall, 91% of respondents restricted access to arthroplasty for patients with modifiable risk factors. Seventy-two percent of surgeons restricted access for excessive body mass index, 85% for poor diabetic control, and 46% for smoking. Most respondents made decisions based on personal experience or literature review rather than hospital or departmental pressures.

Despite differences in healthcare systems, our findings were similar to those of the AAHKS survey, although their responses were more restrictive in all domains. Differences were noted in responses concerning financial considerations for potentially underprivileged populations. The survey is currently being administered by arthroplasty societies in six other countries, allowing comparison of orthopaedic practice across different healthcare systems around the world.

In conclusion, over 90% of Australian arthroplasty surgeons who responded to the survey address modifiable risk factors prior to surgery.

Obesity is a known risk factor for hip osteoarthritis. The aim of this study was to compare the incidence of obesity in Australians undergoing hip replacements (HR) for osteoarthritis to the general population.

A cohort study was conducted comparing data from the Australian Bureau of Statistics and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 2017-18. Body mass index (BMI) data for patients undergoing primary total hip replacement and resurfacing for osteoarthritis were obtained from the AOANJRR. The distribution of HR patients by BMI category was compared to the general population, in age and sex sub-groups.

During the study period, 32,495 primary HR were performed for osteoarthritis in Australia. Compared to the general population, there was a higher incidence of Class I, II, and III obesity in patients undergoing HR in both sexes aged 35 to 74 years old. Class III obese females and males undergoing HR were on average 6 to 7 years younger than their normal weight counterparts. Class III obese females and males aged 55-64 years old were 2.9 and 1.7 times more likely to undergo HR, respectively (p<0.001).

There is a strong association between increased BMI and relative risk of undergoing HR. Similar findings have been noted in the United States of America, Canada, United Kingdom, Sweden and Spain. A New Zealand Registry study and recent meta-analysis have also found a concerning trend of Class III obese patients undergoing HR at a younger age.

Obese Australians are at increased risk of undergoing HR at a younger age. A national approach to address the prevalence of obesity is needed.

Aims

The aim of this study was to estimate the 90-day periprosthetic joint infection (PJI) rates following total knee arthroplasty (TKA) and total hip arthroplasty (THA) for osteoarthritis (OA).

Aims

This study aimed to describe the use of revision knee arthroplasty in Australia and examine changes in lifetime risk over a decade.

Aims

Displaced femoral neck fractures (FNF) may be treated with partial (hemiarthroplasty, HA) or total hip arthroplasty (THA), with recent recommendations advising that THA be used in community-ambulant patients. This study aims to determine the association between the proportion of FNF treated with THA and year of surgery, day of the week, surgeon practice, and private versus public hospitals, adjusting for known confounders.

Introduction/Aims

The Exeter Stem can be used with metal femoral head that are made of either cobalt chrome, or stainless steel. The aim of this study was to compare the rates of revision of these two metal femoral head types when used with this femoral component.

INTRODUCTION

Accurate knowledge of knee joint kinematics following total knee arthroplasty (TKA) is critical for evaluating the functional performance of specific implant designs. Biplane fluoroscopy is currently the most accurate method for measuring 3D knee joint kinematics in vivo during daily activities such as walking. However, the relatively small imaging field of these systems has limited measurement of knee kinematics to only a portion of the gait cycle. We developed a mobile biplane X-ray (MoBiX) fluoroscopy system that enables concurrent tracking and imaging of the knee joint for multiple cycles of overground gait. The primary aim of the present study was to measure 6-degree-of-freedom (6-DOF) knee joint kinematics for one complete cycle of overground walking. A secondary aim was to quantify the position of the knee joint centre of rotation (COR) in the transverse plane during TKA gait.

Total Hip Arthroplasty (THA) is a successful operation for the management of end stage hip osteoarthritis (OA) but long term success is limited by wear of the polyethylene bearing surface. The aim of this study was to compare the rate of revision at 15 years in patients <55 who had a THA for OA, and received either cross-linked (XLPE) or conventional non cross-linked polyethylene (non-XLPE).

The study population was all patients with primary THAs undertaken for OA from 1999 to 31 December 2016. Outcomes were determined for all procedures, comparing THA performed with non-XLPE and XLPE and including the effect of age, sex, and reason for revision. The principal outcome measure was time to first revision using Kaplan-Meier estimates of survivorship.

There were 17,869 procedures recorded for younger patients <55 years of age undergoing THA for OA and using either non XLPE or XLPE. There was a fivefold increase in the rate of revision for procedures using non-XLPE after seven years. The 15 year cumulative percent revision of primary THA performed for OA in patients <55 with non XLPE was 17.4% (95% CI 15.5,19.5) and for XLPE was 6.6% (95%CI 5.5,7.8) HR >7 years =5.3, p<0.001. Non-XLPE and XLPE were combined with three different femoral head bearing surfaces: ceramic, metal and ceramicised metal. Within each bearing surface, XLPE had a lower rate of revision than non-XLPE. For the most common head size of 28mm XLPE had a lower rate of revision.

The use of XLPE has resulted in a significant reduction in the rate of revision for younger patients undergoing THA for OA at 15 years. This evidence suggests that longevity of THA is likely to be improved and may enable younger patients to undergo surgery, confident of a reduced need for revision in the long term.

Aims

Femoral stems with exchangeable (modular) necks were introduced to offer surgeons an increased choice when determining the version, offset and length of the femoral neck during total hip arthroplasty (THA). It was hoped that this would improve outcomes and reduce complications, particularly dislocation. In 2010, the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) first reported an increased rate of revision after primary THA using femoral stems with an exchangeable neck. The aim of this study was to provide a more comprehensive up-to-date analysis of primary THA using femoral stems with exchangeable and fixed necks.

Introduction

Dislocation is one of the leading causes of revision after primary total hip arthroplasty (THA). Polyethylene wear is one of the risk factors for late dislocations (>2 years). It can induce an inflammatory response resulting in distension and thinning of the pseudocapsule, predisposing the hip to dislocation. Alternatively, eccentric seating of the femoral head in a worn out socket may result in an asymmetric excursion arc predisposing the hip to impingement, levering out and dislocation. Highly cross linked polyethylene has a significantly lower wear rate as compared to conventional polyethylene. Incidence of late dislocations has been shown to be significantly greater with conventional polyethylene bearings as compared to ceramic bearings. However, there is no literature comparing the risk of dislocation between ceramic- on- ceramic (CoC) bearings with metal/ceramic- on- cross linked polyethylene (M/CoP) bearings and this was the aim our study

Traumatic disruption of the pelvic ring has a high risk of mortality. These injuries are predominantly due to high-energy, blunt trauma and severe associated injuries are prevalent, increasing management complexity. This population-based study investigated predictors of mortality following severe pelvic ring fractures managed in an organised trauma system.

Cases aged greater than 15 years from 1st July 2001 to 30th June 2008 were extracted from the population-based state-wide Victorian State Trauma Registry for analysis. Patient demographic, pre-hospital and admission characteristics were considered as potential predictors of mortality. Multivariate logistic regression was used to identify predictors of mortality with adjusted odds ratios (AOR) and 95% confidence intervals (CI) calculated.

There were 348 cases over the 8-year period. The mortality rate was 19%. Patients aged greater than 65 years were at higher odds of mortality (AOR 7.6, 95% CI: 2.8, 20.4) than patients aged 15–34 years. Patients hypotensive at the scene (AOR 5.5, 95% CI: 2.3, 13.2), and on arrival at the definitive hospital of care (AOR 3.7, 955 CI: 1.7, 8.0), were more likely to die than patients without hypotension. The presence of a severe chest injury was associated with an increased odds of mortality (AOR 2.8, 95% CI: 1.3, 6.1), while patients injured in intentional events were also more likely to die than patients involved in unintentional events (AOR 4.9, 95% CI: 1.6, 15.6). There was no association between the hospital of definitive management and mortality after adjustment for other variables, despite differences in the protocols for managing these patients at the major trauma services (Level 1 trauma centres).

The findings highlight the importance of the need for effective control of haemodynamic instability for reducing the risk of mortality. As most patients survive these injuries, further research should focus on long term morbidity and the impact of different treatment approaches.

Delayed union and non-union are complications of fracture healing associated with pain and with functional and psychosocial disability. This study compares the effect on self-reported health outcomes of delayed union or non-union of femoral and tibial shaft fractures treated at two major metropolitan trauma centres in Victoria.

Patients admitted to the Royal Melbourne Hospital and The Alfred with extra- articular femoral and tibial shaft fractures during 2003-2004 and 2005-2006, and followed up by the Victorian Orthopaedic Trauma Outcomes Registry (VOTOR) were included. Hospital medical records were reviewed to identify the outcome of each fracture. Fracture healing was assessed by the need for unplanned revision surgery for delayed union or nonunion, and clinical and radiological evidence of union. Prospectively-gathered VOTOR health outcome measurements included the Short Form 12-Item Health Survey (SF-12), and return to work and pain status at 6 and 12 months post injury.

Of the 520 patients, 260 femoral and 282 tibial shaft fractures were included. In total, 285 fractures progressed to union, 138 fractures developed delayed union or non-union and 119 fractures had an unknown outcome. Factors that were significantly different between the union and delayed union or non-union groups included: fund source, mechanism of injury, other injuries, wound and Gustilo type, and fixation method. On linear regression modelling, an inverse relationship was demonstrated between delayed union or nonunion and the Physical and Mental Component Summary scores of the SF-12. This was statistically significant at both 6 and 12 months post injury unadjusted and adjusted for age, gender and other injuries. On logistic regression modelling, patients with delayed union or non-union showed unadjusted and adjusted risk ratios of 0.85 and 0.82, respectively at 6 months, and 0.82 and 0.76, respectively at 12 months to return to work. Similarly, patients with delayed union or nonunion had unadjusted and adjusted risk ratios of 1.09 and 1.11, respectively at 6 months, and 1.33 and 1.37, respectively at 12 months to have pain. Both were statistically significant at 12 months post injury unadjusted and adjusted for age, gender and other injuries.

Patients with delayed union or non-union of femoral and tibial shaft fractures have poorer physical and mental health at 6 and 12 months post injury. In addition, they are less likely to have returned to work and more likely to still have pain at 12 months post injury.

Introduction

Sir John Charnley introduced his concept of low friction arthroplasty— though this did not necessarily mean low wear, as the initial experience with metal on teflon proved. Although other bearing surfaces had been tried in the past, the success of the Charnley THR meant that metal-on-polyethylene became the standard bearing couple for many years. However, concerns regarding the occurrence of peri-prosthetic lysis secondary to wear particles lead to consideration of other bearing surfaces and even to the avoidance of cement (although this has proven to be erroneous). Bearing combinations include polymers, ceramic and metallic materials and are generally categorised as hard/soft or hard/hard. In general, all newer bearing surface combinations have reduced wear but present with their own strengths and weaknesses, some of which are becoming more apparent with time.

Bearing surfaces must have the following characteristics: low wear rate, low friction, Biocompatibility and corrosion resistance in synovial fluid.

FAI has been implicated in the progression of osteoarthritis (OA) and early detection may allow for treatment, which can slow or halt progression. FAI is a difficult condition to image and there is little objective evidence about imaging accuracy. We aim to measure the accuracy of five imaging modalities.

Three blinded observers retrospectively reviewed five different modalities from two age and sex matched groups: A patient group referred to the outpatient clinic with a clinical diagnosis of FAI and a control group who had had CT scans of the pelvis for suspected trauma, where the Pelvic scan had been reported as showing no injuries.

The imaging modalities were: Standard x-ray; Antero-Posterior, Lateral; Condition-specific x-ray projections; Dunn view, lateral internal rotation; Standard Computer Tomography (CT) multiplanar reconstruction (MPR); axial, sagittal and coronal; Condition-specific CT MPR; angled axial, angled coronal; 3D modelling; and surface rendered dynamic.

We found marked variations in the sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictiive Value (NPV) for each of the following imaging modalities: Standard X-ray; Sensitivity 51.9; Specificity; 57.1; PPV; 40; NPV; 68.3 Special X-rays; Sensitivity; 66.7; Specificity; 57.1; PPV; 46.1; NPV; 75.7. Standard CT MPR; Sensitivity; 40.7; Specificity; 75.5; PPV; 47.8; NPV; 69.8 Special CT MPR; Sensitivity; 48.1; Specificity; 57.1; PPV; 46.4; NPV; 70.8 Dynamic 3D CT models; Sensitivity; 55.6; Specificity; 69.3; PPV; 42.8; and NPV; 71.8.

The Dynamic 3D CT models (where the observer can manipulate the model in real time three dimension to control the perspective) proved to be the most accurate, closely followed by the special X-Ray views, which were also the most sensitive. The Standard CT MPRs were the most specific but had a low sensitivity.

This is the first study to measure sensitivity, specificity and PPV and NPV for these imaging modalities in FAI. We recommend the use of condition-specific X-Ray views as well as 3D CT Models for optimal imaging accuracy in this condition. Standard X-Ray views and CTs proved less useful.

A key determinant of long-term implant survival following primary TKA is post- operative alignment of the limb and components. The aim of this study was to compare the accuracy of the Vector-Vision CT-free navigation system versus conventional hand-guided TKA by comparing post-operative alignment.

In a retrospective study 51 sets of post-operative radiographs were analysed, 33 computer-guided and 18 hand-guided. A specific protocol for the measurement of post-operative TKA radiographs was outlined and a novel Trigonometric Method (TM) of angle measurement was compared with the traditional Goniometer Method (GM) of measurement.

The standardised protocol was applied to all 51 sets of radiographs. In total, six angles were measured on each radiograph by two independent observers and compared between the computer-guided and hand-guided groups.

A protocol for the measurement of post-operative TKA radiographs was delineated with step-by-step instructions. The TM of angle measurement had a precision of 1.06° compared with 1.5° using the GM. The standard deviation of the TM was significantly smaller than the GM (p=0.033) and the intra-class correlation coefficient (ICC) of the TM was 0.94 versus 0.90 for the GM.

For the Mechanical Axis (MA), 91% of patients in the computer-guided group attained a MA within 180±3o compared with only 78% in the hand-guided group. T he absolute median raw deviation from 180° was 0.8 in the navigated group and 1.9° in the hand-guided group (p=0.029). Thus, the navigated group was associated with significantly less variability about the neutral 180°. For the other five angle measurements, a higher percentage of patients attained a more neutral alignment with computer-guided TKA; however, these did not reach statistical significance

The computer-assisted group demonstrated significantly more neutral alignment following TKA, and this may in turn lead to reduced TKA failure rates and improved implant longevity. In addition, a new TM of angle measurement was found to be more superior in terms of precision in comparison to the traditional method.