Prosthetic joint infection (PJI) is a serious complication following joint replacement. Antiseptic solutions are often used for intraoperative wound irrigation particularly in cases of revision for PJI. Antiseptic irrigation is intended to eradicate residual bacteria which may be either free floating or in residual biofilm although there is no clear clinical efficacy for its use. Also, reviewing the scientific literature there is discordance in in vitro results where some studies questions antiseptic efficacy whilst others suggest that even at low concentration antiseptic agents are effective at eradicating bacterial biofilms.

The aim of this in vitro study was to establish the efficacy of undiluted antiseptic agents at eradication of a typical PJI forming biofilm and determine the importance of an antiseptic neutralisation step in this assessment.

Mature Staphylococcus epidermidis biofilms grown on TiAl6V4 discs were submerged in chlorohexidine (CHL) gluconate 4%, povidone-iodine (PI) 10% or phosphate-buffered saline (PBS) control solution. The discs were then rinsed, the biofilm bacteria suspended in solution using sonication and vortexing, and the viable count (CFU/ml) of the bacterial suspensions determined. The rinse/suspension solution was either (a) PBS or (b) Dey-Engley neutralization broth (NB).

When PBS was used to rinse/suspend the biofilm a highly significant, 7.5 and 4.1, mean log reduction in biofilm vitality was observed from the control, for CHL 4% and PI 10%, respectively. However, when NB was the rinse/suspension solution the apparent antiseptic biofilm eradication efficacy was replaced with a statistically significant but clinically irrelevant less the one log-reduction in biofilm vitality.

Clinical antiseptic agents are ineffective at eradicating S. epidermidis biofilm in an in vitro PJI model and absence of a neutralisation step gives the false impression of efficacy. Antiseptics alone are an ineffective treatment for biofilm related PJI and no substitute for meticulous debridement.

Prosthetic joint infection (PJI) is an important cause of arthroplasty failure. There is no method to disclose the presence or map the distribution of the in vivo biofilm on infected arthroplasty despite the recognition that such a tool would aid intraoperative decision making and improve novel implant design. The aim of this study was to test the efficacy of four dyes to disclose bacterial biofilm in an in vitro setting.

Four dyes with known affinity to bacterial biofilm were assessed to determine their efficacy to disclose biofilms in an in vitro model of PJI. Three dyes (Methylene Blue, Indocyanine Green and Rose Bengal) have established clinical utility and the other, Thioflavin T, is known to fluoresce in the presence of amyloid a known biofilm constituent. The efficacy of the dyes to discriminate between biofilms of different mass and vitality (high, low or the non-inoculated control) was determined after three minutes exposure of the biofilm to the dyes by calculating the amount of dye bound to the biofilm via sonication and spectrophotometry, quantification of the dye through standardised photographic imaging of the stained biofilm and the calculation of inter-observer agreement. Each experiment was performed in triplicate for each dye and repeated three times.

For each of the disclosure dyes assessed there was significant difference demonstrated between the amount of dye bound to the high and low mass biofilms (p<0.05) as well as in the amount of dye quantified in photographic and fluorescent image assessment between biofilms of differing mass (p<0.01). There was excellent agreement between three observers, for each disclosure dye, in determining the biofilm mass of each stained disc (Kappa>0.91).

This study demonstrates the efficacy of biofilm disclosure dyes in an in vitro PJI model which could one day be used to disclose and map the clinical biofilm in vivo.

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.

There has been recent interest in the treatment of Dupuytren's disease by minimally invasive techniques such as needle fasciotomy and collagenase injection, but only few studies have reported the outcomes following open fasciotomy. This study attempts to address this gap, with a retrospective analysis of a large series of patients who underwent an open fasciotomy by a single surgeon over a five-year period. The aim of the study was to determine the requirement for re-operation in the cohort and to analyse the revisionary procedures performed.

Theatre coding data was used to identify a consecutive series of patients who underwent open fasciotomy over a five-year period between 2000 and 2005. Within this group medical records were obtained for those patients who underwent a secondary procedure for recurrence. All procedures were carried out by a single surgeon in a regional hand unit using an unmodified open technique.

A total of 1077 patients underwent open fasciotomy for Dupuytren's disease. Of these, 865 (80.3%) were male and 212 (19.7%) were female. The mean age at initial surgery was 64.4 years (range 21.7 to 93.7 years) for males and 68.3 (range 43.6 to 89.8 years) for females. Of the 1077 patients who underwent open fasciotomy, 143 patients (13.3%) subsequently underwent a second procedure for recurrence.

The medical records were available for 97 patients. The median time to re-operation in this group of patients was 42.0 months (95% CI, 8.3 to 98.0 months). The most common revision procedure being dermofasciectomy (54.2%), followed by fasciectomy (32.6%) and re-do open fasciotomy (13.2%). Mean pre-operative total extension deficit was 88 degrees (range 30–180 degrees) with intra-operative correction to a mean of 9.5 degrees (range 0–45 degrees).

There is no standard definition for recurrence after Dupuytren's surgery. We have looked at the rate of revision surgery after open fasciotomy, in a relatively fixed population serviced over a 5-year period by a single hand surgeon. A low re-operation rate has been identified, with good intra-operative correction achieved by secondary surgery.

Purpose: In children and youth, the prevalence of psychiatric disorder associated with chronic medical illness approximates 30%. The impact of psychiatric disorder on the management of scoliosis has not been well explored in the literature. The objective of this study was to estimate the prevalence of mental health disorders in patients with adolescent idiopathic scoliosis (AIS).

Method: Adolescents being treated for AIS completed the Achenbach Youth Self-Report and one parent completed the Achenbach Child Behaviour Checklist. Both measures are validated for screening of mental health disorders. The prevalence of mental health disorder in this population was estimated on the basis of the proportion that screened positive. Univariate analysis and logistic regression analysis was conducted to estimate the association between variables. A sensitivity analysis was performed to estimate the robustness of the results.

Results: Between October 2006 and February 2008, 61 of 126 adolescents completed the study (48%). Of the 61 subjects, 18 were treated with observation, 26 with bracing, and 17 with surgical intervention. Overall, there were 41 adolescents who screened positive (67%). Sensitivity analysis demonstrated that, of those who did not return the questionnaire, the prevalence of a positive screen would have had to have been less than 0.1% in order to decrease the overall prevalence to 30%. There was a statistically significant difference in the magnitude of the scoliosis between those who screened positive (mean curve magnitude 39 degrees) compared to those who screened negative (mean curve magnitude 30.6 degrees) (p=0.03).

Conclusion: The estimated prevalence of a mental health disorder using the Achenbach questionnaires in patients with AIS is 67%. This is substantially higher than the anticipated prevalence in either the healthy population or those with a chronic illness. The results of this study provide evidence of the high burden of mental health illness amongst those with AIS. The sensitivity analysis demonstrated that the results are robust despite the relatively low response rate.

Introduction: In recent years some countries have shown increasing interest and use of unicompartmental knee arthroplasty (UKA). Several studies have reported increasing use of UKA for osteoarthritis in younger patients with low revision rates. The aim of this study was to determine the outcome of UKA by combining two national databases containing prospectively collected data.

Method: Over 50 000 UKA procedures were analyzed to determine the cumulative percentage revision (CPR). Any reason for revision was used as the end point. The analysis was stratified according to age, gender and type of prosthesis to determine outcomes in patients younger than 65 years

Result: In this study both countries showed declining use of UKA in terms of the proportion of knee replacement procedures and of absolute numbers undertaken per year. The seven year CPR of UKA in patients younger than 65 years was 16.2%, and at 10 years was 17.5%. No significant difference was found between gender, however outcome did vary depending on the type of prosthesis used.

Conclusion: This study reports the outcomes from the two largest databases of UKA. Within 10 years of UKA a substantial number of revisions were seen in patients younger than 65 years, with varying results depending on the type of prosthesis used.

Purpose: We aimed to determine the effect of delay to surgery in hip fracture patients, including in hospital mortality, major complications, minor complications and length of hospital stay.

Method: We identified 615 eligible patients from the VGH Orthopaedic Trauma database between 1998 and 2002. A thorough chart review was performed. Age, gender, time from admission to surgery, pre-existing medical comorbidity, length of acute care hospital stay, major medical complications, minor medical complications and in hospital death were recorded and categorized. Patients were categorized into three risk groups for pre-existing comorbidity, and three groups for delay to surgery (48 hours). Chi-squared tests were performed to determine the association of delay to surgery to death, major complications, minor complications and length of stay, as a categorical variable. Multivariate logistic regression analysis was used to evaluate these associations, while adjusting for age, gender, and pre-existing medical comorbidity. Anvoa test was used to evaluate the association between length of stay, as a continuous variable, and delay to surgery.

Results There were 471 female patients, and 141 male patients. We identified 52 deaths (8.5%), 72 major complications (11.7%) and 238 minor complications (38.7%). The delay to surgery was < 24 hours in 346 patients (56.3%), 24–48 hours in 216 (35.1%), and > 48 hours in 50 (8.1%). The mean length of hospital stay was 23.4 days. Chi squared test showed no statistically significant association between delay to surgery and in hospital death (p= 0.787), despite a trend to increasing death (< 24 hours 8.1%, 24–48 hours 8.3%, > 48 hours 12.2%). There was no statistically significant association between delay and minor complications. Statistically significant associations between delay to OR and length of hospital stay (p= 0.0026), and the occurrence of a major complication (p=0.0085) were found. Regression analysis of major complications revealed an odds ratio of 1.47 for the > 48 hour group compared to the < 24 hour group, with a confidence interval of 1.15–1.87. Regression analysis did not show a statistically significant odds ratio for either death or minor complications.

Conclusion: There is a trend to increasing mortality and minor complications with a delay to surgery in hip fractures. A statistically significant increase in major medical complications and length of hospital stay with delay to surgery was found in our group. Regression analysis including age, gender and pre-existing medical comorbidity supported the significance of the increased risk of major medical complications with delay, adjusted for age, gender, and pre-existing medical comorbidity.

Slipped capital femoral epiphysis (SCFE) is the most common pediatric hip disorder. The most devastating complication is development of avascular necrosis of the femoral head. In order to reduce the potential for this complication occurring following delayed contralateral SCFE, there has been consideration in the literature of prophylactic pinning of the contralateral hip. The objective of this study was to determine the cost-effectiveness of this treatment strategy.

The outcome probabilities and utilities utilised in a decision analysis of prophylactic pinning of the contralateral hip in SCFE, reported by Kocher et al, were used in this study. Costing data, reported in 2005 Canadian dollars, was obtained from our institution. Using this data, an economic evaluation was performed. The time horizon was four years, so as to follow the adolescents to skeletal maturity. Discounting was performed at 3% per year. Sensitivity analyses were conducted to determine the effect of variation of the outcome probabilities and utilities.

In all analyses, prophylactic pinning resulted in cost savings but lower utility, compared to the currently accepted strategy of observation of the contralateral hip. The results were most sensitive to an increase in the probability of a delayed contralateral SCFE to 27%. Using the base case analysis, the incremental cost-effectiveness ratio was $7856.12 per utility gained. Using the most sensitive probability of a delayed contralateral SCFE of 27%, the incremental cost-effectiveness ratio was $27,252.92 per utility gained.

The results of this study demonstrated overall cost savings with prophylactic treatment, however the utility was lower than the standard treatment of observation. For both the base case and sensitivity analysis, the incremental cost-effectiveness ratio was less than the accepted threshold of $50,000 per quality adjusted life year gained. It should be noted that the use of a four year time horizon excluded consideration of the costs related to total hip arthroplasty for the sequelae of AVN. A prospective, randomised controlled trial, with an accompanying economic evaluation, is required to definitively answer the question of the cost-effectiveness of this treatment. On the basis of this cost-effectiveness analysis, prophylactic pinning of the contralateral hip in SCFE cannot be recommended. A prospective, randomised controlled trial, with an accompanying economic evaluation, is required to definitively answer the question of the cost-effectiveness of this treatment.

Avascular necrosis (AVN) of the femoral head is a devastating complication of slipped capital femoral epiphysis (SCFE). The reported prevalence of AVN following unstable SCFE has ranged between fifteen and forty-seven per cent in the literature. The explanation for this discrepancy is not clear. The inter-observer and intra-observer agreement between Orthopaedic surgeons for the radiographic diagnosis of AVN following SCFE has not been reported. It is the objective of this study to estimate these parameters between two experienced pediatric Orthopaedic surgeons for the radiographic diagnosis of AVN following SCFE.

A retrospective review of all one hundred and three cases of SCFE treated at a Canadian pediatric referral center between 1995 and 2005 was performed. Of these, eight were diagnosed, by the treating surgeon, with AVN. Each of these eight children and a random sample of fifteen of the remaining children, who were not diagnosed with AVN, were included in this study. The most recent anteroposterior and lateral radiographs were digitised and presented to two experienced pediatric orthopaedic surgeons in a blinded, random order. Each surgeon reviewed the radiographs independently and recorded which radiographs they believed to be consistent with AVN. The surgeons were told that each patient had SCFE and that some developed AVN, however neither the classification of the slip, nor the proportion who developed AVN were divulged. Each observer repeated this process two weeks after the initial review in order to determine intra-observer agreement. The kappa value was determined to assess inter-observer and intra-observer agreement.

The first observer recorded eight cases of AVN at the initial and seven cases at the second observation time. The intra-observer agreement was 0.9. The second observer recorded six cases of AVN at the initial and five cases at the second observation time. The intra-observer agreement was 0.88. The inter-observer agreement was determined at the first observation time and was 0.79.

On the basis of the results of this study, both the inter-observer and intra-observer agreement for the radiographic diagnosis of AVN following SCFE, amongst experienced pediatric Orthopaedic surgeons, was very high. It is unlikely that the reported discrepancy in prevalence of AVN following SCFE is due to a lack of inter-observer agreement, on the basis of the findings of this study. The inter-observer agreement between less experienced observers requires further study to determine if this may be the source of the variability in the reported prevalence of AVN following SCFE.

Subtrochanteric femoral fractures are uncommon in children, consequently there are no good treatment guidelines in the literature. This series reviewed all subtrochanteric femur fractures in skeletally immature adolescents older than ten years treated at a pediatric trauma center. There were fifteen adolescents with open growth plates. Treatment was non-operative in four and operative in eleven. Each of the adolescents treated non-operatively developed an unsatisfactory result, while eight of the eleven who were treated operatively experienced a satisfactory result. These results suggest improved outcome with operative treatment in this patient population.

It was the purpose of this study to describe treatment options and make recommendations for management of subtrochanteric femur fractures among skeletally immature adolescents older than ten years of age.

This series consisted of a retrospective review of all cases of subtrochanteric fractures in adolescents with open growth plates. The outcome was classified on the basis of radiographic criteria.

There were fifteen adolescents with an average age of thirteen years and one month. The average length of follow-up was two years and nine months. Treatment was non-operative in four and operative in eleven, utilizing a variety of fixation devices. There was fracture union in each case, although there was one delayed union. Complications included limb length discrepancy in three, each of which were treated non-operatively, one transient peroneal nerve palsy and asymptomatic heterotopic ossification. One adolescent, treated with a rigid intramedullary rod, developed avascular necrosis of the femoral head. The result was unsatisfactory in each of the non-operative cases, while eight of the eleven treated operatively developed satisfactory results.

Children less than ten years of age may be treated non-operatively. However, in skeletally immature adolescents, operative treatment resulted in improved outcomes. Rigid intramedullary fixation is contraindicated in skeletally immature adolescents due to the risk of avascular necrosis of the femoral head.

This series is the first to emphasize treatment and make management recommendations regarding subtrochanteric fractures in this age group.

Internal fixation is more effective than non-operative treatment for subtrochanteric femur fractures in skeletally immature adolescents, however the ideal method of fixation requires further study.

Introduction and Aims: Nine countries have established national joint replacement registries. The first population-based national registry, the Swedish Knee Registry, was established in 1975 with the most recent, the UK National Joint Registry (UK NJR), beginning in 2003. We identify commonalities and differences in the structure, function and methods of reporting among these national registries.

Method: Data was collected from the annual reports of the various registries, published literature and personal contact with registry coordinators and directors.

Results: Commonalities include registry ownership, source of funding, procedure types collected, method of data collection and validation of data. Most registries are owned by the national Orthopaedic Association or a government agency. The most common source of funding is government; membership fees and a mandated implant levy are also used. Most national registries collect total hip and knee replacements, primaries and revisions. Hemiarthroplasties are not commonly collected, though some registries collect additional joints (including shoulder, elbow, wrist, finger, ankle and toe). The most common method of data collection is paper-based, usually from theatre, with subsequent data entry at the registry. Electronic data collection is used to supplement the paper-based system in some countries, while the Swedish Hip Registry and the UK NJR utilise a web application for the submission of data. Most registries attempt to validate their data against hospital inpatient data held by government. Differences include reporting of rates, cost per registration and definitions. Failures of primary implants may be reported as cumulative proportions, true incidence rates or survival probabilities. This leads to difficulties in comparison of data among the national registries. The cost of registering a procedure varies up to five-fold across countries.

Conclusion: There are obvious opportunities for collaboration between national joint replacement registries, however some issues need to be addressed. These include definitions of what is collected, for example hemiarthroplasties, and methods of analysis and reporting, especially revision rates.

Introduction and Aim: Following the establishment of the Australian Orthopaedic Association National Joint Replacement Registry, the Australian orthopaedic community has quality prosthesis specific information on knee replacement. This presentation details the demographics of primary total knee replacement, types of prostheses used, methods of fixation and the incidence of, and reasons for, early revision.

Results: Over 36,000 primary total knee replacements with almost 400 subsequent revisions were recorded. Primary total knee replacements were undertaken more commonly in females (56.4%), mostly for osteoarthritis (95.9%), with a mean subject age of 69.6 years.

The Registry recorded 56 different knee prostheses with the 10 most common accounting for 85.5% of all procedures. The patella was not replaced in the majority of cases (58.5%), however this varied considerably with prosthesis type and method of fixation. Cement fixation of the tibial component occurred in 76.9% of cases and the femoral component in 49.5%. Most commonly the insert was fixed (71.3%) and minimally stabilised (86.7%). Posterior stabilised inserts were used in 12.8% of primary cases. The cumulative revision rate at one year was 1.0% and 2.1% at two years. Early revision was minor in 54.1% of cases and major in the remainder. The most common reasons for minor revision were patello-femoral pain (27.1%) and infection (21.7%); for major revision, early loosening (40.2%) and infection (27.5%). Prosthesis type, patella use, method of fixation, degree of constraint and the use of fixed, rotating and/or sliding inserts did not significantly affect revision rates at this early stage.

Conclusion: Although variation is seen in early revision rates depending on the prosthesis type, patella use, method of fixation and other prosthesis specific characteristics, these differences are currently not significant.

Introduction and Aims: The use of resurfacing hip replacements has increased dramatically in recent years. The aim of this study was to compare the early results of this treatment with conventional cemented, cementless and hybrid primary total hip replacement in Australia.

Method: The data used for this report included all conventional primary total hip and resurfacing procedures, as well as any subsequent revisions of those procedures which had been undertaken and reported to the Australian Orthopaedic Association National Joint Replacement Registry (AOA NJRR) before 31 December 2002. Analysis included the determination of demographics, components used and method of fixation. Early revision rates and reasons for failure were also assessed. The AOA NJRR commenced data collection in September 1999 and has had national coverage since 2002, therefore any results reported at this stage are early outcomes.

Results: Almost 33,000 primary total hip replacements were recorded, of these 2130 were resurfacing procedures (6.5%). This proportion of resurfacing was consistent across states with the exceptions of Victoria (11%) and Tasmania (0.6%). Cementless hip replacement was the most common form of primary total hip replacement (41%) with hybrid (34%) and cemented (18.2 %) less common. There was marked state variation in the proportion of cemented and cementless fixation with NSW having a low proportion of cement fixation (4.5%). Early revision rates for cemented conventional primary total hip replacement are significantly less compared to cementless and hybrid hips (cemented v cementless) hazard ratio (adjusted for age and sex) 2.13; 95% CI (1.49, 3.05) p< 0.0001) (cemented v hybrid) hazard ratio (adjusted for age and sex) 1.94; 95% CI (1.37, 2.77) p=0.0002). There was no difference between cementless and hybrid hips. The most common reason for early revision was dislocation and the risk of this was related to head size with larger sizes showing a reduced risk. Although revisions per 100 observed component years were higher for resurfacing hip replacements than for conventional hips (1.73 v 1.18), this difference was not statistically significant. The principal reason for early failure of resurfacing hips was fracture.

Conclusion: The AOA NJRR has identified prosthesis specific differences in early outcomes and failure mechanisms following primary total hip replacement. Continued monitoring of existing and new prostheses will provide surgeons with independent quality information to assist in the selection of the most appropriate prostheses for particular clinical situations.

Introduction and Aims: Austin Moore and Thompson hemiarthroplasties are commonly used for the management of subcapital neck of femur fractures, particularly in the frail elderly. There are no published studies that directly compare the results of these two procedures. The Australian Orthopaedic Association National Joint Replacement Registry (AOA NJRR) has reviewed outcomes for these prostheses.

Method: Data from the AOA NJRR collected from participating hospitals between September 1999 and December 2002 were used to test for differences in revision rates between these two prostheses. Mortality data from the National Death Index were used to censor the time of follow-up and to compare mortality rates following surgery. Further analyses were undertaken to examine the effects of age, gender, diagnosis and regional variation.

Results: The Registry recorded 4080 Austin Moore and 1111 Thompson hemiarthroplasties. Of these, 4023 (98.6%) Austin Moore prostheses were cementless and 1010 (90.9%) Thompsons were cemented. The distributions of age and gender were similar for the two prostheses. There were regional differences in the use of monoblock prostheses during the data collection period. In Victoria, all partial monoblock prostheses used were Austin Moore (N=1560). This contrasts to Queensland and Western Australia where 62.8% and 75.8% respectively of all partial monoblock hip replacements were Thompsons. The cementless Austin Moore prosthesis had a significantly higher rate of revision (122/4023, 3%) than the cemented Thompson prosthesis (9/1010, 0.9%). A Cox model yielded a hazard ratio, adjusted for age and gender, of 3.94 (95% CI: 2.00, 7.76; p < 0.001). None of the 57 cemented Austin Moore and four of the 101 (4%) cementless Thompsons required revision. The cumulative mortality rates for the period to 2001 were similar for the two prostheses (Austin Moore 23.3% and Thompson 24.0%). In the states where sufficient numbers of both types of prostheses were used the difference in outcomes were consistent with the overall results.

Conclusion: The use of the cementless Austin Moore prostheses is associated with an almost four-fold increase in the rate of revision when compared to the cemented Thompson prosthesis.

With increasing primary joint replacement procedures and an ageing population surviving longer, the rate of revision surgery will increase. Revision surgery, however, is associated with increased morbidity and mortality and has a far less successful outcome than primary joint replacement. The mid- to long-term survival rate of the large variety of replacement prostheses remains unknown. Inadequate outcomes data for the majority of prostheses, as well as variability related to different surgical techniques and diagnostic groups, have made it difficult for surgeons to identify the relative effectiveness of different prostheses and treatments. The Federal Government provided funding to the Australian Orthopaedic Association (AOA) to establish the National Joint Replacement Registry (NJRR) in March 1998. The AOA has appointed a committee to manage the Registry and has contracted with the Data Management and Analysis Centre at the University of Adelaide to establish and manage the data systems for the Registry.

The primary aim of the AOA NJRR is to evaluate the effectiveness of different types of joint replacement prostheses and surgical techniques at a national level.

Implementation methods, aspects of database design and early progress in data collection are presented.

From July 1985 to April 1996, 394 PCA total hip replacements were performed using proximally, porous-coated, femoral components. A prospective study using a specifically designed database has been used to follow these patients. There have been 10 deaths and five patients were lost to follow-up (F/Up), leaving 379 for review.

Revision of 33 acetabular components has been performed for loosening; four acetabular liners were revised for recurrent dislocation; and three acetabular liners were revised because of wear. Only three femoral stems have been revised for loosening.

The fully proximally, porous-coated, cementless stem resulted in good survival in the mid-term.

The problems of the acetabular component of cement-less total hip replacement have been the cause of early failure, but close follow-up of patients has enabled the femoral components in these patients to be preserved.

Improved acetabular components, with lower wear characteristics, may prolong the survival of the femoral components of proximally porous –coated femoral components.