Introduction and aims

Cast immobilisation of paediatric forearm fractures has traditionally used plaster of Paris. Recently, synthetic casting materials have been used. There have been no studies comparing the efficacy of these two materials. The aim of this study is to investigate whether one material is superior for paediatric forearm fracture management.

Slipped Capital Femoral Epiphysis (SCFE) is a common paediatric disorder with documented racial predilection. No data exists regarding the Australian indigenous and Australian non-indigenous populations. This study provides a comprehensive demographic and epidemiologic analysis of SCFE in South Australia, with emphasis on establishing associations between increasing obesity and incidence.

A demographic review of all cases of SCFE managed in South Australian public hospitals between 1988 and 2007 was performed. Clinical presentation, surgical management and complication profile information was collected. Given that obesity is implicated in the biomechanical causation of SCFE due to increased shearing forces, particular emphasis was placed on gathering weight, race, gender and age data. A profile of the incidence and nature of SCFE was generated. Comparisons were then drawn between this profile and existing epidemiologic percentile data of weight, age and gender in South Australia.

A rising prevalence of obesity in South Australia corresponded with a rising incidence of SCFE. However, this relationship was not linear as the incidence of SCFE has doubled in the last 20 years and the average weight of SCFE patients has increased markedly.

The indigenous population was found to have higher rates of obesity than the non- indigenous population in South Australia. The indigenous population also has a relative risk of developing a SCFE of over three times the non-indigenous population.

The overall rate of complications in South Australian public hospitals was low, with avascular necrosis being recognised in our profile.

The rise in incidence of SCFE in South Australia; especially noticeable in the indigenous population is associated with an increasing prevalence of obesity. The considerable morbidity associated with SCFE was confirmed in our analysis and further highlights the importance of public health initiatives to tackle obesity in our community.

We report the frequency of door-opening (“theatre traffic”) in orthopaedic operations at three metropolitan hospitals with different theatre policies. Published studies have correlated “theatre traffic” with airborne bacteria levels, which have been associated with raised wound infection rates.

Hospital A had one scoliosis operation and two hip replacements, Hospital B had one knee revision and one knee replacement. Hospital C had one scoliosis operation. A second scoliosis operation was performed at Hospital C after “theatre traffic” education and door signage discouraging entry.

One pair of surgeons performed the scoliosis operations and a different pair did the hips and knees.

Hospital A is private and Hospitals B and C are public.

The scoliosis operation in Hospital A (private) had an average door opening rate of 0.45/min compared to the same operation in Hospital C (public) with an average door opening rate of 1.0/min. The two hip replacements in Hospital A (private) had an average rate of 0.43/min and 0.51/min while the knee revision and knee replacement in Hospital B (public) had average rates of 0.91/min and 0.77/min respectively.

Of concern is the total number of door openings that result from this rate of “theatre traffic”. In the Hospital C (public) operation the total number of door openings equalled 140 over the course of the scoliosis operation. In Hospital B the total number of door openings for the knee revision was 169 and the knee replacement was 72. In contrast, for Hospital A (private) the total number of door openings for the scoliosis operation was 73 and the two hip replacements equalled 30 and 36.

The second study at Hospital C after staff education revealed a 35% decrease to 0.65/min.

There was a difference in “theatre traffic” between private and public hospitals for the same or similar operations. Staff education and door signage dramatically reduced “theatre traffic” in Hospital C. Surgeons and theatre staff need to be aware of “theatre traffic” and its influence on infection rates.

Introduction and Aims: Elevated chromium ion levels can be detected in serum following spinal arthrodesis with stainless steel. Comparing characteristics of spinal implants with chromium levels has not been done extensively before. The aim of our study was to compare an extensive range of implant characteristics with chromium levels.

Methods: Cross-sectional study of 30 patients (26 females and 4 males) who underwent posterior instrumented spinal arthrodesis using Isola implants including cables for adolescent scoliosis between 1998 and 2002. Patients who had postoperative complications and implants removed were excluded. Serum levels of chromium were analysed between October 2006 and June 2007. Post-operative radiography was used to measure rod length and count hooks, screws, cross-connectors and cables. Surface areas of each component of the implant was estimated and totalled. Metal-on-metal interfaces were calculated. Ethics approval was obtained from the WCH Research Ethics Committee.

Results: Both total surface area and total rod length were correlated with serum chromium levels (p = 0.04 and 0.05 respectively). This is the first study to identify a characteristic of spinal implants, other than the late signs of corrosion identified by radiographs, which has significance for serum chromium levels. None of our patients had signs of corrosion, pseudoarthrosis or rod breakage on radiological examination. Compared to raised serum chromium levels, the number of metal-onmetal interfaces approached significance (p = 0.09). Individual numbers of screws, hooks, cables or cross-connectors were not significantly associated with chromium levels.

Conclusions: Total rod length may contribute to elevated chromium levels in patients with stainless steel Isola spinal implants and warrants further investigation.

Introduction: Slipped Capital Femoral Epiphysis (SCFE) is the most common hip problem of adolescence. Obesity and African and Pacific Islander races have been associated with increased susceptibility. In the setting of increasing rates of obesity in Australian adolescents over the last twenty years, it is unknown whether the incidence of this condition is increasing. There are no studies to date on the Australian population and it is unknown whether there is an increased incidence in the local Aboriginal population.

Aims: The demographics of SCFE patients presenting to the Women’s and Children’s Hospital (W& CH) in Adelaide were studied, from 1988 to the present, with particular emphasis on weight and race. This was then compared to weight for age percentiles data in the Australian population. The issues of prophylactic pinning of the contralateral side and the efficacy of the department protocol of “pinning in situ” were also studied.

Method: Systematic chart review, statistical analysis, and comparison with data from the Australian Bureau of Statistics and the Centre for Applied Anthropometry, University of South Australia, pertaining to weight and racial mix in South Australia.

Results: SCFE was associated with obesity. Over 45% of the cohort was above the 95th percentile for weight. The mean weight was in the 85th percentile and the median weight was in the 94th percentile.

As an example, the average weight of children aged 12 to 14 years was 13kgs more than the median value of children in this age group.

There was a clear increase in incidence of this condition over the last twenty years which corresponds with increasing obesity rates in the community.

There was a higher incidence in the indigenous population as compared with the non-indigenous population.

Out of the 236 patients enrolled, 5 cases were complicated by avascular necrosis. The overall complication rate was low.

Rate of progression to contralateral slip was low as was the rate of prophylactic pinning.

Conclusions: Our complication rate when compared to other centres is relatively low and would seem to support our consistent protocol of “pinning in situ”. The low rate of progression to contralateral slip also supports our protocol of watchful surveillance rather than mandatory prophylactic pinning of the contralateral side.

We have shown that SCFE is associated with obesity in Australia when compared with general population data. Obesity is also more common in the Aboriginal population and we postulate that this explains the higher incidence of SCFE in this group. In keeping with increasing rates of obesity amongst Australian adolescents, the increasing incidence of this condition further highlights the importance of public health initiatives to tackle obesity in the community.

Instrumented spinal arthrodesis is a common procedure to correct scoliosis. The long-term consequences of these retained implants is unclear. Concern of possible toxic effects of raised metal ion levels have been reported in arthroplasty literature. We investigated serum metal ion levels in patients having instrumented spinal arthrodesis for scoliosis correction.

The study included patients who underwent posterior spinal arthrodesis using Isola stainless steel instrumentation for scoliosis between 1998 and 2002. Patients having post-operative complications, instrumentation removed, revision surgery or additional in situ metal implants were excluded. Participants completed a questionnaire to evaluate exogenous chromium exposure.

Serum levels of chromium, molybdenum, iron and ferritin were measured in venous blood samples. Participants with elevated serum chromium levels underwent further erythrocyte chromium analysis. Comparisons were made with two control groups;

“non-instrumented” individuals with scoliosis and

Thirty “instrumented” patients (Group 1, 26 females and 4 males), 10 “non instrumented” patients with scoliosis (Group 2) and 10 unaffected volunteers (Group 3) were included in the study. Mean age at surgery was 13.8 years (range 6.6 to 13.2), mean time from surgery 5.7 years (range 3.4 to 8.1). Elevated serum chromium levels were demonstrated in 11/30 (37%) Group 1 participants. In the control groups, elevated serum chromium levels were demonstrated in 0/10 (0%) in Group 2 and 2/10 (20 %) in Group 3. There was a statistically significant (p=0.001) elevation in serum chromium levels between scoliosis participants with retained spinal implants, and those without.

There was no significant correlation found between Groups 1, 2 and 3 for serum molybdenum, iron and ferritin levels. Erythrocyte chromium measurements from all participants (n=31, 100%) were considered within the normal range.

At a multivariant level, the results of a stepwise censored regression (n=50) indicated the significant predictors of serum chromium to be spinal implants (p=0.001), gender (male versus female, p=0.04) and iron grading (low, normal or high, p=0.05).

Time since surgery was found not to have a significant correlation with chromium levels (p=0.147).

Raised serum chromium levels were detected in 37% of patients after instrumented spinal arthrodesis for scoliosis correction. This new finding has relatively unknown health implications but potential genotoxic, dysmorphic and carcinogenic sequelae; this is especially concerning with most scoliosis patients being adolescent females with their reproductive years ahead.

Introduction: Studies suggest pedicle screw constructs are more effective than hybrid or hook constructs for AIS correction. This study assessed the efficacy of three methods of spinal instrumentation in patients treated at the WCH.

Methodology: 30 AIS patients who underwent posterior spinal surgery were matched according to age, fusion levels, and Lenke curve. Three constructs were assessed, hook-exclusive, screw-exclusive and hybrid constructs, with 10 patients in each group. Endpoints included radiographic measures, operative time and complications.

Results: Mean pre-operative Cobb angle was 56.1°, 52.2° and 56.7° for the screw, hybrid and hook group respectively.

Structural curve correction was 63.6°, 60.2° and 58.5° for each group respectively. Compensatory curve correction favoured the hybrid and screw groups.

Thoracic kyphosis correction was 20.7° (most improved), 19.9°, and 15.5° for the screw, hook, and hybrid groups respectively.

Coronal alignment favoured the screw construct group.

Comparison of operative time revealed no significant difference, and complication rates were similar in nature and incidence for all three groups.

Conclusions: Results demonstrate improved correction of structural curve, kyphosis, and coronal alignment in the screw instrumentation group. No additional complications were observed with this method of AIS curve correction.

Introduction: Spinal arthrodesis with stainless steel implants is a common procedure to correct scoliosis however, the long-term consequences of retained implants is unclear. Raised serum metal ion levels have been widely published in arthroplasty literature with concern over possible toxic adverse effects associated with chronic exposure. We investigated serum metal ion levels in patients who had undergone instrumented spinal arthrodesis for scoliosis correction.

Methods: The study included patients who underwent posterior spinal arthrodesis using ISOLA instrumentation for scoliosis between 1998 and 2002. The minimal period of follow up was 3 years. Clinical information was available from a comprehensive Scoliosis Database, Department of Orthopaedic Surgery, Women’s and Children’ Hospital, Adelaide (WCH). Patients having post-operative complications, spinal instrumentation removed, revision surgery or additional in situ metal implants were excluded. Participants completed a questionnaire to evaluate exogenous chromium exposure. Blood samples were collected and processed by the WCH Core Laboratory. Serum levels of chromium, molybdenum, iron and ferritin were measured by Sydney South West Pathology Service. Participants with serum chromium levels outside the normal reference range underwent further analysis to evaluate chromium levels in erythrocyte haemolysate preparations (to assess the valency of abnormal chromium levels detected). Comparisons were made with two control groups; the first being individuals with scoliosis who had not undergone operative intervention and the other, “normal” unaffected volunteers. All control group participants underwent serum and erythrocyte analysis (as above). Ethics approval was obtained from the WCH Research Ethics Committee.

Results: Thirty patients (26 females and 4 males) who underwent instrumented scoliosis surgery, 10 non instrumented scoliosis patients and 10 unaffected volunteers were included in the study. Mean age of the operative group at surgery was 13.8 years (11.1–16.9) with a mean length of time from surgery of 5.8 years (3.5–8.2). In the study group, raised serum chromium levels were demonstrated in 11/30 (36.6%) of patients. Five of the 11 patients with raised chromium levels also had low levels of serum iron and/or ferritin. Erythrocyte levels of chromium were undetectable in all of the 11 (100%) patients. There did not appear to be an exogenous source of chromium exposure in any of these patients. In the non-operative control group with scoliosis, none had elevated serum chromium, iron or ferritin levels. 2/10 (20%) had high molybdenum levels. In the unaffected control group, 1/10 (10%) had raised serum chromium and molybdenum levels. Three control patients had low levels of serum iron and/or ferritin. All control participants, but one, had undetectable erythrocyte chromium levels. There was a significant difference in serum chromium levels between the study and control groups (p=0.01) with the group of patients who underwent instrumented scoliosis surgery having a greater proportion with high chromium and lower proportion with normal chromium.

Discussion: Raised serum chromium levels were detected in patients after instrumented spinal arthrodesis for scoliosis correction. This new finding in young patients has relatively unknown health implications but potential genotoxic and carcinogenic sequelae; this is especially concerning with most scoliosis patients being female and with their reproductive years ahead. These findings should prompt further research in this area, particularly to similarly investigate other spinal implant systems and assess the long term implications of raised chromium levels.