Purpose of the study: Increasing the number of times the operating room doors open increases the number of airborne bacteria and consequently the rate of postoperative infections with sometimes disastrous results, particularly for prosthesis surgery.

Material and methods: An observer counted the number of times the door to the operating room were opened during orthopaedic operations. The study was conducted in a teaching hospital (hospital A) during scoliosis surgery then repeated for a similar operation after posting dissuasive signs and delivery of information to the personnel concerning the risk of contaminating the patient. A study was then conducted for total hip arthroplasty (THA) in another teaching hospital (hospital B) and in a private clinic (hospital C). The same protocol as used in South Australia was applied for these studies.

Results: The mean rate of door opening in hospital A was 0.52/min. This rate was 0.45/min (13.5% less) in the same hospital A after posting dissuasive signs on the doors and providing information to the personnel. In hospital B, the rate was 0.67/min. In hospital C, the rate was 0.42/min (i.e. 37% less). In Australia, the mean rate was 1/min in hospital A before sign posting and information delivery and 0.65 (−35%) after. In hospital B, the rate was 0.87/min and in hospital C 0.47/min (i.e. 46% less).

Discussion: Nearly 50 years ago Sir John Charnley demonstrated that airborne contamination must be controlled in prosthetic orthopaedic surgery. In France airborne contamination is regulated by a series of standards (NF EN ISO 14644 established in 1999) and partially controlled during the design phase of operating rooms with the installation of laminar flow ventilation. Door opening, and particularly swinging doors, causes turbulent airflow increasing bacterial contamination.

Conclusion: Circulation in the operating room should be limited to necessary organisation (prior transport of instruments and consumables, fluoroscope, nursing staff turnover, etc.) and by information and education of all participants. The presence of observers is inevitable in the operating rooms of teaching hospitals. Their entrance and exit should however be limited and their movement within the room controlled. It is also recommended to use cell phones.

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.

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.

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.