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.