AO POSSI, surgical site prevention program

Surgical site infection (SSI) after trauma—Will prevention measures make a difference?

Stephen Kates, Virginia Commonwealth University Richmond, USA
Gonzalo Bearman, Virginia Commonwealth University Richmond, USA
AO Clinical Investigation and Documentation, AO Foundation, CH

Recognizing the challenges posed by bone infections, AO Trauma has defined it as the focus of its current clinical priority program (CPP). The Bone Infection CPP aims to achieve a better understanding of bone infections, provide solutions for the most pressing clinical problems, and have a positive impact on patient care. AO multicenter intervention trial to evaluate the impact of a bundle of measures for the prevention of surgical site infection in fracture patients (AO POSSI) is a multicenter international prospective community trial under the umbrella of the CPP. The purpose of this study is to evaluate the effectiveness of the AO Trauma surgical site infection prevention bundle (AOT SSI Prevention Bundle). In this study, the surgical site infection (SSI) rate before (pre-intervention phase) and after (post-intervention phase) the implementation of the bundle will be obtained and compared. The study hypothesizes that after the successful implementation of the AOT SSI Prevention Bundle, SSI may be reduced from 5 to 3.75 percent in closed fractures and from 10 to 7.5 percent in open fractures. Secondary objectives include 1) to evaluate the surgeon satisfaction with the bundle and the success of its implementation, 2) to perform a health economic analysis, and 3) to identify predictive factors of infection.

The current target sample size is 8,476 patients (4,238 patients for each phase) to be enrolled from 10 to 14 clinics. This sample size was calculated based on an assumption of the pre-intervention infection rates (5 percent in closed fracture and 10 percent in open fractures). At the end of the pre-intervention phase, the baseline infection rate will be assessed and, if necessary, the sample size will be adapted.

This study is currently by far the largest, and maybe the most complicated and most ambitious, clinical study conducted by AO CID. It is off to a good start: five study sites have received ethics approval and eight more sites are in the process of ethics submission or revision. In addition, a REDCap Cloud study database has been set up and is ready to receive patient data.

The pillars of the CPP Bone Infection

Host-pathogen interaction

Learn about how S. aureus adapts to the environment of an implant-associated infection.


Read about the development of new tools to assess implant-associated infections.


Explore how the CPP Bone Infection is running its surgical site prevention program.

Prophylaxis and treatment

Learn about treatment and prevention of implant-associated infections.


Explore the educational program of the CPP Bone Infection.


Read about the first international bone infection registry.


Check the publications of the CPP Bone Infection