Culture negative prosthetic joint infections (PJI) still remain an issue even the advantages in PJI diagnosis. This is the reason why some orthopedic surgeons fear to use preoperative antibiotic prophylaxis when a PJI is suspected. The purpose of the present study was to evaluate the influence of preoperative antibiotic prophylaxis in intraoperative cultures

An enhanced diagnostic protocol for PJI (Zimmerli criteria) was used for the inclusion criteria in order to collect all PJI accounted in a University Hospital. Patients were prospectively randomized in two groups.

The control group received the classical preoperative antibiotic prophylaxis. The study group did not receive prophylaxis prior to surgery

There were 14 patients in each group. They correspond to 13 infections of total hip arthroplasty (THA), 12 infections of total knee arthroplasty (TKA) and 3 reverse shoulder prosthesis (RSA) infections. There were 10 patients in the study group and 10 patients in the control group with at least one positive microbiological criterion. There were 8 patients in each group with culture negative PJI (p>0.05)

Preoperative antibiotic prophylaxis does not affect intraoperative cultures in suspected or confirmed PJI. Therefore it is essential to deliver antibiotic prophylaxis in any patient in which prosthesis is to be implanted in order to protect the prosthesis from infection

Introduction: Prostheses radiolucent lines are currently used to evaluate the components fixation. The objective of this study is to determine concordance and reproducibility of humeral stem radiolucent lines evaluation.

Material and method: Five observers evaluated 64 x-ray belonging to 32 pairs (1 antero-posterior view and 1 outlet view) obtained from 16 shoulder prostheses. 16 x-ray pairs were obtained immediately after surgery and 16 one year after surgery. Evaluation in four degrees of radiolucent width for each of the 7 zones that the humeral component was divided for. Evaluation of the component-cement interface and the cement-bone interface. Each observer made two evaluations of the 64 x-ray separated in 6 weeks. Statistics : index kappa with quadratic weighting.

Results: Intra-observer results: mean kappa index for component-cement interface: 0,3274. mean kappa index for cement-bone interface: 0,5269. Inter-observer results: mean kappa index for component-cement interface: 0,1242. mean kappa index for cement-bone interface: 0,2478. Evaluation of 2 pairs of x-ray of the each prostheses taken in a period of 1 year: component-cement interface: mean of 91,67% of plausible results, cement-bone interface: mean of 80,2% of plausible Results:

Conclusions:

- low kappa index of reproducibility (0,3274–0,5269) of humeral component radiolucent lines evaluation for component-cement interface as well as for cement-bone interface.