Post operative prosthetic joint infection (PJI) is the most common cause of failure of total joint arthroplasty, requiring revision surgery, but a gold standard for the diagnosis and the treatment of PIJ is still lacking [1].

SuPAR, the soluble urokinase plasminogen activation receptor, has been recently described as a powerful diagnostic and prognostic tool, able not only to detect sepsis but also to discriminate different grade of sepsis severity [2,3]

This study aimed to examine the diagnostic value of SuPAR in post operative PJI, in order to explore the possible application of this new biomarker in the early diagnosis of PJI.

The level of SuPAR have been measured in PJI patients and controls (patients undergoing prosthesis revision without infection), and correlated with pro and anti inflammatory markers (CRP C-reactive protein, IL-6, IL-1 TNFα, IL-10, IL-12, IL-8, IL1ra and the chemokine CCL2).

Statistical analysis of Receiver Operating Characteristic (ROC) curves and Area Under the Curve (AUC) was performed

As described in Figure 1, serum SuPAR displayed a strongly significative increase in PJI patients compared to not infected controls, and a significative positive correlation with C-reactive protein, IL-6, IL-1 and TNFα and the chemokine CCL2.

SuPAR displayed a very good AUC, significantly higher than CRP and IL-6 AUC

This study clearly show that the measure of Serum level of SuPAR provide a extremely important benefit because it is a precise indicator of bacterial infection, and the addition of SuPAR serum level measurement to classical inflammatory markers can strongly improve the diagnosis of prosthesis joint infection

The authors acknowledge ViroGates, Denmark for providing suPARNOSTIC Standard Kit.

The authors would also acknowledge the Italian Ministero dell’ Istruzione, Università e Ricerca (MIUR) and Italian Ministero della Salute for providing funds for this research project.

The best surgical modality for treating chronic periprosthetic shoulder infections has not been established, with a lack of randomised comparative studies. This systematic review compares the infection eradication rate and functional outcomes after single- or two-stage shoulder exchange arthroplasty, to permanent spacer implant or resection arthroplasty.

Full-text papers and those with an abstract in English published from January 2000 to June 2014, identified through international databases, were reviewed. Those reporting the success rate of infection eradication after a single-stage exchange, two-stage exchange, resection arthroplasty or permanent spacer implant were included, with a minimum follow-up of 6 months and sample size of 5 patients.

Eight original articles reporting the results after resection arthroplasty (n = 83), 6 on single-stage exchange (n = 75), 13 on two-stage exchange (n = 142) and 8 papers on permanent spacer (n = 68) were included.

The average infection eradication rate was 86.7% at a mean follow-up of 39.8 months (SD 20.8) after resection arthroplasty, 94.7% at 46.8 months (SD 17.6) after a single-stage exchange, 90.8% at 37.9 months (SD 12.8) after two-stage exchange, and 95.6% at 31.0 months (SD 9.8) following a permanent spacer implant. The difference was not statistically significant.

Regarding functional outcome, patients treated with single-stage exchange had statistically significant better postoperative Constant scores (mean 51, SD 13) than patients undergoing a two-stage exchange (mean 44, SD 9), resection arthroplasty (mean 32, SD 7) or a permanent spacer implant (mean 31, SD 9) (p=0.029). However, when considering studies comparing pre- and post-operative Constant scores, the difference was not statistically significant.

This systematic review failed to demonstrate a clear difference in infection eradication and functional improvement between all four treatment modalities for established periprosthetic shoulder infection. The relatively low number of patients and the methodological limitations of the studies available point out the need for well designed multi-center trials to further assess the best treatment option of peri-prosthetic shoulder infection.