Administration of perioperative antibiotic prophylaxis (AP) reduces the risk of prosthetic joint infection (PJI) following primary total hip (THA) and knee (TKA) arthroplasty. The optimal type of antibiotic used, and duration of prophylaxis are subject to debate. We compared the risk of revision surgery for PJI in the first year following THA and TKA by AP regimen. A national survey collecting information on hospital-level AP regimen policy was conducted across the Netherlands and linked to data from the LROI arthroplasty registry for 2011–2015. PJI status was defined using the surgical indication reported at revision by surgeons in the registry form. Restricted cubic splines Poisson model adjusted for hospital clustering were used to conduct the comparisons on 130,712 THAs and 111,467 TKAs performed across 99 institutions. These included 399 THAs and 303 TKAs revised for an indication of PJI. Multiple shot of Cefazolin (MCZ), of cefuroxime (MCX) and single shot of Cefazolin (SCZ) were respectively administrated to 87%, 4% and 9% of patients. For THA, the rates of revision for PJI were respectively 31/10,000 person-years 95%CI[28, 35], 39[25, 59] and 23[15, 34] in the groups which received MCZ, MCX and SCZ; respectively, the rates for TKA were 27[24, 31], 40[24, 62] and 24[16, 36]. No evidence of difference between AP regimens was found in the unadjusted and adjusted model (age, gender, BMI and ASA grade). Further work is advocated to confirm whether there is an association between AP regimen collected at patient-level and the risk of subsequent revision for PJI.

Joint replacement is a highly effective intervention to treat osteoarthritis of the hip, relieving pain and improving mobility and quality of life.(1) Periprosthetic joint infection (PJI) is a devastating complication after arthroplasty. Debridement, antibiotics and implant retention are treatment of first choice in case of early infection after total hip arthroplasty (THA).(2) In case of persisting infection, one- or two-stage revision needs to be performed.(3) The use of different kinds of spacers has been widely debated in the past years.(4)

The aim of this study was to determine which type of spacer should be used during the interval of two-stage revision of an infected THA.

A search term with Boolean operators was constructed. We extracted all information regarding study and patient characteristics and baseline clinical and laboratory findings. Data regarding type of spacer and antibiotics used, timing of second stage surgery, tissue culture results, postoperative regimen, functional outcome and patient satisfaction were extracted.

A total of twenty-six studies met our inclusion criteria and were included for data analysis. Ten studies described various preformed spacers, six studies described functional spacers and eleven studies described custom made spacers. See Table 1 for results.

Research should focus on finding the preferred type of treatment and type of spacer to combine a high success rate of infection treatment with a good functional and patient reported outcome. There is a need for a prospective study evaluating patient satisfaction and functional outcome after two-stage revision THA comparing various spacers. Secondly, research should focus on the optimal timing of the second stage procedure.

Functional spacers achieve a comparable rate of infection eradication in the treatment of periprosthetic hip joint infections as compared to preformed spacers. There is insufficient evidence concerning rehabilitation and functional outcome after two-stage revisionTHA to advocate or discourage the use of either kind of interval spacer.

The use of platelet-leukocyte gel (PLG), made from platelet rich plasma, to stimulate bone formation and wound healing has been investigated extensively. As leukocytes play an important role in the innate host-defence, we hypothesised that PLG might also have antimicrobial properties.

The purpose of this study was to investigate the antimicrobial activity of PLG against Staphylococcus aureus in an in vitro experiment. To determine the contribution of myeloperoxidase (MPO), present in leukocytes, in this process, MPO release was measured.

Platelet rich plasma (PRP) was prepared from whole blood of 6 donors. In this process platelet poor plasma (PPP) was obtained as well. PLG was prepared by mixing PRP with either autologous (PLG-AT) or bovine thrombin (PLG-BT). The antimicrobial activity of PLG-AT, PLG-BT, PRP and PPP was determined in a bacterial kill assay, containing 1x106 CFU/ml of Staphylococcus aureus, during a 24-hour period. MPO release was measured by ELISA.

Cultures showed a rapid decrease in the number of bacteria in the presence of both PLG-AT and PLG-BT, which was maximal between 4 and 8 hours, to approximately 1% of the bacteria in controls. Also PRP and PPP induced a statistically significant bacterial kill, but the effect of PLG-AT was the largest (p=0.093 vs. PLG-BT; p=0.004 vs. PRP and p< 0.001 vs. PPP). PLG-AT, PLG-BT and PRP showed a comparable, gradually increasing MPO release for 8 to 12 hours. Some MPO was also measured in the PPP samples. No correlation between MPO release and bacterial kill could be found.

PLG appears to have potent antimicrobial capacity, but the role of MPO in this activity is questionable. PLG might represent a useful strategy against postoperative infections. Further research should investigate its antimicrobial capacity in the in vivo situation.

A new type of metallic silver bone cement was previously shown to be effective against both antibiotic sensitive and resistant bacteria.

In this study the efficacy of silver bone cement in preventing methicillin- sensitive Staphylococcal infections was compared with plain and tobramycin-containing bone cement, in a rabbit contaminated implant bed model.

In 48 rabbits 0.6%-silver, 1%-silver, plain or tobramycin-loaded (tobra) PMMA bone cement (Simplex^®P; Howmedica, Ireland) was injected into the medullary canal of the right femur after contamination of the implant bed with 105, 106 or 107 colony forming units (CFU) of Staphylococcus aureus. After 14 days bone was collected, homogenised and plated on blood agar plates. After an overnight incubation the number of CFU’s was counted. Bone was also collected for pathological analysis.

The plain and silver cement rabbits were all infected, whereas with tobra cement only 2 rabbits (17%) were infected (p< 0.001). The number of bacteria cultured from bone adjacent to the cement, was 6.4±0.3 and 6.1±0.3 for the 0.6% and 1%-silver rabbits. For the rabbits with plain and tobra cement this was 6.2±0.2 (p> 0.95) and 0.0±0.0 (p< 0.001). Two tobra rabbits had a positive culture of a distal bone sample. Histological sections of plain, 0.6% and 1%-silver cement rabbits all showed signs of infection; these signs were absent in the tobra rabbits.

Silver cement was not effective in preventing infection. However, in the current model bacteria are present directly at and distant from the implant surface, whereas silver cement predominantly exhibits an antimicrobial effect at the direct cement surface. The non-eluting silver cement seems less useful in situations where there are also bacteria present in surrounding tissues, like revision surgery. Whether silver cement has relevance in preventing bacterial colonization of cement, for instance in late haematogenous infections, or not remains to be seen.