Joint aspiration is a useful tool during preoperative workup in suspected periprosthetic infection. The aim of this study was to review efficacy of joint aspiration in our unit and compare results with the published literature.

We undertook a retrospective review of 153 consecutive patients who underwent joint aspirations for suspected periprosthetic infection between 03/2011 and 10/2012 who were identified from the hospital electronic database. As per protocol, joint fluid was sent in an EDTA tube for cell count, Paediatric blood culture bottle and the remainder in a specimen pot.

105 (69%) were TKRs and 48 (31%) were THRs. Intraoperative samples were sent as per protocol in only 40 (26%) cases. The hit rate of positive cultures was 11/153 (7%) and specimens sent in paediatric culture bottles identified more positives than if it was omitted (10.5 Vs 5.5%).

In conclusion, the hit rate of positive cultures is low in this study compared to the literature (7% Vs 33%) and this is likely due to blanket aspiration of all patients who are undergoing revision. In addition, specimens sent in paediatric culture bottles seem to identify more positives. We recommend cases are selected for aspiration according to AAOS guidelines.

We compared the use of broth culture medium for samples taken in theatre with the standard practice of placing tissue samples in universal containers. A total of 67 consecutive patients had standard multiple samples of deep tissue harvested at surgery and distributed equally in theatre either to standard universal containers or to broth culture medium. These samples were cultured by direct and enrichment methods. The addition of broth in theatre to standard practice led to an increase in sensitivity from 83% to 95% and an increase in negative predictive value from 77% to 91%. Placing tissue samples directly into broth in the operating theatre is a simple, inexpensive way to increase the sensitivity of cultures from infected patients, and does not appear to compromise the specificity of these cultures.

Cite this article: Bone Joint J 2014;96-B:1566–70.

Aim. Propionibacterium acnes is an emerging pathogen especially in orthopedic implant infection. Interestingly, we previously reported a difference in the distribution of the clades involved in spine versus hip or knee prosthetic infection. To date, no study has previously explored the direct impact and close relationship of P. acnes on bone cells according to their own genetic background. The aim of this study was to investigate this interaction of P. acnes clinical strains involved in spine material infections, arthroplasty infections and acne lesions with bone cells. Method. From a large collection of 88 P. acnes clinical isolates collected between January 2003 and December 2014, a subset of 11 isolates was studied. Four isolates were recovered from spine infections, two from prosthetic infections (knee and hip), three from acne lesions and two reference strains (ATCC11827 and ATCC6919). Implant-associated infections were confirmed according to Infectious Diseases Society of America guidelines for bone and joint infections. Multi-Locus Sequence Typing (MLST) was carried out on all isolates as described by Lomholt et al. PLoS ONE 2010. Bacterial internalization experiments with MG63 osteosarcoma cells were adapted from Crémet et al. Pathog Dis 2015. Results. Among the nine clinical isolates, three isolates belonged to clonal complexes (CCs) 18; three to CC28 and three to CC36. ATCC isolates belonged to CC18. Bacterial internalization experiments revealed that CC36 P. acnes strains were less invasive than CC18 and CC28 P. acnes strains towards osteoblasts (mean percentage of internalized bacteria (< 0.01% for the CC36 P. acnes strains versus more than 1% for the CC18 and CC28 P. acnes strains). Surprisingly, the ATCC11827 CC18 P. acnes strain exhibited invasiveness similar to CC36 isolates. Conclusions. Evasion mechanism observed for CC36 P. acnes isolates could allow this clade to leave the site of infection, disseminate into deeper tissue layers and beget arthroplasty infection. Inside the deeper tissue, close to the material, the local immune defect fosters the low-grade infections observed with P. acnes clinical strains. On the another hand, for CC18 et CC28 clades, mostly involved in spine infection, the internalization process observed could allow these clades to escape from the numerous immune cells located under the skin and generate an infection locally, favored by the spine instrumentation close to the skin, especially during long spine surgeries

Infection is a complication in hip arthroplasty. It increases mortality and morbidity and is a cause for patient's dissatisfaction. Previous Works report an infection rate between 0,4% e 1,5% in primary hip replacement and between 3,2% in revision hip replacement. The aim of this work was to access the infection rates in one hospital, compare them with the reported rates and investigate possible risk factors for infection. Electronic clinical records were consulted. Patients who underwent total hip arthroplasty (primary or revision) or hemiarthroplasty in one hospital, between the 1st February 2011 and 31st February 2013, were included. Two hundred and sixty one patients (267 surgeries) were included. Demographically, 57,5% were female patients and 42,5% were male patients with an average age of 77,1 years (± 12,3 years). Infection rate for hemiarthroplasty 3,1%, for primary total hip arthroplasty was 1,4% and for revision procedures 4,8%. A statistically significant relation was found between arthroplasty infection and superficial wound infection (p<0,001), wound dehiscence (p<0,001), and surgery performed during summer months (p<0,05). No relation was found with duration of the surgery or the hospital stay or the patient's comorbidities. The infection rate is similar to the rate reported in other clinical centres. Superficial wound complications are a good predictor for arthroplasty infection, so it is important to diagnose and start prompt appropriate management and vigilance. The increase in infection rates in summer months may be related to higher operating room temperature or less routined personal. We concluded, therefore, that infection is a complication in hip arthroplasty being prevention is a key feature when arthroplasty is performed, as well as clinical vigilance for infection signs

In bone and joint infections, several materials can be used for local antibiotic elution at site of infection. Polymethylmethacrylate (PMMA) cement is often used. Recently the use of antibiotic impregnated dissolvable synthetic pure calcium sulphate beads [Stimulan R]1 has been used as an alternative, due to several perceived advantages. We present our experience of using Calcium sulphate beads in infections involving the upper limb. From Jan 2012 to Jan 2015, we used Calcium sulphate beads in 7 complex upper limb infections including 1 elbow replacement, 2 infected non unions, 2 shoulder replacement, 1 wrist fusion and I ORIF elbow. We used combination of Vancomycin and Gentamicin in the beads, using manufacturer's mixing guide for optimum setting. Arthroplasty infections underwent explantation, addition of antibiotic impregnated calcium sulphate beads in the joint space, followed by a second stage, and systemic antibiotics. Fracture non-union cases had surgical debridement, calcium sulphate beads and systemic antibiotics. Follow up (6months to 2 years) indicate no recurrence of infection in any case. The most common organisms isolated were Coagulase negative staphylococcus and Staphylococcus aureus. Others included Group B Streptococcus, Serratia marscesens and Corynebacterium spp. In 2 of 7 cases there was significant drainage from the wound. This settled without further input. For fracture non-union fixation, there was no need to do second procedure to remove beads as they dissolve. In cases of staged revisions, the beads were inserted at first stage with microbiological clearance at 2nd stage. At present there are no reports in the literature of the use of this product in the upper limb. Our experience suggests use of dissolvable pure Calcium sulphate beads impregnated with selected antibiotics, is an effective adjunct to current treatments. Aseptic drainage has been reported and this was seen in some of our cases. It is postulated that the use of Calcium sulphate beads in more superficial joints may lead to more drainage. It may be necessary to avoid packing any beads in the subcutaneous spaces and using lower volumes in upper limb. Further work will include long-term follow up and any evidence of relapse or recurrence of infection

Bone and joint infections of the lower limbs cause significant morbidity for patients. Infection is a devastating complication for prosthetic joint replacements. In this large case series from a single centre in the NE of England, we present our experience of using antibiotic impregnated dissolvable synthetic pure calcium sulphate beads [Stimulan R]1 for local elution of antibiotics at the site of infection. At our centre, from August 2012 to Jan 2015, antibiotic impregnated dissolvable synthetic pure calcium sulphate beads [Stimulan R]1 was used for local elution of antibiotics in 45 patients with lower limb bone or joint infections. Tailored plans were made by Orthopedic surgeon and Microbiologist MDTs based on bacteria and sensitivities. Cases included 20 THR, 13 TKR, 5 Hemiarthroplasties, 4 tibial nonunions, 1 infected femoral plate and 2 paediatric osteomyelitis. Organisms isolated – Coagulase negative Staphs, Staph aureus, MRSA, E coli, Enterococcus, Enterobacter cloacae, Serratia and 1 Salmonella typhimurium!!. In our cases, a combination of Vancomycin and Gentamicin was added to Stimulan beads following manufacturer's mixing guide. In 2 cases, we added Ceftazidime to the beads and Daptomycin in 1 case. In bone infections, surgical debridement and systemic antibiotics were also needed. All arthroplasty infections underwent explantation with addition of antibiotic impregnated beads either at single stage or both stages of 2 stage revisions and systemic antibiotics. Follow up (ranging 9months to 2 years) indicates no failure so far. The beads caused no excessive wound drainage. There was no need to remove beads as they dissolve. In the cases where a staged revision was performed, the beads were inserted at first stage and there was microbiological clearance of infection at 2nd stage. Our series includes some experince in paediatric cases too. As far as we are aware, this is the largest series in the UK from a single centre reporting experience with Stimulan in infected bone and joints of the lower limbs. Our experience suggests use of dissolvable pure Calcium sulphate beads impregnated with carefully selected antibiotics, works as an effective adjunct to current treatments and offers flexibility with choice of antiobiotics that can be added locally. Acknowledgements. Biocomposites UK for supporting attendance at EBJIS. Authors control ownership of all data and analysis

Propionibacterium acnes is an emerging pathogen especially in orthopedic implant infection. Aim of this study was to investigate P. acnes phylogeny and to screen for virulence factors among a large collection of clinical isolates involved in spine material infections, arthroplasty infections and acne lesions. 88 P. acnes clinical isolates were collected between January 2003 and December 2014 at Nantes University Hospital (France). Fifty-eight isolates came from spine infections, 14 from prosthetic infections (knee, hip or shoulder), 14 from acne lesions and two reference strains (ATCC11827 and ATCC6919). Implant associated infections were confirmed using Infectious Diseases Society of America criteria for bone and joint infections. Phylotypes and Multi-Locus Sequence Typing (MLST) was carried out on all isolates as described by Lomholt et al. All isolates were tested by established PCR-based assays for 21 putative virulence factor genes characteristic of P. acnes. MLST analysis revealed an association between clonal complexes (CCs) and origin of P. acnes isolates (p = 0,027). Regarding CCs distribution between different origins, CC36 and phylotype II P. acnes isolates are more frequently observed in prosthetic joint infections. On the other hand, CC18 (IA) and CC28 (IB) P. acnes isolates are more frequently involved in spine infections and acne lesions. Among all virulence factors screened, hyaluronate lyase gene was only present in CC36 and phylotype II P acnes isolates. Other virulence factors were present in all isolates, whatever their origin or CC. Regarding molecular typing results, P. acnes involved in spine infections seem to have a skin origin (same CC as isolates from acne lesion). Interestingly, the origin of prosthetic joint infection isolates seems different and they all carry one more virulence factor. Hyaluronate lyase (Hyl) is a major surface protein of P. acnes with potential antigenetically variable properties that might be essential for P. acnes virulence. Increased tissue permeability caused by the action of hyaluronidase on the extracellular matrix appears to play a role in wound infections, pneumonia, and other sepsis such as bacteremia and meningitis. It could be also take a prominent part in P. acnes prosthetic joint infection pathogenesis

Objective. Bacterial infection is a serious complication after joint replacement surgery. In particular, methicillin-resistant Staphylococcus aureus (MRSA) and epidermidis(MRSE) are very difficult to eradicate in infected prosthetic joint. Therefore, the retention rate of initial prosthesis affected with such resistant microorganisms is still low. Gentian violet shows potent antibacterial activity against gram-positive cocci as minimal bactericidal concentration is less than 0.1 %. In the present study, we investigated the efficacy of treatment with gentian violet against MRSA and MRSE infections after THA, TKA, and bipolar hip hemiarthroplasty (BHP). Methods. There were 8 patients in this study; five patients with deep periprosthetic MRSA infection (2 THA, 2 BHP, 1 revision TKA); 3 patients with MRSE infection (1 revision THA, 1 BHP, 1 TKA). When infection was suspected after the surgery, we quickly obtained synovial fluid and periprosthetic soft tissue from the joint and applied to culture and microscopic examinations for detection of microorganisms. After identification of bacterial species, we immediately debrided the affected joint and washed thoroughly twice with 0.1% solution of gentian violet for 3 minutes each, followed by intra-articular multiple injection of arbekacin sulfate solution. Then we inserted an aspiration tube into the joint and administered appropriate antibiotics intravenously. If the inflammatory symptoms persisted in spite of the first treatment, we repeated the treatment until inflammation signs and intra-articular microorganisms could not be detected. Results. At first we examined the bactericidal activity of gentian violet solution against MRSA and MRSE by culture examination with or without the solution. We confirmed gram-negative bacillicould be alive but the both MRSA and MRSE could not be alive by the treatment with 0.01 % solution of gentian violet for 3 minutes. The treatment with gentian violet allowed subsidence of the infection in all patients. Furthermore, we could preserve 4 prostheses with MRSA infection; 1 THA, 1 revision TKA and 2 BHPs; 2 prostheses with MRSE infection; 1 TKA, 1BHP. However, we could not preserve 2 prostheses, 1 THA with MRSA infection and 1 revision THA with MRSE infection. Thus, the prosthetic retention rate of this study for MRSA and MRSE infections was 75 %. We performed two-stage operation for the 2 patients in whom we could not preserve the prostheses as follows: after excision of the infected total hips followed by successful reimplantation. Moreover, all of the patients in this study are able to keep the walking ability after joint replacements. Conclusion. Infection of methicillin-resistant Staphylococcus species after joint replacement surgery has tended to increase. Gentian violet exerts a potent antibacterial activity against such microorganisms at the concentration of less than 0.1 %. We obtained good retention rate by the treatment using gentian violet against MRSA and MRSE infections after the joint surgeries. In addition, both MRSA and MRSE have not showed drug resistance for gentian violet. Therefore, we suggest that gentian violet will become a promising adjunct agent for infection after joint replacement surgery not only methicillin-sensitive but also methicillin–resistant Staphylococcus species

We conducted a randomised, controlled trial to determine whether changing gloves at specified intervals can reduce the incidence of glove perforation and contamination in total hip arthroplasty. A total of 50 patients were included in the study. In the study group (25 patients), gloves were changed at 20-minute intervals or prior to cementation. In the control group (25 patients), gloves were changed prior to cementation. In addition, gloves were changed in both groups whenever there was a visible puncture. Only outer gloves were investigated.

Contamination was tested by impression of gloved fingers on blood agar and culture plates were subsequently incubated at 37°C for 48 hours. The number of colonies and types of organisms were recorded. Glove perforation was assessed using the water test. The incidence of perforation and contamination was significantly lower in the study group compared with the control group. Changing gloves at regular intervals is an effective way to decrease the incidence of glove perforation and bacterial contamination during total hip arthroplasty.