Periprosthetic joint infections (PJI) are challenging complications following arthroplasty. Staphylococci are a frequent cause of PJI and known biofilm producers. Reoperations for PJI of the hip or knee between 2012 and 2015 performed at Sahlgrenska University Hospital were identified. Medical records were reviewed, and clinical parameters recorded for patients whose intraoperative bacterial isolates had been stored at the clinical laboratory. Staphylococcal strains isolated from reoperations due to first-time PJI were characterised by their ability to form biofilms using the microtiter plate test. The study group included 49 patients (70 bacterial strains) from first-time PJI, whereof 24 (49%) patients had recurrent infection. Strong biofilm production was significantly associated with recurrent infection. Patients infected with strong biofilm producers had a five-fold increased risk for recurrent infection. Strong biofilm production was significantly associated with increased antimicrobial resistance and PJI recurrence. This underscores the importance of determining biofilm production and susceptibility as part of routine diagnostics in PJI. Strong staphylococcal biofilm production may have implications on therapeutic choices and suggest more extensive surgery. Furthermore, despite the increased biofilm resistance to rifampicin, results from this study support its use in staphylococcal PJI

Aims. Current treatments of prosthetic joint infection (PJI) are minimally effective against Staphylococcus aureus biofilm. A murine PJI model of debridement, antibiotics, and implant retention (DAIR) was used to test the hypothesis that PlySs2, a bacteriophage-derived lysin, can target S. aureus biofilm and address the unique challenges presented in this periprosthetic environment. Methods. The ability of PlySs2 and vancomycin to kill biofilm and colony-forming units (CFUs) on orthopaedic implants were compared using in vitro models. An in vivo murine PJI model of DAIR was used to assess the efficacy of a combination of PlySs2 and vancomycin on periprosthetic bacterial load. Results. PlySs2 treatment reduced 99% more CFUs and 75% more biofilm compared with vancomycin in vitro. A combination of PlySs2 and vancomycin in vivo reduced the number of CFUs on the surface of implants by 92% and in the periprosthetic tissue by 88%. Conclusion. PlySs2 lysin was able to reduce biofilm, target planktonic bacteria, and work synergistically with vancomycin in our in vitro models. A combination of PlySs2 and vancomycin also reduced bacterial load in periprosthetic tissue and on the surface of implants in a murine model of DAIR treatment for established PJI. Cite this article: Bone Joint J 2020;102-B(7 Supple B):3–10

Aims. The aims of this study were to develop an in vivo model of periprosthetic joint infection (PJI) in cemented hip hemiarthroplasty, and to monitor infection and biofilm formation in real-time. Methods. Sprague-Dawley rats underwent cemented hip hemiarthroplasty via the posterior approach with pre- and postoperative gait assessments. Infection with Staphylococcus aureus Xen36 was monitored with in vivo photoluminescent imaging in real-time. Pre- and postoperative gait analyses were performed and compared. Postmortem micro (m) CT was used to assess implant integration; field emission scanning electron microscopy (FE-SEM) was used to assess biofilm formation on prosthetic surfaces. Results. All animals tolerated surgery well, with preservation of gait mechanics and weightbearing in control individuals. Postoperative in vivo imaging demonstrated predictable evolution of infection with logarithmic signal decay coinciding with abscess formation. Postmortem mCT qualitative volumetric analysis showed high contact area and both cement-bone and cement-implant interdigitation. FE-SEM revealed biofilm formation on the prosthetic head. Conclusion. This study demonstrates the utility of a new, high-fidelity model of in vivo PJI using cemented hip hemiarthroplasty in rats. Inoculation with bioluminescent bacteria allows for non-invasive, real-time monitoring of infection. Cite this article: Bone Joint J 2021;103-B(7 Supple B):9–16

Aims. Periprosthetic joint infections (PJIs) with prior multiple failed surgery for reinfection represent a huge challenge for surgeons because of poor vascular supply and biofilm formation. This study aims to determine the results of single-stage revision using intra-articular antibiotic infusion in treating this condition. Methods. A retrospective analysis included 78 PJI patients (29 hips; 49 knees) who had undergone multiple prior surgical interventions. Our cohort was treated with single-stage revision using a supplementary intra-articular antibiotic infusion. Of these 78 patients, 59 had undergone more than two prior failed debridement and implant retentions, 12 patients had a failed arthroplasty resection, three hips had previously undergone failed two-stage revision, and four had a failed one-stage revision before their single-stage revision. Previous failure was defined as infection recurrence requiring surgical intervention. Besides intravenous pathogen-sensitive agents, an intra-articular infusion of vancomycin, imipenem, or voriconazole was performed postoperatively. The antibiotic solution was soaked into the joint for 24 hours for a mean of 16 days (12 to 21), then extracted before next injection. Recurrence of infection and clinical outcomes were evaluated. Results. A total of 68 patients (87.1%) were free of infection at a mean follow-up time of 85 months (24 to 133). The seven-year infection-free survival was 87.6% (95% confidence interval (CI) 79.4 to 95.8). No significant difference in infection-free survival was observed between hip and knee PJIs (91.5% (95% CI 79.9 to 100) vs 84.7% (95% CI 73.1 to 96.3); p = 0.648). The mean postoperative Harris Hip Score was 76.1 points (63.2 to 92.4) and Hospital for Special Surgery score was 78. 2 (63.2 to 92.4) at the most recent assessment. Polymicrobial and fungal infections accounted for 14.1% (11/78) and 9.0% (7/78) of all cases, respectively. Conclusion. Single-stage revision with intra-articular antibiotic infusion can provide high antibiotic concentration in synovial fluid, thereby overcoming reduced vascular supply and biofilm formation. This supplementary route of administration may be a viable option in treating PJI after multiple failed prior surgeries for reinfection. Cite this article: Bone Joint J 2022;104-B(7):867–874

Prosthetic joint infections (PJIs) with prior multiple failed surgeries for re-infection (PMFSR) represented a huge challenge for surgeons because of poor vascular supply and biofilm formation. This study aims to determine the results of single-stage revision using intra-articular antibiotic infusion for treatment of PJIs with PMFSR. A retrospective analysis included 78 PJIs (29 hips; 49 knees) with PMFSR, who were treated with single-stage revision using intra-articular antibiotic infusion. Previous failure was defined as infection recurrence requiring surgical intervention. Besides intravenous pathogen-sensitive agents, a intra-articular infusion of vancomycin, imipenem or voriconazole was performed post-operatively. The antibiotic solution was soaked into the joint for 24 hours then extracted before next injection. Recurrence of infection and clinical outcomes were evaluated. Of these 78 patients, 59 had more than twice failed debridement and implant retentions, 12 patients had a failed arthroplasty resection, 3 hips underwent a failed two-stage revision and 4 cases had a failed one-stage revision before their single-stage revision. A total of 68 patients (87.1%) were free of infection at a mean follow-up time of 85 months. No significant difference in infection control rate was observed between hip and knee PJIs (89.7% versus 85.7%). The mean postoperative Harris hip score was 76.1 points and HSS score was 78. 2 at the most recent assessment. Single-stage revision with intra-articular antibiotic infusion can provide high antibiotic concentration in synovial fluid therefore overcome poor vascular supply and biofilm formation, which can be a viable option in treating PJI with PMFSR

Introduction. PJI is a devastating complication following total joint arthroplasty. In this study, we explore the efficacy of a bacteriophage-derived lysin, PlySs2, against in-vitro biofilm on titanium implant surfaces and in an acute in-vivo murine debridement antibiotic implant retention (DAIR) model of PJI. Methods. In-vitro: Xen 36 S. aureus biofilm was grown on Ti-6Al-4V mouse tibial implants for 1 day or 5 days and subsequently exposed to growth media, 1000× minimal inhibitory concentration (MIC) Vancomycin, or 5× MIC PlySs2. Implants were sonicated and analyzed for Colony Forming Units (CFU). In-vivo: A Ti-6Al-4V implant was inserted into the proximal tibia of C57BL/6J mice (n=21). All mice received 10. 4. CFU inoculation of Xen 36 S. aureus to the knee joint capsule and the infection was permitted 5 days to progress. On day 5 the mice were separated into three groups (n=7/group): (1) no further surgical intervention (control group), (2) irrigation and debridement (I&D) with saline, (3) I&D with 2mg/mL PlySs2. No implant-exchange was performed to mimic a debridement, antibiotic, and implant retention (DAIR) therapeutic strategy. All mice were sacrificed at day 10. Results. CFU counts for 1-day and 5-day in-vitro grown biofilm on implants demonstrate a >3log-fold reduction with PlySs2 compared to Vancomycin (p=0.01) with no significant difference between Vancomycin and control. In-vivo the addition of PlySs2 to Vancomycin treated mice reduces bacterial load in the periposthetic tissue and implant (p<0.05) with 5 days of treatment. Conclusion. PlySs2 5× MIC exhibits superior anti-microbial effect compared to Vancomycin on implants with 1-day and 5–5day biofilm maturities. The addition of PlySs2 to Vancomycin treatment of an acute established PJI further reduces tissue CFU and implants CFU. For any tables or figures, please contact the authors directly

Introduction. We studied free (= local powder) tobramycin and doxycycline, and controlled release (= local lipid bilayer) doxycycline formulations in a rat model representing a generic joint infection. We . hypothesized. that evidence of infection (quantitative colony forming units (CFU), qualitative SEM, histopathology) (1a) would be reduced with local vs. systemic antibiotic, (1b) any antibiotic would be superior to control (2) there would be a difference among antibiotics, and (3) antibiotic would not be detectable in serum at 4-week euthanasia. Methods. Study groups. included infected and non-infected (1) control, (2) systemic ceftriaxone (daily), (3) local tobramycin, (4) local doxycycline and (5) controlled release doxycycline. With IACUC approval, (10 rats/group; power =0.8), 50-μl, 10×4 CFU Staphylococcus aureus, slowly injecting into distal femoral medullary canal, reliably created joint infection. Antibiotic formulation was introduced locally into cavity and joint, pin was inserted, and tissues closed. After 4-weeks, serum, pin, bone and synovium were obtained. CFU/ml of bone and synovium were quantified using macrotiter method. SEM imaged biofilm on surface of pin, histopathology identified tissue response, liquid chromatography/mass spectrometry measured plasma antibiotic. Kruskal-Wallis one-way ANOVA compared groups. Results. Groups receiving antibiotic reported lower CFU/ml in synovium compared with control (no treatment) group (1b), but there was no difference between systemic, free or controlled antibiotics (1a). Different results with different antibiotics were shown, with free tobramycin reducing CFU/ml to a greater extent than free doxycycline in the synovium (2) (p<0.05). Antibiotic in plasma was nondetectable all groups (3). SEM revealed some biofilm on pin in all groups. . Limitations. include inoculation method, single observation period, administration of only one bacterial and antibiotic dose, and not including pairing local and systemic antibiotic. Conclusion. There was no difference in infection reduction nor detectable antibiotic in serum for any antibiotic formulation, but CFU's in synovium differed based on antibiotic formulation. For any tables or figures, please contact the authors directly

Introduction. Tantalum trabecular metal components are increasingly used to reconstruct major bone defects in revision arthroplasty surgery. It is known that some metals such as silver have antibacterial properties. Recent reports have raised the question as to whether Tantalum components are protective against infection in revision surgery. This is based on a retrospective, single institution review, of revision cases comparing tantalum with titanium acetabular implants, which reported a lower incidence of subsequent infection in the tantalum group. This laboratory study aimed to establish if tantalum had any intrinsic antibacterial properties against planktonic bacteria or ability to inhibit biofilm formation. Materials and methods. Equal sized pieces of tantalum (Trabecular metal, Zimmer UK) and titanium (Trilogy, Zimmer UK) were sterilised and then incubated with a low dose inoculum of either Staphylococcus aureus or Staphylococcus epidermidis for 24 hours. After serial dilution, colony forming units were quantified on MH agar plates. To establish the ability to inhibit biofilm formation these tantalum and titanium pieces were then washed twice, sonicated and washed again to remove loosely adhered planktonic bacteria. They were then re-incubated for 24 hours prior to quantifying colony forming units. All experiments were performed in triplicate. Results. More than 1×10. 8. cfu/ml were observed in both the titanium and tantalum experiments. After washing and sonication more than 2×10. 7. cfu/ml were observed for both tantalum and titanium groups. The results were the same for both Staph Aureus and Staph Epidermidis. Discussion. Compared with titanium controls tantalum did not demonstrate any intrinsic antibacterial activity or ability to inhibit biofilm formation. The intrinsic properties of tantalum do not account for the previously observed reduction in subsequent infection when tantalum was used in the revision procedure. Conclusion. Tantalum does not have any intrinsic antimicrobial properties or ability to inhibit biofilm formation

Introduction. Debridement, antibiotics, and implant retention (DAIR) for acute prosthetic hip infection is a popular low morbidity option despite less than optimal success rates. We theorized that the delay between DAIR and explantation in failed cases may complicate eradication due to biofilm maturation and entrenchment of bacteria in periprosthetic bone. We ask, what are the results of two-stage reimplantation after a failed DAIR versus an initial two-stage procedure?. Methods. 114 patients were treated with 2-stage exchange for periprosthetic hip infection. 65 were treated initially with a 2-stage exchange, while 49 underwent an antecedent DAIR prior to a 2-stage exchange. Patients were classified according to MSIS host criteria. Failure was defined as return to the OR for infection, a draining sinus, or systemic infection. Results. Treatment failure occurred in 42.9% (21 of 49) of patients treated with an antecedent DAIR. In contrast, treatment failure occurred in only 12.3% (8 of 65) of initial 2-stage procedures (p< 0.001). Relative Risk of return to the OR after a 2-stage reimplantation with an antecedent DAIR compared to initial resection was 4.52 (95% CI 1.71, 11.9). MSIS host grading was similar between groups and did not influence the rate of failure. The DAIR cohort had increased hospitalization length and greater number of operative procedures (p< 0.001). Conclusion. We have shown that if irrigation and debridement fails to treat acute prosthetic hip infection, subsequent attempts at two-stage reimplantation may be compromised. Additionally, in the antecedent DAIR group, the average number of infection-related procedures (5) was nearly twice that of those initially resected (2.7). This by nature implies a significantly greater burden to the patient and cost to the healthcare system

Aims. Tantalum (Ta) trabecular metal components are increasingly used to reconstruct major bone defects in revision arthroplasty surgery. It is known that some metals such as silver have antibacterial properties. Recent reports have raised the question regarding whether Ta components are protective against infection in revision surgery. This laboratory study aimed to establish whether Ta has intrinsic antibacterial properties against planktonic bacteria, or the ability to inhibit biofilm formation. Materials and Methods. Equal-sized pieces of Ta and titanium (Ti) acetabular components were sterilised and incubated with a low dose inoculum of either Staphylococcus (S.) aureus or S. epidermidis for 24 hours. After serial dilution, colony forming units (cfu) were quantified on Mueller-Hinton agar plates. In order to establish whether biofilms formed to a greater extent on one material than the other, these Ta and Ti pieces were then washed twice, sonicated and washed again to remove loosely adhered planktonic bacteria. They were then re-incubated for 24 hours prior to quantifying the number of cfu. All experiments were performed in triplicate. Results. More than 1x10. 8. cfu/ml were observed in both the Ta and Ti experiments. After washing and sonication, more than 2x10. 7. cfu/ml were observed for both Ta and Ti groups. The results were the same for both S. aureus and S. epidermidis. Conclusion. Compared with Ti controls, Ta did not demonstrate any intrinsic antibacterial activity or ability to inhibit biofilm formation. Hence, intrinsic antimicrobial properties of Ta do not account for the previously observed reduction in the frequency of subsequent infections when Ta was used in revision procedures. . Cite this article: Bone Joint J 2017;99-B:1153–6

Reliability of microbiological diagnosis of prosthetic joint infection [PJI] strongly depends on the ability to dislodge microorganisms from biofilm and on the rate of contaminating samples during collection in the operating room and processing. The aim of a correct protocol is to avoid false negative and false positive results in order to adapt the correct therapy for each patient. The object of the present study was to evaluate the impact of a novel closed bag system designed for samples collection and processing based on dithiothreitol (DTT), which is a sulfydryl compound able to remove bacteria from biofilm (MicroDTTect, 4i, Italy), on isolation of contaminant microorganisms in hip prostheses. Specimens (prostheses, spacers, periprosthetic tissues) were aseptically collected according to a standard protocol into the device, which was transported to the laboratory for culture. Three different models of the system were prospectively evaluated, each being a development of the previous one. The first generation device consisted in an “open” system (DTT eluate was collected with a syringe and dispensed into sterile tubes), the second generation device in a “partially closed” system (DTT eluate collected directly in sterile vacuum tubes) and the third generation device in a “completely closed system” (DTT reservoir directly connected with sealed tubes inside the device). PJI was diagnosed following criteria established by MSIS. The overall contamination rate, sensitivity and specificity of the first generation “open” system MicroDTTect were respectively 2.6% (1/39), 82.3% and 95.4% in 39 hips. The second generation “partially closed” device was characterized by a contamination rate of 1.96% (1/51), a sensitivity of 84% and a specificity of 96.1% in 51 hips. Contamination rate further decreased in the third generation “closed” system (1.89%, 2/106), while sensitivity (91.3%) and specificity (96.7%) improved in 106 hips. Differences have been also observed in hips (106) when compared to knees (70 cases) prosthetic infections (sensitivity 91.3% vs 89.3% and specificity 96.7% vs 100%). Our data show as, thanks to its ease of use, low contamination rate and high sensitivity, MicroDTTect can represent a useful tool for improving the microbiological diagnosis of PJIs in hip revisions and has replaced sonication in our practice

Introduction. Ultra-high molecular weight polyethylene (UHMWPE) can provide local sustained delivery of therapeutics. 1,2. For example, it can deliver analgesics to address post-arthroplasty pain. 2. Given that several analgesics, such as bupivacaine (anesthetic) and tolfenamic acid (NSAID), were shown to possess antibacterial activity against Staphylococci, we hypothesize that analgesic-loaded UHMWPE can also yield antimicrobial effects, preventing the development of periprosthetic joint infections. Methods. Bupivacaine and tolfenamic acid were incorporated into UHMWPE via phase-separated compression molding. Drug release from the prepared samples was measured using high-performance liquid chromatography. Antibacterial studies of the obtained materials were conducted against methicillin-sensitive, and methicillin-resistant S. aureus, as well as S. epidermidis. Time-kill curves were obtained to characterize antimicrobial activity against planktonic bacteria. The dynamics of bacterial adhesion were assessed to characterize antibiofilm activity. Scanning electron microscopy (SEM) was used to visualize adherent bacteria. Anticolonizing activity of the tested materials was characterized using the “daughter cell” method as outlined elsewhere. 3. Cytotoxicity profile of drug-loaded UHMWPEs was evaluated using MG-63 osteoblast cell line. Results. The bupivacaine release rate generally increased with increasing drug loading (e.g. a model knee implant loaded with bupivacaine would release ca. 15–500 mg over 24 hours). While also proportional, drug release from UHMWPE loaded with tolfenamic acid was much lower. The bacterial viability curves showed that bupivacaine-loaded UHMWPE possessed moderate antibacterial activity against planktonic MSSA, MRSA, and S. epidermidis, slowing bacteria proliferation by up to 70%. Bupivacaine-loaded UHMWPE also mitigated biofilm formation and development during the initial culture period. SEM images confirmed the observed antibiofilm effect (Fig. 1). Tolfenamic acid-loaded UHMWPE allowed proliferation of planktonic bacteria. At the same time, these materials showed pronounced dose-dependent anticolonizing activity against tested strains, providing 3-log reduction of “daughter” cells. Bupivacaine- and tolfenamic acid-loaded UHMWPEs showed little-to-no cytotoxicity against osteoblasts. Discussion & Conclusions. We demonstrated for the first time that bupivacaine-loaded UHMWPE possesses dose-dependent antibacterial properties against planktonic and adherent MSSA, MRSA, and S. epidermidis – pathogens commonly associated with periprosthetic joint infections. Pronounced anticolonizing activity was evident for tolfenamic acid-loaded UHMWPE. Due to the low solubility of tolfenamic acid, the material's antibacterial effect against planktonic bacteria was lower. These results demonstrate that analgesic-loaded UHMWPE, used as a tool in multimodal pain management, can also yield antibacterial effects, opening an entirely new avenue for providing post-arthroplasty antibacterial prophylaxis. This pioneering approach has a potential to reduce patients' morbidity and mortality after arthroplasty. For any tables or figures, please contact the authors directly

Aims

Periprosthetic joint infection (PJI) in total hip arthroplasty in the elderly may occur but has been subject to limited investigation. This study analyzed infection characteristics, surgical outcomes, and perioperative complications of octogenarians undergoing treatment for PJI in a single university-based institution.

Aims

The aims of this study were to determine the incidence and factors for developing periprosthetic joint infection (PJI) following hemiarthroplasty (HA) for hip fracture, and to evaluate treatment outcome and identify factors associated with treatment outcome.

Aims

Femoral cement-in-cement revision is a well described technique to reduce morbidity and complications in hip revision surgery. Traditional techniques for septic revision of hip arthroplasty necessitate removal of all bone cement from the femur. In our two centres, we have been using a cement-in-cement technique, leaving the distal femoral bone cement in selected patients for septic hip revision surgery, both for single and the first of two-stage revision procedures. A prerequisite for adoption of this technique is that the surgeon considers the cement mantle to be intimately fixed to bone without an intervening membrane between cement and host bone. We aim to report our experience for this technique.

Aims

The purpose of this study was to evaluate unexpected positive cultures in total hip arthroplasty (THA) revisions for presumed aseptic loosening, to assess the prevalence of low-grade infection using two definition criteria, and to analyze its impact on implant survival after revision.

Aims

To explore the effect of different types of articulating antibiotic-loaded cement spacers in two-stage revision for chronic hip prosthetic joint infection (PJI).

Aims

Vitamin E-infused highly crosslinked polyethylene (VEPE) has been introduced into total hip arthroplasty (THA) with the aim of further improving the wear characteristics of moderately and highly crosslinked polyethylenes (ModXLPE and HXLPE). There are few studies analyzing the outcomes of vitamin E-infused components in cemented arthroplasty, though early acetabular component migration has been reported. The aim of this study was to measure five-year polyethylene wear and acetabular component stability of a cemented VEPE acetabular component compared with a ModXLPE cemented acetabular component.

Aims

The aim of this study was to investigate whether the use of antibiotic-loaded bone cement influenced the risk of revision surgery after primary total hip arthroplasty (THA) for osteoarthritis.

Aims

Of growing concern in arthroplasty is the emergence of atypical infections, particularly Cutibacterium (formerly Propionibacterium) sp. infections. Currently, the dermal colonization rate of Cutibacterium about the hip is unknown. Therefore, the aim of this study was to investigate colonization rates of Cutibacterium sp. at locations approximating anterior and posterolateral approaches to the hip joint.