Prosthetic joint infection (PJI) represents the second most frequent complication of total joint arthroplasty (TJA) with up to 20% of low-grade PJI treated as aseptic failure. Sensitive diagnostic criteria have been provided by EBJIS. However, to date there is no single test to reliably diagnose all PJIs. Studies of Mazzucco et al. and Fu et al. suggest that synovial fluid (SF) viscosity could be considered as an important marker for PJI. The primary aim of our study was to determine if SF viscosity is a more reliable diagnostic criterion of PJI than the SF cell count with differential (CCD), and the combined diagnostic value of SF viscosity and CCD. We prospectively analysed the viscosity of SF samples obtained during TJA of hip and knee revisions. We sampled 2.5–5mL of SF for viscosity and CCD. Intraoperatively, 1mL of the sample was analysed for the CCD. The remaining SF was centrifuged for 4min at 7000rpm. The viscosity of the supernatant was determined on Ostwald viscometer as the time required to pass the viscometer at 20°C. During each surgery at least 5 microbiological and multiple histopathological samples were harvested, and explant sonication was performed. The diagnosis was based on EBJIS definition. The viscosity threshold for detecting PJI was set at 65 seconds.Aim
Method
Two-stage replacement is a frequent procedure in patients with chronic PJI. However, results in the literature after this procedure differ, ranging from 54% to 100% of infection eradication. Positive cultures at reimplantation, when performing the second stage, are perceived as a risk factor for reinfection. This study aims to determine the impact of positive cultures during the second stage on the outcome of patients undergoing a 2-stage septic replacement and the impact of antibiotic holidays between the first and the second stage. We systematically searched four databases from inception to May 31, 2022. We combined terms related to PJI, joint replacement and culture results. We analysed the risk of failure when positive cultures at second stage and performed a subgroup analysis by antibiotic holiday period.Aim
Method
Patients with late acute periprosthetic joint infections (PJI) and treated with surgical debridement have a high failure rate. Previous studies have shown that rheumatoid arthritis (RA) is an independent risk factor for treatment failure. We conducted a case-control study to identify predictors for failure in late acute PJI treatment in RA patients. We hypothesize that patients with RA have a higher failure rate compared to controls due to the use of immunosuppressive drugs. Data of an international multicenter retrospective observational study was used. Late acute PJI was defined as a sudden onset of symptoms and signs of a PJI, more than 3 months after implantation. Failure of treatment was defined as persistent signs of infection, relapse with the same or reinfection with a different micro-organism, need for prosthesis removal or death. Cases with RA were matched with cases without RA based on the affected joint. A Cox survival analyses, stratified for RA, was used to calculate hazard ratio's (HR) for failure. Subgroup analyses were used to explore other predictors for treatment failure in RA patients.Aim
Method
Debridement, antibiotics and implant retention (DAIR) are considered as an optimal curative treatment option for prosthetic joint infection (PJI) when the biofilm is still immature and radical debridement is achievable. There are two main groups of patients suitable for DAIR. Those with an early acute PJI and patients with acute hematogenous PJI. However, there is also a third group of early PJI resulting from a wound healing problem or leaking hematoma. These may be either high or low grade depending on the microorganisms that infected the artificial joint “ We retrospectively analysed 100 successive DAIR procedures on prosthetic hip and knee joints performed between January 2010 and January 2022, from total of 21000 primary arthroplasties implanted within the same time period. We only included PJI in primary total replacements with no previous surgeries on the affected joint. Patients data (demographics, biochemical, microbiological, histopathological results, and outcomes) were collected from hospital bone and joint infection registry. The aim of surgery was radical debridement and the mobile parts exchange. The standardized antibiotic regime based on antibiofilm antibiotics.Aim
Methods
The cut-off values for synovial fluid leukocyte count and neutrophils differential (%PMN) for differentiating aseptic from septic failure in total knee arthroplasties were already defined in the past. Our goal was to determine the cut-off values for synovial fluid leukocyte count and %PMN in failed total hip arthroplasties (THA). Patients undergoing revision THA were prospectively included. In perioperative assessment phase, synovial fluid leukocyte count and %PMN were determined. During the surgery, at least 4 intraoperative samples for microbiological and one for histopathological analysis were obtained. Infection was defined as presence of sinus tract, inflammation in histopathological samples, and ≥2 tissue and/or synovial fluid samples growing the same microorganism. Exclusion criteria were systemic inflammatory diseases, revision surgery performed less than 3 months from index surgery and insufficient tissue sampling. Receiver operating characteristic (ROC) curves were constructed to assess the diagnostic performance and Youden's J statistic was computed to identify optimal cut-off values.Aim
Method
Prosthetic joint infection (PJI) presents the second most common complication of total joint arthroplasty (TJA). Accumulating evidence suggests that up to 20% of aseptic failures are low-grade PJI. However, there is still no single test to reliably diagnose all PJI. In his thesis, Mazzucco emphasized the viscosity differences between normal, osteoarthritic, and rheumatic synovial fluid. Similarly, a recent study by Fu et al. reported significantly lower viscosity in patients with PJI compared to the aseptic failure cohort. The primary aim of our study was to determine whether synovial fluid viscosity is a more reliable diagnostic criterion for PJI compared to the synovial fluid cell count with differential and serum C-reactive protein (CRP) levels. We prospectively analyzed the viscosity of synovial fluid samples obtained during TJA of hip and knee joint revision procedures. We sampled 2.5–5 mL of synovial fluid for viscosity measurement. The samples were centrifuged (4 min at 7000 rpm) and the resulting supernatant was immediately transferred into the Ostwald viscometer. Viscosity was derived from the time required for a given volume of synovial fluid to pass the viscometer at 20 °C. The synovial fluid samples were also analysed for their cell count with differential and serum CRP was measured. The definite diagnosis of PJI was established on basis of EBJIS criteria. For the viscosity, the threshold for detecting PJI was set at 65 seconds.Aim
Method
One of the most accurate and inexpensive tests in detection of prosthetic joint infection (PJI) is synovial fluid white blood cell (WBC) count and differential. Since leukocytes produce many different interleukins (IL) in situation of PJI, we hypothesized that ILs could be even more accurate in detection of PJI. The aim of the study was to test, if the synovial fluid IL-6 level is superior to WBC count and differential in detection of PJI. Unselected patients undergoing total hip or knee revision surgery were prospectively included. In perioperative assessment phase, WBC count, differential and IL-6 levels of synovial fluid were measured. Patients were labelled as positive or negative according to the predefined cut-off values for IL-6 (230pg/ml) and WBC count with differential (1,7 × 109 WBC/ml with ≥65% of granulocytes). During the surgery, at least 4 intraoperative samples for microbiological and one for histopathological analysis were obtained. PJI was defined as presence of sinus tract, inflammation in histopathological samples, and growth of the same microorganism in at least two or more samples of periprosthetic tissue or synovial fluid. Binary diagnostic test was performed to check the diagnostic strength of both methods in detection of PJI.Aim
Methods
”There is not a lot of data of the frequency and impact of unwanted events including glove perforation, contamination of the surgical field (drape perforation, laceration, detachment, bone bounced back from an unsterile object), unsterile object in the surgical field (hair, sweat droplet…), defecation, elevated air temperature, and others. Mishaps occur in every surgical theatre. These events should influence the surgical site infection rate but it is not clear to what extent. We wanted to calculate the frequency and measure the impact of these events on the infection and revision rate of the relative patients.” ”In our institution, scrub nurses prospectively record untoward events in the theatres. Surgeons register complications before discharge. Stratified failures are recorded since 2002 within a registry. We analysed the respective databases and compared the revision and infection rate in the group with untoward effects with the outcome of all arthroplasty patients within the same time period. Two tailed Z statistical test was used for analysis.”Aim
Method
Late acute prosthetic joint infections (PJI) treated with surgical debridement and implant retention (DAIR) have a high failure rate. The aim of our study was to evaluate treatment outcome in late acute PJIs treated with DAIR versus implant removal. In a large multicenter study, late acute PJIs were retrospectively evaluated. Failure was defined as: PJI related death or the need for prosthesis removal or suppressive antibiotic therapy because of persistent or recurrent signs of infection. Late acute PJI was defined as < 3 weeks of symptoms more than 3 months after the index surgery.Aim
Method
Debridement, antibiotics and implant retention (DAIR) is the recommended treatment for all acute prosthetic joint infections (PJI). However, the efficacy of DAIR and identification of risk factors for failure in patients with late acute PJI, is not well described. Patients diagnosed with late acute PJI between 2005 and 2015 were retrospectively evaluated. Late acute PJI was defined as the development of acute symptoms (≤ 3 weeks) occurring ≥ 3 months after arthroplasty. Failure was defined as: i) the need for implant removal, ii) infection related death, iii) the need for suppressive antibiotic therapy due to persistent signs of infection and/or iv) relapse or reinfection during follow-up.Aim
Method
Treatment of enterococcal periprosthetic joint infections (PJI) is challenging due to heterogeneous pathogenesis, non-standardized management strategies and lack of biofilm-active antibiotics. Previous studies report treatment success from 50–76%. We evaluated the characteristics and outcome of enterococcal PJI, in particular the influence of antimicrobial treatment regimens. Consecutive patients with enterococcal PJI treated at two specialized orthopaedic institutions were retrospectively included from 2010 to 2017. PJI was defined by the proposed European Bone and Joint Infection Society (EBJIS) criteria. Adequate antimicrobial treatment was considered when the antibiotic was appropiate for the treatment of enterococcal bone infections (activity, dose, oral bioavailability, bone penetration). The treatment success (defined as no relapse of enteroccal infection) and clinical success(i.e. infection-free status) was evaluated and compared using Fishers exact test.Aim
Method
Optimum position of pedicle screws can be determined preoperatively by CT based planning. We conducted a comparative study in order to analyse manually determined pedicle screw plans and those that were obtained automatically by a computer software and found an agreement in plans between both methods, yet an increase in fastening strengths was observed for automatically obtained plans. Automatic planning of pedicle screw positions and sizing is not inferior to manual planningSummary
Hypothesys
Total hip arthroplasty (THA) is one of the most successful surgical procedures ever performed. Nevertheless if procedure is performed by high or low volume surgeons; more than 50% of cups are still placed out of the safe zone, which is connected to lower survival rate of the prosthesis. The idea was to develop an imageless navigation system for safe and accurate positioning of the cup in THA procedures, without a need of any preoperative computer tomography (CT) or magnetic resonance imagining (MRI). The validation of the system was approved by National Ethics Committee. The committee allowed the validation on 10 patients who all signed the agreement for participation in the study. Unselected patients undergoing THA were included. All patients had had performed preoperative x-rays of pelvis and hips for standard preoperative planning. Immediately before skin incision, anterior pelvic plane (APP) was defined with help of specially developed electromagnetic navigation system (Guiding Star, E-Hip module, Ekliptik d.o.o., Ljubljana, Slovenia) and specificaly designed hardware tool which is essential for accurate APP determination [Fig.1]. In all patients THAs were performed through direct lateral approach and all implanted components (Allofit S cup and Alloclassic stem, Zimmer Inc., Warsaw, Indiana, USA) were implanted with freehand technique according to preoperative plan. After placement of the cups their inclination and anteversion angles were determined with aforementioned navigation system [Fig. 2]. The day after surgery, low dose CT scans of pelvises of operated patients were performed and DICOM format files were up-loaded into EBS software (Ekliptik d.o.o., Ljubljana, Slovenia), a multipurpose application for perioperative planning, measuring and constructing where virtual copies of pelvises were generated. On virtual pelvises the position of the cups was measured by independent person [Fig.3]. Measurements were compared, statistically analysed and the deviation calculated with root mean square error (RMSE) method. Afterwards the average error (eaver) and standard deviation (σ) between intraoperatively determined and postoperatively measured angles were calculated.Background
Methods
