Mitigating calcar fracture risk with automated impaction during total hip arthroplasty.

Background: Automated broaching has recently been introduced for total hip arthroplasty (THA), with the goal of improving surgical efficiency and reducing surgeon workload. While studies have suggested that this technique may improve femoral sizing and alignment, little has been published regarding its safety, particularly with regard to calcar fractures. The purpose of our study was to evaluate the risk of calcar fracture during automated broaching, and to determine if this risk can be mitigated. Methods: We queried our prospective institutional database and identified 1596 unilateral THAs performed by the senior author using automated impaction between 2019 and 2023. We identified the incidence of calcar fracture with automated impaction, and whether the fracture occurred during broaching or stem insertion. We additionally determined calcar fracture incidence within two consecutive subgroups of patients using different stem insertion techniques; subgroup (1): automated broaching with automated stem insertion for all patients; versus subgroup (2): automated broaching with automated stem insertion ONLY if a cushion of cancellous bone separated the broach from the calcar, otherwise the stem was placed manually. Continuous and categorical variables were analyzed with Student's t-test and Fisher's exact test, respectively. Results: Seventeen calcar fractures occurred intraoperatively (1.1 %). Only two fractures occurred during automated broaching (0.1 %), while fifteen occurred during final stem impaction (0.9 %) (p = 0.007). Four calcar fractures (1.4 %) occurred in subgroup 1, compared to two in subgroup 2 (0.6 %) (p = 0.28). Conclusions: Our study found a calcar fracture incidence of 1.1 % using automated impaction, consistent with historically reported rates of 0.4-3.7 %. We found that calcar fractures are more likely to occur during stem insertion than during femoral broaching. We recommend that if any part of the final broach is in direct contact with the calcar, the final stem should be impacted manually to minimize fracture risk.

Diagnosis of periprosthetic loosening of total hip and knee arthroplasty using 68Gallium-Zoledronate PET/CT.

PURPOSE: Periprosthetic loosening is a major complication after total hip and knee arthroplasty. Early and accurate diagnosis is essential to choose the right therapeutic path and to avoid further complications. The aim of the study was to evaluate the diagnostic performance of 68Gallium-Zoledronate ([68Ga]Ga-DOTAZol) PET/CT in detecting periprosthetic loosening in total hip (THA) and total knee arthroplasty (TKA). METHODS: This retrospective study included 26 patients with painful prosthesis (THA n = 17; TKA n = 16) and clinical suspicion of periprosthetic loosening, but without a confirmed diagnosis. Patients underwent [68Ga]Ga-DOTAZol PET/CT at least one year post-implantation. Diagnosis was confirmed through revision surgery or long-term clinical follow-up, with an observation period of at least 6 months. The analysis included both an assessment of the prosthesis as a unit and a separate evaluation of the individual components. Statistical analysis involved calculating sensitivity, specificity and accuracy using SPSS. RESULTS: Overall, a sensitivity of 77.8%, a specificity of 95.8% and an accuracy of 90.9% were found for detecting periprosthetic loosening, when considering the prosthesis as a unit. Individual component analyses showed a sensitivity of 71.4% and specificity of 96.2%. CONCLUSION: The use of [68Ga]Ga-DOTAZol PET/CT in periprosthetic loosening is a remarkable diagnostic tool and a promising approach. In comparison to established radionuclide tracers, 68Gallium-Zoledronate offers notable advantages due to its availability via 68Ge/68Ga-generators, improving its potential for clinical application.

NCB-PP® locking plates outcomes in the treatment of periprosthetic femoral fractures. Analysis of a retrospective cohort of 89 patients.

INTRODUCTION: The management of periprosthetic femoral fractures is particularly complex in an elderly, frail population, with an increasing incidence due to the increase in femoral prosthesis surgery. The use of locking plates is now widely recommended. The primary objective of this study was to present the results of NCB-PP® locking plates in the management of periprosthetic femoral fractures. The secondary objective was to determine the influence of weight-bearing time on morbidity and mortality and on walking ability. The hypothesis of this study was that NCB-PP® plates would provide radio-clinical results equivalent to those reported in the literature with no influence of time to re-weighting on complication rate and walking level at 1 year post-operatively. MATERIALS AND METHODS: 89 patients (mean age 81 ± 11.9 (28-99), with a female predominance 62/89 (69.7%)) underwent 89 periprosthetic femur fractures (74 THA, 11 TKA and 4 interprosthetic) and treated with NCB-PP® plates were retrospectively included between January 2014 and September 2022. Patients were then divided into 2 groups according to the time to postoperative full weight bearing: "immediate" (n = 30) and "delayed" (n = 59) (a minimum of 6 weeks post-operatively). RESULTS: The mean follow-up time was 14.6 months. At 6 months post-operatively, 91.8% of patients were consolidated. At 1 year, 36.2% had resumed independent walking, 8.7% required one crutch, 13% two crutches, 33.3% walked with a walker and 8.7% were considered non-walkers. There were 12 complications (13.5%), including 7 mechanical (7.9%) and 5 infections (5.6%), with 10 patients (11.2%) requiring a revision surgery. Mortality at 6 months and 1 year was respectively 9 and 12.4%. There was no significant difference between pre- and post-operative walking levels (p = 0.45). There was no influence of the time to reweighting on the level of walking at 1 year (p = 0.874), on complications (p = 0.17) or on mortality at 1 year (p > 0.99). CONCLUSION: This study confirms the initial hypothesis and the results of preliminary studies on a smaller sample size regarding bone union of periprosthetic femoral fractures with NCB-PP® plates, with a low rate of mechanical complications. The proportion of patients returning to their previous walking level remains low, but early full weight bearing is still possible without increasing the rate of mechanical complications. LEVEL OF EVIDENCE: IV; retrospective cohort study.

Effect of pH and hydroxyapatite-like layer formation on the antibacterial properties of borophosphate bioactive glass incorporated poly(methyl methacrylate) bone cement.

Infection is a leading cause of total joint arthroplasty failure. Current preventative measures incorporate antibiotics into the poly (methyl methacrylate) (PMMA) bone cement that anchors the implant into the natural bone. With bacterial resistance to antibiotics on the rise, the development of alternative antibacterial materials is crucial to mitigate infection. Borate bioactive glass, 13-93-B3, has been studied previously for use in orthopedic applications due to its ability to be incorporated into bone cements and other scaffolds, convert into hydroxyapatite (HA)-like layer, and enhance the osseointegration and antibacterial properties of the material. The purpose of this study is to better understand how glass composition and change in surrounding pH effects the composite's antibacterial characteristics by comparing the incorporation of 30% wt/wt 13-93-B3 glass and pH neutral borophosphate bioactive glass into PMMA bone cement. We also aim to elucidate how HA-like layer formation on the cement's surface may affect bacterial adhesion. These studies showed that 13-93-B3 incorporated cements had significant reduction of bacterial growth surrounding the composite beyond 24 h of exposure when compared to a neutral borate bioactive glass incorporated cement (p < 0.01) and cement only (p < 0.0001). Additionally, through soaking cement composites in simulated body fluid and then exposing them to a bioluminescent strand of staphylococcus aureus, we found that the presence of a HA-like layer on the 13-93-B3 or pH neutral glass incorporated cement disks resulted in an increase in bacterial attachment on the composite cement's surface, where p < 0.001, and p < 0.05 respectively. Overall, our studies demonstrated that borate bioactive glass incorporated PMMA bone cement has innate antimicrobial properties that make it a promising material to prevent infection in total joint arthroplasties.

A Case of Severe Acute Kidney Injury Due to an Antibiotic-Loaded Cement Spacer for Infected Knee Arthroplasty.

The treatment for periprosthetic joint infection frequently involves the placement of a high-dose antibiotic-loaded bone cement spacer (ALCS) into the debrided joint. Typical antibiotics in the spacer include aminoglycosides and vancomycin. It has been believed that systemic absorption of intraarticular antibiotics would be low and early experience suggested that the risk of acute kidney injury (AKI) from ALCS was minimal. However, recent case reports and case series have suggested a risk of acute kidney injury due to antibiotic absorption, though confounding factors are common. We report a case of severe AKI requiring hemodialysis with extremely high systemic tobramycin levels after the placement of an ALCS with increased dosing of antibiotics after previous failure to resolve a periprosthetic joint infection with a prior ALCS. There was no concomitant use of intravenous nephrotoxic antibiotics nor other confounding factors. Despite dialysis, the patient needed urgent removal of the ALCS to control tobramycin levels with subsequent resolution of the AKI. This case highlights the potentially serious nephrotoxicity of ALCS's, the importance of antibiotic type and dosing, and the value of close monitoring after ALCS placement, especially in a patient with chronic kidney disease.

Are Red Blood Cell Distribution Width and Platelet Count Useful for Diagnosing Periprosthetic Joint Infection in Patients Undergoing Re-Revision Arthroplasty.

OBJECTIVE: Accurate and prompt identification of periprosthetic joint infections (PJIs) is critical prior to re-revision arthroplasty to ensure optimal surgical outcomes. Among routinely measured blood indices, red blood cell distribution width (RDW) and platelet count (PLT) have shown strong correlations with infection presence. This study aimed to assess the utility of RDW and PLT for diagnosing PJI in patients scheduled for re-revision arthroplasty. METHODS: This retrospective research encompassed all patients who underwent re-revision hip or knee arthroplasty at our institution from 2008 to 2022. Participants were categorized into either the PJI (n = 41) or the non-PJI (n = 47) group following the guidelines established in the 2013 International Consensus Meeting on PJI. In this analysis, RDW and PLT counts were evaluated alongside conventional inflammatory markers, including C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). The efficacy of these diagnostics was evaluated by the area under the receiver operating characteristic (ROC) curve ([area under the curve AUC]). RESULTS: RDW demonstrated a modest AUC of 0.678 with sensitivity at 61.0% and specificity at 71.7%, using a threshold of 14.5%. PLT was on par with ESR, showing an AUC of 0.773, and both sensitivity and specificity around 73% at a threshold of 201 × 109/L. CRP presented the highest diagnostic accuracy with an AUC of 0.815, achieving a sensitivity of 82.9% and specificity of 73.9% at a 6.9 mg/L threshold, surpassing ESR's AUC of 0.754. None of the biomarkers, individually or combined, outperformed CRP alone (p > 0.05). CONCLUSIONS: In the context of re-revision arthroplasty, RDW and PLT demonstrate limited efficacy as diagnostic biomarkers for PJI. However, CRP retains its reliability as a biomarker when the diagnostic threshold is appropriately recalibrated.

Atypical Vancouver B1 periprosthetic fracture of the proximal femur in the United Kingdom: a case report challenged by myeloma, osteoporosis, infection, and recurrent implant failures.

The indications for total hip replacement are increasing and not limited to osteoarthritis. Total hip replacement may also be done for trauma and pathological fractures in patients otherwise physiologically fit and active. This trend has led to an inevitable rise in complications such as periprosthetic femoral fracture. Periprosthetic femoral fracture can be challenging due to poor bone quality, osteoporosis, and stress fractures. We present a case of periprosthetic femoral fracture in a 71-year-old woman with some components of an atypical femoral fracture. The fracture was internally fixed but was subsequently complicated by infection, implant failure needing revision, and later stress fracture. She was on a bisphosphonate after her index total hip replacement surgery for an impending pathological left proximal femur fracture, and this may have caused the later stress fracture. Unfortunately, she then experienced implant breakage (nonunion), which was treated with a biplanar locking plate and bone grafting. The patient finally regained her premorbid mobility 13 months after the last surgery and progressed satisfactorily towards bony union.

Enhanced Risk of 90-Day Medical and 2-Year Implant Related Complications in Total Shoulder Arthroplasty Patients with Osteoporosis.

BACKGROUND: As the average age of patients undergoing shoulder arthroplasty (SA) increases, the frequency of SA patients with osteoporosis is expected to rise. While the effects of osteoporosis have been described in the broader orthopedic literature, it is presently unclear how osteoporosis affects SA postoperative medical and implant-related outcomes. METHODS: A multicenter database TriNetX was queried for patients between 2011-2021 who underwent SA with and without osteoporosis. Patients with less than 2-years of follow-up and those with a prior shoulder hemiarthroplasty were excluded. Primary outcomes included 2-year periprosthetic joint infection (PJI), prosthesis dislocation, periprosthetic fracture, and revision surgery. Secondary outcomes included 90-day medical complications and readmissions. Osteoporotic and control patient cohorts were propensity matched in a 1:1 ratio. RESULTS: 7,842 patients were included after matching in each cohort. Baseline demographic variables were similar between groups, except osteoporotic patients had a lower BMI (28.6 vs 31.0 kg/m2; p < 0.001). Osteoporotic patients undergoing SA were more likely to experience wound disruptions, stroke, pulmonary embolism, deep vein thrombosis, myocardial infarction, anemia, pneumonia, renal failure, transfusion, and readmission within 90 days after surgery. At 2 years postoperative, osteoporotic SA patients experienced an elevated risk of mechanical loosening, PJI, dislocation, periprosthetic fracture, and required revision surgery at a higher rate than control patients. CONCLUSIONS: Osteoporotic patients undergoing shoulder arthroplasty are at greater risk for medical complications within the 90-day peri-operative period as well as implant-related complications within 2 years of surgery. Patients and surgeons should be aware of the potential higher risk of complications in osteoporotic patients following SA, and further investigation into benefits of preoperative management and treatment of osteoporosis is necessary.

Perioperative Glycemic Variability Influences Infection Rates Differently Following Revision Hip and Knee Arthroplasty.

INTRODUCTION: Recent investigations have determined that abnormal postoperative glycemia following primary total joint arthroplasty is associated with adverse events. Our study aimed to determine if hyperglycemia and glycemic variability following aseptic revision total joint arthroplasty (rTJA) were associated with periprosthetic joint infection (PJI) within two years postoperatively. METHODS: A retrospective review was performed of 2,208 patients within a single institution undergoing aseptic rTJA from 2012 to 2019. Postoperative glucose values were recorded. Glycemic variability was measured via three parameters: coefficient of variation (%CV), mean amplitude of glycemic excursions (MAGE), and J-index. Logistic regression analyses were performed to examine associations with PJI at 90-day, 1-, and 2-year follow-up. RESULTS: In revision hips, all glycemic measures were not associated with PJI at any timepoint in logistic regression analyses, except for MAGE, which predicted PJI at one year (P = 0.045); body mass index (BMI) was the only factor associated with PJI at all timepoints in all models. In revision knees, all glycemic measures were not associated with PJI at any timepoint in logistic regression analyses; however, PJI rates differed between diabetics and non-diabetics at all time-points (P < 0.05). CONCLUSIONS: Our findings illustrate that decreasing preoperative BMI and postoperative glycemic variability may be critical in reducing PJI rates in revision hips. Furthermore, patients who have diabetes should be counseled that they remain at higher risk of PJI regardless of perioperative glucose control after revision knee surgery.

Risk factors for mortality in periprosthetic femur fractures about the hip-a retrospective analysis.

PURPOSE: Fractures around the hip are known to be an indicator for fragility and are associated with high mortality and various complications. A special type of fractures around the hip are periprosthetic femur fractures (PPF) after Total Hip Arthroplasty (THA). The aim of this study was to investigate the mortality rate associated with PPF after THA and to identify risk factors that may increase it. METHODS: Consecutive patients (N = 158) who were treated for a PPF after THA in our university hospital between 2010 and 2020 were identified and mortality was assessed using the residential registry. Univariate (Kaplan-Meier-Estimator) and multivariate (Cox-Regression) statistical analysis was performed to identify risk factors influencing mortality. RESULTS: One-year-mortality rate was 23.4% and 2-year mortality was 29.2%. Mortality was significantly influenced by age, gender, treatment, type of comorbidity and time of surgery (p < 0.05). Surgical treatment during regular working hours (8 to 18 h) reduced mortality by 53.2% compared to surgery on call (OR: 0.468, 95% CI 0.223, 0.986; p = 0.046). For every year of age, mortality risk increased by 12.9% (OR: 1,129, 95% CI 1.078, 1.182; p < 0.001). The type of fracture according to the Vancouver classification had no influence on mortality (p = 0.179). Plate fixation and conservative treatment were associated with a higher mortality compared to revision arthroplasty (plate: OR 2.8, 95% CI 1.318, 5.998; p = 0.007; conservative: OR 2.5, 95% CI 1.421, 4.507; p = 0.002). CONCLUSION: Surgical treatment during regular working hours is associated with lower mortality compared to surgery outside these hours. In this retrospective cohort, time to surgery showed no significant impact on all-cause mortality, and revision arthroplasty was associated with lower mortality than conservative treatment or plate fixation. LEVEL OF EVIDENCE: IV (Retrospective cohort study).

Total Femoral Replacement in Periprosthetic Femur Fracture: A Case Report.

Total femur replacement (TFR) is one of the most extensive endoprosthetic reconstruction procedures. The most common indication for the use of total femoral replacement is limb salvage in malignant bone tumors of the femur. This procedure is rarely performed outside the paradigm of oncological limb reconstruction. With the increased incidence of total hip and total knee replacements, complications of these procedures are also on the rise. Cases of complicated revision arthroplasties with severe bone loss, infection, and comminuted periprosthetic fractures may not have adequate residual bone stock for satisfactory fixation of megaprosthesis. With limited reconstruction options, most of these cases are offered lower limb amputation. TFR can be used as a limb salvage option in place of amputation in such cases. There have been a few case reports of TFR for non-oncological indications in the literature. We present a case of periprosthetic comminuted distal femur fracture with a loose megaprosthesis following a road traffic accident (RTA), which was managed with TFR. At four years of follow-up, the patient showed good radiological as well as clinical outcomes.

High-Dose Compound Betamethasone Used in Local Infiltration Analgesia Does Not Increase Reinfection Rates Following Periprosthetic Joint Infection Treatment.

BACKGROUND: The administration of cocktails that contain glucocorticoids for local infiltration analgesia (LIA) is highly advocated and has been shown to be effective in managing pain in total joint arthroplasty (TJA). However, it remains ambiguous whether this protocol maintains its safety and efficacy in the treatment of periprosthetic joint infection (PJI), a devastating complication of TJA. METHODS: A comprehensive retrospective study was carried out on 299 single-stage revision cases for PJI spanning the years 2010 to 2021. Of these, 127 received LIAs containing high-dose compound betamethasone (CB) were termed the CB group, and the other 172 were termed the non-CB group. The rates of reinfection and other postoperative complications, along with postoperative visual analog scale (VAS) scores, and opioid consumption were compared. RESULTS: During minimum 2-year follow-up, there was no significant difference in the reinfection rate between the non-CB and CB groups (9.3 versus 8.7%; P = 0.85), consistent within the subsets of hip (8.4 versus 4.5%; P = 0.51) and knee (10.4 versus 13.3%; P = 0.60) PJIs individually. The administration of high-dose CB was neither an independent risk factor for reinfection (P > 0.05; 95% CI [confidence interval] including 1) nor was it associated with the occurrence of reinfection (P > 0.05). The incidence of postoperative nausea and vomiting (PONV) was significantly lower in the CB group (P < 0.05). In the initial 48-hour postoperative period, the CB group exhibited lower mean scores in both resting and movement VAS evaluations (P < 0.05). Notably, the movement VAS scores of the CB group remained lower even at 72 hours post-surgery for knee PJIs (P < 0.001). Furthermore, within the first 72 hours post-surgery, the necessity for additional opioid analgesics in the CB group was significantly reduced compared to the non-CB group (P < 0.05). CONCLUSION: A LIA with a high-dose compound betamethasone reduces postoperative pain, opioid consumption, and the incidence of PONV following a single-stage revision without affecting reinfection and other complication rates.

Systemic iodine levels increase with povidone-iodine irrigation, but does this affect thyroid functions? A case-control study.

BACKGROUND: Intraoperative irrigation with diluted povidone iodine (PI) can be used to reduce the incidence of infection-related complications in arthroplasty surgeries. Since PI is associated with many interventions, especially skin antisepsis, its systemic effects are being studied. The aim of our study is to evaluate the systemic effects of PI, which we use as an irrigation solution, by means of urine iodine and thyroid function tests. METHODS: In this case-control study, 96 patients who underwent knee or hip arthroplasty were included and divided into two groups according to the irrigation solution. In the first group, PI was added to the standard irrigation. The second group was considered as the control group and only standard irrigation was applied. Urine iodine, thyroid stimulating hormone, free T3 and free T4 values were compared in the preoperative and postoperative periods of these two groups. In this way, the effect of absorbed iodine on thyroid functions was investigated. RESULTS: In the diluted PI group, urinary iodine levels were measured at maximum levels (450 µg/L) in the early postoperative period in most of the patients. The statistically significant difference in urinary iodine levels between the PI group and the control group, which started in the early postoperative period, continued until the last follow-up on the 14th postoperative day. In terms of thyroid functions, the observed differences were not statistically significant. CONCLUSION: Studies to reduce periprosthetic infection show that PI can be preferred for irrigation before the closure of the joint area in total joint arthroplasty. Although the success of this treatment in periprosthetic infection has been investigated, its systemic examination has not been demonstrated. It was determined that PI treatment, which was seen to decrease in the systemic circulation within 14 days, did not show a statistically significant change in terms of thyroid functions when used at the determined concentration and duration. These results should be evaluated with larger and longer-term studies. TRIAL REGISTRATION: Clinical trials ID no. NCT05599841.

Combining Multiple Spectroscopic Techniques to Reveal the Effects of Staphylococcus aureus Infection on Human Bone Tissues.

Osteomyelitis (OM) and periprosthetic joint infections (PJIs) are major public health concerns in Western countries due to increased life expectancy. Infections usually occur due to bacterial spread through fractures, implants, or blood-borne transmission. The pathogens trigger an inflammatory response that hinders bone tissue regeneration. Treatment requires surgical intervention, which involves the precise removal of infected tissue, wound cleansing, and local and systemic antibiotic administration. Staphylococcus aureus (SA) is one of the most common pathogens causing infection-induced OM and PJIs. It forms antimicrobial-resistant biofilms and is frequently found in healthcare settings. In this proof-of-concept, we present an approach based on multiple spectroscopic techniques aimed at investigating the effects of SA infection on bone tissue, as well as identifying specific markers useful to detect early bacterial colonization on the tissue surface. A cross-section of a human femoral diaphysis, with negative-culture results, was divided into three parts, and the cortical and trabecular regions were separated from each other. Two portions of each bone tissue type were infected with SA for one and seven days, respectively. Multiple techniques were used to investigate the impact of the infection on bone tissue, Brillouin-Raman microspectroscopy and attenuated total reflection Fourier transform infrared spectroscopy were employed to assess and develop a new noninvasive diagnostic method to detect SA by targeting the bone of the host. The results indicate that exposure to SA infection significantly alters the bone structure, especially in the case of the trabecular type, even after just one day. Moreover, Raman spectral markers of the tissue damage were identified, indicating that this technique can detect the effect of the pathogens' presence in bone biopsies and pave the way for potential application during surgery, due to its nondestructive and contactless nature.

High mortality rate and restricted mobility in above knee amputation following periprosthetic joint infection after total knee arthroplasty: A systematic review.

PURPOSE: To systematically review the literature on the outcomes of above knee amputation as a salvage procedure after periprosthetic joint infection in total knee arthroplasty. METHODS: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Medline, Scopus, Web of Science, and Embase electronic databases were utilized to identify all studies evaluating clinical outcomes of patients with above knee amputation following PJI from inception to June 24, 2023. Studies were excluded for failure to report functional outcomes specifically related to AKA in PJI following TKA, utilizing surgical interventions other than amputation, AKA indicated for other reasons than PJI, technical studies, conference abstracts, case reports and non-English language. The quality of studies was assessed with the Methodological Index for Non-Randomized Studies (MINORS) criteria. RESULTS: Seven retrospective studies, categorized as Therapeutic Level III evidence, were analyzed, involving a total of 188 patients who underwent AKA following PJI after TKA. The findings consistently indicate that post-AKA, patients experienced a notable decline in their level of independence and reported worsening ambulatory status. Infection and wound complications were common post-AKA, leading to revision surgeries, while the mortality rate ranged from 9 to 50% in the included studies. Polymicrobial organisms were frequently found in pre-AKA PJI, with MRSA being a common causative organism. CONCLUSIONS: AKA due to PJI following TKA is associated with restricted mobility and high mortality rate. Polymicrobial infections and MRSA were identified as common infecting organisms, emphasizing the complexities and challenges associated with managing these infections. The reported functional outcomes, ambulatory status, complications, reoperations, and mortality rates highlight the importance of providing comprehensive, individualized care to these patients.

High and Low Dosage of Vancomycin in Polymethylmethacrylate Cements: Efficacy and Mechanical Properties.

INTRODUCTION: Prosthetic joint infections (PJIs) are difficult to treat and represent a significant burden to the healthcare system. Two-stage revision surgery with placement of an antibiotic-loaded cement spacer is currently the gold standard for treatment in the United States for late-onset infections. We evaluate the efficacy of varying doses of vancomycin added to antibiotic-containing acrylic cement spacers and discuss the biomechanical and antimicrobial properties of using high versus low doses of vancomycin in cement spacers in the hip and knee. MATERIALS AND METHODS: Commercially available Copal cement containing either gentamicin and clindamycin (G + C) or gentamicin and vancomycin (G + V) was prepared with the manual addition of low (2 g) and high (6 g) doses of vancomycin. In vitro mechanical testing was then carried out according to ISO 5833 and DIN 53435, as well as inhibition zone assays against common PJI pathogens. Additionally, inhibition zone assays were conducted on two commercially available prefabricated spacers containing gentamicin: Copal Exchange G and Cemex Spacer-K. RESULTS: In biomechanical testing, Copal G + V with the addition of 6 g of vancomycin failed to meet the ISO standard. Copal G + C and Copal G + V with low and high dosages of vancomycin were all effective against the tested pathogens and displayed constant efficacy for a duration of 42 days. High doses of vancomycin showed significantly lower mechanical stability. Moreover, Copal Exchange G showed significantly larger inhibition zones across 42 days. DISCUSSION: While higher concentrations of vancomycin appear to improve the antimicrobial efficacy of cement, they also reduce its mechanical stability. Despite its smoother surface, the Copal Exchange G spacer exhibits large inhibition zones after 1 day and maintains consistently large inhibition zones over 6 weeks. Thus, it may be preferred for use in two-stage revision surgery. CONCLUSION: Copal Exchange G is more effective than Cemex Spacer K against S. aureus and E. coli. The manual addition of vancomycin to cement containing double antibiotics is very effective. The influence on ISO compression is low, the ISO bending modulus is increased, and ISO bending, DIN bending, and DIN impact, are reduced.

Safety of Intraoperative Cell Salvage in Two-Stage Revision of Septic Hip Arthroplasties.

(1) Background: The aim of this study was to evaluate the safety of intraoperative cell salvage (ICS) during reimplantation in the two-stage revision of septic hip arthroplasties. (2) Methods: As part of an internal quality control study, blood cultures were taken from the processed ICS blood during reimplantation and examined for possible bacterial load (study group). Due to a high rate of bacterial detection with uncertain clinical significance, consecutive ICS samples were also examined from patients undergoing aseptic revision hip arthroplasty (control group). Microbiological samples, patient and surgical characteristics and the follow-up data were analyzed retrospectively. (3) Results: 9 out of 12 (75%) patients in the study group and 5 out of 8 (63%) patients in the control group had positive ICS blood cultures. There was no significant difference between the groups (p = 0.642). The initial pathogens causing the periprosthetic joint infection (PJI) were not detected, but the bacterial spectrum resembled skin flora, with a high proportion of coagulase-negative staphylococci. No complications due to possible bloodstream-associated infections were observed. In summary, the detected pathogens were interpreted as contamination without clinical significance. (4) Conclusions: ICS in the context of reimplantation was considered a safe and recommendable procedure to optimize patient blood management.

Diagnosis and Treatment of Acute Periprosthetic Infections with the BioFire® System within a Time-Dependent and Bacterium-Dependent Protocol: Review and Prosthesis-Saving Protocol.

Despite ongoing efforts to enhance diagnostic and treatment processes, the success rate for eradicating infections, particularly prosthetic joint infections (PJIs), currently stands at around 50%. For acute infections occurring shortly after arthroplasty, guidelines recommend a treatment known as DAIR (debridement, antibiotics, and implant retention). This approach is suggested for infections within 30 days post-arthroplasty or with less than 3 weeks of symptoms, provided that there is a stable implant and adequate soft-tissue mass. Several authors have suggested extending the use of DAIR beyond the initial 3-week period in specific cases. This extension practice seems increasingly feasible due to the rapid diagnostic capabilities offered by BioFire®. This technology allows for quick pathogen identification, aiding in the exclusion of cases that do not fit the criteria for the DAIR/DAPRI (debridement, antibiotic pearls and retention of the implant) protocol based on pathogen identification. The aim of this review is to re-examine the current literature on acute infections and present our proposed "prosthesis-saving" protocol, which integrates the BioFire® molecular diagnostic system. Continued research and assessment of the efficacy and safety of these protocols, especially regarding extended treatment timelines, are crucial for advancing the management of acute infections and enhancing outcomes for PJI patients.

Intra and Inter-Rater Variability in the Interpretation of White Blood Cell Scintigraphy of Hip and Knee Prostheses.

Background: White blood cell (WBC) scintigraphy plays a major role in the diagnostic approach to periprosthetic infections. Although the procedure has been standardized by the publication of several guidelines, the interpretation of this technique may be susceptible to intra and inter-variability. We aimed to assess the reproducibility of interpretation between nuclear medicine physicians and by the same physician and to demonstrate that Cohen's coefficient is more unstable than Gwet's coefficient, as the latter is influenced by the prevalence rates. Methods: We enrolled 59 patients who performed a Technetium-99m WBC (99mTc-WBC) scintigraphy for suspected hip or knee prosthesis infection. Three physicians, blinded to all patient clinical data, performed two image readings. Each WBC study was assessed both visually and semi-quantitatively according to the guidelines of the European Association of Nuclear Medicine (EANM). For semi-quantitative analysis, readers drew an irregular Region of Interest (ROI) over the suspected infectious lesion and copied it to the normal contralateral bone. The mean counts per ROI were used to calculate lesion-to-reference tissue (LR) ratios for both late and delayed images. An increase in LR over time (LRlate> LRdelayed) of more than 20% was considered indicative of infection. Agreement between readers and between readings was assessed by the first-order agreement coefficient (Gwet's AC1). Reading time for each scan was compared between the three readers in both the first and the second reading, using the Generalized Linear Mixed Model. Results: An excellent agreement was found among all three readers: 0.90 for the first reading and 0.94 for the second reading. Both inter- and intra-variability showed values ≥0.86. Gwet's method demonstrated greater robustness than the Cohen coefficient when assessing the intra and inter-rater variability, since it is not influenced by the prevalence rate. Conclusions: These studies can contribute to improving the reliability of nuclear medicine imaging techniques and to evaluating the effectiveness of trainee preparation.

Simultaneous Periprosthetic Joint Infection and Infective Endocarditis: Prevalence, Risk Factors, and Clinical Presentation.

BACKGROUND: Infective endocarditis (IE) and periprosthetic joint infections (PJI) occur due to hematogenous bacterial spread, theoretically increasing the risk for concurrent infections. There is a scarcity of literature investigating this specific association. We aimed to assess the prevalence, comorbidities, and clinical presentation of patients who have simultaneous PJI and IE. METHODS: We retrospectively identified 655 patients (321 men, 334 women; 382 total hip arthroplasty, 273 total knee arthroplasty) who developed a PJI from July 1, 2015, to December 31, 2020, at one institution. There were two groups created: patients diagnosed with PJI with IE (PJI + IE) and PJI patients who did not have IE (PJI). We analyzed clinical outcomes and comorbidities. RESULTS: There were nine patients who had PJI with IE (1.4% of PJI patients). The C-reactive protein (170.9 versus 78, P = 0.026), Elixhauser comorbidity score (P = 0.002), length of hospital stay (LOS) (10.9 versus 5.7 days, P = 0.043), and the two-year post-discharge mortality rate (55.6 versus 9.0%, P = 0.0007) were significantly greater in the PJI+IE group. Comorbidities such as iron deficiency anemia (P = 0.03), coagulopathy (P = 0.02), complicated diabetes mellitus (P = 0.02), electrolyte disorders (P = 0.01), neurological disease (P = 0.004), paralysis (P = 0.04), renal failure (P = 0.0001), and valvular disease (P = 0.0008) occurred more frequently in the PJI + IE group. Modified Duke's criteria were met for possible or definite IE in 8 of the 9 patients (88.9%). CONCLUSION: Concurrent PJIs and IE, although rare, are a potentially devastating disease state with increased LOS and two-year mortality rates. This emphasizes the need for appropriate IE workups in patients who have a PJI. The modified Duke's criteria is effective in establishing a diagnosis for IE in this scenario.