Introduction. Despite the implementation of numerous preventive measures in recent years, the persistent challenge of periprosthetic infections remains. Among the various strategies, metallic modification of implants, particularly with silver, has emerged as a promising avenue. Silver's antimicrobial properties, coupled with its low human toxicity, render it an appealing option. However, ongoing debate surrounds its comparative efficacy in infection prevention when contrasted with titanium-coated prostheses. Methods. The PubMed database was systematically searched up to March 2024. Studies in English that met predetermined inclusion/exclusion criteria and utilized “Megaprosthesis AND infection” and “ silver-coated AND infection “ as key terms were included. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) statement guided the article selection process. Results. From a pool of 1892 potential papers after literature screening, 11 studies with a total of 1419 patients were meticulously selected for analysis. Among these patients, 638 were treated with silver-coated implants, while 781 received titanium-coated implants, resulting in 166 recorded cases of infection. Remarkably, the infection rate stood at 9.2% for the silver-coated group, contrasting with 13.4% for the titanium-coated group. The subsequent analysis unveiled a notable discrepancy in proportions (P difference = -0.0473, 95%CI: -0.088 to -0.006), signaling a statistically significant decrease in infections within the silver-coated cohort. Furthermore, the I2 statistic, denoting heterogeneity in effect sizes, stood at 21.8% (95%CI: 0.0-66.9), indicating a modest degree of variability among the studies. Conclusion. In conclusion, our systematic review and meta-analysis shed light on the potential of silver-coated implants in mitigating periprosthetic infections. Despite the persistent challenge posed by such infections, our findings suggest a statistically significant decrease in infection rates among patients treated with silver-coated implants compared to those with titanium-coated ones

Aim. There is controversy regarding the use of Antibiotic-loaded cement (ALBC) as compared to non-antibiotic-loaded cement (NALBC) to reduce the overall infection rate without affecting implant survival or adding additional risks on fixation for primary total knee arthroplasty (TKA). Method. To conduct the analysis, we utilized the Catalan Arthroplasty Registry (RACat) for the TKAs implanted between 2005 and 2017. The primary variable recorded was the use of cement with or without antibiotics. Other recorded variables included were age, sex, diabetes mellitus, obesity, Charlson index and type of hospital. We analyzed the effect of ALBC vs. NALBC in reducing the risk of prosthetic infection at 3, 6, 12, and 24 months as well as prosthetic survival due to mechanical causes at 1, 5, and 10 years. Univariate and multivariable analyses of risk factors were conducted. Thereby, an interactive predictive model that determines the risk of prosthetic infection based on each patient's characteristics was created. Results. A total of 28,287 TKAs from the RACat were analyzed. In that total, there were 19,788 NALBC and 8,499 ALBC. The infection rates for TKAs with NALBC vs. those with ALBC at 3, 6, 12, and 24 months were respectively: 1.69% vs. 1.39% (p=0.132); 1.81% vs. 1.56% (p=0.147); 2.14% vs. 1.73% (p=0.030); 2.51% vs. 1.86% (p=0.001). A statistically significant reduction in periprosthetic infection rate was observed in the ALBC group at 12 and 24 months. No differences were observed between the two groups in terms of prosthetic mechanical survival. Being younger, male and having had previous knee surgery or having a high comorbidity index all led to a higher risk of prosthetic revision due to infection. Conclusions. The use of ALBC as a fixation method for TKA leads to a reduction in the risk of prosthetic infection without altering the mechanical survival of the implant. The creation of a predictive model helps determine the individualized risk of prosthetic infection based on the patient's characteristics

Introduction: We have previously described modification of Ti that renders the implant surface bactericidal and prevents bacterial colonization in vitro. This study evaluates the efficacy of the same surface in preventing periprosthetic infection in a small mammal model. Methods: Control or VancTi rods were incubated with S. aureus (Ci=104CFU/mL) in TSB containing 0, 5×10-3, 4, or 100 μg/mL vancomycin at 37°C for 24h. Bacteria were detected by fluorescence (Live/Dead BacLight) and imaged by confocal microscopy. Resistance was tested by incubating control or VancTi rods with S. aureus for 0–8 weeks. Adherent bacteria were tested every 7 days on vancomycin screening agar (6μg/mL). Results: Using a percutanous approach, the intercondylar region of the knee in rats were identified. The intrameduallry canal of the femur was retrograde reamed using an 18-gauge needle. Infection was induced by injection of 103 CFU S. aureus in 150uL of saline into the femoral canal followed by insertion of a 20 mm Ti implant. Animals were harvested at various time points. At harvest, animals were euthanized with CO2.. Detailed analysis including radiographic, micro-CT, histological, bacteriological, and clinical evaluation was performed. Results: All animals showed signs of infection within the first few post-operative days with increased soft tissue swelling and limited mobility. At 1 week 75% of the animals showed radiographic signs of periprosthetic infection including periosteal reaction, abscess formation, widened canal, bone destruction, and formation of involucrum. PPI could be prevented in 92% of cases when modified Ti-Van was used. In one animal despite the use of antibiotic-tethered implant, PPI occurred partially due to the pin insertion penetrating the bone cortex. Discussion: Biologically modified implants with bactericidal surface can have a promising role in management of periprosthetic infection. The modified implant described herein contains a nanoscale surface of covalently linked antibiotics that can potentially confer bactericidal properties throughout the life of the implant

Background. Total hip arthroplasty (THA) has become one of the most commonly performed elective procedures. Today, there are nearly 50 000 annual hospitalizations for hip replacement surgery in Canada. This number is projected to increase significantly with the aging population. Periprosthetic joint infection (PJI) is the 3rd leading cause of failure following THA and is reported to occur at an incidence of 1–3%. A two-stage revision THA is the current gold standard treatment and this has a tremendous economic impact on the healthcare system. The purpose of this study is to create an accurate cost estimate of two-stage revision THA and, in turn, evaluate the economic burden of PJI as it compares to primary THA in a Canadian healthcare context. Methods. We conducted a retrospective review of primary THA cases and two-stage revision THA for PJI at our institution. Patients were matched for age and BMI. We recorded all costs associated with each procedure, including: OR time, equipment, length of hospital stay, readmission rates, and any other inpatient resource use. Unit costs were obtained using administrative data from the case costing department at London Health Sciences Centre. Billing fees associated with the procedure were obtained from the Ontario Schedule of Benefits. Descriptive statistics were used to summarize the demographic characteristics of patients, hospital costs and resource use data. Patients with PJI were compared to the matched cohort of primary THA using the t-test (for continuous variables), and the chi-square test (for categorical variables). Results. Fifty consecutive cases of revision THA were matched to 50 patients who underwent uncomplicated primary THA between 2006 and 2014. Periprosthetic infection was associated with a significant increase in hospital stay (26.5 vs. 2.0; t=4.95, p<0.001), clinic visits (9.5 vs. 3.8; T= 6.49, p<0.001), readmission rates (12 vs. 1; X. 2. 11.1, p<0.001) and overall cost ($39 953 vs. $7 460; T=73, p<0.001) in comparison to the primary arthroplasty cohort. Conclusion. Two-stage revision for infected THA is a significant economic burden to the healthcare system. Our data suggests a 5-fold increase in healthcare cost when compared to primary THA. This may be an important consideration when distributing resources among Canadian tertiary care centres

Total hip arthroplasty (THA) has become one of the most commonly performed elective procedures. Today, there are nearly 50 000 annual hospitalisations for hip replacement surgery in Canada. This number is projected to increase significantly with the aging population. Periprosthetic joint infection (PJI) is the 3rd leading cause of failure following THA and is reported to occur at an incidence of 1–3%. A two-stage re-vision THA is the current gold standard treatment and this has a tremendous economic impact on the healthcare system. The purpose of this study is to create an accurate cost estimate of two-stage revision THA and, in turn, evaluate the economic burden of PJI as it compares to primary THA in a Canadian healthcare context. We conducted a retrospective review of primary THA cases and two-stage revision THA for PJI at our institution. Patients were matched for age and BMI. We recorded all costs associated with each procedure, including: OR time, equipment, length of hospital stay, readmission rates, and any other inpatient resource use. Unit costs were obtained using administrative data from the case costing department at London Health Sciences Centre. Billing fees associated with the procedure were obtained from the Ontario Schedule of Benefits. Descriptive statistics were used to summarise the demographic characteristics of patients, hospital costs and resource use data. Patients with PJI were compared to the matched cohort of primary THA using the t-test (for continuous variables), and the chi-square test (for categorical variables). Twenty consecutive cases of revision THA were matched to 20 patients who underwent uncomplicated primary THA between 2006 and 2014. Periprosthetic infection was associated with a significant increase in hospital stay (26.5 vs. 2.0; p<0.001), clinic visits (9.5 vs. 3.8; p<0.001), readmission rates (12 vs. 1; p<0.001) and overall cost ($39 953 vs. $7 460; p<0.001) in comparison to the primary arthroplasty cohort. Two-stage revision for infected THA is a significant economic burden to the healthcare system. Our data suggests a 5-fold increase in healthcare cost when compared to primary THA. This may be an important consideration when distributing resources among Canadian tertiary care centres

Periprosthetic infection (PPI) is one of the most devastating complications of total knee arthroplasty (TKA). It is widely accepted that resection arthroplasty supplemented with intravenous antibiotics and delayed exchange arthroplasty is the treatment modality of choice for infected TKA. However, the outcome after reimplantation has varied and unpredictable results have been reported. This study evaluates the outcome of this treatment strategy in a single high volume specialised center. Furthermore, our study aims to identify the factors that lead to failure of this treatment. A thorough review of our joint registry database revealed that 80 patients with an infected TKA underwent resection arthroplasty at our institution during 2000–2005. Sixty-five patients underwent two-stage exchange arthroplasty while the remaining 15 failed to have the second stage reimplantation due to ill health or underwent arthrodesis or amputation. The latter 15 were excluded from the analysis. All patients were followed up prospectively for at least two years. Detailed data including demographics, comorbidities, surgical history, and medication intake was collected. Intraoperative data, organism profile, and complications were also documented. Failure was defined as patient requiring additional surgical procedure for control of infection or loosening. Two-stage exchange arthroplasty successfully eradicated infection in 45 patients (31%) without need for further treatment. Twelve patients (18%) had recurrent infection that necessitated another resection arthroplasty. Eleven (17%) patients required irrigation and debridement for postoperative purulent drainage which successfully treated infection in 5 cases (46%). The remaining 6 patients failed and required resection arthroplasty. Three additional patients had early loosening of components and required revision arthroplasty. The exact cause of loosening in these patients could not be determined, and despite lack of isolation of organisms infection was suspected. Our analysis identified that irrigation and debridement prior to resection arthroplasty are major risk factors for failure. Current strategies to treat periprosthetic infection remain imperfect. Two-stage exchange arthroplasty with all its inherent problems and inconveniences imparted a modest success in treatment of PPI at our high volume specialised center. The rise in the number of resistant and virulent organisms, increase in the number of patients with severe medical comorbidities who develop infection may account for the decline in the success of two-stage resection arthroplasty. Novel strategies for treatment of PPI are desperately needed

Periprosthetic infection with extensive bone loss is a complex situation. The appropriate management of large bone defects has not been established. Without reconstruction amputation/disarticulation is the likely outcome. Aim of the study was to Analyse preliminary results of direct exchange endoprosthetic reconstruction for periprosthetic infection associated with segmental bone defects. Study of patients with periprosthetic infection and severe osteolysis treated by direct exchange tumour prostheses between June, 2005 and May, 2008 (4 – Distal femoral & 2 – Total femoral Replacements). Microbiological evidence of infection was confirmed with regular monitoring of radiograph, crp, esr and wcc. Community based antibiotic therapy was provided by infectious disease team based in our institution. The mean age and follow up were 74.2 years and 26.5 months respectively. Mean duration of antibiotics was 6 weeks intravenous(community based) and 3.5 months oral. 1 patient required intervention by plastic surgeons at index procedure. Radiographs at 6, 12 & 24 months showed no changes from immediate post-op. CRP, ESR and WBC count were within normal limits at the end of antibiotic therapy. One patient required prolonged pain relief with poor mobility due to instability in the opposite knee. One patient had infection recurrence. Knee range of movements averaged full extension to 95 degrees. The mean oxford knee scores pre and post operatively were 58 and 39.4 respectively. We conclude that salvage endoprosthetic reconstruction has provided effective pain relief, stability and improved mobility in our experience. It has provided an oppourtunity to avoid amputation. Multidisciplinary support from plastic surgeons and specialist microbiologists is essential

Currently two-stage resection arthroplasty is the preferred method for surgical treatment of periprosthetic infection in North America. However, the success of this treatment strategy has varied from 54% to 98% based on previous reports. The exact reason for this variation in outcome is not known. The purpose of this study was to determine the efficacy of this treatment modality and delineate patient risk factors that result in recurrent infection and failure. During the period of this study (2000–2005) 77 patients with an infected THA were treated at our institution. Fifty-four patients underwent two-stage exchange arthroplasty while the remaining 22 failed to have the second stage reimplantation due to ill health. The latter 22 were excluded from the analysis. All patients were followed up prospectively for at least two years after reimplantation. Detailed data including demographics, comorbidities, surgical history, and medication intake was collected. Intraoperative data, organism profile, and complications were also documented. Failure was defined as patient requiring additional surgical procedure for control of infection or loosening. Two-stage exchange arthroplasty successfully eradicated infection in 36 patients (67%) without need for further treatment. Seven patients (13%) had recurrent infection that necessitated resection arthroplasty. Eleven (20%) patients required irrigation and debridement for postoperative purulent drainage which successfully treated infection in 8 of the cases. The remaining 3 patients failed and required resection arthroplasty. Three additional patients had early loosening of components and required revision arthroplasty. The exact cause of loosening in these patients could not be determined and despite lack of isolation of organisms infection was suspected. Multivariate analysis identified previous medical comorbidity and postoperative allogenic transfusion as risk factors for failure. Current strategies to treat periprosthetic infection remain imperfect. Two-stage exchange arthroplasty with all its inherent problems and inconveniences imparted a modest success in treatment of PPI at our high volume specialized center. With the increase in the number of virulent and resistant organisms, and the rise in arthroplasties being performed in infirm patients with medical comorbidities the success of this procedure is likely to be jeopardized. Novel treatment modalities to combat this dreaded condition is needed

Two of the major complications of total hip and knee arthroplasty is periprosthetic infection and aseptic loosening. The serum marker Procalcitonin (PCT) has been shown to be a sensitive indicator of bacterial infection, but very little is known of its behaviour in Orthopaedic practice. The diagnosis of periprosthetic infection still remains a difficult diagnosis. A prospective study over 6 months of 59 patients undergoing either primary total hip or knee arthroplasty was performed, which included 32 hips. The mean age was 70 years. There were no exclusion criteria. Serum blood samples for PCT, CRP, ESR and WCC were taken pre- operatively and on days 1, 3 and 5 post- operatively. Patient records were reviewed after their routine 6 week follow- up. There was no clinical suspicion of infection at this stage, or during their hospital stay. Fifty patients (85%) had PCT concentrations within the normal range (< 0.5ng/ml) on all 4 days, and only 5 recorded a value > 1.0ng/ml. Only 1 patient had an elevated level on day 5. The other markers all showed sporadic elevation over the 3 post- operative days. The usefulness of PCT in diagnosing surgical infection has been frequently researched in cardio- thoracic and abdominal surgery. However, there is debate as to what cut- off value should represent infection, ranging from 1– 10ng/ml. This is largely because the natural acute phase response caused by these operations elevates PCT levels. This study convincingly shows that PCT, unlike the routine inflammatory markers, is not significantly stimulated by primary hip and knee arthroplasty. This would imply that PCT may be useful in diagnosing periprosthetic infection. A large multicentre study involving patients undergoing revision surgery would help validate this assumption

Report of a case of migrating periprosthetic infection from a hip replacement to a contralateral knee joint undergoing a total knee replacement. We present a 74-year old female patient who underwent a total hip arthroplasty of the left hip after a subcapital fracture of the femur. Four months after the index procedure the patient presented with signs and symptoms of infection of the operated joint. Staph aureus and Enterococcus faecalis were recognized as the infecting bacteria. The implants were removed, cement spacers were placed and a total hip arthroplasty was performed again after three months. Unfortunately, infection ensued again and the patient underwent three more procedures until the joint was considered clean and t he hip remained flail without implants. The patient elected to undergo a total knee arthroplasty due to severe osteoarthritis of right knee. Intraoperatively tissue samples were taken and sent for cultures which identified Enterococcus faecalis present in the knee joint. Enterococcus migrated from the infected hip to nonoperated knee joint. Intravenous antibiotics were administered for three weeks but the knee presented with infection of the arthroplasty ten months after its insertion. The implants were removed the joint was debrided and cement spacers were inserted. The patient decided not to proceed with another procedure and she remains with the cement spacers in her knee. Rare report of migrating periprosthetic infection. Nosocomial enterococci acquired resistance cannot be ruled out. Unique characteristics in enterococci antibiotic resistance and biofilm formation

Problem: Deep infection after hip- or knee-replacement is a severe complication that may lead to implant removal or arthrodesis. Aim: In our hospital intraoperativ subcoutanues culture samples were taken before wound closure. We wanted to know if positive cultures are of any predicitive value in relation to early or late periprosthetic infection. If so, is there a consequence in treatment ? Also costs were analysed. Material and methods: In 2002 we performed 167 primary hip and knee replacements. We retrospectivaly analysed the outcome of 159 cases over a follow-up period of up to 28 month. Results: In 96.8% of the cases a culture sample was taken. Of these 5.8% showed germ growth. In only 4 cases positive cultures were followed by a change in treatment, either antibiotics or revision. Of nine patients with revision surgery only one had a positive culture. Four cases showed germ growth during revision surgery after sterile cultures during implantation. Most often different bacterias were found in primary and revision surgery. In 1.25% deep periprosthetic infection occured. One required second stage knee-replacement, one case ended in resection arthroplasty. Conclusion: Intraoperative culture sample is of no predictive value in primary joint replacement. There is no correlation between positiv cultures and indication for revision surgery. However costs for culture analysis and antibiotics are low compared to the increase of expense caused by periprosthetic infections

Introduction: Periprosthetic infection remains a main complication in arthroplasty. In case of a possible infection the surgeon has to have a concept of treatment which can be individually adjusted. Materials and Methods: To increase the success of implant retaining surgery VAC Instill therapy combining instillation of an antiseptic solution and VAC therapy was performed in 23 patients with periprosthetic hip infections. 19 patients had an early and 4 a late infection of the arthroplasty. Lavasept was used for irrigation. Results: Definitive wound closure was possible in all patients following 2.1 VAC exchange operations in average. The follow up was 19 months in average. In five of the 23 patients (22%) there was recurrent infection which made the explantation of the implant necessary. In early infection the success rate was 84%, in late infection 50%. Conclusion: VAC Instill therapy can be successfully used for salvage of infected endoprosthesis especially in case of early infection. The success rate seems to be higher than irrigation alone or suction drainage

Introduction: Periprosthetic infection is still the most severe complication in THA. In spite of vigorous efforts over the last decades the problem has not been solved nor minimized. Standardised procedures for prophylaxis and treatment have long been established. Reported results reach into the mid 80 % but did not improve remarkably in the last ten years. Our latest follow-up reveals a success rate of 87,5 %. A close analysis of the involved unsatisfying cases will help to improve future results. Material + Methods: 105 consecutive one stage exchanges of THA for periprosthetic infection in 1996 were investigated after 7 years through questionnaire, telephone interview and clinical examination. An overall success rate of 87,5 % was found and the failures were analysed. Criteria like age, co morbidities, ASA, duration of infection anamnesis, number of infection related interventions, lab-findings, local findings like fistulas, x-ray rating, operation time, surgeon, complication postoperative and the bacteria involved were compared. Results: In general it shows that the most desolate cases in all categories line up for a primary failure. The ASA rating is remarkably higher and local findings like fistulas are present in nearly all patients. The bacteria involved are staphylococci in 70 %. Over 50 % had a combination of two or more pathogens and two patients showed an additional pathogen in the samples taken during the operation. The pattern of the involved bacteria is remarkably severe. But there are also three cases where no sign of higher risk or lower chances could be detected. Conclusions: Knowing about causes of failure in the specific one stage exchange situation does lead to adaptation in the concept of treatment for those specific cases. With successful application, better results through individual therapy-concepts will be possible

Introduction: Periprosthetic infection is still the most severe complication in THA. In spite of vigorous efforts over the last decades the problem has not been Solved nor minimized. Standardised procedures for prophylaxis and treatment have long been established. Reported results reach into the mid 80% but did not improve remarkably in the last ten years. Our latest follow-up reveals a success rate of 88.6%. A close analysis of the involved unsatisfying cases will help to improve future results. Material and Methods: 105 consecutive one stage exchanges of THA for periprosthetic infection in 1996 were investigated after 7 years through questionnaire, telephone interview and clinical examination. An overall success rate of 88.6% was found and the failures were analysed. Criteria like age, co morbidities, ASA, duration of infection anamnesis, number of infection related interventions, lab-findings, local findings like fistulas, x-ray rating, operation time, surgeon, complication postoperative and the bacteria involved were compared. Results: In general it shows that the most desolate cases in all categories line up for a primary failure. The ASA rating is remarkably higher and local findings like fistulas are present in nearly all patients. The bacteria involved are staphylococci in 70%. Over 50% had a combination of two or more pathogens and two patients showed an additional pathogen in the samples taken during the operation. The pattern of the involved bacteria is remarkably severe. But there are also three cases where no sign of higher risk or lower chances could be detected. Conclusions: Knowing about causes of failure in the specific one stage exchange situation does lead to adaptation in the concept of treatment for those specific cases. With successful application, better results through individual therapy-concepts will be possible

Infection following total hip or knee arthroplasty is a serious complication. We noted an increase in post-operative infection in cases carried out in a temporary operating theatre. We therefore compared those cases performed in standard and temporary operating theatres and examined the deep periprosthetic infection rates. A total of 1233 primary hip and knee arthroplasties were performed between August 2012 and June 2013. 44% were performed in temporary theatres. The two groups were matched for age, sex, BMI and ASA grade. The deep infection rate for standard operating theatres was 0/684 (0%); for temporary theatres it was 8/539 (1.5%); p=0.001. Use of a temporary operating theatre for primary hip and knee arthroplasty was associated with an unacceptable increase in deep infection. We do not advocate the use of these theatres for primary joint arthroplasty

Debridement of an infected total joint arthroplasty with retention of mechanically stable components is often performed for acute cases of periprosthetic infection (PPI). However, the reported success of such a procedure to fully eradicate infection has varied widely. The objective of this study was to elucidate the efficacy of debridement in both infected THA and TKA and attempt to identify risk factors responsible for failure. During the years 2000–2005, 71 TKA and 69 THA underwent irrigation and debridement for acute PPI (< 4 weeks). All patients were followed up prospectively for at least two years. Detailed data including demographics, comorbidities, surgical history, and medication intake was collected. Intraoperative data, organism profile, and complications were also documented. Failure was defined as patient requiring additional surgical procedure for control of infection or loosening. Of the 140 patients, 24% required repeat irrigation and debridement for postoperative drainage, hema-toma formation, or systemic symptoms. One third of these revision debridement patients underwent multiple consecutive debridements. Two-stage resection arthroplasty was required in 65 patients (46%) of the entire cohort. Fifty-eight percent of the patients with resection required revision of their cement spacer block due to continuous drainage and systemic symptoms indicative of persistent infection. We noted a total of 86 failures (61%) that required either an additional debridement or resection arthroplasty after the first debridement procedure. The failure rates of THA (62%) and TKA (55%) individually were similar (p=0.253). Although the concept of conservative management of PPI with debridement and retention of components is an attractive alternative to resection arthroplasty, we have found that 60% of patients undergoing this procedure will inevitably undergo two-stage arthroplasty. Furthermore, more than half of the patients that required resection arthroplasty developed infection of their spacer that entailed revision of the cement block. Therefore, we can conclude that this procedure has a high failure rate and should be implemented in only a select group of patients

Serological tests including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are frequently used in the preoperative workup to screen for periprosthetic infection (PPI) in total hip arthroplasty (THA). The cut-off points reported in the literature are arbitrarily chosen by investigators. Similarly, the values used in laboratories to distinguish elevated results vary from one institute to another. Therefore, we intended to define the appropriate cut-off points of ESR and CRP that can be used to differentiate infection from aseptic failure of THA. A review of our joint registry database revealed that 515 THA revisions (131 infected cases) were performed during 2000–2005. Intraoperative samples for culture were taken in all cases. The criteria used for diagnosis of infection were a positive intraoperative culture on solid media, presence of an abscess or sinus tract that communicated with the joint, positive preoperative aspiration culture, and/or elevated fluid cell count and neutrophil differential of the aspirated fluid. Non-infected patients with confounding factors that can elevate ESR and CRP including collagen vascular disease, inflammatory arthropathy, malignancy, and urinary tract infection were excluded. Receiver operator curves were used to determine the ideal cut-off point for both ESR and CRP. The mean value of ESR in the infected group (77mm/ hr) was significantly higher compared to that of the non-infected cohort (29mm/hr) (p=0.0001). Similarly, infected patients presented with a greater mean CRP (9.8 mg/dl) than their non-infected cohort (1.48 mg/ dl) (p=0.0001). The infection threshold for ESR was 45mm/hr with a sensitivity of 85% and specificity of 79%, while the optimal cut-off value for CRP was defined as 1.6 mg/dl which yielded a sensitivity of 86% and specificity of 83%. The optimal threshold values we determined are higher than the arbitrarily chosen values cited in the literature for ESR (30mm/hr) and CRP (1mg/dl). Although it has been previously reported that the sensitivity and specificity of CRP are far greater than that of ESR, we found that the two tests have comparable diagnostic value

Background. Additive manufacturing (AM) has created many new avenues for material and manufacturing innovation. In orthopaedics, metal additive manufacturing is now widely used for production of joint replacements, spinal fusion devices, and cranial maxillofacial reconstruction. Plastic additive manufacturing on the other hand, has mostly been utilized for pre-surgical planning models and surgical cutting guides. The addition of pharmaceuticals to additively manufactured plastics is novel, particularly when done at the raw material level. The purpose of this study was to prove the concept of antibiotic elution from additively manufactured polymeric articles and demonstrate feasibility of application in orthopaedics. Methods. Using patented processes, three heat-stable antibiotics commonly used in orthopaedics were combined with six biocompatible polymers (2 bioresorbable) into filament and powder base materials for fused deposition modeling (FDM) and selective laser sintering (SLS) AM processes. Raw materials of 1%, 2%, and 5% antibiotic concentrations (by mass) were produced as well as a blend of all three antibiotics each at 1% concentration. Thin disks of 25 mm diameter were manufactured of each polymer with each antibiotic at all concentrations. Disks were applied to the center of circular petri dishes inoculated with a bacterium as per a standard zone of inhibition, or Kirby-Bauer disk diffusion tests. After 72 hours incubation, the zone of inhibited bacterial growth was measured. Periprosthetic joint infection (PJI) of the knee was selected as the proof-of-concept application in orthopaedics. A series of tibial inserts mimicking those of a common TKR system were manufactured via SLS using a bioresorbable base material (Figure 1). Three prototype inserts were tested on a knee wear simulator for 333,000 cycles following ISO 14242–1:2014 to approximate 2–4 months of in vivo use between surgeries of a 2-stage procedure for PJI. Gravimetric measurement and visual damage assessment was performed. Results. Bacterial growth was inhibited to a mean diameter of 32.3 mm (FDM) and 42.2 mm (SLS) for nearly all combinations of polymers and concentrations of antibiotics. Prototype tibial inserts experienced an average of 200 mg of wear during testing and demonstrated no evidence of cracking, delamination or significant deformation (Figure 2). Conclusion. Bench-level testing of these novel antibiotic-eluting polymers demonstrates feasibility for their application in orthopaedic medicine. In particular, treatment of stubborn PJI with potential for increased and sustained antibiotic elution, patient-specific cocktailing, and maintenance of knee joint structure and function compared to existing PJI products and practices. Subsequent testing for these novel polymers will determine static and dynamic (wear-induced) antibiotic elution rates. For any figures or tables, please contact the authors directly

Aim: The purpose of our study is to present the survival results, clinical outcome and complications from the use of APC in cases with a history of periprosthetic infection. Materials and Methods: Between 1986 and 1999, twenty-two patients (twenty-two hips) 11 male and 11 female (mean age 57.5 years – range 38 to 77 years) with massive bone loss (Paprosky IIIA 2 cases, IIIB 4 cases, and IV 16 cases) were included to our study. They all had a history of periprosthetic infection after an average of 3.3 (range 1 to 5) revision hip arthroplasties and were submitted to a two stage revision arthroplasty using an allograft-prosthesis composite. Results: At an average follow-up of eleven years (range, eight to twenty years), 14 patients were alive, 7 patients died, and 1 patient was lost to follow-up. The ten year survival of the allograft-prosthesis composites was 74.9 per cent (95 per cent confidence interval 55.1 to 94.7 per cent, 4 cases remaining at risk). Seven cases presented with APC failure needing re-revision, 2 due to re-infection (4 and 23 months from revision by the same microorganism species as for the initial infection (Staph aureus to both cases), 3 due to allograft non union (at 21, 43, 79 months) and 2 cases due to graft resorption (164, 175 months post revision). Delayed healing and wound drainage occurred to 2 more cases. Conclusion: Reconstruction of massive proximal femoral bone loss with an allograft-implant composite is a demanding procedure. Biologic means of reconstruction is a major advantage preserving bone stock for future surgery. However, high complication rate should be considered

Purpose:. Two-stage revision is the gold standard treatment for chronic periprosthetic infection of the hip or knee. Implantation of a functional antibiotic spacer allows patients the option of two stage revision or living with the spacer in place. Some patients may be satisfied with the activity level that they attain with the functional antibiotic spacer and may avoid the morbidity of a second surgery. Methods:. We retrospectively examined the outcomes of 30 joints in 27 patients treated for chronic periprosthetic infection of the hip or knee at a mean follow-up of 27 months (range 11–46 months). Comparing the patients treated with two-stage revision to those patients living with a functional antibiotic spacer, we used University of California Los Angeles activity scores, modified Harris hip scores, and patient satisfaction measures to answer two main questions: (1) Is there a significant difference in activity level? (2) Is there a significant difference in patient satisfaction? Patient satisfaction was measured on a 1–100 scale with 100 being completely satisfied. Results:. There were no statistically significant differences in the American Society of Anesthesiologists scores between the groups—mean 2.69 in the two-stage group and mean 3.00 in the spacer group (p value 0.255). Statistically significant differences were found between the groups for University of California Los Angeles activity scores—mean 5.3 in the two-stage group and mean 2.8 in the spacer group (p value 0.027). There were no statistically significant differences in modified Harris hip scores—mean 55.6 in the two-stage group and mean 41.6 in the spacer group (p value 0.34). In the subgroup analysis of the modified Harris hip score questions, there was a statistically significant difference in the need for support when ambulating—mean 4.21 in the two-stage group and mean 2.45 in the spacer group (p value 0.024)—and in the distance that can be walked—mean 6.15 in the two-stage group and mean 2.0 in the spacer group (p value 0.005). No statistically significant differences were found in patient satisfaction measures—mean 70.0 in the two-stage group and mean 76.6 in the spacer group (p value 0.65)—though the mean satisfaction measure was higher in the spacer group. Conclusion:. Patients living with a functional antibiotic spacer are less active than patients undergoing a two-stage revision for chronic periprosthetic infection of the hip or knee. Specifically, patients living with a functional antibiotic spacer need more support when ambulating and ambulate shorter distances than patients, who undergo two-stage revision surgery. Despite the decreased activity level, patients living with a functional antibiotic spacer are just as satisfied with the outcome of their joint as those patients treated with a two-stage revision. Patients with modest activity goals may be satisfied to live with a functional antibiotic spacer and to avoid a second surgery