Two-stage reconstruction with total implant removal and re-implantation after infection control is considered the gold standard treatment forinfection after hip arthroplasty. However, removal of the well-fixed stem or cup may cause substantial bone loss and other complications, thereby making reconstruction difficult. We evaluated whether an infection posttotal hip arthroplasty can be treated without removal of the radiographically and clinically well-fixed femoral stem or acetabular cup. Patients with a chronic infection aftertotal hip arthroplasty, with a radiographically well-fixed, cementless stem or cup, were selected. During the first surgical stage, we retained the stem or cup if we were unable to removethese with a stem or cup extractor. An antibiotic-impregnated cement spacer was then implanted. After control of infection (C-reactive proteinlevel within normal value), we performed the secondstage of re-implantation surgery. Treatment failure was defined as uncontrolled infection requiringremoval of the retained implant. From January 2004 to December 2013, 16 patients underwent partial component-retained 2-stage reconstruction. Thirteen patients (81.3%) were free of infection, with a mean follow-up time of 5 years. The remaining 3 patients, who had high-risk comorbidities and, of whom, 2 were infected by high-virulence organism, had uncontrolled infection and required furthersurgery to remove the retained implant. We conclude that partial component-retained 2-stage reconstruction could be an alternative treatment option for chronic infection afteran uncemented total hip arthroplasty with a radiographically and clinically well-fixed component in selected patients, who are notimmunocompromised and are infected by a low-virulence organism

We report our clinical experience with three patients in whom squamous cell carcinomas developed secondarily to chronic bone infections. The diagnosis was delayed in each case. There are several well recognised warning signs which should alert the physician to the possibility of malignant change having occurred in the region of chronic bony infection. Close attention to these signs will prevent undue delay in diagnosis and avoid the associated complications. As chronic osteomyelitis becomes less common in first world countries we need to remain aware of the possible complications which can be encountered. The diagnosis in each of our cases was delayed by the fact that the possibility of malignant change was not considered by several experienced orthopaedic surgeons. When there is change in signs and symptoms or altered flora within the discharge one must be alerted to the possibility of malignant change. This should prevent delays in diagnosis. Radiological progression should probably be regarded as malignant change until proven otherwise. With early diagnosis and treatment the prognosis for a patient with squamous cell carcinoma is good. Key words: Osteoclastoma, Osteomyelitis, Sinus tract, Squamous cell carcinoma

Aim. Studies have shown that retention of antibiotic cement spacer in selected elderly patients with low functional demand represents a viable option for periprosthetic joint infections (PJI) treatment. 1,2. . The aim of this study is to compare the efficacy in infection treating among modular taylored preformed and hand-made antibiotic spacers. Our hypothesis is that modular tailored preformed spacer provides a better rate of infection resolution, better radiological and functional outcomes compared to hand-made spacers. Materials and methods. We identified 48 patients treated with antibiotic cement spacer for shoulder chronic infection between 2015 and 2021 in our institution; (13 hand-made spacers and 35 modular tailored preformed spacers). We collected data about comorbidities, associated microorganism, infection resolution, clinical and radiographic evaluation. Results. The mean age at surgery was 63.2 years, (45.8% female − 54.2% male), mean BMI 28.3. The mean time of infection diagnosis after first surgery was 30 months; (31.2% infection after ORIF in proximal humeral fractures, 68.8% PJI after shoulder arthroplasty). The main pathogens were Propionibacterium Acnes (37.5%), Staphylococcus Epidermidis (29.2%), Staphylococcus Aureus (16.7%), negative intraoperative coltures (14.6%), Enterococcus (4.17%), Pseudomonas Aeruginosa (4.17%). The mean time of antibiotic spacer retention was 18 months: 23 patients (47.9%) underwent second stage surgery for prosthesis implantation; 2 removed the spacer because of spacer dislocation, 2 died during follow up; while 21 patients still hold the antibiotic spacer (17 patients in treatment with prefabricated spacers and 4 with self-constructed spacer). The mean value for clinical assessment for patients with modular tailored preformed spacer were: Constant Score 34 – QuickDASH 40 – SST 33 – ASES Score 66 – VAS 2. Patients treated with hand-made spacer registered the following scores: Constant Score 20 – QuickDASH 51 – SST 25 – ASES Score 38 – VAS 6. Two patients presented fracture of the spacer (one hand-made spacer and one tailored preformed). Conclusions. According to our data patients treated with modular tailored preformed antibiotic spacer show better functional outcomes. Patients are more likely to retain the spacer as a permanent implant, avoiding the risks of a second stage surgery in those low-demanding patients, achieving a reasonable satisfying quality of shoulder motion without pain

Aim

Vancomycin-intermediate Staphylococcus aureus (VISA) was associated with persistent infection and treatment failure. To date, two staphylococcal virulence mechanisms have been associated with persistence secondary to host immune evasion and vancomycin therapeutic failure: i) bacterial internalization in non-phagocytic cells and ii) biofilm formation. The present study aimed to compare clinical pairs of isolates composed by VISA and their Vancomycin-Susceptible (VSSA) progenitors toward these bacterial adaptive mechanisms.

We report the results of imaging with labelled white cells in 52 patients before the revision of 54 cemented joint prostheses at which the diagnosis of infection was made from biopsies. Twenty-five hips were imaged with 111In-oxine-labelled cells; 20 hips and 11 knees were imaged with 99mTc-hexamethylpropylene-amineoxime-labelled cells. Of these, 13 hips and five knees proved to be infected. The scans taken together had an accuracy of 82%, a sensitivity of 44% and a specificity of 100%. Indium scans gave 37% sensitivity, 99mTc labelling 50% sensitivity. Infected arthroplasties with positive scans had presented significantly earlier than those with negative scans, the time after the original insertion being 1.1 years for the true-positive scans and 6.1 years for the false-negative scans. The value of labelled white-cell scans in the detection of infection in failed joint replacements is dependent on the activity of the infection. There is reduced sensitivity to the more insidious infections which affect arthroplasties and aspiration under controlled conditions remains an important investigation.

Aims

Recently, several synovial biomarkers have been introduced into the algorithm for the diagnosis of a prosthetic joint infection (PJI). Alpha defensin is a promising biomarker, with a high sensitivity and specificity, but it is expensive. Calprotectin is a protein that is present in the cytoplasm of neutrophils, is released upon neutrophil activation and exhibits anti-microbial activity. Our aim, in this study, was to determine the diagnostic potential of synovial calprotectin in the diagnosis of a PJI.

Aims

The aim of this study was to determine if a three-month course of microorganism-directed oral antibiotics reduces the rate of failure due to further infection following two-stage revision for chronic prosthetic joint infection (PJI) of the hip and knee.

When using a staged approach to eradicate chronic infection after total hip replacement, systemic delivery of antibiotics after the first stage is often employed for an extended period of typically six weeks together with the use of an in situ antibiotic-eluting polymethylmethacrylate interval spacer. We report our multi-surgeon experience of 43 consecutive patients (44 hips) who received systemic vancomycin for two weeks in combination with a vancomycin- and gentamicin-eluting spacer system in the course of a two-stage revision procedure for deep infection with a median follow-up of 49 months (25 to 83). The antibiotic-eluting articulating spacers fractured in six hips (13.9%) and dislocated in five patients (11.6%). Successful elimination of the infecting organisms occurred in 38 (92.7%) of 41 hips with three patients developing superinfection with a new organism. We conclude that prolonged systemic antibiotic therapy may not be essential in the two-stage treatment of a total hip replacement for Gram-positive infection, provided that a high concentration of antibiotics is delivered locally using an antibiotic-eluting system

Aim. The treatment of chronic orthopedic device-related infection (ODRI) often requires multiple surgeries and prolonged antibiotic therapy. In a two-stage exchange procedure, the treatment protocol includes device removal and placement of an antibiotic-loaded bone cement spacer to achieve high local antibiotic concentrations. At the second stage, further surgery is required to remove the spacer and replace it with the definitive device. We have recently developed a thermo-responsive hyaluronan hydrogel (THH) that may be loaded with antibiotics and used as delivery system. Since the material is bio-resorbable, it does not require surgical removal and may therefore be suitable for use as treatment strategy in a single-stage exchange. This aim of this study was to evaluate gentamicin sulphate (Genta)-loaded THH (THH-Genta) for treating a chronic Staphylococcus aureus ODRI in sheep using a single-stage procedure. Methods. Twelve Swiss-alpine sheep received an IM tibia nail and an inoculation of a gentamicin-sensitive clinical strain of Staphylococcus aureus. After letting a chronic infection develop for 8 weeks, a revision procedure was performed: the implant was removed, the IM canal debrided and biopsies were taken for culture. The IM canal was then filled with 25ml THH-Genta (1% Genta) or left empty (control group) prior to the implantation of a sterile nail. An ultrafiltration probe was placed within the IM cavity to collect extracellular fluid and determine local antibiotic levels for 10 days. Both groups received systemic amoxicillin and clavulanic acid for 2 weeks, followed by 2 weeks without treatment for antibiotic washout. At euthanasia, IM nail, bone marrow, bone and tissue samples were harvested for quantitative bacteriology. Results. All sheep were infected at revision surgery as confirmed by cultures of biopsies and sonication of the IM nail. Local Genta concentrations ranged on average from 830µg/ml postoperatively to below 5µg/ml after 8 days. At euthanasia, S. aureus was detected in 5/5 IM nails, 5/5 bone marrow samples, and 8/25 superficial soft tissue samples in the control group (one control sheep was excluded for having a superinfection). In the THH-Genta group, S. aureus was cultured from 0/6 IM nails, 1/6 bone marrow samples, and 1/30 superficial soft tissue samples. Conclusions. The THH showed a Genta release pattern that started with high local concentrations and decreased to low concentrations within 10 days. Local Genta delivery by THH combined with systemic antibiotics significantly reduced infection rates whereas systemic therapy alone was unable to eradicate infection in any animal

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

Aims. Debridement, antibiotics, and implant retention (DAIR) remains one option for the treatment of acute periprosthetic joint infection (PJI) despite imperfect success rates. Intraosseous (IO) administration of vancomycin results in significantly increased local bone and tissue concentrations compared to systemic antibiotics alone. The purpose of this study was to evaluate if the addition of a single dose of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes. Methods. A retrospective case series of 35 PJI TKA patients, with a median age of 67 years (interquartile range (IQR) 61 to 75), who underwent DAIR combined with IO vancomycin (500 mg), was performed with minimum 12 months' follow-up. A total of 26 patients with primary implants were treated for acute perioperative or acute haematogenous infections. Additionally, nine patients were treated for chronic infections with components that were considered unresectable. Primary outcome was defined by no reoperations for infection, nor clinical signs or symptoms of PJI. Results. Mean follow-up for acute infection was 16.5 months (12.1 to 24.2) and 15.8 months (12 to 24.8) for chronic infections with unresectable components. Overall non-recurrence rates for acute infection was 92.3% (24/26) but only 44.4% (4/9) for chronic infections with unresectable components. The majority of patients remained on suppressive oral antibiotics. Musculoskeletal Infection Society (MSIS) host grade was a significant indicator of failure (p < 0.001). Conclusion. The addition of IO vancomycin at the time of DAIR was shown to be safe with improved results compared to current literature using standard DAIR without IO antibiotic administration. Use of this technique in chronic infections should be applied with caution. While these results are encouraging, this technique requires longer follow-up before widespread adoption. Cite this article: Bone Joint J 2021;103-B(6 Supple A):185–190

The February 2024 Research Roundup. 360. looks at: If you use a surgical helmet, you should seal your gown-glove interface; The use of iodophor-impregnated drapes in patients with iodine-related allergies: a case series and review of the literature; Location of the ovaries in children and efficacy of gonadal shielding in hip and pelvis radiography; Prehospital tranexamic acid administration does not improve outcomes in severe trauma patients; Silver-coated distal femur megaprosthesis in chronic infections with severe bone loss: a multicentre case series

Introduction. Debridement, Antibiotics and Implant Retention (DAIR) remains the norm for the treatment of acute periprosthetic joint infection (PJI) despite less than optimal success rates. Intraosseous (IO) administration of vancomycin has been shown to have significantly increased local bone and tissue concentrations compared to systemic antibiotics, with lower systemic antibiotic levels compared to intravenous. The purpose of this study was to evaluate if the addition of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes. Methods. A retrospective review of 35 PJI TKA patients who underwent DAIR combined with IO vancomycin (500mg) was performed with minimum 12-month follow-up. 26 patients were treated for acute perioperative or acute hematogenous infections following primary TKA. Nine were treated for chronic infections with components that were considered unresectable (ie) constructs with ingrown cones, sleeves, or long cemented stems in elderly comorbid patients. Primary outcome was defined by no reoperations for infection nor clinical signs or symptoms of PJI. Results. The average follow up for acute infection was 16.5 months (range 12.1–24.2) and 15.8 months (range 12–24.8) for chronic infections with unresectable components. Overall eradication rates for acute infection was 93.1% while only 44.4% for chronic infections with unresectable components. MSIS host grade was a significant indicator of failure (p<0.001). Conclusion. The use of IO vancomycin at the time of DAIR yielded improved results compared to standard irrigation and debridement in acute periprosthetic infections. Its use in chronic infections should remain cautious. While these results are encouraging, this technique requires longer follow-up before widespread adoption

Aim. The purpose of this study is to report the overall infection control rate and prognostic factors associated with acute, hematogenous and chronic PJIs treated with DAIR. Methods. All DAIR procedures performed at 2 institutions from 2009 to 2018 (n=104) were reviewed and numerous data were recorded, including demographics, preoperative laboratory tests, Charleston Comorbidity Index, surgical information and organism culture results. Treatment success was defined according to the criteria reported by Diaz-Ledezma. A multivariable analysis was utilized to identify prognostic factors associated with treatment and a Kaplan-Meier survival analysis was used to depict infection control rate as a function of time. Results. The overall treatment success rate in the current cohort of patients was 67.3% at a median 38.6 (23.5–90.7) months follow-up. Patients with a duration of infectious symptoms greater than 10 days were more likely to fail (P=0.035, odds ratio 8.492, 95% confidence interval 1.159–62.212). There was no difference among acute, hematogenous and chronic infections in terms of failure rate even when time was considered (p=0.161). Conclusion. With careful patient selection, DAIR is a reasonable treatment option for PJI and its use in the setting of chronic infection does not appear to be a contraindication. Performing the DAIR procedure within 10 days of the presentation of symptoms had higher rates of treatment success

Materials & Methods. Chronic osteomyelitis is a complex and challenging condition the successful treatment of which requires a specialist multidisciplinary approach. Prior to tertiary referral to a specialist Orthoplastic Unit, patients often receive multiple courses of antibiotics, in usually unsuccessful attempts, to eradicate infection. This often results in the development of chronic polymicrobial infection. We reviewed the intra-operative cultures of patients treated in our Orthoplastic unit over a 9-year period from 2012–2021 to determine the spectrum of polymicrobial cultures and the relationship to pre-operative cultures. Results. We reviewed the electronic care records and laboratory results of all patients referred to or directly admitted to our unit with a diagnosis of chronic osteomyelitis between 2012–2021. We checked all culture results, antibiotic sensitivities and prescription for treatment. We also checked for any recurrence of infection within 1 year. 60 patients were treated over the 9-year period. 9 upper and 51 lower limbs. The most common referral sources were from the surgical specialties of Trauma & Orthopaedics and Plastic Surgery (62%) while an equal amount came from the Emergency Department and other inpatient medical teams, each making up 15%. A small cohort (8%) developed the infection while still being followed up post fixation. Aetiology of Infection were post fracture fixation 41 (68%), spontaneous osteomyelitis 10 (17%), soft tissue infection 4 (7%). The remaining 5 patients (8%) had a combination failed arthroplasty, arthrodesis and chronic infection from ring sequestrum. 58 patients (97%) had positive cultures with 26 being polymicrobial. 12 cultures were gram negative (G-ve), 11 G+ve 12, 4 anaerobic and 1 Fungal. In 24 patients (40%) the pre-operative cultures and antibiotic sensitivities did not correspond to the intra-operative cultures and sensitivities. 55 patients (92%) required dual or triple therapy with 8% requiring further debridement and extended therapy. 2 (3%) patients had failed treatment requiring amputation. Conclusions. Chronic osteomyelitis is a complex and challenging condition the successful treatment of which requires early referral to a specialist Orthoplastic unit. Less than half of organisms cultured pre-operatively reflect the causative organisms cultured intra-operatively with 52% of these infections being polymicrobial. After initial treatment, 8% of patients will require a further combination of extended antibiotic therapy and surgery to eradicate infection

Aims. The aim of this study was to compare the mid-term patient-reported outcome, bone remodelling, and migration of a short stem (Collum Femoris Preserving; CFP) with a conventional uncemented stem (Corail). Methods. Of 81 patients who were initially enrolled, 71 were available at five years’ follow-up. The outcomes at two years have previously been reported. The primary outcome measure was the clinical result assessed using the Oxford Hip Score (OHS). Secondary outcomes were the migration of the stem, measured using radiostereometric analysis (RSA), change of bone mineral density (BMD) around the stem, the development of radiolucent lines, and additional patient-reported outcome measures (PROMs). Results. There were no statistically significant differences between the groups regarding PROMs (median OHS (CFP 45 (interquartile range (IQR) 35 to 48); Corail 45 (IQR 40 to 48); p = 0.568). RSA showed stable stems in both groups, with little or no further subsidence between two and five years. Resorption of the femoral neck was evident in nine patients in the CFP group and in none of the 15 Corail stems with a collar that could be studied. Dual X-ray absorbiometry showed a significantly higher loss of BMD in the proximal Gruen zones in the CFP group (mean changes in BMD: Gruen zone 1, CFP -9.5 (95% confidence interval (CI) -14.8 to -4.2), Corail 1.0 (95% CI 3.4 to 5.4); Gruen zone 7, CFP -23.0 (95% CI -29.4 to -16.6), Corail -7.2 (95% CI -15.9 to 1.4). Two CFP stems were revised before two years’ follow-up due to loosening, and one Corail stem was revised after two years due to chronic infection. Conclusion. The CFP stem has a similar clinical outcome and subsidence pattern when compared with the Corail stem. More pronounced proximal stress-shielding was seen with the CFP stem, suggesting diaphyseal fixation, and questioning its femoral neck-sparing properties in the long term. Cite this article: Bone Joint J 2022;104-B(5):581–588

Aim. Low-grade infections are difficult to diagnose. As the presence of a chronic infection requires extensive surgical debridement and antibiotic treatment, it is important to diagnose a SII prior to surgery, especially when the hardware is revised. We investigated whether serum inflammatory markers or nuclear imaging can accurately diagnose a chronic spinal instrumentation infection (SII) prior to surgery. Method. All patients who underwent revision spinal surgery after a scoliosis correction between 2017 and 2019 were retrospectively evaluated. The diagnostic accuracy of serum C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR), . 18. F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) and Technetium-99m-methylene diphosphonate (99mTc-MDP) 3-phase bone scintigraphy (TPBS) to diagnose infection were studied. Patients with an acute infection or inadequate culture sampling were excluded. SII was diagnosed if ≥ 2 of the same microorganism(s) were isolated from intra-operative tissue cultures. Results. 31 patients were included. The indication for hardware extraction was pseudoarthrosis in the majority of patients (n = 15). 22 patients (71%) were diagnosed with SII. In all infected cases, Cutibacterium acnes was isolated, including 5 cases with a polymicrobial infection. Sensitivity, specificity, PPV and NPV was: 4.5%, 100%, 100% and 30.0% for CRP >10.0 mg/L, 5.5%, 100%, 100% and 29% for ESR > 30 mm/h; 56%, 80%, 83% and 50% for FDG-PET/CT and 50%, 100%, 100% and 20% for TPBS, respectively. Conclusions. The prevalence of SII in patients undergoing revision spinal surgery is high, with Cutibacterium acnes as the main pathogen. No diagnostic tests could be identified that could accurately diagnose or exclude SII prior to surgery. Future studies should aim to find more sensitive diagnostic modalities to detect low-grade inflammation

Objectives. This study aims to investigate whether bacteria are present in intervertebral discs (IVDs) and their influence. Causality between chronic infection of the IVD and its degenerative process gained great interest recently. Granville Smith et al. (2021) identified 36 articles from 34 research studies investigating bacteria in IVDs, from these 27 studies found, Cutibacterium acnes being the most abundant. However, whether bacteria identified were present in vivo or if they represent contamination remains unclear. Methods. Human IVD tissue was fixed in paraffin and Immunohistochemical stained for Gram-positive bacteria. NP cells in monolayer have been stimulated with LPS (0.1–50 µg/ml) and Peptidoglycan (0.1–50 µg/ml) for 24, 48 and 72 hrs to investigate their influence. The concentration of proinflammatory and catabolic cytokines in the media is being measured using ELISA. RNA extracted and RT-qPCR utilised for factors associated with disc degeneration matrix genes, matrix degrading enzymes, cytokines, neurotrophic factors and angiogenic factors. Results. Bacteria were detected within IVD tissue. Bacteria was internalized by the NP cells and influenced the nuclei morphology. Preliminary results of the exposure of NP cells to bacterial components demonstrate that ADAMTS4 as well as IL-8 were showed an increase in gene expression after LPS and peptidoglycan treatment compared to the non-treated control. Underlining these results, IL-8 protein was increased in treated groups, whereas peptidoglycan treated groups showed a dose dependence. Conclusion. This study demonstrates that Gram positive bacteria are present within the IVD. The exposure of NP cells to peptidoglycans indicates that bacterial components trigger a stress response. Conflicts of Interest: No conflict of interest. Sources of Funding: This project is part of the Disc4All Training network to advance integrated computational simulations in translational medicine, applies to intervertebral disc degeneration and funded by Horizon 2020 (H2020-MSCA-ITN-ETN-2020 GA: 955735)

Aim. To describe the risk factors, microbiology and treatment outcome polymicrobial prosthetic joint infections (PJI) compared to monomicrobial PJI. Methods. Between January 2011 and December 2021, a total of 536 patients were diagnosed with PJI at our institution. Clinical records were revised, and 91(16.9%) had an isolation of two or more pathogens. Age, sex, previous conditions, Charlson comorbidity score, previous surgery, PJI diagnosis and surgical and antibiotic treatment, from the index surgery onwards were reviewed and compared between groups. Results. Polymicrobial PJI success rate was 57.1%, compared to 85.3% of the monomicrobial PJI(p=0.0036). There were no statistically significative differences between acute and chronic infections. In terms of related risk factors, revision surgery(p=0.0002), fracture(p=0.002), tobacco(p=0.0031) and Body Mass Index (BMI) between 20–25(p=0.0021) were associated to monomicrobial PJI, whereas overweight(p=0.005) and obesity(p=0.02) were linked to polymicrobial PJI. Regarding pathogens, the most common microorganism isolated in monomicrobial was S.aureus (33.5%), followed by S. epidermidis(20%) and gram negative bacilli (12.2%); while S. epidermidis(56%), gram negative bacilli (41.8%) and E.colli (30.8%) were the most frequent in the polymicrobial PJI. Enterococci(p=0.0008), S. epidermidis(p=0.007), E.colli (p=0.0008), gram negative bacilli (p=0.00003) and atypical bacteria (p=0.00001) statistically significative linked to polymicrobial PJI; while S.aureus (p=0.018) was related to monomicrobial PJI. Conclusion. Polymicrobial PJI showed worse outcome compared to monomicrobial PJI in our cohort. In terms of risk factors, overweight, obesity and some pathogens like gram negative bacilli, atypical bacteria, enterococci, S. epidermidis and E.colli were associated with Polymicrobial PJI

This study aimed to identify long-term physical and psychosocial health outcomes in children with overwhelming musculoskeletal sepsis. Children admitted to the Paediatric Intensive Care Unit (PICU) from 1st January 2002 to 31st December 2017 with a musculoskeletal focus of infection were identified. A medical notes review was completed to determine survival and morbidity. Present-day clinical assessment of the musculoskeletal and respiratory systems along with questionnaires on health-related quality of life, mental health and sleep were performed. 70 patients were identified over 15 years. Seven children died acutely (five Pasifika and two Māori children) indicating 10% mortality. Recurrence/chronic infection affected 23%. Growth disturbance affected 18%. The hip joint and proximal femur suffered the worst long-term complications. Children under 2 years most at risk of long-term disability. No patients had chronic respiratory illness beyond 90 days. Fifteen children had symptoms of acute neurological impairment, three of whom had permanent acquired brain injury. Twenty-six survivors (41%) were assessed a mean of 8.2 years (SD 4.5, range 2– 18 years) after discharge. Health-related quality of life scores were on par with normative data. All patients who underwent pulmonary function tests had normal results. Six patients and eight parents screened positive for moderate to severe post-traumatic stress disorder. Paediatric multifocal musculoskeletal sepsis can result in complex illness with multi-organ complications for some children. Māori and Pasifika children are most at risk. Children under 2 years and those with proximal femur and/or hip involvement are most likely to have chronic musculoskeletal sequelae and permanent disability. Other outcomes are favourable with no evidence of chronic lung disease or mean reduced quality of life. A period of rehabilitation for children with identified acquired brain injury should be part of discharge planning

Survival of sepsis has been documented worldwide, but little is documented about the long-term health outcomes of multifocal sepsis from acute musculoskeletal infection - the first study of its kind in New Zealand. Children admitted to the Paediatric Intensive Care Unit (PICU) from 1. st. January 2002 to 31. st. December 2017 with a musculoskeletal focus of infection were identified from hospital coding data. Notes review from discharge to present day determined survival and morbidity. Present-day clinical assessment of the musculoskeletal and respiratory systems along with questionnaires on health-related quality of life, mental health and sleep were performed. Seventy patients were studied. Seven children died acutely (five Pasifika and two Māori children) indicating 10% mortality. Long-term survival was favourable with no recorded deaths after discharge. Recurrence/chronic infection occurred in 23%, a mean of 1.1 year after discharge. Growth disturbance occurred in 18%, a mean of 3 years after discharge. The hip joint and proximal femur have the worst complications. Children under 2 years are most at risk of long-term disability. No patients had chronic respiratory illness beyond 90 days. Fifteen children had symptoms of acute neurological impairment, three of whom had permanent brain injury. Twenty-six survivors (41%) were assessed a mean of 8.2 years after discharge. Health-related quality of life scores were on par with normative data. Six patients and eight parents screened positive for moderate to severe post-traumatic stress disorder. Paediatric multifocal musculoskeletal sepsis can result in complex illness with long hospital stay and multi-organ complications. Māori and Pasifika children, those under two and those involving the proximal femur/or hip are most at risk. Other outcomes are favourable with no evidence of chronic lung disease or poor quality of life. A period of rehabilitation for children with identified acquired brain injury should be part of discharge planning

Aim. Osteomyelitis (OM) is a debilitating infection of the bone that originates from hematogenous spreading of microbes or contamination after surgery/fracture. OM is mainly caused by the opportunistic bacterium Staphylococcus aureus (SA), which can evade the host immune response, acquire antibiotic resistance and chronically colonize the musculoskeletal tissue . 1,2. , yet the underlying molecular and cellular processes are largely unclear. This study aimed to characterize the pathogenetic mechanisms of SA-OM with a focus on the long pentraxin 3 (PTX3), a soluble pattern recognition molecule and bone tissue component that is emerging as a new player in osteoimmunology . 3. and a diagnostic marker of periprosthetic joint infections, a common form of OM. 4. . Method. A murine model of OM based on intra-bone injection of SA was developed that closely mimicked surgery/trauma-related OM in humans and allowed addressing the role of PTX3 in gene-modified (Ptx3-/-) animals. Local and systemic infection and inflammation were assessed via microbiology, flow cytometry, histochemistry and microCT techniques. Results. SA-injected mice developed chronic infection with measurable levels of viable bone-resident bacteria up until 30 days from microbial challenge. The infection was confined to the treated limbs only and accompanied by extensive tissue remodelling. The bacterial load was higher in WT than Ptx3. -/-. animals at 6 and 14 days from SA injection. Accordingly, WT mice had enhanced systemic inflammation with expanded innate immune compartment in the spleen and increased serum levels of inflammatory cytokines and chemokines. PTX3 levels were higher in SA- than vehicle (PBS)-injected WT animals both in the serum and bone tissue. Furthermore, administration of a PTX3-targeting antibody reduced the bacterial burden in the bones of SA-injected WT mice. Conclusions. In a mouse model of SA-OM, genetic deficiency of PTX3 protected from infection and inflammation, pointing to this pentraxin as a crucial player in OM pathogenesis and a novel therapeutic target in bone infections. The study was approved by the Italian Ministry of Health (approval n. 520/2019-PR issued on 19/07/2019) and supported by Fondazione Beppe and Nuccy Angiolini

Aim. The objective of this systematic review is to evaluate the current evidence for or against this up-and-coming treatment modality. Method. A comprehensive literature search in accordance with the Preferred Reporting Items for Systematic review and Meta-analysis (PRISMA) guidelines was conducted using PubMed, Embase, MEDLINE and Cochrane databases. Exclusion criteria included patients < 18 years of age, follow-up <11 months, and a score < 6 on the National Institute of Health quality assessment tool. Results. 15 articles, encompassing 631 PJIs in 626 patients, were included in the final analysis, all level IV case series. The quality of many studies was impeded by a retrospective design (14/15), a relative small study population (10 out of 15 studies had less than 50 patients), selection bias, and remarkable heterogeneity in terms of catheter type, antibiotic type, dose and duration of IA antibiotics and techniques of surgical revision. 347 were chronic infections, 66 acute infections and 218 unknown. The majority was treated with single-stage revision with adjuvant IA antibiotic infusion (499/631, 79.1%). The remaining PJIs were treated with stand-alone IA antibiotic infusion (77/631, 12.2%), DAIR with adjuvant IA antibiotic infusion (36/631, 5.7%) or two-stage revision with adjuvant IA antibiotic infusion (19/631, 3.0%). Mean duration of IA antibiotic infusion was 19 days (range 3–50), although most patients received a combination of both IA and systemic (IV or PO) antibiotics. An overall failure rate (defined as failures of infection eradication/total PJIs) of approximately 11% was found. The use of IA antibiotic infusion as a stand-alone treatment was associated with a higher failure rate. In total 117 complications occurred in 631 cases (18.5%). Of these, 71 were non-catheter-related (60.7%) and 46 were catheter-related (39.3%). The most common catheter-related complications were premature loss of the catheter (18/46), developing a fistula (5/46), and elevated blood urea nitrogen (BUN) and creatinine levels (12/46). Conclusions. Due to the lack of comparative studies the (added) benefit of IA antibiotic infusion in the treatment of PJI remains uncertain. From a theoretical point of view it seems likely that is should not be used as a stand-alone treatment. A prospective randomized controlled trial using a well-described infusion protocol is needed to see if the potential benefits justify the increased costs, labour and catheter-related complications of this treatment modality

Aim. Serum parameters continue to be a focus of research in diagnosing periprosthetic joint infections (PJI). Several workgroups have recently proposed serum Albumin-Globulin-Ratio (AGR) as a potential new biomarker. Due to controversies in the literature, its usability in clinical practice remains uncertain. The aim of this study was to assess the value of serum AGR in diagnosing PJI preoperatively, especially in comparison with the well-established marker C-reactive Protein (CRP). Method. From January 2015 to June 2022, patients with indicated revision hip (rTHA) and knee (rTKA) arthroplasty were included in this retrospective cohort study of prospectively collected data. A standardized diagnostic workup was performed using the 2021 European Bone and Joint Infection Society (EBJIS) definition of PJI, excluding CRP. Diagnostic accuracies of serum AGR and CRP were calculated by receiver operating characteristic curve (ROC) analysis. A z-test was used to compare the area under the curves (AUC). Results. A total of 275 patients with rTHA and rTKA were included, 144 joints (52.4%) were identified as septic. Decreased AGR and elevated CRP were strongly associated with PJI, optimal diagnostic thresholds were calculated with 1.253 and 9.4 mg/L, respectively. Sensitivities were 62.5% (95%-confidence interval: 54.3–70.0) and 73.6% (65.8–80.1), and specificities 84.7% (77.5–89.9) and 87.8% (80.9–92.4), respectively. CRP showed a significantly higher AUC than AGR (0.807 (0.761–0.853) and 0.736 (0.686–0.786); p<0.0001). Subgroup analysis of acute versus chronic infections yielded significantly higher diagnostic accuracies in acute PJI for both parameters (p<0.0001). Similar results were observed when focusing on the causative microorganism; a better diagnostic performance was observed in high-virulence PJI compared to low-virulence PJI (p≤0.005). Furthermore, higher AUCs were calculated in knee PJI compared with hip PJI, with a significant difference for AGR (p=0.043). Conclusions. Due to its limited diagnostic accuracy, serum AGR cannot be recommended as an additional marker for diagnosing PJI. Serum parameters are generally unspecific and can be influenced by comorbidities and other foci of infection. Additionally, parameters may remain within normal levels in low-grade PJI. Evaluating AGR, further possible pitfalls must be considered, for example an increased latency until bottom values are reached and the impact of malnutrition

Aim. The gold standard treatment for late acute hematogenous (LAH) periprosthetic joint infection (PJI) is surgical debridement, antibiotics and implant retention (DAIR). However, this strategy is still controversial in the case of total knee arthroplasty (TKA) as some studies report a higher failure rate. The aim of the present study is to report the functional outcomes and cure rate of LAH PJI following TKA treated by means of DAIR at a long-term follow-up. Method. A consecutive prospective cohort consisting of 2,498 TKA procedures was followed for a minimum of 10 years (implanted between 2005 and 2009). The diagnosis of PJI and classification into LAH was done in accordance with the Zimmerli criteria (NEJM 2004). The primary outcome was the failure rate, defined as death before the end of antibiotic treatment, a further surgical intervention for treatment of infection was needed and life-long antibiotic treatment or chronic infection. The Knee Society Score (KSS) was used to evaluate clinical outcomes. Surgical management, antibiotic treatment, the source of infection (primary focus) and the microorganisms isolated were also assessed. Results. Among the 2,498 TKA procedures, 10 patients were diagnosed with acute hematogenous PJI during the study period (0.4%). All those 10 patients were operated by means of DAIR, which of course included the polyethylene exchange. They were performed by a knee surgeon and/or PJI surgeon. The failure rate was 0% at the 8.5 years (SD, 2.4) follow-up mark. The elapsed time between primary total knee replacement surgery and the DAIR intervention was 4.7 years (SD, 3.6). DAIR was performed at 2.75 days (SD 1.8) of the onset of symptoms. The most common infecting organism was S. aureus (30%) and E. coli (30%). There were 2 infections caused by coagulase-negative staphylococci and 2 culture-negative PJI. All culture-positive PJI microorganisms were susceptible to anti-biofilm antibiotics. The source of infection was identified in only 3 cases. The mean duration of antibiotic treatment was 11.4 weeks (SD 1.9). The postoperative clinical outcomes were excellent, with a mean KSS of 84.1 points (SD, 14.6). Conclusions. Although the literature suggests that TKA DAIR for acute hematogenous periprosthetic joint infection is associated with high rates of failure, the results presented here suggest a high cure rate with good functional outcomes. Some explanations for this disparity in results may be the correct diagnosis of LHA, not misdiagnosing acute chronic PJI, and a thorough debridement by surgeons specialized in PJI

Aims. Two-stage exchange revision total hip arthroplasty (THA) performed in case of periprosthetic joint infection (PJI) has been considered for many years as being the gold standard for the treatment of chronic infection. However, over the past decade, there have been concerns about its safety and its effectiveness. The purposes of our study were to investigate our practice, collecting the overall spacer complications, and then to analyze their risk factors. Methods. We retrospectively included 125 patients with chronic hip PJI who underwent a staged THA revision performed between January 2013 and December 2019. All spacer complications were systematically collected, and risk factors were analyzed. Statistical evaluations were performed using the Student's t-test, Mann-Whitney U test, and Fisher's exact test. Results. Our staged exchange practice shows poor results, which means a 42% mechanical spacer failure rate, and a 20% recurrent infection rate over the two years average follow-up period. Moreover, we found a high rate of spacer dislocation (23%) and a low rate of spacer fracture (8%) compared to the previous literature. Our findings stress that the majority of spacer complications and failures is reflecting a population with high comorbid burden, highlighted by the American Society of Anesthesiology grade, Charlson Comorbidity Index, and Lee score associations, as well as the cardiac, pulmonary, kidney, or hepatic chronic conditions. Conclusion. Our experience of a two-stage hip exchange revision noted important complication rates associated with high failure rates of polymethylmethacrylate spacers. These findings must be interpreted in the light of the patient’s comorbidity profiles, as the elective population for staged exchange has an increasing comorbid burden leading to poor results. In order to provide better results for this specific population, our conclusion suggests that comparative strategy studies are required to improve our therapeutic indication. Cite this article: Bone Jt Open 2022;3(6):485–494

Two-stage exchange revision total hip arthroplasty performed in case of infection has been considered during many years the gold standard for treatment of chronic infection. Nevertheless, during the last decade, concerns have risen regarding its safety and its efficiency. The purpose of our study was to, first investigate the spacer complications, then to analyze their risks factors. We retrospectively included 125 patients with chronic hip periprosthetic joint infection who underwent a two stage exchange revision arthroplasty performed between January 2013 and December 2019. All spacer complications were systematically collected and risk factors were analyzed. Statistical evaluation were performed using the Student and Mann-Whitney tests. Our study confirms the hypothesis of a high-risk strategy with 42% of patients who had a mechanical spacer failure and a 20% recurrence of infection during the average two years period of follow-up. We found a high rate of spacer migration (23%) and a low rate of spacer fracture (8%) compared to literature. The most important finding was that the majority of spacer complications and failures were found in a population with high medical comorbidities as highlighted by the ASA, Charlson and Lee score associations, as well as with the cardiac, pulmonary, kidney or hepatic chronic conditions. This study showed that a two-stage hip exchange revision is a high-risk procedure regarding complications and mechanical failures of PMMA spacers. In patients with high medical comorbidities, other strategies may be considered and interdisciplinary cooperation with other facilities are needed to identify and control each risk factor

Aim. We aimed to assess the incidence and the outcome of Gram-negative prosthetic-joint infections (PJI) in 3 international tertiary hospital. Method. We included patients with Gram-negative PJI at Humanitas Clinical and Research Hospital (Milan, Italy), Centre Hospitalier Universitaire Vaudois (Lausanne, Switzerland) and Hospital Parc de Salut Mar (Barcelona, Spain) between 2014 and 2018 in a retrospective cohort. We described the treatment's success rate according to Gram-negative species and type of surgical procedure. Results. In the present cohort we have 780 PJI out of which 71 (9.1%) were caused by Gram-negative bacteria (polymicrobial infection 30%, Escherichia coli 25%, Pseudomonas aeruginosa 20%, Proteus spp. 4%, Klebsiella spp. 3%, Morganella morganii 3%, Enterobacter 3%, others 12%). Gram-negative PJI were more common in females (60%) than males (40%). Sixty percent had a hip infection, 40% a knee infection, the median age was 74 years and the median ASA score was 3. It was a chronic infection in 60% of the cases and an acute one in 40%. Two-step exchange was performed in 55%, débridement and retention (DAIR) in 30%, one-step exchange in 11% and implant removal without replacement in 4% of the patients. The overall treatment success rate was 89%. The success rate was better for two-step exchange (95%) compared to DAIR (81%) and one-step exchange (87%) (p=0.068). The median antibiotic duration was 68 days and ciprofloxacin was used in 70% of the cured patients versus in 88% of the failures (p=0.388). Infections caused by Escherichia coli were associated with a lower success rate (83%) especially compared to Pseudomonas aeruginosa (93%) and polymicrobial infections (90%) (p=0.358). Finally, the success rate was better in knee PJI compared to hip PJI (97% versus 83%, p=0.121) and in females compared to males (93% versus 82%, p=0.121). Conclusions. The treatment's success of Gram-negative PJI is comparable to reported rates for all bacteria. However, our results suggest that surgical management with two-step exchange might be useful in selected patients’ groups such as those with Escherichia coli PJI. Moreover, ciprofloxacin use seems not to improve cure rate

Aim. Staphylococcus epidermidis (S. epidermidis) is one of the main pathogens responsible for bone and joint infections especially those involving prosthetic materials (PJI). Although less virulent than S. aureus, S. epidermidis is involved in chronic infections notably due to its ability to form biofilm. Moreover, it is frequently multiresistant to antibiotics. In this context, the development of additional or alternative antibacterial therapies targeting the biofilm is a priority. Method. The aim of this study was to evaluate in vitro the activity of phage lysin exebacase (CF-301) against biofilms formed by 19 S. epidermidis clinical strains responsible for PJI. We determined the remaining viable bacteria inside the biofilm (counting after serial dilution and plating) and the biomass (bacteria and extracellular matrix, using crystal violet staining) after 24h of exposition to exebacase at different concentrations, alone (0.05; 0.5; 5; 50 and 150 mg/L) or in combination (5, 50 and 150 mg/L) with antibiotics commonly used to treat multi-resistant S. epidermidis PJI (rifampin (1 mg/L), vancomycin (10mg/L) and daptomycin (10mg/L)). In this study, synergy was defined as a significantly higher effect of the association in comparison to the sum of the effect of each molecule. Results. Exebacase showed a dose-dependent reduction of biomass, ranging from 11 % at 0.5 mg/L to 66 % at 150 mg/L. Exebacase showed a significant bactericidal activity at 50 and 150 mg/l, with a mean decrease of the inoculum of 0.94 and 1.7 log, respectively. In addition, synergistic effects were observed in association with i) rifampin (1 mg/L) showing a mean decrease up to 84% of the biomass and 3.5 log CFU at 150 mg/L of exebacase, ii) vancomycin (10 mg/L) showing a mean decrease up to 81% of the biomass and 2.82 log CFU at 150 mg/L of exebacase, iii) and daptomycin (10 mg/L) showing a mean decrease up to 85% of the biomass and 3.1 log CFU at 150 mg/L of exebacase. Conclusions. Exebacase showed, in vitro, synergistic activity with antibiotics against S. epidermidis biofilms. It is a promising adjuvant therapy to rifampin, vancomycin and daptomycin in the context of PJI. Further studies are needed, in vitro to understand the mechanism of action on S. epidermidis biofilm and the heterogeneity of strain behaviour and in vivo to confirm the present data

Aim. To retrospectively evaluate infection eradication rate of DAIR procedures performed in our tertiary referral center. We analyzed whether the outcome was influenced by time of infection after arthroplasty, previous surgery or causative pathogen. Methods. We retrospectively collected data of 81 patients treated with DAIR for periprosthetic joint infections after hip (n=48) and knee (n=33) arthroplasty between 2011 and 2017. Patients were divided into 3 groups: acute early infections (occurring <4 weeks, 29 cases), late chronic infections (occurring >4 weeks postoperative, 49 cases) and acute haematogenous infections (occuring >3 months after surgery with symptoms less than 4 weeks, 3 cases). Primary outcome was successful infection eradication after treatment within one year. Eradication failure was determined as unplanned subsequent surgery because of persistent infection, use of suppressive antibiotics or signs of infection at one year follow-up. Results. Patients treated with DAIR (n=25) after previous infection treatment such as DAIR, one- or a two-stage revision showed a success of 44% versus 71% in patients treated with DAIR after primary arthroplasty (n=56). A majority of the patients had a monomicrobial PJI (72%) versus polymicrobial (22%), while 6% were culture negative. Acute early infections, late chronic infections and hematogenous infections had a success rate of 66%, 61% and 67% respectively. The most common pathogen in monomicrobial infections was Staphylococcus aureus (19%) followed by Staphylococcus epidermis (12%). Patients with Staphylococcus aureus infections had a success rate of 60% compared to 80% for Staphylococcus epidermis infections. Conclusion. Our study shows that good results can be expected when DAIR is performed in patients with acute and late chronic PJI even in a more difficult-to-treat patient population. Interestingly, in 4 out of 10 patients who received a secondary DAIR procedure, the implant could still be retained. Lastly, specific causative organisms can lead to a lower success rate of DAIR

Aim. Although established serum inflammatory biomarkers, such as serum C-reactive protein (CRP) and serum white blood cell count (WBC), showed low accuracies in the literature, they are still commonly used in diagnosing periprosthetic joint infections (PJI). For a sufficient preoperative diagnosis novel more accurate serum parameters are needed. The aim of our study was to evaluate the performances of the established and novel routinely available serum parameters in diagnosing periprosthetic joint infections when using the proposed European Bone and Joint Infection Society (pEBJIS) criteria. Method. In this retrospective study, 177 patients with an indicated revision surgery after a total joint replacement were included from 2015 to 2019. The easily accessible and routinely available serum parameters CRP, WBC, the percentage of neutrophils (%N), the neutrophils to lymphocytes ratio (NLR), fibrinogen and the platelet count to mean platelet volume ratio (PC/mPV) were evaluated preoperatively. The performances were examined via receiver operating characteristic (ROC) curve analysis (AUC). The curves were compared using the z-test. Seventy-five cases (42%) showed a PJI based on the pEBJIS-criteria. Results. The sensitivities of serum CRP (cut-off: ≥10mg/L), WBC (≥10×10^9 cells/L), %N (≥69.3%), NLR(≥ 3.82), fibrinogen (≥ 457 mg/dL), and PC/mPV (≥ 29.4) were calculated with 68% (95% CI: 57–78), 36% (26 – 47), 66% (54 – 76), 63% (51 – 73), 69% (57 – 78), and 43% (32 – 54), respectively. Specificities were 87% (79 – 93), 89% (81 – 94), 67% (57 76), 73% (63 – 81), 89% (80 – 93), and 81% (72 – 88), respectively. Serum CRP and fibrinogen showed better performances than the other evaluated serum parameters (p<0.0001). The median serum CRP (17.6 mg/L) in patients with PJI caused by a low virulence microorganism was lower compared with infections caused by high virulence organisms (49.2 mg/L; p=0.044). Synovial fluid leucocyte count and histology showed better accuracies than serum CRP, serum WBC, %N, NLR, serum fibrinogen, and PC/mPV (p<0.0001). Conclusions. Although serum CRP and fibrinogen showed the best performances among the evaluated serum inflammatory markers, their results should be interpreted with caution in clinical practice. Serum parameters may remain normal in chronic infections or may be elevated in patients with other inflammatory conditions. In addition, they also correlated poorly with synovial fluid leukocyte count and histology. Therefore, serum parameters are still insufficient to confirm or exclude a periprosthetic joint infection. Hence, they can only be recommended as suggestive criteria in diagnosing PJI

Aims. This study aimed to explore whether serum combined with synovial interleukin-6 (IL-6) measurement can improve the accuracy of prosthetic joint infection (PJI) diagnosis, and to establish the cut-off values of IL-6 in serum and synovial fluid in detecting chronic PJI. Methods. Patients scheduled to have a revision surgery for indications of chronic infection of knee and hip arthroplasties or aseptic loosening of an implant were prospectively screened before being enrolled into this study. The Musculoskeletal Infection Society (MSIS) definition of PJI was used for the classification of cases as aseptic or infected. Serum CRP, ESR, IL-6, and percentage of polymorphonuclear neutrophils (PMN%) and IL-6 in synovial fluid were analyzed. Statistical tests were performed to compare these biomarkers in the two groups, and receiver operating characteristic (ROC) curves and area under the curve (AUC) were analyzed for each biomarker. Results. A total of 93 patients were enrolled. There was no difference in demographic data between both groups. Synovial fluid IL-6, with a threshold of 1,855.36 pg/ml, demonstrated a mean sensitivity of 94.59% (95% confidence interval (CI) 81.8% to 99.3%) and a mean specificity of 92.86% (95% CI 82.7 to 98.0) for detecting chronic PJI. Then 6.7 pg/ml was determined to be the optimal threshold value of serum IL-6 for the diagnosis of chronic PJI, with a mean sensitivity of 97.30% (95% CI 85.8% to 99.9%) and a mean specificity of 76.79% (95% CI 63.6% to 87.0%). The combination of synovial IL-6 and serum IL-6 led to improved accuracy of 96.77% in diagnosing chronic PJI. Conclusion. The present study identified that a combination of IL-6 in serum and synovial IL-6 has the potential for further improvement of the diagnosis of PJI. Cite this article: Bone Joint Res 2020;9(9):587–592

Aim. Shoulder prosthesis chronic infection is a rare but serious complication, likely to lead to re-interventions and poor functional outcome. Two-stage exchange surgery is considered the standard procedure by most authors. Our hypothesis was that one-stage revision procedure is a valid therapeutic option in the management of chronic infections of shoulder arthroplasty. Method. This was a mono-center retrospective cohort study. All patients who underwent, during the inclusion period, a one-stage revision procedure for a chronic infection of shoulder arthroplasty were included. All patients underwent clinical evaluation (Constant-Murray score), radiological examination (standard X-rays) and a blood test (Complete Blood Count and C-reactive protein), at a minimal one-year follow-up. Primary endpoint of this study was the infectious outcome and secondary endpoints were the functional and radiographic outcomes. Results. 16 shoulder prosthesis in 14 patients (5 females, 9 males) were included. Mean time between primary prosthesis implantation and exchange surgery was 40 months (1–145). Mean follow up was 30,5 months. The principal micro-organism involved was Propionibacterium acnes (9/16) and multiple organisms were found in 6 patients. In 14/16 (87,5%) shoulders, we found no sign of persistent infection at last follow-up. 2/16 (12,5%) shoulders were considered as still infected. On these 2 patients still infected, one refused further revision and the other was not in a good enough medical condition to undergo another procedure. 2 patients required an additional one-stage procedure for a new infection (new pathogen) after a period of two years, both free of infection at last follow-up. At last follow-up, mean Constant score was 54,8 (23–82). 7/14 (50%) patients were satisfied or very satisfied with the global fonctionnal result. Conclusions. One-stage revision procedure seems to be a valid therapeutic option in the management of infected shoulder prosthesis, as it allowed us to eradicate the infection in 87,5% patients in our serie, with a fair clinical result

Aim. The aim of the study was to assess the accuracy of the alpha defensin lateral flow test for diagnosis of periprosthetic joint infection (PJI) using an optimized diagnostic algorithm and three classification systems. In addition, we compared the performance with synovial fluid leukocyte count, the most sensitive preoperative test. Method. In this prospective multicenter study we included all consecutive patients with painful prosthetic hip and knee joints undergoing diagnostic joint aspiration. Alpha defensin lateral flow test was used according to manufacturer instructions. The following diagnostic criteria were used to confirm infection: Musculoskeletal Infection Society (MSIS), Infectious Diseases Society of America (IDSA) and Swiss orthopedics and Swiss Society of Infectious Diseases (SOSSID). In the latter, PJI was confirmed when at least one of following criteria applied: macroscopic purulence, sinus tract, positive cytology of joint aspirate (>2000 leukocytes/μl or >70% granulocytes), histological proof of acute inflammation in periprosthetic tissue, positive culture (from aspirate, tissue or sonication fluid). Infection was classified as chronic, if symptom duration was more than 3 weeks or if infection manifested after more than 1 month after surgery. The sensitivity and specificity of the alpha defensin lateral flow test and leukocyte count in synovial fluid were calculated and compared using McNemar Chi-square test. Results. Of 151 included patients evaluated for painful prosthetic joints (103 involved knees, 48 hips), the median patient age was 69 years (range, 41–94 years) and 75 patients were female. Systematically evaluating the included patients according to the different diagnostic criteria, MSIS and IDSA revealed both 33 patients with PJI (22%), whereas SOSSID disclosed 47 septic failures (31%), among them 36 chronic infections (77%). Sensitivity of the test was 79% when applying MSIS criteria, 70% with IDSA criteria and 57% with SOSSID criteria. Specificity ranged from 96% (IDSA) to 98% (MSIS) and 99% (SOSSID). Applying the most stringent definition criteria (SOSSID), leukocyte count showed significantly higher sensitivity than the alpha defensin lateral flow test (91% vs. 57%, p<0.001), especially in chronic infections (88% vs. 48%, p<0.001.) In acute infections, both tests detected all infection cases. Processing turnaround time was shorter in Alpha defensin lateral flow test than automated leukocyte count (10 min vs. 2–4 hours). Conclusions. Semi-quantitative alpha defensin test was rapid and highly specific for diagnosing PJI (> 95%). However, sensitivity was limited, especially when applying definition criteria including also low grade infections (SOSSID criteria). Therefore, the alpha defensin lateral flow test does not allow a reliable exclusion of PJI, especially not in chronic infections but may be used as confirmatory test

Staphylococcus aureus (SA), the predominant pathogen in human osteomyelitis, is known to persist by forming intracellular reservoirs, including in bone cells (Schwarz et al., 2019, Yang et al., 2018, Krauss et al., 2019, Gao et al., 2020, Bosse et al., 2005), promoting decreased antibiotic susceptibility. However, there are no evidence-based treatment guidelines for intracellular SA infections in osteomyelitis. We sought to address this by systematically reviewing the literature and, testing a selection of antibiotic treatments in a clinically relevant in vitro assay. We conducted a systematic review of the literature to determine the current evidence for the efficacy of antibiotics against intracellular SA infections relevant to osteomyelitis. For the antibiotics identified as potentially useful, we determined their minimal inhibitory concentration (MIC) against 11 clinical osteomyelitis SA- isolates. We selected those for further testing reported able to reach a higher concentration in the bone than the identified MIC against the majority of strains. Thus, rifampicin, oxacillin, linezolid, levofloxacin, oritavancin and doxycycline were tested in human SaOS-2-osteocyte infection models (Gunn et al., 2021) of acute (1d) or chronic (14d) infection to clear intracellular SA. Antibiotics were tested at 1x/4x/10x the MIC for the duration of 1d or 7d in each model. A systematic review found that osteoblasts and macrophages have mostly been used to test immediate short-term activity against intracellular SA, with a high variability in methodology. However, some extant evidence supports that rifampicin, oritravancin, linezolid, moxifloxacin and oxacillin may be effective intracellular treatments. While studies are ongoing, in vitro testing in a clinically relevant model suggests that rifampicin, oxacillin and doxycycline could be effectively used to treat osteomyelitic intracellular SA infections. Importantly, these have lower MICs against multiple clinical isolates than their respective clinically-achievable bone concentrations. The combined approach of a systematic review and disease-relevant in vitro screening will potentially inform as to the best approach for treating osteomyelitis where intracellular SA infection is confirmed or suspected

Aim. Antibiotics have limited activity in the treatment of multidrug-resistant or chronic biofilm-associated infections, in particular when implants cannot be removed. Lytic bacteriophages can rapidly and selectively kill bacteria, and can be combined with antibiotics. However, clinical experience in patients with surgical infections is limited. We investigated the outcome and safety of local application of bacteriophages in addition to antimicrobial therapy. Method. 8 patients (2 female and 6 male) with complex orthopedic and cardiovascular infections were included, in whom standard treatment was not feasible or impossible. The treatment was performed in agreement with the Article 37 of the Declaration of Helsinki. Commercial or individually prepared bacteriophages were provided by ELIAVA Institute in Tbilisi, Georgia. Bacteriophages were applied during surgery and continued through drains placed during surgery three times per day for the following 5–14 days. Follow-up ranged from 1 to 28 months. Results. Median age was 57 years, range 33–75 years. Two patients were diagnosed with a persistent knee arthrodesis infection, one chronic periprosthetic joint infection (PJI), one cardiovascular implantable electronic device (CIED) infection and four patients with left ventricular assist device (LVAD) infection. The isolated pathogens were multi-drug-resistant Pseudomonas aeruginosa (n=3), methicillin-sensitive Staphylococcus aureus (n=4), methicillin-resistant Staphylococcus aureus (MRSA) (n=1) and methicillin-resistant Staphylococcus epidermidis (MRSE) (n=1). 4 infections were polymicrobial. 5 patients underwent surgical debridement with retention of the implant, 1 patient with PJI underwent the exchange of the prosthesis and one patient with LVAD infection was treated conservatively. All patients received intravenous and oral antibiotic therapy and local application of bacteriophages. At follow-up of 12 month, 5 patients were without signs or symptoms of infection, whereas in one patient with LVAD infection, a relapse was observed with emergence of phage-resistant Pseudomonas aeruginosa. In this patient, no surgical revision was performed. Conclusions. Bacteriophage therapy may represent a valid additional approach, when standard antimicrobial and surgical treatment is not possible or feasible, including in difficult-to-treat infections. In our case series, 5 of 6 patients were infection free after 1 year. Further studies need to address the optimal bacteriophage administration route, concentration, duration of treatment and combination with antimicrobials

Aim. We report on the performance of a simple algorithm using a combination of synovial fluid White blood cell count(WBC), C-reactive protein(CRP) and α-Defensin(AD) tests to aid in the diagnosis of prosthetic joint infections. Methods. Sixty-six synovial fluid samples were collected prospectively in patients with suspected PJI (hip and knee). All samples were tested by: WBC counts (read manually) and CRP test (Alere-Afinion™ validated in-house); and on 37 of these with AD test. Synovial fluid samples were collected in 5 ml ethylenediaminetetraacetic acid (EDTA) tubes. Samples that were very viscous were pre-processed by the addition of 100µl of hyaluronidase solution. Grossly blood stained and clotted samples were excluded. A clinical diagnosis of infection was based IDSA definitions. 1. Cut offs of >3000 × 10. 6. cells/L for total synovial WBC count and >12mg/L for CRP were used to define infection. 2,3. . Results. Of 66 samples tested, 20 samples were categorised as clinically infected. Combination of WBC count and CRP yielded a sensitivity of 95% (95% CI: 75.13% to 99.87%) and specificity of 100% (95% CI: 92.29% to 100.00%). Only one patient, who had a chronic infection with S.epidermidis and S.warneri, had a CRP and WBC count that was falsely negative (<5mg/L and 93 × 10. 6. cells/L respectively). AD test was used on 37 samples (of which 20 were infected). Sensitivity of this test alone was 85.71% (95% CI: 63.66% to 96.95%) and specificity 87.5% (95% CI: 61.65% to 98.45%). There were 2 falsely positive AD test results (one of whom had a metal on metal prosthesis) and 3 false negative results (2 E.coli infections and one patient with chronic infection with S.epidermidis and S.warneri). Conclusion. Use of a combination of synovial fluid WBC count and CRP (both of which can be performed using simple and inexpensive laboratory tests), has a sensitivity of 95% and 100% specificity in the diagnosis of PJI. AD test may be useful on some occasions when near patient testing result may affect patient management

Orthopaedic and trauma implant related infection remains one of the major complications that negatively impact clinical outcome and significantly increase healthcare expenditure. Hydroxyapatite has been used for many years to increase implant osseointegration. Silver has been introduced into hydroxyapatite as an antimicrobial coating for orthopedic implants. This surface coatings can both increase tissue compatibility and prevent implant-related infections. We examined infection markers and blood silver values, liver and kidney function tests of 30 patients with of three groups of orthopedic implants, external fixators, intramedullary nails and hip replacements, coated with Ag + ion doped CaP based ceramic powder to determine safety and effectiveness of this dual-function coating. During 1 year follow-up, the pin sites were observed at the external fixator group, and wound areas for the proximal femoral nail and hip arthroplasty group at regular intervals. In addition, liver and kidney function tests, infection markers and blood silver values were checked in patients. In the external fixator group, only 4 out of 91 pin sites (%4.39) were infected. The wound areas healed without any problem in patients with proximal femoral nails and hip arthroplasty. There was no side effect suggesting silver toxicity such as systemic toxic side effect or argyria in any patient and blood silver level did not increase. Compared to similar patient groups in the literature, much lower infection rates were obtained (p = 0.001), and implant osseointegration was good. In patients with chronic infection, the implants were applied acutely after removing the primary implant and with simple debridement. Unlike other silver coating methods, silver was trapped in hydroxyapatite crystals in the ionic form, which is released from the coating during the process of osseointegration, thus, the silver was released into the systemic circulation gradually that showed antibacterial activity locally. We conclude that the use of orthopedic implants with a silver ion added calcium phosphate-based special coating is a safe method to prevent the implant-related infection. This work was supported by TUBİTAK Project Number 315S101

Cement-in-cement femoral revision is a proven technique in revision total hip arthroplasty, with excellent results when using standard sized Exeter stems. The Exeter 44/00 125 mm short revision stem was introduced in 2004 to facilitate cement-in-cement revision. The stem is 25mm shorter and has a slimmer body to allow greater flexibility to adjust depth of insertion and version of the stem. However, it is not known if this change in stem length and size effects its longer term performance. We therefore reviewed the clinical outcome and survival of the Exeter 44/00 short stem used for cement-in-cement revision in our unit, with a minimum of 5 years follow up. 166 cases were performed between 2004 and 2010. 103 hips were available for 5 year clinical and radiological follow up, with 91 hips surviving to final review in 2017. At 5 years, 43 hips had died, 13 were revised and 7 were too frail to attend clinical review. The fate of all 166 hips were known and included in the survival analysis. Median clinical scores improved significantly. Sixteen hips required re-revision (infection 6, loose cup 3, periprosthetic fracture 3, instability 2, stem fracture with chronic infection 1 and pain 1). Kaplan-meier survival analysis revealed 100% survival for aseptic loosening, 96.8% survival for stem failure and 88.9% survival for all causes. This is the largest series with the longest follow up of the Exeter 44/00 short revision stem. The stem performs equally well as standard Exeter stems with regards to aseptic loosening. The single stem fracture occurred secondary to bone loss in chronic infection, highlighting the importance of providing adequate proximal support for the stem. Periprosthetic fracture occurred in 2.4% of this series of revision cases. Larger registry-based studies may provide additional information on the performance of this stem

Recent evidence suggests that the microbial community, its spatial distribution and activity play an important role in the prolongation of treatment and healing of chronic infections. Standard bacterial cultures often underestimate the microbial diversity present in chronic infections. This lack of growth is often due to a combination of inadequate growth conditions, prior usage of antibiotics and presence of slow-growing, fastidious, anaerobic or unculturable bacteria living in biofilms. Thus, diagnosis of chronic infections is challenged by lack of appropriate sampling strategies and by limitations in microbiological testing methods. The purpose of this study was to improve sampling and diagnosis of prosthetic joint infections (PJI) and chronic wounds, especially considering the biofilm issue. Systematic sampling, sonication of prosthesis and extended culture were applied on patients with chronic wounds and patients with suspected PJIs. Optimized DNA extraction, quantitative PCR, cloning, next generation sequencing and PNA FISH were applied on the different types of specimens for optimized diagnosis. For further investigation of the microbial pathogenesis, in situ transcriptomics and metabolomics were applied. In both chronic wounds and PJIs, molecular techniques detected a larger diversity of microorganisms than culture methods in several patients. Especially in wounds, molecular methods identified more anaerobic pathogens than culture methods. A heterogeneous distribution of bacteria in various specimens from the same patient was evident for both patient groups. In chronic wounds, multiple biopsies from the same ulcer showed large differences in the abundance of S. aureus and P. aeruginosa at different locations. Transcriptomic and metabolomic analyses indicated the important virulence genes and nutrient acquisition mechanisms of Staphylococcus aureus in situ. As an example, diagnosis and treatment of a patient with a chronic biofilm prosthesis infection persisting for 7 years will be presented. Our studies show that diagnosis of chronic biofilm related infections required multiple specimen types, standardized sampling, extended culture and molecular analysis. Our results are useful for improvement of sampling, analysis and treatment in the clinic. It is our ambition to translate studies on bacterial activity into clinical practice in the future

Aim. To evaluate a panel of peripheral blood and synovial fluid biomarkers for the identification of periprosthetic joint infection PJI. Method. Peripheral blood and synovial fluid measurements of CD64, IL-1a, IL-1b, IL-6, IL-8, IL-10, IL-17, Alpha Defensin and CRP were made on samples collected from patients with suspected PJI using a combination of flow cytometry (CD64), ELISA (Alpha Defensin) and MSD Electrochemiluminescence (IL-1a, IL-1b, IL-6, IL-8, IL-10, IL-17). Receiver operating characteristic (ROC) curves which combine sensitivity and specificity were created for each marker using GraphPad PRISM statistical software. The diagnosis of infection was based on MSIS major criteria. Results. A total of 35 infections were identified (12 acute, 23 chronic). The best performing peripheral blood biomarker in both acute and chronic PJI was CRP with an area under the curve (AUC) of 0.88 (sensitivity 83%, specificity 94%) in acute infection and 0.82 in chronic infection (sensitivity 80%, specificity 85%). In synovial fluid the best performing acute infection marker was CRP with an AUC of 0.94 (sensitivity 87.5%, specificity 95%) and in chronic cases was Alpha defensin with an AUC of 0.98 (sensitivity 100%, specificity 85%). Conclusions. CRP measured in peripheral blood shows excellent diagnostic characteristics in both acute and chronic cases. This is also replicated in synovial fluid from acute PJIs but not in chronic infection where Alpha defensin showed the best performance

Aim. Whether pre-operative microbiological sampling contributes to the management of chronic peri-prosthetic infection remains controversial. We assessed agreement between the results of pre-operative and intra-operative samples in patients undergoing single-stage prosthesis exchange to treat chronic peri-prosthetic infection. The tested hypothesis was that agreement between pre-operative and intra-operative samples exceeds 75% in patients undergoing single-stage exchange of a hip or knee prosthesis to treat chronic peri-prosthetic infection. Method. This single-centre retrospective study included 85 single-stage prosthesis exchange procedures in 82 patients with chronic peri-prosthetic infection at the hip or knee. Agreement between pre-operative and intra-operative sample results was evaluated. Changes to the initial antibiotic regimen made based on the intra-operative sample results were recorded. Associations between sample agreement and infection-free survival were assessed. Results. Of 149 pre-operative samples, 109 yielded positive cultures, in 75/85 cases. Of 458 intra-operative samples, 354 yielded positive cultures, in 85/85 cases. Agreement was complete in 54 (63%) cases and partial in 9 (11%) cases; there was no agreement in the remaining 22 (26%) cases. The complete agreement rate was significantly lower than 75% (p=0.01). The initial antibiotic regimen was inadequate in a single case. Agreement between pre-operative and intra-operative samples was not significantly associated with infection-free survival. Conclusions. Pre-operative sampling may contribute to the diagnosis of peri-prosthetic infection but is neither necessary nor sufficient to confirm the diagnosis and identify the causative agent. The spectrum of the initial antibiotic regimen cannot be safely narrowed based on the pre-operative sample results. We suggest the routine prescription of a probabilistic broad-spectrum antibiotic regimen immediately after the prosthesis exchange, even when a pathogen was identified before surgery. No funding from any part was received for the purpose of this study

Aims. The aim of this study was to determine the prevalence and characteristics of C-reactive protein (CRP)-negative prosthetic joint infection (PJI) and evaluate the influence of the type of infecting organism on the CRP level. Patients and Methods. A retrospective analysis of all PJIs affecting the hip or knee that were diagnosed in our institution between March 2013 and December 2016 was performed. A total of 215 patients were included. Their mean age was 71 years (. sd. 11) and there were 118 women (55%). The median serum CRP levels were calculated for various species of organism and for patients with acute postoperative, acute haematogenous, and chronic infections. These were compared using the Kruskal–Wallis test, adjusting for multiple comparisons with Dunn’s test. The correlation between the number of positive cultures and serum CRP levels was estimated using Spearman correlation coefficient. Results. Preoperative CRP levels were normal (< 10 mg/l) in 77 patients (35.8%) with positive cultures. Low-virulent organisms were isolated in 66 PJIs (85.7%) with normal CRP levels. When grouping organisms by species, patients with an infection caused by Propionibacterium spp., coagulase-negative staphylococci (CNS), and Enterococcus faecalis had significantly lower median serum CRP levels (5.4 mg/l, 12.2 mg/l, and 23.7 mg/l, respectively), compared with those with infections caused by Staphylococcus aureus and Streptococcus spp. (194 mg/l and 89.3 mg/l, respectively; p < 0.001). Those with a chronic PJI had statistically lower median serum CRP levels (10.6 mg/l) than those with acute postoperative and acute haematogenous infections (83.7 mg/l and 149.4 mg/l, respectively; p < 0.001). There was a significant correlation between the number of positive cultures and serum CRP levels (Spearman correlation coefficient, 0.456; p < 0.001). Conclusion. The CRP level alone is not accurate as a screening tool for PJI and may yield high false-negative rates, especially if the causative organism has low virulence. Aspiration of the joint should be used for the diagnosis of PJI in patients with a chronic painful arthroplasty, irrespective of CRP level. Cite this article: Bone Joint J 2018;100-B:1482–86

Periprosthetic infection is a challenging complication of total knee arthroplasty (TKA) which reported incidence varies from 1 to 2% in primary TKA and 3–5% in revision TKA. Persistent infection of TKA may benefit from knee arthrodesis when all reconstruction options have failed. Knee arthrodesis also demonstrated better functional results and pain relief than other salvage procedures such as above-knee amputation. The purpose of this study was to analyze treatment results in patients who underwent knee arthrodesis following infected TKA. Retrospective study with review of the data of all patients treated in our department with knee arthrodesis for chronic infection of knee arthroplasty between 2009 and 2014. Clinical and radiographic data were evaluated as well as several variables: technique used, fusion rate, time to fusion, need for further arthrodesis and complications. Patients with less than 8 months of follow-up were excluded from this study. 46 patients were treated with knee arthrodesis in our department from 2009 to 2014 for chronic infection of total knee arthroplasty. The sample included 26 (57%) women and 20 (43%) men, median age of 70 years. In 45 patients, the technique used was compressive external fixation, while an intramedullary modular nail was used in 1 patient. Mean follow-up of these patients was 35 months (8–57). Primary knee fusion was obtained in 32 (70%) patients with a mean time to fusion of 5,8 months (4–9). 9 (20%) patients needed rearthrodesis and 7 (15%) ultimately achieved fusion. 33 (72%) patients underwent knee arthrodesis in a single surgical procedure, while 13 (28%) firstly removed knee arthroplasty and used a spacer before arthrodesis. Overall complication rate was 35%; 7 (15%) patients experienced persistent infection and 4 (9%) of these undergone above knee amputation. Treatment of septic total knee replacement is a surgical challenge. Compressive external fixation was the method of choice to perform knee arthrodesis following chronic infected TKA. Although complication rate was worrisome, overall fusion rate was satisfactory and this arthrodesis method can be safely performed in one stage

INTRODUCTION. Total joint arthroplasty continues to gain acceptance as the standard of care for the treatment of severe degenerative joint disease, and is considered one of the most successful surgical interventions in the history of medicine. However, infection of these implants, called Periprosthetic Joint Infection (PJI), remains one of the biggest challenges facing orthopaedics today. PJI can lead to additional surgeries, revision, fusion and amputation. Diagnosis of PJI. It is important to accurately diagnose PJI because its management differs from that of other causes of arthroplasty failure. In acute infection, the local signs and symptoms (e.g., severe pain, swelling, erythema, and warmth at the infected joint) of inflammation are generally present. On the other hand, chronic infection usually has a more subtle presentation, with pain alone, and is often accompanied by loosening of the prosthesis at the bone-implant interface. The diagnosis of PJI has proven quite challenging, as both acute and chronic infections can be difficult to differentiate from other forms of inflammation. The reported literature on the diagnosis of PJI has focused on evaluated laboratory tests that were never developed specifically for the diagnosis of PJI. These include the erythrocyte sedimentation rate (ESR), the serum C-reactive protein (CRP), the synovial fluid white blood cell count and the leukocyte differential. Because these tests were not made for the purpose of diagnosing PJI, it has been the responsibility of the orthopaedic community to evaluate and recommend their interpretation. This has resulted in significant confusion regarding the appropriate thresholds and optimal combination of these tests. These difficulties were the motivation for the development of a specific test for the detection of PJI. The Synovasure® Test for Periprosthetic Joint Infection (PJI). The promising diagnostic capabilities of synovial fluid biomarkers for PJI have already been reported in the literature. These biomarkers include inflammatory proteins, cytokines, and microbicidal peptides / proteins that are known to be involved in the host response to infection. Studies have demonstrated that the alpha-defensin microbicidal peptide present in human neutrophils is an ideal biomarker for PJI due to the distinct separation it achieves between positive and negative results. A specific test allowing to measure the concentration of the alpha-defensin in the synovial fluid has been developed. The specificity and the sensitivity of this test for the detection of a PJI are respectively 96% and 97%. This test has been proven to have also a high reproducibility, its results not being influenced by antibiotics. DISCUSSION. A lateral flow version of this test (Synovasure PJI, distributed exclusively in Europe by Zimmer GmbH) has been recently developed. It allows reading the results in 10 minutes and it doesn't require any laboratories for its interpretation. Currently, this test device is in clinical evaluation in more than 200 European hospitals. CONCLUSIONS. In case that the clinical evaluation of this test device is positive, this method will be a new paradigm for the diagnosis of periprosthetic joint infection

The objective of this study is to report the epidemiology and results of treatment of deep infection after a reverse shoulder arthroplasty. This is a multicenter retrospective study involving 457 reverse prostheses performed between 1992 and 2002. Fifteen patients (3%) (mean age 71 ± 9 years) presented with a deep infection. Eight were primary arthroplasties and seven were revision procedures. There were five associated peri-operative fractures and three early postoperative complications requiring surgical treatment. Infection was treated by debridement (n=4), prosthetic resection (n=10) or two-stage revision (n=1). The infection rate was 2% (8/363) for a primary reverse arthroplasty and 7% (7/94) for revisions. The infection was diagnosed at a mean of seventeen months (range, one to fifty-seven) post-operatively, corresponding to two acute, five sub-acute and eight chronic infections. The most common pathogen was P. acnes in six cases (40%). At a mean follow-up of thirty-four ± nineteen months, there were twelve remissions (80%) and three recurrent infections. The two acute infections (one debridement and one resection) and the eight chronic infections (seven resections and one two-stage revision) were in remission. Among the five sub-acute infections, the two resections were in remission, whereas the three debridements recurred. Overall, the ten resections were in remission with seven patients disappointed and three satisfied, a mean Constant score of thirty-one ± eight points and a mean active anterior elevation of 53 ± 15°. The two-stage exchange was in remission but remained disappointed with a Constant score of twenty-seven points and an active anterior elevation of 90°. Infection compromises the functional results of the reverse prosthesis whatever the treatment performed. Acute infections appear to be satisfactorily treated by debridement or resection. Both resection and two-stage revision can successfully treat sub-acute and chronic infection; however, debridement alone is ineffective and not recommended. There is a high rate of infection when the reverse prosthesis is used in revision arthroplasty. Prevention, by looking for such infection before surgery and by performing a two-stage procedure is recommended in the case of any uncertainty

Total joint arthroplasty continues to gain acceptance as the standard of care for the treatment of severe degenerative joint disease. However, the Periprosthetic Joint Infection (PJI) remains one of the biggest challenges facing orthopaedics today. It is important to accurately diagnose PJI because its management differs from that of other causes of arthroplasty failure. The most common symptom of PJI is pain. In acute infection, the local signs and symptoms (e.g., severe pain, swelling, erythema, and warmth at the infected joint) of inflammation are generally present. On the other hand, chronic infection usually has a more subtle presentation, with pain alone, and is often accompanied by loosening of the prosthesis at the bone-implant interface. The diagnosis of PJI has proven quite challenging, as both acute and chronic infections can be difficult to differentiate from other forms of inflammation. The reported literature on the diagnosis of PJI has focused on evaluated laboratory tests that were never developed specifically for the diagnosis of PJI. Because these tests were not made for the purpose of diagnosing PJI, it has been the responsibility of the orthopaedic community to evaluate and recommend their interpretation. This has resulted in significant confusion regarding the appropriate thresholds and optimal combination of these tests. These difficulties were the motivation for the development of a specific test for the detection of PJI. The promising diagnostic capabilities of synovial fluid biomarkers for PJI have already been reported in the literature. Studies have demonstrated that the alpha-defensin microbicidal peptide present in human neutrophils is an ideal biomarker for PJI due to the distinct separation it achieves between positive and negative results. A specific test allowing to measure the concentration of the alpha-defensin in the synovial fluid has been developed. The specificity and the sensitivity of this test for the detection of a PJI are respectively 96% and 97%. This test has been proven to have also a high reproducibility, its results not being influenced by antibiotics. A lateral flow version of this test (Synovasure PJI, distributed exclusively in Europe by Zimmer GmbH) has been recently developed. It allows reading the results in 10 minutes and it doesn't require any laboratories for its interpretation. Currently, this test device is in clinical evaluation in more than 200 European hospitals. In case that the clinical evaluation of this test device is positive, this method will be a new paradigm for the diagnosis of periprosthetic joint infection

A well-fixed uncemented acetabular component is most commonly removed for chronic infection, malposition with recurrent dislocation, and osteolysis. However, other cups may have to be removed for a broken locking mechanism, a bad “track record”, and for metal-on-metal articulation problems. Modern uncemented acetabular components are hemispheres which have 3-dimensional ingrowth patterns. Coatings include titanium or cobalt-chromium alloy beads, mesh, and now the so-called “enhanced coatings”, such as tantalum trabecular metal, various highly porous titanium metals, and 3-D printed metal coatings. These usually pose a problem for safe removal without fracture of the pelvis or creation of notable bone deficiency. Preoperative planning is essential for safe and efficient removal of these well-fixed components. Strongly consider getting the operative report, component “stickers”, and contacting the implant manufacturer for information. There should a preoperative check list of the equipment and trial implants needed, including various screwdrivers, trial liners, and a chisel system. The first step in component removal is excellent 360-degree exposure of the acetabular rim, and this can be accomplished by several approaches. Then, the acetabular polyethylene liner is removed; a liner that is cemented into a porous shell can be “reamed out” using a specific device. Following this, any central or peripheral screws are removed; broken or stripped screw heads add an additional challenge. A trial acetabular liner is placed, and an acetabular curved chisel system is used. There are two manufacturers of this type of system. Both require the known outer acetabular diameter and the inner diameter of the trial liner. With the curved chisel system and patience, well-fixed components can be safely removed, and the size of the next acetabular component to be implanted is usually 4mm larger than the one removed. There are special inserts for removal of monobloc metal shells. Remember that removal of these well-fixed components is more difficult in patients compared to models, and is just the first step of a successful acetabular revision

Aims

Serum inflammatory parameters are widely used to aid in diagnosing a periprosthetic joint infection (PJI). Due to their limited performances in the literature, novel and more accurate biomarkers are needed. Serum albumin-to-globulin ratio (AGR) and serum CRP-to-albumin ratio (CAR) have previously been proposed as potential new parameters, but results were mixed. The aim of this study was to assess the diagnostic accuracy of AGR and CAR in diagnosing PJI and to compare them to the established and widely used marker CRP.

Aims. The aim of this study was to characterize the factors leading to transfemoral amputation after total knee arthroplasty (TKA), as well as the rates of mortality and functional independence after this procedure in these patients. Patients and Methods. This was a multicentre retrospective review with a prospective telephone survey for the assessment of function. All patients with a TKA who subsequently required transfemoral amputation between January 2001 and December 2015 were included. Demographic information, medical comorbidities, and postoperative mortality data were collected. A 19-item survey was used for the assessment of function in surviving patients. Results. A total of 111 patients were included. Their mean age was 61.0 years (42.0 to 88.0) at the time of TKA, with a subsequent mean of 3.7 operations (0 to 15) over a mean period of 6.1 years (0.05 to 30.1) before amputation. The indication for amputation was chronic infection in 97 patients (87.4%). The rate of five-year survival was 51.7%, and advanced age (p = 0.001) and renal failure (p = 0.045) were associated with an increased risk of mortality. Of the 62 surviving patients, 34 completed the survey; 32 (94.1%) owned a prosthesis but only 19 (55.9%) used it; 19 (55.9%) primarily used a wheelchair for mobility; 27 (79.5%) had phantom pain; and 16 (47.1%) required chronic pain medication. Only 18 patients (52.9%) were satisfied with the quality of life. Conclusion. Patients with complications after TKA, in whom transfemoral amputation is considered, should be made aware of the high rate of mortality and the poor functional outcome in the survivors. Alternative forms of treatment including arthrodesis of the knee should be investigated