Aim. Megaprosthesis have become a standard option in limb preserving surgery after bone resection in musculoskeletal tumors. Recently they have also been used in complex revision arthroplasty in cases with massive bone loss. The aim of this study was to analyze the incidence of periprosthetic joint infection (PJI) both in primary oncology cases and aseptic revision cases and analyze which are the significant risk factors for PJI with a special interest on the use of prophylactic antibiotic loaded calcium sulfate beads. Method. All patients undergoing surgery with the use of megaprosthesis in our institution between January/2012 and December/2022 were retrospectively reviewed. Data was collected from electronic medical records. We identified 108 procedures involving megaprosthesis in 90 patients with an average follow-up of 37 months. Indications were 79 primary musculoskeletal tumors and 29 aseptic complex revision arthroplasty. Results. Table 1 shows relevant clinical information. No significant risk factor was found either in uni or multivariate analysis. PJI rate was 15% (12/79) for primary musculoskeletal surgery and 31% (9/29) for complex revision surgery. The use of antibiotic loaded calcium sulfate beads did not show an advantage – 22% (9/41) with vs. 18% (12/67) without. Conclusions. In this relatively small series it was not possible to show a significal association between PJI and certain known risk factors such as gender, ASA score, site of surgery (knee) and revision surgery. The use of antibiotic loaded calcium sulfate beads as prophylaxis was not beneficial in reducing PJI rates in our cohort. We acknowledge the limitations of our study: a small sample group, in a single institution with heterogeneity in terms of diagnosis and surgical site. We recognize the need for a multicentric study with a larger cohort to validate these findings. For any tables or figures, please contact the authors directly

Introduction. Patients (2.7M in EU) with positive cancer prognosis frequently develop metastases (≈1M) in their remaining lifetime. In 30-70% cases, metastases affect the spine, reducing the strength of the affected vertebrae. Fractures occur in ≈30% patients. Clinicians must choose between leaving the patient exposed to a high fracture risk (with dramatic consequences) and operating to stabilise the spine (exposing patients to unnecessary surgeries). Currently, surgeons rely on their sole experience. This often results in to under- or over-treatment. The standard-of-care are scoring systems (e.g. Spine Instability Neoplastic Score) based on medical images, with little consideration of the spine biomechanics, and of the structure of the vertebrae involved. Such scoring systems fail to provide clear indications in ≈60% patients. Method. The HEU-funded METASTRA project is implemented by biomechanicians, modellers, clinicians, experts in verification, validation, uncertainty quantification and certification from 15 partners across Europe. METASTRA aims to improve the stratification of patients with vertebral metastases evaluating their risk of fracture by developing dedicated reliable computational models based on Explainable Artificial Intelligence (AI) and on personalised Physiology-based biomechanical (VPH) models. Result. The METASTRA-AI model is expected to be able to stratify most patients with limited effort end cost, based on parameters extracted semi-automatically from the medical files and images. The cases which are not reliably stratified through the AI model, are examined through a more detailed and personalised biomechanical VPH model. These METASTRA numerical tools are trained through an unprecedentedly large multicentric retrospective study (2000 cases) and validated against biomechanical ex vivo experiments (120 specimens). Conclusion. The METASTRA decision support system is tested in a multicentric prospective observational study (200 patients). The METASTRA approach is expected to cut down the indeterminate diagnoses from the current 60% down to 20% of cases. METASTRA project funded by the European Union, HEU topic HLTH-2022-12-01, grant 101080135

Aims

Transfusion after primary total hip arthroplasty (THA) has become rare, and identification of causative factors allows preventive measures. The aim of this study was to determine patient-specific factors that increase the risk of needing a blood transfusion.

Aims

Our objective was describing an algorithm to identify and prevent vascular injury in patients with intrapelvic components.

Aim. To describe the impact of a failed DAIR in the further prognosis of the prosthesis after a PJI. Method. A retrospective multicentrically study was conducted, including 10 institutions from all over the country. PJI-confirmed patients who underwent DAIR clinical records were revised. Age, sex, relevant previous conditions, Charlson comorbidity score, previous surgery, PJI diagnosis and surgical and antibiotic treatment, from the index surgery onwards. DAIR failure was defined as the removal of the prosthesis and/or an antibiotic suppressive treatment. Results. 95 failed DAIR were identified, 43 of whom were treated with another DAIR (70% success rate), 20 with one-stage revision (75% success rate) and 25 with two-stage revision (92% success rate). As risk factors for the failure of a second DAIR, a non-specialized surgical team(p=.0034), mobile components exchange(p=.009) and polymicrobial infections(p=.03) were identified. Regarding to one-stage revisions, no risk factors were identified, and regarding to two-stage revisions, polymicrobial infection were identified (p=.028). Conclusions. A second DAIR could sabe up to 70% of the prosthesis in our series. Furthermore, the outcome of the subsequent one or two-stage revision does not seem to be affected bay the previous failed DAIR. In terms of risk factors of failure, non-specialized surgical team, no mobile components exchange, and polymicrobial infections were identified for the DAIR, and polymicrobial infections for the two-stage revisions

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.

Abstract

Aims

With resumption of elective spine surgery services in the UK following the first wave of the COVID-19 pandemic, we conducted a multicentre British Association of Spine Surgeons (BASS) collaborative study to examine the complications and deaths due to COVID-19 at the recovery phase of the pandemic. The aim was to analyze the safety of elective spinal surgery during the pandemic.

Aim

There have been many attempts to define the criteria by which prosthetic joint infection (PJI) is diagnosed. Our aim is to validate the 2021 European Bone and Joint Infection Society (EBJIS) definition of PJI.

Aim. Bone and joint infections (BJI) need frequently prolonged antibiotic treatment at high dosage for a total of 6 or 12 weeks depending the type of infection. Impact of such prolonged antibiotic exposure on the gut microbiota has never been assessed. Method. We performed a national multicentric prospective study of patients with BJI to monitor the gut microbiota dynamic all along antimicrobial treatment. Clinical data and stool collection were performed at the baseline visit (B) within 24h before starting antibiotics, at the end of the treatment (EOT) and 2 weeks after antibiotic withdrawal during a follow-up visit (FU). Microbiota composition was determined by shotgun metagenomic sequencing. Biological markers of gut permeability and inflammation were monitored at each time point. Results. Sixty-two patients were enrolled: 27 native BJI, 14 osteosynthesis-related BJI and 21 prosthetic joint infections (PJI). At EOT there was a significant loss of alpha-diversity that recovered at FU in patients with native BJI and PJI but not in patients with osteosynthesis-related BJI (p<0.05, Wilcoxon test). At EOT, we observed an increase of Proteobacteria and Bacteroidetes that partially recovered at FU. Principal Component Analysis (PCoA) of the Bray Curtis distance, showed a significant change of the gut microbiota at the end of treatment compared to baseline (p<0.01, PERMANOVA) that only partially recover at FU. The taxonomic analysis showed that microbiota composition at FU does not differ significantly at the genus level when comparing patients treated for 6 weeks to patients treated for 12 weeks. No particular antibiotic (especially fluoroquinolones) was associated with a lower Shannon index or distinct dynamic of recovery at the end of treatment. PCoA analysis of the Bray Curtis distance shows that patients with elevated plasma level of CRP (≥5mg/L) at EOT had a distinct gut microbial composition compared to others. Conclusions. In patients with BJI, antibiotics altered the gut microbiota diversity and composition with only partial recovery 2 weeks after antibiotic withdrawal, independently on the duration of the therapy and on the type of the antibiotic used. Elevated CRP at EOT might reflect persistent alteration of the gut microbiota. Assessment of long-term impact after the end of treatment is on-going

Background

Septic arthritis diagnostic is an emergency which implies a treatment with antibiotics and hospitalization. The diagnosis is based on the cytobacteriological examination of the synovial fluid (SF), but direct bacteriological examination is insensitive, and the result of the culture is obtained only after several days. Therefore, there is still a need for a rapid, simple and reliable method for the positive diagnosis of septic arthritis. Such method must allow avoiding both unrecognized septic arthritis leading to major functional consequences, and overdiagnosis that will induce unnecessary expensive hospitalization and unjustified treatment. Mid-infrared (MIR) spectroscopy, that gives a metabolic profiling of biological fluids, has been proposed for early and fast diagnosis.

Aims. Microbiological diagnosis of bone and joint infections (BJIs) is pivotal. However, no consensus exists about the best choice for techniques to be used and the best indications for molecular methods. Our objectives were: (i) to compare the performance of various microbiological diagnostic methods (cultural and molecular) on synovial fluid specimens and (ii) to select an algorithm for optimizing the diagnosis of BJIs in adults. Methods. This prospective multicentric study (in Lyon and Saint-Etienne, France) included 423 joint fluid samples, collected from 333 adult patients (median age 69 years) suspected for BJI on the basis of medical history and clinical symptoms. For each inclusion, joint fluid and blood culture were collected concomitantly. The synovial fluid was also inoculated into blood culture bottles. Cytology, culture (using 5 solid media and an enrichment broth, incubated for 15 days), universal 16S rRNA PCR and PCR targeting Staphylococcus spp, S.aureus, Streptococcus spp, S.pneumoniae, Kingella kingae, Borrelia burgdorferi and Propionibacterium acnes were systematically performed on synovial fluid. Results. Prosthetic materials were present in 65.0% of the cases and 31.7% of the patients had received antibiotics in the 15 days before puncture. Out of 423 joint fluids, 265 (62.6%) were positive by at least one diagnostic technique (cultural or molecular): 219 mono- and 46 poly-microbial, for a total of 322 bacteria. Identified bacteria were staphylococci in 54.0%, streptococci-enterococci in 15.2%, Gram-negative bacilli in 14.0%, anaerobic species in 10.9% and other bacteria in 5.9% of cases. Comparing the individual performance of each cultural technique, blood culture bottles showed the highest rate of positivity (detecting 61.4 and 58.4% of the bacteria, for the paediatric and anaerobic bottles, respectively) but cannot be performed alone and require to be combined with solid media. The 16S rDNA PCR was positive in only 49.2% of the cases whereas higher detection was obtained with specific PCR. Blood cultures performed concomitantly with joint puncture were positive in only 9.7% of the cases. Conclusions. In order to simplify the culture procedures and to precise the place of PCR for synovial fluid, we propose the following algorithm: joint fluids should be inoculated onto 3 solid media (blood and chocolate agars for 2 days, anaerobic blood agar for 10 days), associated with inoculation into blood culture bottles for 10 days. If culture remains negative, 16S rDNA PCR and/or Staphylococcus PCR should be added. Applying this algorithm on our cohort, 93.6% of the bacteria would have been detected

Aim. The frequency of arthroplasty among older people is increasing. Taking care of Prosthetic Joint infection (PJI) in this specific population is a challenge. The purpose of this multicentric retrospective study was to evaluate the bacterial epidemiology of hip and knee PJI in octogenarians and nonagenarians over ten years. Method. Data were collected using two softwares* in each of the 4 Centers participating. Inclusion criteria:. -. age ≥ 80 years PJI (knee or hip). -. between January 2007 and December 2016. -. microbiological data available (strains isolated from osteo-articular samples). Bacterial identification: biochemical methods, followed by Malditof since 2009. For Staphylococcus aureus, Pseudomonas aeruginosa and Enterobacteriaceae, resistance profiles to antibiotics frequently used in PJI were collected. Antimicrobial susceptibility testing: disk diffusion (recommendations: French Society of Microbiology yearly updated). Results. 413 patients were included: median age was 85 years and sex ratio was 0.6. 137 were knee PJI and 276 hip. 34% of the infections occurred < 1 month after implantation, and 49% > 6 months after implantation. Among all bacterial isolates (N=817), there was 55% of Gram positive cocci and 36% of Gram negative rods. 112 (27%) were polymicrobial infections. There was a majority of gram negative rods (41%) among isolates from polymicrobial infections. Concerning drug resistance, there was a stable proportion of ESBL among Enterobacteria (16%), whereas Methicillin resistance among S. aureus decreased from 43% in 2007 to 12% in 2016. Conclusions. An important proportion of PJI in older patients are polymicrobials, and a lot of them involve gram negative rods, almost as frequently as S. aureus. These infections are difficult to treat, and resistance of gram negative strains is one of the obstacles to overcome among these patients where surgery is not always possible. * Sirweb (I2A) and Glims (MIPS)

Aim. Propionibacterium acnes (PA) is an important cause of shoulder prosthetic joint infections (SPJIs) for which the optimal treatment has not yet been determined. Rifampicin and Levofloxacin both showed not benefit in recent experimental models of PA-SPJIs. We describe herein the experience of five different medical French centers in order to assess factors associated with patient's outcome with special emphasize on antibiotic regimens. Method. A multicentric retrospective study was performed, on consecutive patients with PA – related SPJIs diagnosed on the basis of at least 2 or more positive cultures of either per-operative or joint aspiration and clinical history compatible with a PJI according to the current guidelines. All patients had surgical management, followed by systemic antibiotic therapy. Remission was defined as an asymptomatic patient with functioning prosthesis at the last contact. Results. Fifty-nine patients of mean age 66.2 ± 10.5 years were included. Most patients were at least ASA 2 (66%), 8 (14%) diabetes mellitus, 3 (5%) had neoplasia. Fourteen patients (24%) had acute, 34 (58%) subacute, and 11 late infections (19%). The mean delay from symptoms of infection to surgery was 89 ± 141 days (1–660). Surgical management consisted in implant exchange in 40 (68%) patients. Antibiotic treatment included mainly clindamycin (49%), levofloxacin (44%) and rifampin (17%), with a mean duration of 52.3 ± 31.9 days. The mean follow-up duration was 540 days ± 488 (range 12 ™ 1925). Forty-five patients were in remission (76%) in this study, 8 patients had a relapsing infection (14%), 1 a recurrence (2%) and 5 a superinfection ™ i.e, due to a different pathogen − (8%). In monovariate analysis, rifampicin/levofloxacin treatment was significantly associated with failure (p=0.038). In multivariate analysis, levofloxacin use and implants retention were significantly related to failure (p=0.02 and p=0.003, respectively). Conclusions. Our results suggest that implant retention and levofloxacin use are two independents factors of failure in patients treated for PA – related SPJIs

Introduction

The causes for revision of primary total hip arthroplasty (THA) are various and quite well known. The developing use of dual-mobility THA (DM-THA) seems a relevant option to decrease the risk of instability. Due to lack of long-term follow-up, this innovative retentive concept is suspected to increase the risk of polyethylene (PE) wear. The aim of the study was to analyse the causes for DM-THA revision and assess whether or not its occurrence is different from that of fixed-standard (FS) THA, particularly for aseptic loosening or wear and/or osteolysis.

In France, 5% of men and 7% of women aged more than 60 years have a joint prosthesis (JP). The incidence of H-PJI following BSI remains unknown (1–2). The aim of this study was to determine prospectively the clinical characteristics of patients with JP and the incidence of H-PJI following a BSI. A prospective observational multicentric study was performed in two French General Hospitals, from December 2012 to April 2015. Each patient with JP, in whom a BSI was diagnosed, was evaluated prospectively by an ID specialist. Data regarding clinical and microbiological characteristics were collected. A follow-up by phone call was performed monthly during 6 months to determine the incidence of H-PJI following BSI. During the study period, 97 patients of mean age ± SD of 82.1 ± 10.4 years were identified, with a predominance of women (n=61). Nineteen patients (20%) had neoplasia, and 32 diabetes mellitus (33%). Most patients had one (n=61; 63%) or two JP (n=29; 30%); with a predominance of hip arthroplasty (n=77; 79%). Predominant pathogens were E. coli (n=41; 42%), S. aureus (n=23; 23%) and S. pneumoniae (n=8; 8%). At the onset of BSI, the JP was concomitantly infected in 10 (10.3%) patients (including 8 S. aureus, 1 E. coli and 1 P. mirabilis), thus 87 were studied for the incidence of H-PJI following BSI of another source. Among these 87 patients, no H-PJI was detected, with a complete 6-month follow-up available for 29 patients (34%), incomplete follow-up for 26 patients (30%), loss of follow-up for 3 patients (3%), and death occurring in 29 patients (34%). The comparison between the patients with no H-PJI detected (« No Event Group ») and the deceased patients (« Death Group ») showed that patients of the « No Event Group » had a lower rate of neoplasia (14% vs 34%; P=0.025). Our preliminary results show that patients with JP in whom a BSI occurred were old, and had a high mortality rate. In our study, the incidence of secondary H-PJI appears to be low, since no event was detected during the follow-up. The incidence of H-PJI may have been underestimated due to the high mortality rate. We would like to thank Dron Hospital and Bethune Hospital medical teams. The authors declare that there are no conflicts of interest

Introduction. 20 cases of bone defect have been treated by the induced membrane technique avoiding allograft, microsurgery and amputation. Material and Methods. 9 cases of long bone defect (humerus and 2 bones arm) and 11 cases of bone defct at the hand have been included in this multicentric prospective study (3 centers). 11 cases were traumatic, 7 cases were septic non union and 2 cases were tumor. At hand level's bone reached at least one phalanx, and for long bone the mean defect was 5cm (3–11). All cases were treated by the induced membrane technique which consists in stable fixation, flap if necessary and in filling the void created by the bone defect by a cement spacer (PMMA). This technique needs a second stage procedure at the 2. nd. month where the cement is removed and the void is filled by cancellous bone. The key point of this induced membrane technique is to respect the foreign body membane which appeared around the cement spacer and which create a biologic chamber after the second time. Bone union was evaluated prospectively in each case by an surgeon not involved in the treatment by Xray and CT scan. Failure was defined as a non union at 1 year, or an uncontrolled sepsis at 1 month. Results. 3 cases failed to achieve bone union, 2 at hand level and 1 for long bone. No septic complications occured and all septic cases werre stopped. In 14 cases bone union was achieved with a delay of 5 months (1, 5–12). 2 biopsies allowed to proove us that osteoid tissue was created by the technic. At hand level all fingers have included. At shoulder and elbow level, function reached 75% of motion than controlateral side. Discussion. Masquelet first reported 35 cases of large bone defect of tibia non union treated by the induced membrane technic which allow to fill bone defect with cancellous bone alone. The cement spacer allows to induce a foreign body membrane which constitute a biological chamber. Works on animal model reported by Pellissier and Viatteau showed the properties of the membrane: secretion of growths factors (VEGF, TGFbéta1, BMP2) and osteoinductive activitie of the cells. The induced membrane seem to play the role of a neo periosteum. Using this technic is possible in emergency or in septic condition where bone defect can not been solved by shortening. This technic avoids to use microsurgical technic and the limit is the quantity of avalaible cancellous bone

Summary

open tibia fractures are best treated in an orthopaedic-plastic surgical multidisciplinary setting.

Purpose

Reverse shoulder prosthesis may lead to scapular notching, caused by attrition of the upper humeral component with scapular neck. We compared the clinical and radiographic results obtained with a SMR prosthesis, which allows a concentric or an eccentric glenosphere to be applied.

Purpose. Evaluate the demographics, stages and outcomes in Myxoid (ML) and Round Cell liposarcoma (RCL). Establish the incidence of local recurrence and metastases. Outline the use and benefits of radiotherapy and chemotherapy. Provide guidelines for future management of these rare tumors. Method. Multicentric retrospective study of 421 cases of MRCLS primarily managed by multidisciplinary sarcoma teams in Canada. Data were collected in each centers through a standardized database and statistically analysed. Results. There were 247 males (59%) Age ranged from 14 to 88 years old (avg: 46 yrs) and the average follow-up was 5.9 yrs (range: 1 mo–21.3 yrs). Tumor volume averaged 745 cc (range: 1.5–14580 cc). The proximal lower limb, including the thigh, the buttock and the inguinal region, was the location in 314 cases (75%). Tumors were deep in 81%. On histology 305 patients were classified as pure myxoid liposarcoma, 87 had mixed myxoid/round cell histology (≥ 5% round cell content)and 19 were pure round cells only. AJCC staging were Ia: 44, Ib: 114, IIa: 115, IIb: 57, IIc: 2, III: 56, IV: 9, unknown: 24. Radiotherapy was given to 310 pts and chemotherapy to 26 pts as part of initial management. 419 underwent surgery (407 limb salvage and 12 amputations) Margins were R0 in 309, R1 in 94 and R2 in 15 patients. Overall 10 yrs local control rate was 92% and no differences were recorded between ML and RCL. Radiotherapy was significant in preventing local relapse (p= 0.03) but did not impact survival. Metastatic disease was recorded in 82 patients (19%). Chemotherapy did not prevent metastatic occurrence and survival was statistically worse for the chemotherapy group (p= 0.01). Location of first metastasis was often multiple (29), followed by lung or soft tissue (14 each), retroperitoneum (12) and bone (10). Thirty-four patients had bone involvement with spine involved in 27. The 5 and 10 yrs metastatic free survival were respectively 84 and 73% for ML and 73 and 49% for RCL (p= 0.003). Latest disease status were: 323 alive with no evidence of disease, 27 alive with disease, 8 alive with unknown status, 52 deadfrom tumor and 11 dead from other causes. Conclusion. Myxoid and Round cell Liposarcoma present different prognoses. Metastatic disease at the time of diagnosis is an unusual event. Local control is good but radiotherapy decreased the incidence of local relapse. The effectiveness of chemotherapy remains to be established for round cell liposarcoma. New staging stategies need to be identified to account for the unusual metastatic pattern of these sarcoma