INTRODUCTION. Adult reconstructive orthopedic surgery in the United States is facing an imminent logjam due to the increasing divergence of the demand for services and the ability for the community to supply those services. In combination with several other factors, a perfect storm is brewing that may leave the system overtaxed and the patient population suffering from either a lack of treatment, or treatment by less qualified providers. A key component to improving the overall efficiency of surgical care is to introduce enabling technologies that can effectively increase the throughput while simultaneously improving the quality of care. One such enabling technology that has proven itself in many industries is robotics, which has recently been introduced in surgery with even more recent applications in orthopedic surgery. A surgeon interactive robotic arm has been developed for partial knee arthroplasty (PKA) and total hip arthroplasty (THA). This study aims to analyse the efficiency of a new robotic technology for use in orthopaedic surgery. METHODS. 18 robotic arm assisted PKA's across 10 sites were recorded to accurately capture the timeline elemental tasks throughout the procedure. Two camera angles were set up to capture both surgical staff group dynamics and individual procedural steps. 17 tasks were identified and measured from video data. (Fig 1) The robotic arm specific tasks were analyzed for correlation to total surgical time (measured as first incision to last suture). The tasks for the surgeons with the shortest and longest total times were compared directly to determine areas of opportunity. RESULTS. Average total time across 18 surgeries was 55 ± 19 min (range: 30–98 min). There was no correlation between bone registration time and total time (p=0.271) and no correlation between femoral burring time and total time (p=0.230). Per task time comparison of the two surgeons exhibited an average time variation of 3.5 min per task (range: 0.7–8.4 min) (Fig 2). The robotic elements of the procedure exhibited an average time variation of 3.3 min per task while the non robotic elements of the procedure (boxed) exhibited an average time variation of 3.8 min per task. CONCLUSION. Our preliminary results indicate that introducing robotic technology in to the OR does not directly lead to an increase in total surgical time. On average, non robotic specific elements of the procedure exhibited a larger opportunity for efficiency gain. This is likely due to the fact that a large population of surgeon users are not only new to the robotic technology, but new to PKA. Further video collection and analysis will lead to an efficiency benchmarking program that aims to establish methods for best practices in achieving efficiency throughout a robotic arm assisted PKA procedure

Aims

Early large treatment effects can arise in small studies, which lessen as more data accumulate. This study aimed to retrospectively examine whether early treatment effects occurred for two multicentre orthopaedic randomized controlled trials (RCTs) and explore biases related to this.

Aims

During the COVID-19 pandemic, drilling has been classified as an aerosol-generating procedure. However, there is limited evidence on the effects of bone drilling on splatter generation. Our aim was to quantify the effect of drilling on splatter generation within the orthopaedic operative setting.

Aims

This study aimed to investigate the risk of postoperative complications in COVID-19-positive patients undergoing common orthopaedic procedures.

Introduction. The health sector contributes the equivalent of 4.4% of global net emissions to the climate carbon footprint. It has been suggested that between 20% and 70% of health care waste originates from a hospital's operating room, the second greatest component of this are the textiles used, and up to 90% of waste is sent for costly and unneeded hazardous waste processing. Waste from common orthopaedic operations was quantified, the carbon footprint calculated, and cost of disposal assessed. A discussion of the circular economy of textiles, from the author of the textile guidance to the Green Surgery Report follows. Methods. The amount of waste generated from a variety of trauma and elective orthopaedic operations was calculated across a range of hospital sites. The waste was separated primarily into clean and contaminated, paper or plastic. The carbon footprint and the cost of disposal across the hospital sites was subsequently calculated. Results. Elective procedures can generate up to 16.5kg of plastic waste per procedure. Practices such as double draping the patient contribute to increasing the quantity of waste. The cost to process waste vary widely between hospital sites, waste disposal contractors and the method of waste disposal. Conclusion. This study sheds new light on the environmental impact of waste produced in trauma and elective orthopaedic procedures. Mitigating the environmental impact of the operating room requires a collective drive for a culture change to sustainability and social responsibility. Each clinician can impact upon the carbon footprint of their operating theatre. Consideration should be given to the type of textiles used within the operating theatre

Conferences centered around surgery suffers from gender disparity with male faculty having a more dominant presence in meetings compared to female faculty. Orthopedic Surgery possibly suffers the most from this problem of all surgical specialties, and is reflective of a gender disparity in the field. The objective of this study was to investigate the prevalence of “manels”, or male-only sessions, in eight major Orthopedic Surgery meetings hosted in 2021 and to quantify the differences in location of practice, academic position, years of practice, and research qualifications between male and female faculty. Eight Orthopedic conferences organized by major Orthopedic associations (AAOS, COA, OTA, EFORT, AAHKS, ORS, NASS, and AOSSM) from February 2021 to November 2021 were analyzed. Meeting information was retrieved from the conference agendas, and details of chairs and speakers were obtained from Linkedin, Doximity, CPSO, personal websites, and Web of Science. Primary outcomes included: one) percentage of male faculty in all included sessions and two) overall percentage of manels. Secondary outcomes included one) percentage of male speakers and chairs in all included sessions, two) overall percentage of male-chair and male-speaker only sessions. Comparisons for outcomes were made between conferences and session topics (adult reconstruction hip, adult reconstruction knee, practice management/rehabilitation, trauma, sports, general, pediatrics, upper extremity, musculoskeletal oncology, foot and ankle, spine, and miscellaneous). Mean number of sessions for male and female were compared after being stratified into quartiles based on publications, sum of times cited, and H-indexes. Data was analyzed with non-parametric analysis, chi-square tests, or independent samples t-tests using SPSS version 28.0.0.0 with a p-value of < 0 .05 being considered statistically significant. Of 193 included sessions, 121 (62.3%) were manels and the mean percentage of included faculty that was male was 88.9% Apart from the topics of practice management/rehabilitation and musculoskeletal oncology, male representation was very high. Additionally, most included conferences had an extremely high percentage of male representation apart from meetings hosted by the COA and ORS. Non-manel sessions had a greater mean number of chairs (p=0.006), speakers (p < 0 .001), and faculty (p < 0 .001) than manel sessions. Of 1080 total included faculty members, 960 (88.9%) were male. Male faculty were more likely to be Orthopedic surgeons than female faculty (p < 0 .001) while also more likely to hold academic rank as a professor. Mean number of sessions between male and female faculty within their respective quartiles of H-indexes, sum of times cited, and number of publications did not reach statistical significance. Mean years of practice between male and female faculty was also not significantly different. There is a high prevalence of manels and an overall lack of female representation in Orthopedic meetings. Orthopedic associations should aim to make efforts to increase gender equity in future meetings

Background and aim. Implant-associated osteomyelitis is one of the most feared complications following orthopedic surgery. Although the risk is low it is crucial to achieve adequate antibiotic concentrations proximate to the implant for a sufficient amount of time to protect the implant surface and ensure tissue integration. The aim of this study was to assess steady-state piperacillin concentrations in the proximity of an orthopedic implant inserted in cancellous bone. Method. Six female pigs received an intravenous bolus infusion of 4 g/0.5 g piperacillin/tazobactam over 30 min every 6 h. Steady state was assumed achieved in the third dosing interval (12–18 h). Microdialysis catheters were placed in a cannulated screw in the proximal tibial cancellous bone, in cancellous bone next to the screw, and in cancellous bone on the contralateral tibia. Dialysates were collected from time 12 to 18 h and plasma samples were collected as reference. Results. Time above the minimal inhibitory concentration (fT>MIC) was evaluated for MIC of 8 (low target) and 16 μg/mL (high target). For the low piperacillin target (8 μg/mL), comparable mean fT>MIC across all the investigated compartments (mean range: 54–74%) was found. For the high target (16 μg/mL), fT>MIC was shorter inside the cannulated screw (mean: 16%) than in the cancellous bone next to the screw and plasma (mean range: 49–54%), and similar between the two cancellous bone compartments. Conclusions. To reach more aggressive piperacillin fT>MIC targets in relation to the implant, alternative dosing regimens such as continuous infusion may be considered

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

Aim. Prosthetic joint infections (PJI) remain a great challenge in orthopedic surgery with a high mortality rate. It is particularly complicated by biofilms and infections caused by Methicillin-resistant Staphylococcus aureus (MRSA). It concurrently shields bacteria from host immune responses and confers resistance to antibiotics. This study aims to investigate the efficacy of radioimmunotherapy as an innovative therapeutic modality to address the challenges posed by MRSA and its biofilm. Method. We induced specific monoclonal antibodies 4497-IgG1 as carriers, which target wall teichoic acids (WTA) existing on MRSA and its biofilm. Radionuclides actiniumr-225 (. 225. Ac, α-emitter) and lutetium-177 (. 177. Lu, β-emitter) were conjugated with mAbs using DOTA as chelator. Quality control was assessed using thin layer chromatography and immunoreactivity assays. . 225. Ac- and . 177. Lu-labelled 4497-IgG1 were employed to evaluate the susceptibility of MRSA and its biofilm to the radioimmunotherapy in vitro. Planktonic MRSA and biofilms, at concentrations of 10. 8. and 10. 7. CFU/mL, were incubated at 37°C for 60 minutes in PBS containing either . 225. Ac-mAb (0 - 14.8 kBq) or . 177. Lu-mAb (0 - 14.8 MBq). Radiolabelled dunituximab and free radionuclides serve as isotype-matched negative control. The bacterial viability and metabolic activity were subsequently quantified using CFU and XTT assays. Results. The radiochemical purity of the . 225. Ac-mAbs and . 177. Lu-mAbs complex were determined to be 95.4% and 96.16%. Immunoreactivity fractions of them were measured at 81.8% and 80.8%. . 225. Ac-mAbs and . 177. Lu-mAbs exhibited significant and dose-dependent antimicrobial effects on both planktonic MRSA and biofilm. . 225. Ac- and . 177. Lu-4497IgG1 at doses of 7.4 kBq and 7.4 MBq resulted in more than 4-log reduction in bacterial counts. In biofilms, 2-log reduction at the highest . 225. Ac radioactivity of 14,8kBq. The . 177. Lu complex showed a strong dose-dependent effect, with a reduction of up to 4-log. The XTT assay confirmed these findings, showing a decrease in metabolic activity corresponding to a decrease in bacterial counts, and a slight increase in metabolic activity at the lower dose. Conclusions. Our study demonstrates the efficacy of . 225. Ac and . 177. Lu-labelled 4497-IgG1 antibodies in mediating dose-dependent bactericidal effects against planktonic MRSA and biofilms in vitro. This indicates that radioimmunotherapy could be a potential targeted therapeutic strategy against MRSA and its biofilm. Further research in preclinical and clinical settings is warranted to validate and refine these findings on biofilm-associated implant infections

The use of cannabis is increasingly medically relevant as it is legalized and gains acceptance more broadly. However, the effects of marijuana use on postoperative outcomes following orthopedic surgery have not been well-characterized. This study seeks to illuminate the relationship between marijuana use and the incidence postoperative complications including: DVT, PE, nonunion, and infection following common orthopedic procedures. This study was conducted using a national orthopaedic claims insurance database. We identified all patients undergoing knee arthroscopy, shoulder arthroscopy, operatively managed long bone fractures (humerus, femur, tibia and/or fibula, and radius and/or ulna), and single-level lumbar fusion. The proportion of patients within each surgery cohort who had a diagnostic code for marijuana dependence was assessed. The rates of DVT, PE, and infection within 90 days were assessed for all patients. The rate of nonunion was assessed for the long bone fracture and lumbar fusion cohorts. Univariate analyses of marijuana dependence on all outcomes were performed, followed by a multivariate logistic regression analysis controlling for known patient comorbidities. We identified 1,113,944 knee arthroscopy, 747,938 shoulder arthroscopy, 88,891 lumbar fusion, and 37,163 long bone fracture patients. Out of the 1,987,936 patients, 24,404 patients had a diagnostic code for marijuana dependence. Within all four surgical subgroups, the marijuana dependence cohort experienced increased rates of infection, PE, and DVT, as well as increased rates of nonunion in the lumbar fusion and long bone fracture populations. In the multivariate analyses controlling for a variety of patient risk factors including tobacco use, marijuana dependence was identified as an independent risk factor for infection within all four surgical subgroups (Knee: OR 1.85, p < 0.001; Shoulder: OR 1.65, p < 0.001; Spine: OR 1.45, p < 0.001; Long bone: OR 1.28, p < 0.001), and for nonunion in the lumbar fusion (OR 1.38, p < 0.001) and long bone fracture (OR 1.31, p < 0.001) subgroups. Our data suggests that marijuana dependence may be associated with increased rates of infection and nonunion following a variety of orthopaedic procedures. During preoperative evaluation, surgeons may consider marijuana use as a potential risk factor for postoperative complications, especially within the context of marijuana legalization. Future research into this relationship is necessary

The 2020-2021 Canadian Residency Matching Service (CaRMS) match year was altered on an unprecedented scale. Visiting electives were cancelled at a national level, and the CaRMS interview tour was moved to a virtual model. These changes posed a significant challenge to both prospective students and program directors (PDs), requiring each party to employ alternative strategies to distinguish themselves throughout the match process. For a variety of reasons, including a decline in applicant interest secondary to reduced job prospects, the field of orthopaedic surgery was identified as vulnerable to many of these changes, creating a window of opportunity to evaluate their impacts on students and recruiting residency programs. This longitudinal survey study was disseminated to match-year medical students (3rd and 4th year) with an interest in orthopaedic surgery, as well as orthopaedic surgery program directors. Responses to the survey were collected using an electronic form designed in Qualtrics (Qualtrics, 2021, Provo, Utah, USA). Students were contacted through social media posts, as well as by snowball sampling methods through appropriate medical student leadership intermediates. The survey was disseminated to all 17 orthopedic surgery program directors in Canada. A pre-match and post-match iteration of this survey were designed to identify whether expectations differed from reality regarding the effect of the COVID-19 pandemic on the CaRMS match 2020-2021 process. A similar package was disseminated to Canadian orthopaedic surgery program directors pre-match, with an option to opt-in for a post-match survey follow-up. This survey had a focus on program directors’ opinions of various novel communication, recruitment, and assessment strategies, in the wake of the COVID-19 pandemic. Students’ responses to the loss of visiting electives were negative. Despite a reduction in financial stress associated with reduced need to travel (p=0.001), this was identified as a core component of the clerkship experience. In the case of virtual interviews, students’ initial trepidation pre-CaRMS turned into a positive outlook post-CaRMS (significant improvement, p=0.009) indicating an overall satisfaction with the virtual interview format, despite some concerns about a reduction in their capacity to network. Program directors and selection committee faculty also felt positively about the virtual interview format. Both students and program directors were overwhelmingly positive about virtual events put on by both school programs and student-led initiatives to complement the CaRMS tour. CaRMS was initially developed to facilitate the matching process for both students and programs alike. We hope to continue this tradition of student-led and student-informed change by providing three evidence-based recommendations. First, visiting electives should not be discontinued in future iterations of CaRMS if at all possible. Second, virtual interviews should be considered as an alternative approach to the CaRMS interview tour moving forward. And third, ongoing virtual events should be associated with a centralized platform from which programs can easily communicate virtual sessions to their target audience

Aim. Surgical site infections caused by Staphylococcus aureus (S. aureus) are associated with considerable clinical and economic burden. Studies assessing this burden in Germany have been limited to specific institutions, selected patient groups or not specific to S. aureus infections (SAI). This study was undertaken to further understand the burden of SAI following orthopedic surgeries in Germany. Method. All patients with at least one spine, endoprosthetic hip or knee surgery between 2012 and 2015 captured in the AOK PLUS claims database were included in this analysis. SAI were identified using S. aureus-specific ICD-10 codes following surgery. Exclusion criteria included: younger than 18, SAI in the 90 days preceding index, any surgery in the 180 days preceding index, surgery at the same body location as index in the preceding 365 days, or more than one surgery of interest during index hospitalization. Cumulative incidence and incidence density were used to assess SAI. Mortality, healthcare resource utilization and costs were compared between SAI and non-SAI group during the 1year follow-up post index surgery. Multivariate analyses were conducted while controlling for sex, age, Charlson Comorbidity Index (CCI), location of surgery, length of index hospitalization, recent fractures, other bacterial infections during index hospitalization and outpatient prescriptions for antibiotics in the year pre-index. Results. In total, 74,327 patients were included who underwent a knee (21,285), hip (29,429), or spine surgery (23,613). Mean age was 69.6 years, 61.6% were female and the mean CCI was 2.3. The SAI incidence post-orthopedic surgery was 20.2 cases per 1,000 patient-years within 1 year of index hospitalization; the cumulative incidence was 1.9%. Knee surgeries were associated with lower SAI risk compared to hip surgeries (HR=0.8; p=0.024), whereas spine surgeries did not differ significantly. Compared to non-SAI group, the SAI group had on average 4.4 times the number of hospitalizations (3.1 vs. 0.7) and 7.7 times the number of hospital days (53.5 vs. 6.9), excluding the index hospitalization (p-values<0.001). One year post-orthopedic mortality was 22.38% in the SAI and 5.31% in the non-SAI group (p<0.001). The total medical costs were significantly different between SAI and non-SAI groups (42,834€ vs. 13,781€; p<0.001). Adjusting for confounders, the SAI group had nearly 2 times the all-cause direct healthcare costs (exp(b)=1.9; p<0.001); and 2.5 times the risk of death (OR=2.5; p<0.001) compared to the non-SAI group. Conclusions. S. aureus infection risk after orthopedic surgeries persists and is associated with significant economic burden and risk of mortality

Introduction. Innovations in surgical robotics and navigation have significantly improved implant placement accuracy in total knee arthroplasty (TKA). However, many comparative studies have not been shown to substantially improve revision rates or other clinical outcome scores. We conducted a simulation study based on the reported distribution of patient-specific characteristics and estimated potential effect of coronal plane alignment (CPA) on risk of revision to evaluate the hypothesis that most published study designs in this area have been too underpowered to detect improvements in revision rates. Methods. To model previously reported studies, we generated a series of simulated TKA patient populations, assigning each patient a set of patient-specific factors (age at index surgery, BMI, and sex (Fig.1a)), as well as one surgeon-controlled factor (CPA) (Fig.1b) based on registry data and published literature. We modelled the survival probability for an individual patient at time t as a Gaussian function (exp[-(t/(k∗τ. max. )). 2. ]), where τ. max. (99.5 years) is selected to ensure the mean survival probability of the patient population matched 92% at 15 years. The value of k was adjusted for simulated patients within a range of 0 to 1 as a function of their patient and surgeon-specific factors (Fig.2). To evaluate power associated with a study design, we ran a Monte Carlo simulation generating 10,000 simulated populations of ten different cohort sizes. We divided the patient population into two groups: one group was assigned CPAs governed by the precision of a navigated/robotic approach (σ=1.5°), and the other CPAs governed by the precision of a conventional approach (σ=3°). We then simulated the time to failure for each patient, computed the corresponding Kaplan-Meier survival curves, and applied a Log-Rank test to each study to test for statistical difference. From the 10,000 simulations associated with each cohort size, we determined the percentage of simulated studies that found a statistically significant difference at each time point. Results. Figure 3 shows a contour plot illustrating the probability that a survival analysis with a specific study design would find statistical significance between the conventional and navigated/robotic patient groups. Entries from recently published literature are overlaid for context. No studies achieved statistical significance (p<0.05). Discussion. The effectiveness of navigated/robotic surgery is one of the most controversial debates in orthopedic surgery. The results from this simulation suggest that most revision studies aiming to settle this debate are likely significantly underpowered, falling below the normal 80% threshold. Limitations of this analysis include using only a single surgeon-controlled variable in the survival simulation, and only a single precision for the navigated/robotic approaches. Further studies will include more implant-related risk factors and a wider range of precisions for navigated/robotic procedures. Based on this simulation, it appears the effect size afforded by navigated/robotic surgeries on revision rates in TKA surgery is too small to recommend broad application, especially since adoption could involve added costs and unforeseen risks associated with novelty. Clinically, it may be beneficial to examine the use of robotics/navigation on high-risk patients, where studies are likely to have higher power due to larger effect sizes. For any figures or tables, please contact the authors directly

Background. Need for hip or knee arthroplasty is rapidly increasing in aging society nowadays. Accordingly, orthopedic surgeries for patients with various diseases of high mortality rates are becoming indispensable. Patients with liver cirrhosis undergoing major orthopedic surgery like joint arthroplasty are at risk of many complications including infection and excessive bleeding. In this study, we want to present helpful measures to prevent expected complications that can occur with hip or knee arthroplasty performed on patients with liver cirrhosis through comparative analysis on the prognosis of relevant patients studied at our hospitals. Patients and method. The study involves a retrospective comparison on 210 patients who underwent hip (71 patients) or knee (138 patients) arthroplasty in Chonnam National University Hospital, Hwasun Chonnam National University Hospital or Chonnam National University Bitgoeul Hospital. Prognoses of patients with underlying disease of liver cirrhosis and those without are compared with measures of amount of bleeding, transfer to an intensive care unit or medical department, duration of hospital stay, readmission within 30 days, 90 days and post-operative complication. To find out the rationale behind the differences in prognosis between these two groups, comparisons on total surgical time and blood loss during surgery were made. Also, the objectivity of the surgical treatment at our hospitals was ensured through comparing the postoperative short- and long-term mortality rates of the patients with liver cirrhosis who underwent hip or knee arthroplasty at our hospitals. Results. Among patients who underwent hip or knee arthroplasty, those with underlying condition of the liver cirrhosis show an increase in amount of bleeding, duration of hospital stay, number of blood transfusion, infection rate and a decrease in long-term survival rate compared to those who do not have liver cirrhosis. It was found that all of these factors were differed with severity of liver cirrhosis (measured according to Child-Pugh Score) and combined another disease (CRF) and became more profound when severity of liver cirrhosis increased. Conclusion. It was possible to show that the risk of arthroplasty on patients with liver cirrhosis is much higher than on cases of normal patients. Performing arthroplasty on patients with liver cirrhosis seems to put them under higher risk of increased blood loss and infection rates. Therefore, it is advised to prepare adequate preoperative and postoperative medical care, decrease surgical time and bleeding loss when performing hip or knee arthroplasty on patients with cirrotic liver disease

Aims. COVID-19 represents one of the greatest global healthcare challenges in a generation. Orthopaedic departments within the UK have shifted care to manage trauma in ways that minimize exposure to COVID-19. As the incidence of COVID-19 decreases, we explore the impact and risk factors of COVID-19 on patient outcomes within our department. Methods. We retrospectively included all patients who underwent a trauma or urgent orthopaedic procedure from 23 March to 23 April 2020. Electronic records were reviewed for COVID-19 swab results and mortality, and patients were screened by telephone a minimum 14 days postoperatively for symptoms of COVID-19. Results. A total of 214 patients had orthopaedic surgical procedures, with 166 included for analysis. Patients undergoing procedures under general or spinal anaesthesia had a higher risk of contracting perioperative COVID-19 compared to regional/local anaesthesia (p = 0.0058 and p = 0.0007, respectively). In all, 15 patients (9%) had a perioperative diagnosis of COVID-19, 14 of whom had fragility fractures; six died within 30 days of their procedure (40%, 30-day mortality). For proximal femoral fractures, our 30-day mortality was 18.2%, compared to 7% in 2019. Conclusion. Based on our findings, patients undergoing procedures under regional or local anaesthesia have minimal risk of developing COVID-19 perioperatively. Those with multiple comorbidities and fragility fractures have a higher morbidity and mortality if they contract COVID-19 perioperatively; therefore, protective care pathways could go some way to mitigate the risk. Our 30-day mortality of proximal femoral fractures was 18.2% during the COVID-19 pandemic in comparison to the annual national average of 6.1% in 2018 and the University Hospital Coventry average of 7% for the same period in 2019, as reported in the National Hip Fracture Database. Patients undergoing procedures under general or spinal anaesthesia at the peak of the pandemic had a higher risk of contracting perioperative COVID-19 compared to regional block or local anaesthesia. We question whether young patients undergoing day-case procedures under regional block or local anaesthesia with minimal comorbidities require fourteen days self-isolation; instead, we advocate that compliance with personal protective equipment, a negative COVID-19 swab three days prior to surgery, and screening questionnaire may be sufficient. Cite this article: Bone Joint Open 2020;1-9:520–529

Background. Hip Hemiarthroplasty is one of the commonest orthopaedic operation done in UK with recent NHFD data from 2017 report showing that 43% of the 77000 patients who presented to hospital had hemiarthroplasty. Literature suggests dislocation rate of 0.8% – 6.1% for Hip Hemiarthroplasty. Dislocation of hemiarthroplasty may lead to significant morbidity and mortality. Aim. To investigate if acetabular dysplasia has a significant association with hemiarthroplasty dislocation. Methodology. Retrospective multicentre review. Review of radiographs of patients receiving a hip hemiarthroplasty for a hip fracture measuring Acetabular index (sharp angle) and Lateral Centre edge angle(CEA). A large acetabular index and lower value for the center-edge angle suggest acetabular dysplasia. Measurements were made for 20 patients with dislocation and 20 patients without dislocation. Statistical assessment of the results with unpaired t test was performed. Results. Mean acetabular angle for those with dislocation was 42.65 degrees versus 37.8 for those without dislocation giving a p value of 0.000861. Mean Center-edge angle of those with dislocation was 26.1 degrees versus 37 for those without dislocation giving a p value of 0.000019. Conclusion. This study showed that the hemiarthroplasty dislocation group had higher acetabular index and Lower Center-edge angle compared to the hemiarthroplasty group without dislocation clearly demonstrating that acetabular dysplasia is implicated in the aetiology of hip hemiarthroplasty dislocation. Hence careful review of the pre-op X-rays for dysplastic features would benefit in making a sound management plan

BACKGROUND. Optimal perioperative fluid management has not been established in patients undergoing orthopaedic surgical procedures. Our purpose was to investigate the effects of perioperative fluid management on patients experiencing TKA. METHODS. One hundred thirty patients who met inclusion criteria undergoing primary unilateral TKA were prospectively randomized into traditional (TFG) vs. oral (OFG) perioperative fluid management groups. The TFG had a predetermined amount of intravenous fluids (IVF) administered in the perioperative period. The OFG began drinking a minimum of three, 20-ounces servings of clear fluids daily for three days prior to surgery. This cohort also drank 10-ounces of clear fluids 4 hours prior to surgery. Perioperative IVF were discontinued when the patient began oral intake or when the total amount of IVF reached 500mL. Outcome measures included: body-weight (BW) fluctuations, knee motion, leg girth, bioelectrical impendence, quadriceps activation, functional outcomes testing, KOOS JR, VR-12, laboratory values, vital signs, patient satisfaction, pain scores, and adverse events. RESULTS. The TFG had increased BW the evening of surgery (7.0±4.3 vs. 3.0±3.9, p=0.000), post-operative day (POD) #1 (9.1±4.3 vs. 4.7±3.9, p=0.000), and POD #2 (6.2±5.0 vs. 4.4±4.0, p=0.032). Bioelectrical impedance showed less limb edema in the OFG (4.2±29.7 vs. 17.8±30.3, p=0.000) on POD#1. Urine specific gravity differences were seen preoperatively between groups (OFG, more hydrated, p=0.002). Systolic blood pressure change from baseline was greater in the OFG upon arrival to the floor (19.4±13.5 vs. 10.6±12.8, p=0.000) and 8 (23.4±13.3 vs. 17.0±12.9, p=0.006) and 16 (25.8±13.8 vs. 25.8±13.8, p=0.046) hours after floor arrival. The TFG had more UOP on POD#1 (3369mL±1343mL vs. 2435mL±1151mL). CONCLUSIONS. Oral fluid intake with IVF restriction in the perioperative period after TKA may offer short-term benefits with swelling and BW fluctuations. The authors continue to limit perioperative IVFs and encourage patient initiated fluid intake

Aim. To compare outcomes and incidence of adverse events (AE) of colistin versus tigecycline for treatment of patients with carbapenem-resistant Acinetobacter baumannii (CRAB) osteomyelitis. Method. Retrospective study. Records of 111 patients with microbiologically confirmed CRAB osteomyelitis were analyzed. Colistin (34 cases) and tigecycline (31 cases) were the main drugs used for treatment of extremely-drug resistant (XDR) isolates. Patients who received these two antimicrobials were compared according to baseline features (sex, age, length of hospital stay, Charlson index, presence of comorbidities or immunosuppression, previous renal disease, smoking, alcoholism or use of illicit drugs, previous orthopedic surgery on affected limb, topography of infection, classification of osteomyelitis, ASA score, infection related to pressure ulcer or neuropathic foot, presence of implant, need for soft tissue repair or negative pressure therapy and previous antimicrobial use), clinical outcome after 12 months of treatment (remission of infection was considered the favorable outcome; recurrence of infection, amputation and death were considered unfavorable outcomes; loss of follow-up was analyzed separately) and AE during treatment (impaired renal function; liver abnormalities; nausea; skin rash; neurological abnormalities and other events in general). Quantitative variables were described using summary measures and compared using Student's t or Mann-Whitney tests. Qualitative characteristics were described with absolute and relative frequencies and compared using chi-square or exact tests (Fisher's exact or likelihood ratio test). Results. Regarding baseline characteristics, proportion of male patients was higher in the group treated with colistin (p = 0.028). In the group treated with tigecycline, there was a significant predominance of smokers (p = 0.021) and patients with chronic osteomyelitis (p = 0.036). Regarding clinical outcomes after 12 months of treatment, there was no difference between groups. Overall incidence of AE was significantly higher among patients treated with colistin (p=0,047), as well as renal impairment (p = 0.003). Incidence of nausea was higher in patients treated with tigecycline (p = 0.046), but there was no difference between groups in relation to altered liver enzymes and other events. Conclusions. In this retrospective analysis, there was no significant difference between clinical outcomes of patients with CRAB osteomyelitis treated with colistin compared to tigecycline. Although the occurrence of nausea was greater in the group receiving tigecycline, this antimicrobial appeared to have a better safety profile for treatment of osteomyelitis related to XDR A. baumannii

Aim. Periprosthetic joint infections (PJI) and surgical site infections (SSI) are one of the most severe complications in joint arthroplasty. Decolonization measures prior to elective orthopedic surgeries have shown to reduce the risk of infection especially in patient identified as carriers of S. aureus. However additional screening measures can be difficult to implement in daily routine. The objective was to study the influence of universal decolonization with polihaxanid on SSI rates. Method. Between January 2017 and December 2018 patients scheduled for hip or knee joint arthroplasty in 5 participating orthopedic centers received polyhexanid containing decolonization set consisting of oral, nasal and wipes. Patients were instructed to perform a 5 day decolonization regimen 4 days prior to surgery. SSIs were recorded according to modified CDC criteria for a surveillance period of 90days after surgery. Results. During the study period, 4437 decolonization sets were distributed to patients. 1869 patients consented to participate in the study and provide detailed feedback on compatibility and compliance. Overall SSI rate was 0.87 per 100 surgeries prior to introduction of the decolonization, while it was 0.97 per 100 surgeries during the period of decolonization and 0.59 per 100 surgeries in those using the decolonization set. SSI rates due to Staphylococcus aureus were 0.32 per 100 surgeries, 0.21 per 100 surgeries and 0.05 per 100 surgeries respectively. In patients receiving an elective hip-joint arthroplasty SSI rate was 0.93 per 100 surgeries prior to introduction, while it was 1.17 per 100 surgeries during the intervention period and 0.96 per 100 surgeries in patients that used the decolonization set. However SSI rates due to Staphylococcus aureus were 0.30 per 100 surgeries, 0.14 per 100 surgeries and 0.10 per 100 surgeries respectively. In patients receiving, an elective knee-joint arthroplasty SSI rate was 0.52 per 100 surgeries prior to introduction, while it was 0.53 per 100 surgeries during the intervention period and 0.12 per 100 surgeries in patients that used the decolonization set. However, SSI rates due to Staphylococcus aureus were 0.20 per 100 surgeries, 0.13 per 100 surgeries and 0.00 per 100 surgeries respectively. In addition to these preliminary results, we will provide and present a further analysis of the study results. Conclusions. Polyhexanid based universal decolonization measures were safely implemented. Universal decolonization with polyhexanid might have a benefit on S. aureus SSI rates in patients with joint arthroplasty, especially in elective knee arthroplasty. Further evaluations are needed

INTRODUCTION. In orthopedic surgery, the lower limb alignment defined by the HKA parameter i.e. the angle between the hip, knee and ankle centers, is a crucial clinical criterion used for the achievement of several surgeries. It can be intraoperatively determined with Computer Assisted Orthopedic Surgery (CAOS) systems by computing the 3D location of these joint centres. The hip centre used for the computation of the HKA is defined by the experts as the anatomical centre of the femoral head. However, except for Total Hip Replacement procedure, the hip joint is not accessible and the hip center is computed using functional methods. The two most common are the Least Moving Point (LMP) and the Pivoting (PIV). MATERIALS AND METHODS. We have analysed on six cadaveric lower limbs the intra-observer variability of both the anatomical and the functional hip centres. The differences between the HKAs angle obtained with the anatomical hip centre (HCANAT) and those obtained with the functional hip centres coming from the LMP (HCLMP) and the PIV (HCPIV) algorithms have also been analysed. RESULTS. The intra-observer variability was on average (standard deviation) 0.9(0.6)mm, 9(5.2)mm and 7.5(4)mm for respectively the HCANAT, HCLMP and the HCPIV variations. The average impact on the HKA was 1° and 0.8 ° respectively for HCLMP and HCPIV with a maximum of 4°. DISCUSSION. Several papers in the literature have studied the accuracy and the robustness of methods allowing CAOS systems to determine the functional hip centre. All of these studies have been performed with simulated data. This study shows results coming from in-vitro data. The results concerning the intra-observer variability shows that the procedure is very robust and reproducible for the determination of HCANAT. However, functional methods are much less reproducible even if the Pivoting method seems to be a little better. Given these results, the impact of the functional methods on the HKA has been analysed. We have therefore compared the HKA obtained with HCANAT with those obtained with HCLMP and HCPIV. The results are extremely encouraging since, despite the intra-observer variability, the differences between the anatomical and the functional HKAs are, on average, less than 1° with a maximum inferior to 4°. The impact on the HKA is therefore limited and the accuracy of the functional methods to assess the HKA are sufficient regarding the clinical needs