Aims. A higher failure rate has been reported in haematogenous periprosthetic joint infection (PJI) compared to non-haematogenous PJI. The reason for this difference is unknown. We investigated the outcome of haematogenous and non-haematogenous PJI to analyze the risk factors for failure in both groups of patients. Methods. Episodes of knee or hip PJI (defined by the European Bone and Joint Infection Society criteria) treated at our institution between January 2015 and October 2020 were included in a retrospective PJI cohort. Episodes with a follow-up of > one year were stratified by route of infection into haematogenous and non-haematogenous PJI. Probability of failure-free survival was estimated using the Kaplan-Meier method, and compared between groups using log-rank test. Univariate and multivariate analysis was applied to assess risk factors for failure. Results. A total of 305 PJI episodes (174 hips, 131 knees) were allocated to the haematogenous (n = 146) or the non-haematogenous group (n = 159). Among monomicrobial infections, Staphylococcus aureus was the dominant pathogen in haematogenous PJI (76/140, 54%) and coagulase-negative staphylococci in non-haematogenous PJI (57/133, 43%). In both groups, multi-stage exchange (n = 55 (38%) in haematogenous and n = 73 (46%) in non-haematogenous PJI) and prosthesis retention (n = 70 (48%) in haematogenous and n = 48 (30%) in non-haematogenous PJI) were the most common surgical strategies. Median duration of antimicrobial treatment was 13.5 weeks (range, 0.5 to 218 weeks) and similar in both groups. After six years of follow-up, the probability of failure-free survival was significantly lower in haematogenous compared to non-haematogenous PJI (55% vs 74%; p = 0.021). Infection-related mortality was significantly higher in haematogenous than non-haematogenous PJI (7% vs 0% episodes; p = 0.001). Pathogenesis of failure was similar in both groups. Retention of the prosthesis was the only independent risk factor for failure in multivariate analysis in both groups. Conclusion. Treatment failure was significantly higher in haematogenous compared to non-haematogenous PJI. Retention of the prosthesis was the only independent risk factor for failure in both groups. Cite this article: Bone Joint J 2023;105-B(12):1294–1302

Aims. Patients with cauda equina syndrome (CES) require emergency imaging and surgical decompression. The severity and type of symptoms may influence the timing of imaging and surgery, and help predict the patient’s prognosis. Categories of CES attempt to group patients for management and prognostication purposes. We aimed in this study to assess the inter-rater reliability of dividing patients with CES into categories to assess whether they can be reliably applied in clinical practice and in research. Methods. A literature review was undertaken to identify published descriptions of categories of CES. A total of 100 real anonymized clinical vignettes of patients diagnosed with CES from the Understanding Cauda Equina Syndrome (UCES) study were reviewed by consultant spinal surgeons, neurosurgical registrars, and medical students. All were provided with published category definitions and asked to decide whether each patient had ‘suspected CES’; ‘early CES’; ‘incomplete CES’; or ‘CES with urinary retention’. Inter-rater agreement was assessed for all categories, for all raters, and for each group of raters using Fleiss’s kappa. Results. Each of the 100 participants were rated by four medical students, five neurosurgical registrars, and four consultant spinal surgeons. No groups achieved reasonable inter-rater agreement for any of the categories. CES with retention versus all other categories had the highest inter-rater agreement (kappa 0.34 (95% confidence interval 0.27 to 0.31); minimal agreement). There was no improvement in inter-rater agreement with clinical experience. Across all categories, registrars agreed with each other most often (kappa 0.41), followed by medical students (kappa 0.39). Consultant spinal surgeons had the lowest inter-rater agreement (kappa 0.17). Conclusion. Inter-rater agreement for categorizing CES is low among clinicians who regularly manage these patients. CES categories should be used with caution in clinical practice and research studies, as groups may be heterogenous and not comparable. Cite this article: Bone Joint J 2023;105-B(9):1007–1012

Aims. The aim of this meta-analysis was to determine the pooled incidence of postoperative urinary retention (POUR) following total hip and knee arthroplasty (total joint replacement (TJR)) and to evaluate the risk factors and complications associated with POUR. Methods. Two authors conducted searches in PubMed, Embase, Web of Science, and Scopus on TJR and urinary retention. Eligible studies that reported the rate of POUR and associated risk factors for patients undergoing TJR were included in the analysis. Patient demographic details, medical comorbidities, and postoperative outcomes and complications were separately analyzed. The effect estimates for continuous and categorical data were reported as standardized mean differences (SMDs) and odds ratios (ORs) with 95% CIs, respectively. Results. A total of 31 studies were included in the systematic review. Of these, 29 studies entered our meta-analysis, which included 3,273 patients diagnosed with POUR and 11,583 patients without POUR following TJR. The pooled incidence of POUR was 28.06%. Demographic risk factors included male sex (OR 1.81, 95% CI 1.26 to 2.59), increasing age (SMD 0.16, 95% CI 0.04 to 0.27), and American Society of Anesthesiologists grade 3 to 4 (OR 1.39, 95% CI 1.10 to 1.77). Patients with a history of benign prostatic hyperplasia (OR 1.99, 95% CI 1.41 to 2.83) and retention (OR 3.10, 95% CI 1.58 to 6.06) were more likely to develop POUR. Surgery-related risk factors included spinal anaesthesia (OR 1.44, 95% CI 1.19 to 1.74) and postoperative epidural analgesia (OR 2.82, 95% CI 1.65 to 4.82). Total hip arthroplasty was associated with higher odds of POUR compared to total knee arthroplasty (OR 1.10, 95% CI 1.02 to 1.20). Postoperatively, POUR was associated with a longer length of stay (SMD 0.21, 95% CI 0.02 to 0.39). Conclusion. Our meta-analysis demonstrated key risk variables for POUR following TJR, which may assist in identifying at-risk patients and direct patient-centered pathways to minimize this postoperative complication. Cite this article: Bone Jt Open 2024;5(7):601–611

We introduce a new technique called the “Posterior Cruciate Referencing Technique” (PCRT), a specific combination of surgical technique, devices and instrumentation. Careful anatomic preservation of the posterior cruciate ligament (PCL) based upon a specific reference point off the tibia allows for use of sloped tibial components to achieve consistent functional behavior of the PCL. We discuss the preclinical design and development leading to availability of this device, and subsequent early clinical experience with this approach. Posterior cruciate ligament (PCL) retention in total knee arthroplasty (CR-TKA) has been a feature of certain styles of TKA since the inception of predictable TKA in the early 1970s. It has been adapted and promoted as advantageous for a number of real and theoretical benefits. In reality, however, PCL retention has proven inconsistent when applied across a broad range of surgical environments. A number of adaptations in surgical technique, device modification and instrumentation have been developed to try to improve the predictability of the surgical intervention and subsequent postoperative performance. It is our belief that currently recommended surgical techniques can lead to inconsistencies in surgical judgment and consequently performance of CR devices because they inadvertently compromise the anatomy and hence functional performance of the PCL. A study by Shannon et al showed that, during CR-TKA, the PCL was either partially or completely removed as a result of the tibial cut in two out of three cases [1]. Unlike the long held and validated approach of ligament releases for fixed New Technique for Functional Posterior Cruciate Retention in TKA varus and valgus deformity that, along with alignment, allow successful long 45 term outcomes, ligament release of the PCL to balance the knee in flexion, whether by bone cuts or physical release, may compromise its overall function and explain kinematic differences in expected versus observed performance. Our hypothesis is that devices, surgical techniques and instruments designed around anatomical and functional preservation of the PCL would promote a reproducible surgical approach and consistent clinical performance of a CR-TKA. This manuscript provides the rationale for development of a new technique called the “Posterior Cruciate Referencing Technique” (PCRT), a combination of technique, instruments and devices specifically designed to preserve the PCL anatomy and take advantage of the functional performance of the PCL. We discuss the anatomical, radiographic, kinematic and mechanical testing approach that suggests that this is a safe and effective approach for primary CR-TKA. Conclusion: This manuscript presents a body of work that elucidates specific issues of implant design and technical implantation that may have led to inadvertent compromise of function of the PCL during CR-TKA. We believe that such compromises may explain the inconsistent kinematic behavior of these devices in the hands of surgeons who use them, and may result in clinical outcomes that were unintended. We have provided the rationale for a new technique of implantation the Posterior-Cruciate Referencing Technique (PCRT) -which mates specific referencing approaches of the PCL and tibial resection, with implants, to address PCL functional New Technique for Functional Posterior Cruciate Retention in TKA behavior. We have provided laboratory, pre-clinical and early clinical evaluations that suggest that this will prove a safe and effective approach to CR-TKA

Aims. In metal-on-metal (MoM) hip arthroplasties and resurfacings, mechanically induced corrosion can lead to elevated serum metal ions, a local inflammatory response, and formation of pseudotumours, ultimately requiring revision. The size and diametral clearance of anatomical (ADM) and modular (MDM) dual-mobility polyethylene bearings match those of Birmingham hip MoM components. If the acetabular component is satisfactorily positioned, well integrated into the bone, and has no surface damage, this presents the opportunity for revision with exchange of the metal head for ADM/MDM polyethylene bearings without removal of the acetabular component. Methods. Between 2012 and 2020, across two centres, 94 patients underwent revision of Birmingham MoM hip arthroplasties or resurfacings. Mean age was 65.5 years (33 to 87). In 53 patients (56.4%), the acetabular component was retained and dual-mobility bearings were used (DM); in 41 (43.6%) the acetabulum was revised (AR). Patients underwent follow-up of minimum two-years (mean 4.6 (2.1 to 8.5) years). Results. In the DM group, two (3.8%) patients underwent further surgery: one (1.9%) for dislocation and one (1.9%) for infection. In the AR group, four (9.8%) underwent further procedures: two (4.9%) for loosening of the acetabular component and two (4.9%) following dislocations. There were no other dislocations in either group. In the DM group, operating time (68.4 vs 101.5 mins, p < 0.001), postoperative drop in haemoglobin (16.6 vs 27.8 g/L, p < 0.001), and length of stay (1.8 vs 2.4 days, p < 0.001) were significantly lower. There was a significant reduction in serum metal ions postoperatively in both groups (p < 0.001), although there was no difference between groups for this reduction (p = 0.674 (cobalt); p = 0.186 (chromium)). Conclusion. In selected patients with Birmingham MoM hips, where the acetabular component is well-fixed and in a satisfactory position with no surface damage, the metal head can be exchanged for polyethylene ADM/MDM bearings with retention of the acetabular prosthesis. This presents significant benefits, with a shorter procedure and a lower risk of complications. Cite this article: Bone Jt Open 2024;5(6):514–523

Introduction. Retention and removal of children's orthopaedic metalwork is a contentious issue that has implications for current resource allocation, health economics, complication risks and can impact on future treatments. Understanding how to guide families make informed choices requires an overview of all the relevant evidence to date, and knowledge of where the evidence is lacking. Our aim was to systematically review the literature and provide a meta-analysis where possible, recommending either retention or removal. Materials and Methods. A search of the literature yielded 2420 articles, of which 22 papers were selected for the study analysis. Inclusion criteria: Any paper (evidence level I-IV) assessing the risks or benefits of retaining or removing orthopaedic metalwork in children. Exclusion criteria: Spinal implants; implant number < 40; < 75% recorded follow up; papers including implants in their analysis that always require removal; patients aged >18 years. Results. In total, 4988 patients (6412 implants) were included across all 22 studies. There was a significant amount of heterogenicity between studies. Overall the short term risks of metalwork retention and removal are low, with a few exceptions. In forearm plating re-fracture rates following removal were lower than those seen in studies looking at retained metalwork, provided removal occurred later than 12 months from the initial operation. Forearm re-fracture rates after removal of flexible nails significantly increased if removal was performed before 6 months. Major complications following routine metalwork removal from the proximal femur are relatively rare, with re-fracture rates of 1–5%. The majority of these re-fractures are seen in neuromuscular patients or in patients where removal occurs earlier than 6 months. Routine metalwork removal following SUFE had a complication rate of 30–60%. Conclusions. We found that there are certain subgroups of children that benefit from retention of metalwork and some that benefit from removal. There are several subgroups that we have identified which do not yet have sufficient long term evidence to make a balanced recommendation. We advise that families are made aware of what is known and what is unknown in order to allow for shared decision making

Aims. The principle strategies of fracture-related infection (FRI) treatment are debridement, antimicrobial therapy, and implant retention (DAIR) or debridement, antimicrobial therapy, and implant removal/exchange. Increasing the period between fracture fixation and FRI revision surgery is believed to be associated with higher failure rates after DAIR. However, a clear time-related cut-off has never been scientifically defined. This systematic review analyzed the influence of the interval between fracture fixation and FRI revision surgery on success rates after DAIR. Methods. A systematic literature search was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, in PubMed (including MEDLINE), Embase, and Web of Science Core Collection, investigating the outcome after DAIR procedures of long bone FRIs in clinical studies published until January 2020. Results. Six studies, comprising 276 patients, met the inclusion criteria. Data from this review showed that with a short duration of infection (up to three weeks) and under strict preconditions, retention of the implant is associated with high success rates of 86% to 100%. In delayed infections with a fracture fixation-FRI revision surgery interval of three to ten weeks, absence of recurrent infection was reported in 82% to 89%. Data on late FRIs, with a fracture fixation-FRI revision surgery interval of more than ten weeks, are scarce and a success rate of 67% was reported. Conclusion. Acute/early FRI, with a short duration of infection, can successfully be treated with DAIR up to ten weeks after osteosynthesis. The limited available data suggest that chronic/late onset FRI treated with DAIR may be associated with a higher rate of recurrence. Successful outcome is dependent on managing all aspects of the infection. Thus, time from fracture fixation is not the only factor that should be considered in treatment planning of FRI. Due to the heterogeneity of the available data, these conclusions have to be interpreted with caution. Cite this article: Bone Joint J 2021;103-B(2):213–221

Acute post-operative urinary retention (POUR) is a recognized complication following lower limb arthroplasty. Its occurrence may have patient and ultimately medico-legal implications. Identifying high-risk patients and the associated risk factors pre-operatively, is vital to tackle this issue and reduce its occurrence, which ultimately, may enhance the overall success of our operations. Our aim was to assess the incidence of POUR following elective lower limb arthroplasty and analyze the related factors that could potentially predict the likelihood of developing POUR in our patient cohort. A prospective audit of 158 patients was conducted in our department. POUR was defined as inability to pass urine voluntarily within the first 24 hours following elective lower limb arthroplasty leading to the insertion of a urinary catheter. Surgical-related factors including intra-operative fluid use, type of spinal anesthetic, duration of surgery, time from surgery till insertion of a urinary catheter as well as patient-related factors including medication, urological history and Body Mass index (BMI) was collected and analyzed. 21 (13.3%) patients developed post-operative urinary retention, 11 (52%) and 10 (48%) following knee and hip replacements respectively. Of which, 19 (90.5%) were male and 2 (9.5%) were female with an average age of 66 yrs. 13 (62%) had a previous urological history and 10 (48%) were on retention associated medication. Bupivacaine as a spinal anesthetic was associated with an increased risk of developing post-operative urinary retention. The average time till catheter insertion was 14 hrs. Only 2 (10%) had an unsuccessful TWOC on discharge. Bupivacaine as a spinal anesthetic and a previous urological history can be considered as risk factors for the development of POUR. Pre-operative urinary catheterization should be considered in this high-risk group of patients

Aims. Fracture-Related Infection (FRI) is a severe complication caused by microbial infection of bone. It is imperative to gain more insight into the potentials and limitations of Debridement, Antibiotics and Implant Retention (DAIR) to improve future FRI treatment. The aims of this study were to: 1) determine how time to surgery affects the success rate of DAIR procedures of the lower leg performed within 12 weeks after the initial fracture fixation operation and 2) evaluate whether appropriate systemic antimicrobial therapy affects the success rate of a DAIR procedure. Methods. This multinational retrospective cohort study included patients of at least 18-years of age who developed an FRI of the lower leg within 12 weeks after the initial fracture fixation operation, between January 1st 2015 to July 1st 2020. DAIR success was defined by the absence of recurrence of infection, preservation of the affected limb and retention of implants during the initial treatment. The antimicrobial regimen was considered appropriate if the pathogen(s) was susceptible to the given treatment at the correct dose as per guideline. Logistic regression modelling was used to assess factors that could contribute to the DAIR success rate. Results. A total of 120 patients were included, of whom 70 DAIR patients and 50 non-DAIR patients. Within a median follow-up of 35.5 months, 21.4% of DAIR patients developed a recurrent FRI compared to 12.0% of non-DAIR patients. The DAIR procedure was successful in 45 patients (64.3%). According to the Willenegger and Roth classification, DAIR success was achieved in 66.7% (n=16/24) of patients with an early infection (<2 weeks), 64.4% (n=29/45) of patients with a delayed infection (2–10 weeks) and 0.0% (0/1) of patients with a late infection (>10 weeks). Univariate analysis showed that the duration of infection was not associated with DAIR success in this cohort (p=0.136; OR: 0.977; 95%CI: [0.947–1.007]). However, an appropriate antimicrobial regimen was associated with success of DAIR (p=0.029; OR: 3.231; 95%CI: [1.138–9.506]). Conclusions. Although the results should be interpreted with caution, an increased duration of infection was not associated with a decreased success rate of a DAIR procedure in patients with FRI of the lower leg. The results of this study highlight the multifactorial contribution to the success of a DAIR procedure and emphasize the importance of adequate antimicrobial treatment. Therefore, time to surgery should not be the only key-factor when considering a DAIR procedure to treat FRI

In metal-on-metal (MoM) hip replacements or resurfacings, mechanical induced corrosion can lead to a local inflammatory response, pseudo tumours and elevated serum metal ions, requiring revision surgery. The size and diametral clearance of Anatomic (ADM) and Modular (MDM) Dual Mobility bearings matches that of certain MOM components. Presenting the opportunity for revision with exchange of the metal head for ADM/MDM bearings without removal of the acetabular component if it is well-fixed and appropriately positioned. Between 2012 and 2020, across two centres, 94 patients underwent revision of a MoM hip replacement or resurfacing. The mean age was 65.5 (33–87) years. In 53 patients (56.4%), the acetabular component was retained, and dual mobility bearings were used (DM); in 41 (43.6%) the acetabulum was revised (AR). DM was only considered where the acetabular component was satisfactorily positioned and well-integrated into bone, with no surface damage. Patients underwent clinical and radiographic follow-up to at least one-year (mean 42.4 (12–96) months). One (1.1%) patient died before one-year, for reasons unrelated to the surgery. In the DM group, two (3.8%) patients underwent further surgery; one (1.9%) for dislocation and one (1.9%) for infection. In the AR group, four (12.2%) underwent further procedures; two (4.9%) for loosening of the acetabular component and two (4.9%) following dislocations. There were no other dislocations in either group. In the DM group, operative time (68.4 v 101.5 mins, p<0.001), postoperative drop in haemoglobin (16.6 v 27.8 g/L, p<0.001), and length of stay (1.8 v 2.4 days, p<0.001) were significantly lower. There was a significant reduction in serum metal ions postoperatively in both groups (p<0.001 both Cobalt and Chromium) although there was no difference between groups for this reduction (p=0.674 Cobalt; p=0.186 Chromium). In selected patients with MoM hip arthroplasty, where the acetabular component is well-fixed, in a satisfactory position and there is no surface damage, the metal head can be exchanged for ADM/MDM bearings with retention of the acetabular prosthesis. Presenting significant benefits through a less invasive procedure, and a low risk of complications, including dislocation

Aim. Debridement, Antibiotics, Irrigation, and implant Retention (DAIR) is a surgical treatment protocol suitable for some patients with fracture related infection (FRI). Clinically relevant pre-clinical models of DAIR are scarce and none have been developed in large animals. Therefore, this project aimed to develop a large animal model for FRI including a DAIR approach and compare outcomes after 2 or 5 weeks of infection. Method. Swiss Alpine sheep (n=8), (2–6 years, 50–80 kg) were included in this study. This study was approved by cantonal Ethical authorities in Chur, Switzerland. A 2 mm osteotomy was created in the tibia and fixed with a 10-hole 5.5 mm steel plate. Subsequently, 2.5 mL of saline solution containing 10. 6. CFU/mL of Staphylococcus aureus MSSA (ATCC 25923) was added over the plate. Sheep were observed for 2 (n=3) or 5 weeks (n=5) until revision surgery, during which visibly infected or necrotic tissues were removed, and the wound flushed with saline. All samples were collected for bacterial quantification. After revision surgery, the sheep were treated systemically for 2 weeks with flucloxacillin and for 4 weeks with rifampicin and cotrimoxazole. After 2 further weeks off antibiotics, the animals were euthanized. Bacteriological culture was performed at the end of the study. Bone cores were isolated from the osteotomy site and processed for Giemsa & Eosin and Brown and Brenn staining. A radiographical examination was performed every second week. Results. Bacteriological evaluation of the retrieved samples during revision surgery showed no significant difference between the 2 vs 5 weeks infection periods in term of total CFU counts. At the end of the study, radiographical examination showed callus formation over the osteotomy site in both groups, although the osteotomy was not completely healed in either group. At euthanasia, the 2 weeks infection group showed a higher soft tissue burden compared to the 5 weeks group, whereby the infection in the 5 weeks group was primarily located in the bone and bone marrow. Conclusions. The large animal model of FRI and DAIR was successfully established. Bacteriological outcomes highlight that the increasing duration of the infection does not change the outcome but the location of the infection from a predominantly soft tissue infection to a deeper bone and intramedullary (IM) channel infection. The debridement of the IM channel could potentially reduce the infection burden by eliminating those bacteria not easily reached by systemic antibiotics, though is not practical using conventional techniques

Abstract. Background. Infections are rare and poorly studied complications of unicompartmental knee athroplasty (UKA) surgery. They are significantly less common compared to infections after total knee arthroplasties (TKAs). Optimal management of periprosthetic joint infections (PJIs) after a UKA is not clearly defined in the literature. We present the results of a multicentre retrospective series of UKA PJIs treated with Debridement, Antibiotics and Implant Retention (DAIR). Methodology. Patients presenting between January 2016 and December 2019 with early UKA infection were identified at three specialist centres using the Musculoskeletal Infection Society (MSIS) criteria. All patients underwent a standardized treatment protocol consisting of the DAIR procedure and antibiotic therapy comprising two weeks of intravenous (IV) antibiotics followed by six weeks of oral therapy. The main outcome measure was overall survivorship free from reoperation for infection. Results. A total of 3225 UKAs (2793 (86.2%) medial and 432 (13.8%) lateral UKAs) were performed between January 2016 and December 2019. Nineteen patients had early infections necessitating DAIR. The mean follow-up period was 32.5 months. DAIR showed an overall survivorship free from septic reoperation of 84.2%, with an overall survivorship free from all-cause reoperation of 78.95%. The most common bacteria were Coagulase-negative Staphylococci, Staphylococcus aureus and Group B Streptococci. Three patients required a second DAIR procedure but remained free from re-infection at follow-up obviating the need for more demanding, staged revision surgery. Conclusions. In infected UKAs, the DAIR procedure produces a high rate of success, with a high survivorship of the implant

Prosthetic joint infections (PJI) caused by Streptococcus species are relatively common. The aim of our study was to assess outcome after treatment for early and late PJI with Streptococcus species after a follow-up of two years. For this study we retrospectively included all patients with primary or revision total knee arthroplasty (TKA) or total hip (THA) arthroplasty, a minimum of two periprosthetic tissue cultures positive for Streptococcus species and a minimum follow-up of one year. According to international guidelines patients were classified as having early or late PJI. All patients with an early PJI were treated according to a standard treatment protocol, i.e. debridement and retention of the prosthesis, followed by adequate antibiotic therapy. Patients with late PJI underwent a debridement followed by adequate antibiotic therapy or joint revision. Patients’ hospital records were reviewed and we evaluated the status of the original prosthesis after an infection. Forty cases were included; 24 early and 16 late PJI. For early PJI, open debridement was performed in all patients, after a mean of 19 (range: 9 – 80) days. At final follow-up 21 prostheses (88%) were still in situ and without clinical signs of infection. Eight cases (41%) of late PJI were successfully treated with debridement and retention. Nine patients (59%) underwent a one- or two-stage revision. At final follow-up 16 patients (100%) with late PJI had a prosthesis in situ. Streptococcus dysgalactiae species accounted for more than 50% of the early infections, followed by Streptococcus agalactiae with 30%. In case of PJI with Streptococcus species open debridement and retention of the prosthesis should be performed followed by adequate and long-term antibiotic treatment. As expected, the retention rate for early PJI is much higher than that for late PJI

Abstract. Introduction. Periprosthetic joint infection (PJI) is a common cause of revision total knee surgery. Although debridement and implant retention (DAIR) has lower success rates in the chronic setting, it is an accepted treatment for acute PJI. There are two broad DAIR strategies: single debridement or a planned double debridement performed days apart. The purpose of this study is to evaluate the cost-effectiveness of single versus double DAIR with antibiotic beads for acute PJI in total knee arthroplasty (TKA). Methodology. A decision tree using single or double DAIR as treatment strategies for acute PJI was constructed. Quality Adjusted Life Years (QALYs) and costs associated with the two treatment arms were calculated. Treatment success rates, failure rates, and mortality rates were derived from the literature. Medical costs were derived from both the literature and Medicare data. A cost-effectiveness plane was constructed from multiple Monte Carlo trials. A sensitivity analysis identified parameters most influencing the optimal strategy decision. Results. Double DAIR with antibiotic beads was the optimal treatment strategy both in terms of the health utility state (82% of trials), and medical cost (97% of trials). Strategy tables demonstrated that as long as the success rate of double debridement is 10% or greater than the success rate of a single debridement, the two-stage protocol is cost-effective. Conclusions. This Markov analysis demonstrates that in the setting of acute PJI following TKA, a double DAIR with antibiotic beads is more cost effective than single DAIR from a societal perspective

Aim. Acute hematogenous periprosthetic joint infection (AHI) is a diagnosis on the rise. The management is challenging and the optimum treatment is not clearly defined. The purpose of this study was to evaluate the characteristics of AHI, and to study risk factors affecting treatment outcome. Methods. We retrospectively analysed 44 consecutive episodes with AHI in a total hip or knee arthroplasty beween 2013 and 2020 at a single center. AHI was defined as abrupt symptoms of infection ≥ 3 months after implantation in an otherwise well functioning arthroplasty. We used the Delphi criteria to define treatment failure with a minimum of 1-year follow-up. Results. AIH was most often caused by Staphylococcus aureus (36%) and streptococcal species (32%), but a broad spectrum of microbes were identified. The majority of patients (25/44) were treated with debridement and retention of the implant (DAIR), with a success rate of 40%, significantly lower than in patients treated with removal of the implant (94%, p=0.001). Staph aureus infections (p=0.004), knee arthroplasties (p=0.03), and implant-age < 2 years (p=0.034) were associated with treatment failure. The 2-year mortality rate was 19%. Conclusions. The main findings in this study were that outcome following DAIR in AHIs is poor, that the majority of infections were caused by virulent microbes, and we found a high mortality rate. Removal of the implant should more often be considered

Aims

Fracture-related infection (FRI) is commonly classified based on the time of onset of symptoms. Early infections (< two weeks) are treated with debridement, antibiotics, and implant retention (DAIR). For late infections (> ten weeks), guidelines recommend implant removal due to tolerant biofilms. For delayed infections (two to ten weeks), recommendations are unclear. In this study we compared infection clearance and bone healing in early and delayed FRI treated with DAIR in a rabbit model.

Introduction: Urinary retention is a significant complication following hip and knee arthroplasty. Published literature has shown that the insertion of a catheter post-op is associated with an increased incidence of deep joint sepsis, however, pre-operative catheterisation has not. The International Prostate Symptom Score (IPSS) is an internationally validated scoring system used by Urologists to assess the severity of obstructive urinary symptoms and response to treatment. The purpose of this study was to quantify the incidence of urinary retention following major joint arthroplasty in an elective orthopaedic unit and to investigate whether a patient’s pre-operative IPSS score could be used to predict the likelihood of post-operative urinary retention. Patients and Methods: Over a 9 month period, 118 patients were enrolled prospectively into this study. 28 patients were admitted for knee replacement(TKR) and 90 patients for hip replacement (THR). All patients were asked to fill out an IPSS questionnaire form on admission. Demographics including age, mode of anaesthetic, intra-operative blood loss and operative time were recorded. Results: In our study group of 118 patients, 43(36.4%) developed urinary retention postoperatively. 29(32.2%) patients following THR developed urinary retention, whereas 14(50%) of the men who had a TKR developed urinary retention post-op. Of the 25 patients with a pre-operative IPSS score > /=10, 14(56%) went into retention. The mean pre-operative IPSS score was 7.74 for those who went into retention, compared to 5.0 for the other patients (p < 0.05). Type of anaesthesia, blood loss and operative time were non-contributory. Conclusion: This study shows a high rate of post-operative urinary catheterisation in our patient group. Despite the mean IPSS score being higher in patients requiring catheterisation, our results did not show any conclusive evidence that this scoring system could be used to predict the development of post-operatively urinary retention in patients presenting for hip or knee arthroplasty

Purpose. The success rate of surgical debridement and prostheses retention for acute periprosthetic joint infection (PJI) is controversial. This study aims to report our experience in managing acute PJI following total knee arthroplasty (TKA) with surgical debridement and prostheses retention, and to identify the prognostic factors that may influence the surgical outcomes. Methods. A retrospective review from our prospective joint replacement register in Queen Mary Hospital, Hong Kong, of patients who were managed with surgical debridement and prosthesis retention for acute PJI after TKA between 1998 and 2013 was performed. The diagnosis of acute PJI was based on the 2011 Musculoskeletal Infection Society (MSIS) PJI diagnostic criteria. Both the early post-operative infections and the late haematogenous infections were included (Tsukayama type 2 and 3). Surgical outcomes were defined as successful if patients’ clinical symptoms had been relieved; inflammatory marker levels including C-Reactive Protein (CRP), Erythrocyte Sedimentation Rate (ESR) and White Blood Cell (WBC) count had returned to normal; X-rays showed no prosthetic loosening; and no lifelong antibiotic suppression was required. Outcomes were defined as failed if patients required any further surgeries (e.g., re-debridement, one or two-stage revision), or needed lifelong antibiotic suppression. All Patients’ perioperative data, i.e., age, primary diagnosis, pre-operative CRP, ESR, WBC, haemoglobin, albumin, glucose level, time lag from symptoms onset to debridement, synovial fluid total cell count and bacteriology were traced and recorded. SPSS 22.0 was used to calculate and compare the statistical differences between surgically successful group and failed group regarding the factors above. Results. 34 patients with 35 TKAs were included. There were 19 female and 15 male. The primary diagnoses included 29 osteoarthritis (OA) and 5 rheumatoid arthritis (RA). 8 had history of diabetes mellitus (DM). 25 knees received primary TKA and 10 knees received revision TKA, including 6 revisions for PJI and 4 for aseptic loosening. 12 belonged to Tsukayama type 2 (early post-operative infection) and 23 belonged to Tsukayama type 3 (late haematogenous infection). During a mean follow-up time of 45.9±44.2 months, 12 were successfully treated while 23 failed, including 15 required re-operations and 8 needed lifelong antibiotic suppression. The success rate of debridement was 34.2%. Statistical analyses showed no significant differences between the two groups on patients’ age, time lag from symptoms onset to debridement, pre-operative CRP, ESR, WBC, haemoglobin, albumin, glucose level or synovial fluid total cell count. (Table 1) Patients’ primary diagnosis, previous revision surgeries or staphylococcal infections had no significant impacts on the surgical outcome, either. Debridement with polyethylene insert exchange, however, had a significantly higher success rate than debridement alone. (Table 2). Conclusions. We concluded that debridement with prosthesis retention has a low success rate for acute periprosthetic infection in TKA. No significant prognostic factors could be identified, except that debridement with polyethylene insert exchange has higher success rate than debridement alone

Aims

This systematic review and meta-analysis aimed to compare the influence of patellar resurfacing following cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA) on the incidence of anterior knee pain, knee-specific patient-reported outcome measures, complication rates, and reoperation rates.

Introduction: To investigate the presence or absence of osteonecrosis of femoral head (ONFH) in patients undergoing massive corticosteroid therapy, we have performed magnetic resonance imaging (MRI) early after administration. In some patients, MRI revealed an increase in hip fluid. In this study, we evaluated retention of hip fluid early after massive steroid therapy by MRI. Materials and Methods: The subjects were 14 patients (28 joints) in whom oral administration of prednisolone at an initial dose of 40 mg/day or more or pulse therapy was performed. They consisted of 3 men (6 joints) and 11 women (22 joints). Ages ranged from 17 to 72 years, with a mean of 38.2 years. We evaluated retention of hip fluid in T2-weighted MRI images or T2 fat-suppressed images within 3 months after massive steroid therapy according to the joint fluid grading established by Mitchell et al and evaluated volume of hip fluid by integrating an area (by using Mac scope ver 2.58). Results: Average volume of all joints was 7.18 cm. 3. Eleven joints were evaluated as Grade 1, in which a small amount of joint fluid is noted, and their average volume was 3.98 cm. 3. Fifteen joints were evaluated as Grade 2, in which retention involves the entire femoral neck, and their average volume was 8.96 cm. 3. Two joints were evaluated as Grade 3, in which marked retention involves the excavation of the cupsula articularis, and their average volume was 11.45 cm. 3. No joint was evaluated as Grade 0, in which no joint fluid is detected. Discussion: The pathogenesis of corticosteroid-related ONFH is multifactorial; various hypotheses have been proposed, suggesting the involvement of arteriosclerosis, thrombosis, fat embolization, vascular endothelial disorder, venous return disorder, enhanced blood coagulation, fibrinolytic abnormalities, and bone tissue apoptosis. However the detailed mechanism remains to be clarified. In this survey, when regarding Grade 2 or higher joints as showing a significant increase in hip fluid, the increase was noted in 17 joints (60.7%). We understood objectively by an increase in hip fluid by estimating its volume. An increase in hip fluid early after massive steroid therapy may persistently increase intraarticular pressure, affecting influx of nutrient vessels in the femoral neck or venous return, which is considered to be a tamponade effect. This may be an etiological factor involved in ONFH