Aims. The aim of this study was to evaluate the healthcare costs and benefits of enoxaparin compared to aspirin in the prevention of symptomatic venous thromboembolism (VTE) after total hip arthroplasty (THA) or total knee arthroplasty (TKA) using data from the CRISTAL trial. Methods. This trial-based economic analysis reports value for money as incremental cost per quality-adjusted life-year (QALY) gained in 2022 Australian dollars, compared to a single threshold value of AUD$70,000 per QALY. Event costs were estimated based on occurrence of VTEs and bleeds, and on published guidelines for treatment. Unit costs were taken from Australian sources. QALYs were estimated using CRISTAL six-month follow-up data. Sensitivity analyses are presented that vary the cost of VTE treatment, and extend the analyses to two years. Results. The CRISTAL trial found that enoxaparin was more effective than aspirin in preventing symptomatic VTE within 90 days of THA or TKA (risk difference 1.97% (95% confidence interval (CI) 0.54% to 3.41%; p = 0.007)). The additional cost after a THA or TKA was AUD$83 (95% CI 68 to 97) for enoxaparin, and enoxaparin resulted in an additional 0.002 QALYs (95% CI -0.002 to 0.005). Incremental cost per QALY gained was AUD$50,567 (95% CI 15,513, dominated) for enoxaparin. We can be 60% confident that the incremental cost per QALY does not exceed the willingness-to-pay threshold of AUD$70,000. Increasing the cost of VTE treatment and extension of costs and consequences to two years suggested greater confidence that enoxaparin is good value for money (70% and 63% confidence, respectively). Conclusion. This analysis provides strong evidence that enoxaparin thromboprophylaxis following THA or TKA reduced VTEs, but weak evidence of net economic benefits over aspirin. If the value of avoiding VTEs is high, and there is a strong likelihood of VTE-related health impairments, we can be more confident that enoxaparin is cost-effective compared to aspirin. Cite this article: Bone Joint J 2024;106-B(6):589–595

Aims. We investigated the efficacy and safety profile of commonly used venous thromboembolism (VTE) prophylaxis agents following hip and knee arthroplasty. Methods. A systematic search of PubMed, Embase, Cochrane Library, Web of Science, and OrthoSearch was performed. Prophylaxis agents investigated were aspirin (< 325 mg and ≥ 325 mg daily), enoxaparin, dalteparin, fondaparinux, unfractionated heparin, warfarin, rivaroxaban, apixaban, and dabigatran. The primary efficacy outcome of interest was the risk of VTE, whereas the primary safety outcomes of interest were the risk of major bleeding events (MBE) and wound complications (WC). VTE was defined as the confirmed diagnosis of any deep vein thrombosis and/or pulmonary embolism. Network meta-analysis combining direct and indirect evidence was performed. Cluster rank analysis using the surface under cumulative ranking (SUCRA) was applied to compare each intervention group, weighing safety and efficacy outcomes. Results. Of 86 studies eligible studies, cluster rank analysis showed that aspirin < 325 mg daily (SUCRA-VTE 89.3%; SUCRA-MBE 75.3%; SUCRA-WC 71.1%), enoxaparin (SUCRA-VTE 55.7%; SUCRA-MBE 49.8%; SUCRA-WC 45.2%), and dabigatran (SUCRA-VTE 44.9%; SUCRA-MBE 52.0%; SUCRA-WC 41.9%) have an overall satisfactory efficacy and safety profile. Conclusion. We recommend the use of either aspirin < 325 mg daily, enoxaparin, or dabigatran for VTE prophylaxis following hip and knee arthroplasty. Cite this article: Bone Joint J 2024;106-B(9):924–934

Aims. Cutibacterium acnes (C. acnes; previously known as Propionibacterium acnes or P. acnes) periprosthetic hip and knee infections are under-reported. While culture contamination with C. acnes occurs, true infections are important to recognize and treat. We sought to describe the demographics and treatment outcomes of patients with C. acnes periprosthetic joint infections (PJIs) of the hip and knee. Methods. Patients with C. acnes PJI between January 2005 and December 2018 were retrospectively reviewed utilizing the institutional total joint registry. Patients with monomicrobial PJI and two or more positive cultures were considered to have true C. acnes PJI. Patients with polymicrobial infection or with only one positive culture were excluded. This resulted in 35 PJIs (21 hips and 14 knees); the patients’ mean age was 63 years (35 to 84) and 15 (43%) were female. Mean follow-up was five years (1 to 14). Results. The median time to positive culture was five days (IQR 5 to 6) and median synovial fluid cell count was 22,583 cells (IQR 15,200 to 53,231). The median ESR was 25 mm/hr (IQR 7 to 37), and CRP was 15 mg/l (IQR 3 to 29). Of the 35 PJIs, 18 (51%) were treated with chronic antibiotic suppression without surgical intervention, and the remainder were treated with two-stage exchange arthroplasty. The two-year survival free of any revision was 94%. Four patients failed treatment due to symptomatic infection, with three treated with two-stage exchange and one treated with irrigation and debridement with modular component exchange for a survival rate of 89% and 83% at two and five years, respectively. Conclusion. Laboratory evidence of C. acnes PJI in this cohort was typical compared to more conventional organisms. Cultures grew more quickly than previously thought in patients with C. acnes PJI. Treatment with two-stage exchange or chronic antibiotic suppression alone both had few treatment failures at mid-term follow-up. Cite this article: Bone Joint J 2024;106-B(12):1426–1430

Aims. Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are common orthopaedic procedures requiring postoperative radiographs to confirm implant positioning and identify complications. Artificial intelligence (AI)-based image analysis has the potential to automate this postoperative surveillance. The aim of this study was to prepare a scoping review to investigate how AI is being used in the analysis of radiographs following THA and TKA, and how accurate these tools are. Methods. The Embase, MEDLINE, and PubMed libraries were systematically searched to identify relevant articles. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews and Arksey and O’Malley framework were followed. Study quality was assessed using a modified Methodological Index for Non-Randomized Studies tool. AI performance was reported using either the area under the curve (AUC) or accuracy. Results. Of the 455 studies identified, only 12 were suitable for inclusion. Nine reported implant identification and three described predicting risk of implant failure. Of the 12, three studies compared AI performance with orthopaedic surgeons. AI-based implant identification achieved AUC 0.992 to 1, and most algorithms reported an accuracy > 90%, using 550 to 320,000 training radiographs. AI prediction of dislocation risk post-THA, determined after five-year follow-up, was satisfactory (AUC 76.67; 8,500 training radiographs). Diagnosis of hip implant loosening was good (accuracy 88.3%; 420 training radiographs) and measurement of postoperative acetabular angles was comparable to humans (mean absolute difference 1.35° to 1.39°). However, 11 of the 12 studies had several methodological limitations introducing a high risk of bias. None of the studies were externally validated. Conclusion. These studies show that AI is promising. While it already has the ability to analyze images with significant precision, there is currently insufficient high-level evidence to support its widespread clinical use. Further research to design robust studies that follow standard reporting guidelines should be encouraged to develop AI models that could be easily translated into real-world conditions. Cite this article: Bone Joint J 2022;104-B(8):929–937

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Histology is widely used for diagnosis of persistent infection during reimplantation in two-stage revision hip and knee arthroplasty, although data on its utility remain scarce. Therefore, this study aims to assess the predictive value of permanent sections at reimplantation in relation to reinfection risk, and to compare results of permanent and frozen sections.

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The purpose of this study was to determine the association between prior sleeve gastrectomy in patients undergoing primary total hip and knee arthroplasty, and 90-day complications, incidence of revision arthroplasty, and patient-reported outcome scores at final follow-up.

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Revision total knee arthroplasty (rTKA) and revision total hip arthroplasty (rTHA) are complex procedures with higher rates of re-revision, complications, and mortality compared to primary TKA and THA. We report the effects of the establishment of a revision arthroplasty network (the East Midlands Specialist Orthopaedic Network; EMSON) on outcomes of rTKA and rTHA.

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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.

Aims. The diagnosis of periprosthetic joint infection (PJI) can be difficult. All current diagnostic tests have problems with accuracy and interpretation of results. Many new tests have been proposed, but there is no consensus on the place of many of these in the diagnostic pathway. Previous attempts to develop a definition of PJI have not been universally accepted and there remains no reference standard definition. Methods. This paper reports the outcome of a project developed by the European Bone and Joint Infection Society (EBJIS), and supported by the Musculoskeletal Infection Society (MSIS) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Implant-Associated Infections (ESGIAI). It comprised a comprehensive review of the literature, open discussion with Society members and conference delegates, and an expert panel assessment of the results to produce the final guidance. Results. This process evolved a three-level approach to the diagnostic continuum, resulting in a definition set and guidance, which has been fully endorsed by EBJIS, MSIS, and ESGIAI. Conclusion. The definition presents a novel three-level approach to diagnosis, based on the most robust evidence, which will be useful to clinicians in daily practice. Cite this article: Bone Joint J 2021;103-B(1):18–25

Aims. To investigate whether chronic kidney disease (CKD) is associated with the risk of all-cause revision or revision due to a periprosthetic joint infection (PJI) after primary hip or knee arthroplasty. Methods. This retrospective cohort study comprised 18,979 consecutive hip and knee arthroplasties from a single high-volume academic hospital. At a median of 5.6 years (interquartile range (IQR) 3.5 to 8.1), all deaths and revisions were counted. To overcome the competing risk of death, competing risk analysis using the cumulative incidence function (CIF) was applied to analyze the association between different stages of CKD and revisions. Confounding factors such as diabetes and BMI were considered using either a stratified CIF or the Fine and Gray model. Results. There were 2,111 deaths (11.1%) and 677 revisions (3.6%) during the follow-up period. PJI was the reason for revision in 162 cases (0.9%). For hip arthroplasty, 3.5% of patients with CKD stage 1 (i.e. normal kidney function, NKF), 3.8% with CKD stage 2, 4.2% with CKD stage 3, and 0% with CKD stage 4 to 5 had undergone revision within eight years. For knee arthroplasty, 4.7% with NKF, 2.7% with CKD stage 2, 2.4% with CKD stage 3, and 7% of CKD stage 4 to 5 had had undergone revision. With the exception of knee arthroplasty patients in whom normal kidney function was associated with a greater probability of all-cause revision, there were no major differences in the rates of all-cause revisions or revisions due to PJIs between different CKD stages. The results remained unchanged when diabetes and BMI were considered. Conclusion. We found no strong evidence that CKD was associated with an increased risk of all-cause or PJI-related revision. Selection bias probably explains the increased amount of all-cause revision operations in knee arthroplasty patients with normal kidney function. The effect of stage 4 to 5 CKD was difficult to evaluate because of the small number of patients. Cite this article: Bone Joint J 2021;103-B(4):689–695

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The aim of this study was to evaluate the optimal deep tissue specimen sample number for histopathological analysis in the diagnosis of periprosthetic joint infection (PJI).

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The aim of this study was to report health-related quality of life (HRQoL) and joint-specific function in patients waiting for total hip or knee arthroplasty surgery (THA or TKA) in Northern Ireland, compared to published literature and a matched normal population. Secondary aims were to report emergency department (ED) and out-of-hours general practitioner (OOH GP) visits, new prescriptions of strong opioids, and new prescriptions of antidepressants while waiting.

Aims. Periprosthetic joint infections (PJIs) are among the most devastating complications after joint arthroplasty. There is limited evidence on the efficacy of different antiseptic solutions on reducing biofilm burden. The purpose of the present study was to test the efficacy of different antiseptic solutions against clinically relevant microorganisms in biofilm. Methods. We conducted an in vitro study examining the efficacy of several antiseptic solutions against clinically relevant microorganisms. We tested antiseptic irrigants against nascent (four-hour) and mature (three-day) single-species biofilm created in vitro using a drip-flow reactor model. Results. With regard to irrigant efficacy against biofilms, Povidone-iodine treatment resulted in greater reductions in nascent MRSA biofilms (logarithmic reduction (LR) = 3.12; p < 0.001) compared to other solutions. Bactisure treatment had the greatest reduction of mature Pseudomonas aeruginosa biofilms (LR = 1.94; p = 0.032) and a larger reduction than Vashe or Irrisept for mature Staphylococcus epidermidis biofilms (LR = 2.12; p = 0.025). Pooled data for all biofilms tested resulted in Bactisure and Povidone-iodine with significantly greater reductions compared to Vashe, Prontosan, and Irrisept solutions (p < 0.001). Conclusion. Treatment failure in PJI is often due to failure to clear the biofilm; antiseptics are often used as an adjunct to biofilm clearance. We tested irrigants against clinically relevant microorganisms in biofilm in vitro and showed significant differences in efficacy among the different solutions. Further clinical outcome data is necessary to determine whether these solutions can impact PJI outcome in vivo. Cite this article: Bone Joint J 2021;103-B(5):908–915

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Despite numerous studies focusing on periprosthetic joint infections (PJIs), there are no robust data on the risk factors and timing of metachronous infections. Metachronous PJIs are PJIs that can arise in the same or other artificial joints after a period of time, in patients who have previously had PJI.

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To examine whether natural language processing (NLP) using a clinically based large language model (LLM) could be used to predict patient selection for total hip or total knee arthroplasty (THA/TKA) from routinely available free-text radiology reports.

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Gram-negative periprosthetic joint infection (PJI) has been poorly studied despite its rapidly increasing incidence. Treatment with one-stage revision using intra-articular (IA) infusion of antibiotics may offer a reasonable alternative with a distinct advantage of providing a means of delivering the drug in high concentrations. Carbapenems are regarded as the last line of defense against severe Gram-negative or polymicrobial infection. This study presents the results of one-stage revision using intra-articular carbapenem infusion for treating Gram-negative PJI, and analyzes the characteristics of bacteria distribution and drug sensitivity.

Aims. Access to joint replacement is being restricted for patients with comorbidities in a number of high-income countries. However, there is little evidence on the impact of comorbidities on outcomes. The purpose of this study was to determine the safety and effectiveness of hip and knee arthroplasty in patients with and without comorbidities. Methods. In total, 312,079 hip arthroplasty and 328,753 knee arthroplasty patients were included. A total of 11 common comorbidities were identified in administrative hospital records. Safety risks were measured by assessing length of hospital stay (LOS) and 30-day emergency readmissions and mortality. Effectiveness outcomes were changes in Oxford Hip or Knee Scores (OHS/OKS) (scale from 0 (worst) to 48 (best)) and in health-related quality of life (EQ-5D) (scale from 0 (death) to 1 (full health)) from immediately before, to six months after, surgery. Regression analysis was used to estimate adjusted mean differences (LOS, change in OHS/OKS/EQ-5D) and risk differences (readmissions and mortality). Results. Patients with comorbidities had a longer LOS and higher readmission and mortality rates than patients without. In hip arthroplasty patients with heart disease, for example, LOS was 1.20 days (95% confidence interval (CI) 1.15 to 1.25) longer and readmission rate was 1.52% (95% CI 1.34% to 1.71%) and mortality 0.19% (95% CI 0.15% to 0.23%) higher. Similar patterns were observed for knee arthroplasty patients. Patients without comorbidities reported large improvements in function (mean improvement OHS 21.3 (SD 9.91) and OKS 15.9 (SD 10.0)). Patients with comorbidities reported only slightly smaller improvements. In patients with heart disease, mean improvement in OHS was 0.39 (95% CI 0.27 to 0.51) and in OKS 0.56 (95% CI 0.45 to 0.67) less than in patients without comorbidities. There were no significant differences in EQ-5D improvement. Conclusion. Comorbidities were associated with small increases in adverse safety risks but they have little impact on pain or function in patients undergoing hip or knee arthroplasty. These results do not support restricting access to hip and knee arthroplasty for patients with common comorbidities. Cite this article: Bone Joint J 2021;103-B(1):56–64

Aims. The aim of this study was to assess the quality of life of patients on the waiting list for a total hip (THA) or knee arthroplasty (KA) during the COVID-19 pandemic. Secondary aims were to assess whether length of time on the waiting list influenced quality of life and rate of deferral of surgery. Methods. During the study period (August and September 2020) 843 patients (THA n = 394, KA n = 449) from ten centres in the UK reported their EuroQol five dimension (EQ-5D) scores and completed a waiting list questionnaire (2020 group). Patient demographic details, procedure, and date when listed were recorded. Patients scoring less than zero for their EQ-5D score were defined to be in a health state “worse than death” (WTD). Data from a retrospective cohort (January 2014 to September 2017) were used as the control group. Results. The 2020 group had a significantly worse EQ-5D score compared to the control group for both THA (p < 0.001) and KA (p < 0.001). Over one-third (35.0%, n = 138/394) of patients waiting for a THA and nearly a quarter (22.3%, n = 100/449) for KA were in a health state WTD, which was significantly greater than the control group (odds ratio 2.30 (95% confidence interval (CI) 1.83 to 2.93) and 2.08 (95% CI 1.61 to 2.70), respectively; p < 0.001). Over 80% (n = 680/843) of the 2020 group felt that their quality of life had deteriorated while waiting. Each additional month spent on the waiting list was independently associated with a decrease in quality of life (EQ-5D: -0.0135, p = 0.004). There were 117 (13.9%) patients who wished to defer their surgery and the main reason for this was health concerns for themselves and or their family (99.1%, n = 116/117). Conclusion. Over one-third of patients waiting for THA and nearly one-quarter waiting for a KA were in a state WTD, which was approaching double that observed prior to the pandemic. Increasing length of time on the waiting list was associated with decreasing quality of life. Level of evidence: Level III retrospective case control study. Cite this article: Bone Joint J 2021;103-B(4):672–680

Aims. The primary aim of this study was to compare the wear properties of vitamin E-diffused, highly crosslinked polyethylene (VEPE) and one formulation of moderately crosslinked and mechanically annealed ultra-high molecular weight polyethylene (ModXLPE) in patients five years after primary total hip arthroplasty (THA). The secondary aim was to assess the clinical results of patients treated with VEPE by evaluating patient-reported outcome measures (PROMs), radiological evidence of fixation, and the incidence of mechanical failure. Patients and Methods. A total of 208 patients (221 THAs) from four international centres were recruited into a prospective study involving radiostereometric analysis (RSA) and the assessment of clinical outcomes. A total of 193 hips (87%) were reviewed at the five-year follow-up. Of these, 136 (70%) received VEPE (vs ModXLPE) liners and 68 (35%) received ceramic (vs metal) femoral heads. PROMs and radiographs were collected preoperatively and at one, two, and five years postoperatively. In addition, RSA images were collected to measure PE wear postoperatively and at one, two, and five years after surgery. Results. We observed similar bedding in one year postoperatively and wear two years postoperatively between the two types of liner. However, there was significantly more penetration of the femoral head in the ModXLPE cohort compared with the VEPE cohort five years postoperatively (p < 0.001). The only variables independently predictive of increased wear were ModXLPE (vs VEPE) liner type (β = 0.22, p = 0.010) and metal (vs ceramic) femoral head (β = 0.21, p = 0.013). There was no association between increased wear and the development of radiolucency (p = 0.866) or PROMs. No patient had evidence of osteolysis. Conclusion. Five years postoperatively, patients with VEPE (vs ModXLPE) and ceramic (vs metal) femoral heads had decreased wear. The rates of wear for both liners were very low and have not led to any osteolysis or implant failure due to aseptic loosening

Aims. There is uncertainty regarding the optimal means of thromboprophylaxis following total hip and knee arthroplasty (THA, TKA). This systematic review presents the evidence for acetylsalicylic acid (aspirin) as a thromboprophylactic agent in THA and TKA and compares it with other chemoprophylactic agents. Materials and Methods. A search of literature published between 2004 and 2014 was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 13 studies were eligible for inclusion. Results. Evidence from one good quality randomised controlled trial (RCT) showed no difference in rates of venous thrombo-embolism (VTE) in patients given aspirin or low molecular weight heparin (LMWH) following TKA. There was insufficient evidence from trials with moderate to severe risk of bias being present to suggest aspirin is more or less effective than LMWH, warfarin or dabigatran for the prevention of VTE in TKA or THA. Compared with aspirin, rates of asymptomatic deep vein thrombosis (DVT) in TKA may be reduced with rivaroxaban but insufficient evidence exists to demonstrate an effect on incidence of symptomatic DVT. Compared with aspirin there is evidence of more wound complications following THA and TKA with dabigatran and in TKA with rivaroxaban. Some studies highlighted concerns over bleeding complications and efficacy of aspirin. Conclusion. The results suggest aspirin may be considered a suitable alternative to other thromboprophylactic agents following THA and TKA. Further investigation is required to fully evaluate the safety and efficacy of aspirin. Cite this article: Bone Joint J 2016;98-B:1056–61