Aims. To investigate the
Aims. Vancomycin is commonly added to acrylic bone cement during revision
arthroplasty surgery. Proprietary cement preparations containing
vancomycin are available, but are significantly more expensive.
We investigated whether the elution of antibiotic from ‘home-made’
cement containing vancomycin was comparable with more expensive
commercially available vancomycin impregnated cement. Materials and Methods. A total of 18 cement discs containing either proprietary CopalG+V;
or ‘home-made’ CopalR+G with vancomycin added by hand, were made.
Each disc contained the same amount of antibiotic (0.5 g gentamycin,
2 g vancomycin) and was immersed in ammonium acetate buffer in a
sealed container. Fluid from each container was sampled at eight
time points over a two-week period. The concentrations of gentamicin
and vancomycin in the fluid were analysed using high performance
liquid chromatography mass spectrometry. Results. The highest peak concentrations of antibiotic were observed from
the ‘home-made’ cements containing vancomycin, added as in the operating
theatre. The overall elution of antibiotic was, fivefold (vancomycin)
and twofold (gentamicin) greater from the ‘home-made’ mix compared
with the commercially mixed cement. The use of a vacuum during mixing
had no significant effect on antibiotic elution in any of the samples. Conclusion. These findings suggest that the addition of 2 g vancomycin powder
to gentamicin-impregnated
Implantation of allograft
Aims. 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). Methods. In this retrospective diagnostic study, patients undergoing revision surgery after total hip or knee arthroplasty (n = 119) between January 2015 and July 2018 were included. Multiple specimens of the periprosthetic membrane and pseudocapsule were obtained for histopathological analysis at revision arthroplasty. Based on the Infectious Diseases Society of America (IDSA) 2013 criteria, the International Consensus Meeting (ICM) 2018 criteria, and the European
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
Aims. Breast cancer survivors have known risk factors that might influence the results of total hip arthroplasty (THA) or total knee arthroplasty (TKA). This study evaluated clinical outcomes of patients with breast cancer history after primary THA and TKA. Methods. Our total joint registry identified patients with breast cancer history undergoing primary THA (n = 423) and TKA (n = 540). Patients were matched 1:1 based upon age, sex, BMI, procedure (hip or knee), and surgical year to non-breast cancer controls. Mortality, implant survival, and complications were assessed via Kaplan-Meier methods. Clinical outcomes were evaluated via Harris Hip Scores (HHSs) or Knee Society Scores (KSSs). Mean follow-up was six years (2 to 15). Results. Breast cancer patient survival at five years was 92% (95% confidence interval (CI) 89% to 95%) after THA and 94% (95% CI 92% to 97%) after TKA. Breast and non-breast cancer patients had similar five-year implant survival free of any reoperation or revision after THA (p ≥ 0.412) and TKA (p ≥ 0.271). Breast cancer patients demonstrated significantly lower survival free of any complications after THA (91% vs 96%, respectively; hazard ratio = 2 (95% CI 1.1 to 3.4); p = 0.017). Specifically, the rate of intraoperative fracture was 2.4% vs 1.4%, and venous thromboembolism (VTE) was 1.4% and 0.5% for breast cancer and controls, respectively, after THA. No significant difference was noted in any complications after TKA (p ≥ 0.323). Both breast and non-breast cancer patients experienced similar improvements in HHSs (p = 0.514) and KSSs (p = 0.132). Conclusion. Breast cancer survivors did not have a significantly increased risk of mortality or reoperation after primary THA and TKA. However, there was a two-fold increased risk of complications after THA, including intraoperative fracture and VTE. Cite this article:
Aims. 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. Methods. We retrospectively collected data from 226 patients (90 hips, 136 knees) with periprosthetic joint infection who underwent two-stage revision between August 2011 and September 2021, with a minimum follow-up of one year. Histology was assessed via the SLIM classification. First, we analyzed whether patients with positive permanent sections at reimplantation had higher reinfection rates than patients with negative histology. Further, we compared permanent and frozen section results, and assessed the influence of anatomical regions (knee versus hip), low- versus high-grade infections, as well as first revision versus multiple prior revisions on the histological result at reimplantation. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), chi-squared tests, and Kaplan-Meier estimates were calculated. Results. Overall, the reinfection rate was 18%. A total of 14 out of 82 patients (17%) with positive permanent sections at reimplantation experienced reinfection, compared to 26 of 144 patients (18%) with negative results (p = 0.996). Neither permanent sections nor fresh frozen sections were significantly associated with reinfection, with a sensitivity of 0.35, specificity of 0.63, PPV of 0.17, NPV of 0.81, and accuracy of 58%. Histology was not significantly associated with reinfection or survival time for any of the analyzed sub-groups. Permanent and frozen section results were in agreement for 91% of cases. Conclusion. Permanent and fresh frozen sections at reimplantation in two-stage revision do not serve as a reliable predictor for reinfection. Cite this article:
Aims. Total femoral arthroplasty (TFA) is a rare procedure used in cases of significant femoral bone loss, commonly from cancer, infection, and trauma. Low patient numbers have resulted in limited published work on long-term outcomes, and even less regarding TFA undertaken for non-oncological indications. The aim of this study was to evaluate the long-term clinical outcomes of all TFAs in our unit. Methods. Data were collected retrospectively from a large tertiary referral revision arthroplasty unit’s database. Inclusion criteria included all patients who underwent TFA in our unit. Preoperative demographics, operative factors, and short- and long-term outcomes were collected for analysis. Outcome was defined using the Musculoskeletal Infection Society (MSIS) outcome reporting tool. Results. Overall, 38 TFAs were identified. The mean age was 73 years (42 to 80). All patients underwent TFA for non-oncological indications, most commonly as a consequence of infection (53%) and periprosthetic fracture (26%). The mean follow-up time was ten years (0 to 26); 63% of TFAs were considered a success based upon the MSIS outcome reporting tool. The mean time between TFA and death was 8.5 years (0.2 to 19.2), with two patients dying within one year of surgery. Within the cohort, 66% suffered at least one complication, dislocation being most common (37%); 55% of the total cohort required at least one subsequent operation. In total, 70% of TFAs undertaken for infection were considered infection-free at time of final follow-up. The percentage of mobile patients improved from 52% to 65% between pre- and postoperation, with all patients being able to at least transfer from bed to chair at time of final review. Conclusion. This study is the largest in the UK assessing the use of TFA in patients with bone loss secondary to non-oncological conditions. It demonstrates that TFA has a significant complication profile, however it is favourable in terms of mortality and rehabilitation when compared to amputation and disarticulation. Cite this article:
Aims. 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. Methods. Between January 2010 and December 2018, 661 patients with multiple joint prostheses in situ were treated for PJI at our institution. Of these, 73 patients (11%) developed a metachronous PJI (periprosthetic infection in patients who have previously had PJI in another joint, after a lag period) after a mean time interval of 49.5 months (SD 30.24; 7 to 82.9). To identify patient-related risk factors for a metachronous PJI, the following parameters were analyzed: sex; age; BMI; and pre-existing comorbidity. Metachronous infections were divided into three groups: Group 1, metachronous infections in ipsilateral joints; Group 2, metachronous infections of the contralateral lower limb; and Group 3, metachronous infections of the lower and upper limb. Results. We identified a total of 73 metachronous PJIs: 32 PJIs in Group 1, 38 in Group 2, and one in Group 3. The rate of metachronous infection was 11% (73 out 661 cases) at a mean of four years following first infection. Diabetes mellitus incidence was found significantly more frequently in the metachronous infection group than in non-metachronous infection group. The rate of infection in Group 1 (21.1%) was significantly higher (p = 0.049) compared to Groups 2 (6.2%) and 3 (3%). The time interval of metachronous infection development was shorter in adjacent joint infections. Concordance between the bacterium of the first PJI and that of the metachronous PJI in Group 1 (21/34) was significantly higher than Group 2 (13/38; p = 0.001). Conclusion. The findings of this study suggest that metachronous PJI occurs in more than one in ten patients with an index PJI. Female patients, diabetic patients, and patients with a polymicrobial index PJI are at significantly higher risk for developing a metachronous PJI. Furthermore, metachronous PJIs are significantly more likely to occur in an adjacent joint (e.g. ipsilateral hip and knee) as opposed to a more remote site (i.e. contralateral or upper vs lower limb). Additionally, adjacent joint PJIs occur significantly earlier and are more likely to be caused by the same bacteria as the index PJI. Cite this article:
Aims. Periprosthetic joint infections (PJIs) and fracture-related infections (FRIs) are associated with a significant risk of adverse events. However, there is a paucity of data on cardiac complications following revision surgery for PJI and FRI and how they impact overall mortality. Therefore, this study aimed to investigate the risk of perioperative myocardial injury (PMI) and mortality in this patient cohort. Methods. We prospectively included consecutive patients at high cardiovascular risk (defined as age ≥ 45 years with pre-existing coronary, peripheral, or cerebrovascular artery disease, or any patient aged ≥ 65 years, plus a postoperative hospital stay of > 24 hours) undergoing septic or aseptic major orthopaedic surgery between July 2014 and October 2016. All patients received a systematic screening to reliably detect PMI, using serial measurements of high-sensitivity cardiac troponin T. All-cause mortality was assessed at one year. Multivariable logistic regression models were applied to compare incidence of PMI and mortality between patients undergoing septic revision surgery for PJI or FRI, and patients receiving aseptic major
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:
Aims. The COVID-19 pandemic has disrupted the provision of arthroplasty services in England, Wales, and Northern Ireland. This study aimed to quantify the backlog, analyze national trends, and predict time to recovery. Methods. We performed an analysis of the mandatory prospective national registry of all independent and publicly funded hip, knee, shoulder, elbow, and ankle replacements in England, Wales, and Northern Ireland between January 2019 and December 2022 inclusive, totalling 729,642 operations. The deficit was calculated per year compared to a continuation of 2019 volume. Total deficit of cases between 2020 to 2022 was expressed as a percentage of 2019 volume. Sub-analyses were performed based on procedure type, country, and unit sector. Results. Between January 2020 and December 2022, there was a deficit of 158,994 joint replacements. This is equivalent to over two-thirds of a year of normal expected operating activity (71.6%). There were 104,724 (-47.1%) fewer performed in 2020, 41,928 (-18.9%) fewer performed in 2021, and 12,342 (-5.6%) fewer performed in 2022, respectively, than in 2019. Independent-sector procedures increased to make it the predominant arthroplasty provider (53% in 2022). NHS activity was 73.2% of 2019 levels, while independent activity increased to 126.8%. Wales (-136.3%) and Northern Ireland (-121.3%) recorded deficits of more than a year’s worth of procedures, substantially more than England (-66.7%). It would take until 2031 to eliminate this deficit with an immediate expansion of capacity over 2019 levels by 10%. Conclusion. The arthroplasty deficit following the COVID-19 pandemic is now equivalent to over two-thirds of a year of normal operating activity, and continues to increase. Patients awaiting different types of arthroplasty, in each country, have been affected disproportionately. A rapid and significant expansion in services is required to address the deficit, and will still take many years to rectify. Cite this article:
Aims. Nonagenarians (aged 90 to 99 years) have experienced the fastest percent decile population growth in the USA recently, with a consequent increase in the prevalence of nonagenarians living with joint arthroplasties. As such, the number of revision total hip arthroplasties (THAs) and total knee arthroplasties (TKAs) in nonagenarians is expected to increase. We aimed to determine the mortality rate, implant survivorship, and complications of nonagenarians undergoing aseptic revision THAs and revision TKAs. Methods. Our institutional total joint registry was used to identify 96 nonagenarians who underwent 97 aseptic revisions (78 hips and 19 knees) between 1997 and 2018. The most common indications were aseptic loosening and periprosthetic fracture for both revision THAs and revision TKAs. Mean age at revision was 92 years (90 to 98), mean BMI was 27 kg/m. 2. (16 to 47), and 67% (n = 65) were female. Mean time between primary and revision was 18 years (SD 9). Kaplan-Meier survival was used for patient mortality, and compared to age- and sex-matched control populations. Reoperation risk was assessed using cumulative incidence with death as a competing risk. Mean follow-up was five years. Results. Mortality rates were 9%, 18%, 26%, and 62% at 90 days, one year, two years, and five years, respectively, but similar to control populations. There were 43 surgical complications and five reoperations, resulting in a cumulative incidence of reoperation of 4% at five years. Medical complications were common, with a cumulative incidence of 65% at 90 days. Revisions for periprosthetic fractures were associated with higher mortality and higher 90-day risk of medical complications compared to revisions for aseptic loosening. Conclusion. Contemporary revision THAs and TKAs appeared to be relatively safe in selected nonagenarians managed with multidisciplinary teams. Cause of revision affected morbidity and mortality risks. While early medical and surgical complications were frequent, they seldom resulted in reoperation. Cite this article:
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:
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:
Aims. The aim of this study was to evaluate the diagnostic accuracy of the absolute synovial polymorphonuclear neutrophil cell (PMN) count for the diagnosis or exclusion of periprosthetic joint infection (PJI) after total hip (THA) or knee arthroplasty (TKA). Methods. In this retrospective cohort study, 147 consecutive patients with acute or chronic complaints following THA and TKA were included. Diagnosis of PJI was established based on the 2018 International Consensus Meeting criteria. A total of 39 patients diagnosed with PJI (32 chronic and seven acute) and 108 patients with aseptic complications were surgically revised. Results. Using receiver operating characteristic curves and calculating the area under the curve (AUC), an optimal synovial cut-off value of 2,000 PMN/µl was determined (AUC 0.978 (95% confidence interval (CI) 0.946 to 1)). Using this cut-off, sensitivity and specificity of absolute synovial PMN count for PJI were 97.4% (95% CI 91.2 to 100) and 93.5% (95% CI 88.9 to 98.1), respectively. Positive and negative predictive value were 84.4% (95% CI 72.7 to 93.9) and 99.0% (95% CI 96.7 to 100), respectively. Exclusion of 20 patients with acute complications improved specificity to 97.9% (95% CI 94.6 to 100). Different cut-off values for THA (< 3,600 PMN/µl) and TKA (< 2,000 PMN/µl) were identified. Absolute synovial PMN count correlated strongly with synovial alpha-defensin (AD) (r = 0.759; p < 0.001). With a positive AD result, no additional PJI could be identified in any case. Conclusion. Absolute synovial PMN count is a widely available, rapid, cost-effective, and accurate marker in PJI diagnostics, whereas synovial AD appears to be a surrogate parameter of absolute synovial PMN count. Despite limitations in the early postoperative phase, wear, and rheumatic diseases in confirming PJI, an absolute synovial PMN count below 2,000/µl is highly suitable for ruling out PJI, with specific cut-off values for THA and TKA. Cite this article:
Aims. For the increasing number of working-age patients undergoing total hip or total knee arthroplasty (THA/TKA), return to work (RTW) after surgery is crucial. We investigated the association between occupational class and time to RTW after THA or TKA. Methods. Data from the prospective multicentre Longitudinal Leiden Orthopaedics Outcomes of Osteoarthritis Study were used. Questionnaires were completed preoperatively and six and 12 months postoperatively. Time to RTW was defined as days from surgery until RTW (full or partial). Occupational class was preoperatively assessed and categorized into four categories according to the International Standard Classification of Occupations 2008 (blue-/white-collar, high-/low-skilled). Cox regression analyses were conducted separately for THA and TKA patients. Low-skilled blue-collar work was used as the reference category. Results. A total of 360 THA and 276 TKA patients, preoperatively employed, were included. Patients were mainly high-skilled (THA 57%; TKA 41%) or low-skilled (THA 24%; TKA 38%) white-collar workers. Six months post-THA, RTW rates were 78% of low-skilled blue-collar workers compared to 83% to 86% within other occupational classes, increasing after 12 months to 87% to 90% in all occupational classes. Six months post-TKA, RTW rates were 58% of low-skilled and 64% of high-skilled blue-collar workers compared to 80% to 89% of white-collar workers, and after 12 months 79% of low-skilled blue-collar workers compared to 87% to 92% within other occupational classes. High-skilled white-collar workers (THA: hazard ratio (HR) 2.12 (95% confidence interval (CI) 1.32 to 3.40); TKA: HR 2.31 (95% CI 1.34 to 4.00)) and low-skilled white-collar workers (TKA: HR 1.82 (95% CI 1.04 to 3.18)) had a higher hazard to RTW within six months postoperatively. Conclusion. Clear differences existed in time to RTW among both THA and TKA patients in each of the groups studied. These findings may help guide tailored patient-specific information during preoperative consultation and advice postoperatively, as well as to create awareness among workers and their employers. Cite this article:
Aims. 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. Methods. We retrospectively reviewed 32 patients (22 hips and 11 knees) who underwent single-stage revision combined with IA carbapenem infusion between November 2013 and March 2020. The IA and intravenous (IV) carbapenem infusions were administered for a single Gram-negative infection, and IV vancomycin combined with IA carbapenems and vancomycin was applied for polymicrobial infection including Gram-negative bacteria. The bacterial community distribution, drug sensitivity, infection control rate, functional recovery, and complications were evaluated. Reinfection or death caused by PJI was regarded as a treatment failure. Results. Gram-negative PJI was mainly caused by Escherichia coli (8/34), Enterobacter cloacae (7/34), and Klebsiella pneumoniae (5/34). Seven cases (7/32) involved polymicrobial PJIs. The resistance rates of penicillin, cephalosporin, quinolones, and sulfonamides were > 10%, and all penicillin and partial cephalosporins (first and second generation) were > 30%. Of 32 cases, treatment failed to eradicate infection in only three cases (9.4%), at a mean follow-up of 55.1 months (SD 25 to 90). The mean postoperative Harris Hip Score and Hospital for Special Surgery knee score at the most recent follow-up were 81 (62 to 91) and 79 (56 to 89), respectively. One patient developed a fistula, and another presented with a local rash on an infected joint. Conclusion. The use of IA carbapenem delivered alongside one-stage revision effectively controlled Gram-negative infection and obtained acceptable clinical outcomes with few complications. Notably, first- and second-generation cephalosporins and penicillin should be administrated with caution, due to a high incidence of resistance. Cite this article:
Aims. Our aim was to estimate the total costs of all hospitalizations for treating periprosthetic joint infection (PJI) by main management strategy within 24 months post-diagnosis using activity-based costing. Additionally, we investigated the influence of individual PJI treatment pathways on hospital costs within the first 24 months. Methods. Using admission and procedure data from a prospective observational cohort in Australia and New Zealand, Australian Refined Diagnosis Related Groups were assigned to each admitted patient episode of care for activity-based costing estimates of 273 hip PJI patients and 377 knee PJI patients. Costs were aggregated at 24 months post-diagnosis, and are presented in Australian dollars. Results. The mean cost per hip and knee PJI patient was $64,585 (SD $53,550). Single-stage revision mean costs were $67,029 (SD $47,116) and $80,063 (SD $42,438) for hip and knee, respectively. Two-stage revision costs were $113,226 (SD $66,724) and $122,425 (SD $60,874) for hip and knee, respectively. Debridement, antibiotics, and implant retention in hips and knees mean costs were $53,537 (SD$ 39,342) and $48,463 (SD $33,179), respectively. Suppressive antibiotic therapy without surgical management mean costs were $20,296 (SD $8,875) for hip patients and $16,481 (SD $6,712) for knee patients. Hip patients had 16 different treatment pathways and knee patients had 18 treatment pathways. Additional treatment, episodes of care, and length of stay contributed to substantially increased costs up to a maximum of $369,948. Conclusion. Treating PJI incurs a substantial cost burden, which is substantially influenced by management strategy. With an annual PJI incidence of 3,900, the cost burden would be in excess of $250 million to the Australian healthcare system. Treatment pathways with additional surgery, more episodes of care, and a longer length of stay substantially increase the associated hospital costs. Prospectively monitoring individual patient treatment pathways beyond initial management is important when quantifying PJI treatment cost. Our study highlights the importance of optimizing initial surgical treatment, and informs treating hospitals of the resources required to provide care for PJI patients. Cite this article:
