Aims. Removal of infected components and culture-directed antibiotics are important for the successful treatment of chronic periprosthetic joint infection (PJI). However, as many as 27% of chronic PJI patients yield negative culture results. Although culture negativity has been thought of as a contraindication to one-stage revision, data supporting this assertion are limited. The aim of our study was to report on the clinical outcomes for one-stage and two-stage exchange arthroplasty performed in patients with chronic culture-negative PJI. Methods. A total of 105 consecutive patients who underwent revision arthroplasty for chronic culture-negative PJI were retrospectively evaluated. One-stage revision arthroplasty was performed in 30 patients, while 75 patients underwent two-stage exchange, with a minimum of one year's follow-up. Reinfection, re-revision for septic and aseptic reasons, amputation, readmission, mortality, and length of stay were compared between the two treatment strategies. Results. The patient demographic characteristics did not differ significantly between the groups. At a mean follow-up of 4.2 years, the treatment failure for reinfection for one-stage and two-stage revision was five (16.7%) and 15 patients (20.0%) (p = 0.691), and for septic re-revision was four (13.3%) and 11 patients (14.7%) (p = 0.863), respectively. No significant differences were observed between one-stage and two-stage revision for 30- 60- and 90-day readmissions (10.0% vs 8.0%; p = 0.714; 16.7% vs 9.3%; p = 0.325; and 26.7% vs 10.7%; p = 0.074), one-year mortality (3.3% vs 4.0%; p > 0.999), and amputation (3.3% vs 1.3%; p = 0.496). Conclusion. In this non-randomized study, one-stage revision arthroplasty demonstrated similar outcomes including reinfection, re-revision, and readmission rates for the treatment of chronic culture-negative PJI after TKA and THA compared to two-stage revision. This suggests culture negativity may not be a contraindication to one-stage revision arthroplasty for chronic culture-negative PJI in selected patients. Cite this article: Bone Joint J 2021;103-B(3):515–521

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: Bone Joint J 2023;105-B(6):649–656

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: Bone Joint J 2024;106-B(4):372–379

Aims. The aim of this study was to determine the prevalence of depressive and anxiety disorders prior to total hip (THA) and total knee arthroplasty (TKA) and to assess their impact on the rates of any infection, revision, or reoperation. Methods. Between January 2000 and March 2019, 21,469 primary and revision arthroplasties (10,011 THAs; 11,458 TKAs), which were undertaken in 15,504 patients at a single academic medical centre, were identified from a 27-county linked electronic medical record (EMR) system. Depressive and anxiety disorders were identified by diagnoses in the EMR or by using a natural language processing program with subsequent validation from review of the medical records. Patients with mental health diagnoses other than anxiety or depression were excluded. Results. Depressive and/or anxiety disorders were common before THA and TKA, with a prevalence of 30% in those who underwent primary THA, 33% in those who underwent revision THA, 32% in those who underwent primary TKA, and 35% in those who underwent revision TKA. The presence of depressive or anxiety disorders was associated with a significantly increased risk of any infection (primary THA, hazard ratio (HR) 1.5; revision THA, HR 1.9; primary TKA, HR 1.6; revision TKA, HR 1.8), revision (THA, HR 1.7; TKA, HR 1.6), re-revision (THA, HR 2.0; TKA, HR 1.6), and reoperation (primary THA, HR 1.6; revision THA, HR 2.2; primary TKA, HR 1.4; revision TKA, HR 1.9; p < 0.03 for all). Patients with preoperative depressive and/or anxiety disorders were significantly less likely to report “much better” joint function after primary THA (78% vs 87%) and primary TKA (86% vs 90%) compared with those without these disorders at two years postoperatively (p < 0.001 for all). Conclusion. The presence of depressive or anxiety disorders prior to primary or revision THA and TKA is common, and associated with a significantly higher risk of infection, revision, reoperation, and dissatisfaction. This topic deserves further study, and surgeons may consider mental health optimization to be of similar importance to preoperative variables such as diabetic control, prior to arthroplasty. Cite this article: Bone Joint J 2023;105-B(5):526–533

Aims. The aim of this study was to conduct a cross-sectional, observational cohort study of patients presenting for revision of a total hip, or total or unicompartmental knee arthroplasty, to understand current routes to revision surgery and explore differences in symptoms, healthcare use, reason for revision, and the revision surgery (surgical time, components, length of stay) between patients having regular follow-up and those without. Methods. Data were collected from participants and medical records for the 12 months prior to revision. Patients with previous revision, metal-on-metal articulations, or hip hemiarthroplasty were excluded. Participants were retrospectively classified as ‘Planned’ or ‘Unplanned’ revision. Multilevel regression and propensity score matching were used to compare the two groups. Results. Data were analyzed from 568 patients, recruited in 38 UK secondary care sites between October 2017 and October 2018 (43.5% male; mean (SD) age 71.86 years (9.93); 305 hips, 263 knees). No significant inclusion differences were identified between the two groups. For hip revision, time to revision > ten years (odds ratio (OR) 3.804, 95% confidence interval (CI) (1.353 to 10.694), p = 0.011), periprosthetic fracture (OR 20.309, 95% CI (4.574 to 90.179), p < 0.001), and dislocation (OR 12.953, 95% CI (4.014 to 41.794), p < 0.001), were associated with unplanned revision. For knee, there were no associations with route to revision. Revision after ten years was more likely for those who were younger at primary surgery, regardless of route to revision. No significant differences in cost outcomes, length of surgery time, and access to a health professional in the year prior to revision were found between the two groups. When periprosthetic fractures, dislocations, and infections were excluded, healthcare use was significantly higher in the unplanned revision group. Conclusion. Differences between characteristics for patients presenting for planned and unplanned revision are minimal. Although there was greater healthcare use in those having unplanned revision, it appears unlikely that routine orthopaedic review would have detected many of these issues. It may be safe to disinvest in standard follow-up provided there is rapid access to orthopaedic review. Cite this article: Bone Joint J 2022;104-B(1):59–67

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: Bone Joint J 2023;105-B(3):284–293

Aims. Currently, the US Center for Medicaid and Medicare Services (CMS) has been testing bundled payments for revision total joint arthroplasty (TJA) through the Bundled Payment for Care Improvement (BPCI) programme. Under the BPCI, bundled payments for revision TJAs are defined on the basis of diagnosis-related groups (DRGs). However, these DRG-based bundled payment models may not be adequate to account appropriately for the varying case-complexity seen in revision TJAs. Methods. The 2008-2014 Medicare 5% Standard Analytical Files (SAF5) were used to identify patients undergoing revision TJA under DRG codes 466, 467, or 468. Generalized linear regression models were built to assess the independent marginal cost-impact of patient, procedural, and geographic characteristics on 90-day costs. Results. A total of 9,263 patients (DRG-466 = 838, DRG-467 = 4,573, and DRG-468 = 3,842) undergoing revision TJA from 2008 to 2014 were included in the study. Undergoing revision for a dislocation (+$1,221), periprosthetic fracture (+$4,454), and prosthetic joint infection (+$5,268) were associated with higher 90-day costs. Among comorbidities, malnutrition (+$10,927), chronic liver disease (+$3,894), congestive heart failure (+$3,292), anaemia (+$3,149), and coagulopathy (+$2,997) had the highest marginal cost-increase. The five US states with the highest 90-day costs were Alaska (+$14,751), Maryland (+$13,343), New York (+$7,428), Nevada (+$6,775), and California (+$6,731). Conclusion. Under the proposed DRG-based bundled payment methodology, surgeons would be reimbursed the same amount of money for revision TJAs, regardless of the indication (periprosthetic fracture, prosthetic joint infection, mechanical loosening) and/or patient complexity. Cite this article: Bone Joint J 2020;102-B(7):959–964

Aims. In the absence of an identified organism, single-stage revision is contraindicated in prosthetic joint infection (PJI). However, no studies have examined the use of intra-articular antibiotics in combination with single-stage revision in these cases. In this study, we present the results of single-stage revision using intra-articular antibiotic infusion for treating culture-negative (CN) PJI. Methods. A retrospective analysis between 2009 and 2016 included 51 patients with CN PJI who underwent single-stage revision using intra-articular antibiotic infusion; these were compared with 192 culture-positive (CP) patients. CN patients were treated according to a protocol including intravenous vancomycin and a direct intra-articular infusion of imipenem and vancomycin alternately used in the morning and afternoon. In the CP patients, pathogen-sensitive intravenous (IV) antibiotics were administered for a mean of 16 days (12 to 21), and for resistant cases, additional intra-articular antibiotics were used. The infection healing rate, Harris Hip Score (HHS), and Hospital for Special Surgery (HSS) knee score were compared between CN and CP groups. Results. Of 51 CN patients, 46 (90.2%) required no additional medical treatment for recurrent infection at a mean of 53.2 months (24 to 72) of follow-up. Impaired kidney function occurred in two patients, and one patient had a local skin rash. No significant difference in the infection control rate was observed between CN and CP PJIs (90.2% (46/51) versus 94.3% (181/192); p = 0.297). The HHS of the CN group showed no substantial difference from that of CP cases (79 versus 81; p = 0.359). However, the CN group showed a mean HSS inferior to that of the CP group (76 versus 80; p = 0.027). Conclusion. Single-stage revision with direct intra-articular antibiotic infusion can be effective in treating CN PJI, and can achieve an infection control rate similar to that in CP patients. However, in view of systemic toxicity, local adverse reactions, and higher costs, additional strong evidence is needed to verify these treatment regimens. Cite this article: Bone Joint J 2020;102-B(3):336–344

Aims. The purpose of this study is to determine if higher volume hospitals have lower costs in revision hip and knee arthroplasty. Materials and Methods. We questioned the Centres for Medicare and Medicaid Services (CMS) Inpatient Charge Data and identified 789 hospitals performing a total of 29 580 revision arthroplasties in 2014. Centres were dichotomised into high-volume (performing over 50 revision cases per year) and low-volume. Mean total hospital-specific charges and inpatient payments were obtained from the database and stratified based on Diagnosis Related Group (DRG) codes. Patient satisfaction scores were obtained from the multiyear CMS Hospital Compare database. Results. High-volume hospitals comprised 178 (30%) of the total but performed 15 068 (51%) of all revision cases, including 509 of 522 (98%) of the most complex DRG 466 cases. While high-volume hospitals had higher Medicare inpatient payments for DRG 467 ($21 458 versus $20 632, p = 0.038) and DRG 468 ($17 003 versus $16 120, p = 0.011), there was no difference in hospital specific charges between the groups. Higher-volume facilities had a better CMS hospital star rating (3.63 versus 3.35, p < 0.001). When controlling for hospital geographic and demographic factors, high-volume revision hospitals are less likely to be in the upper quartile of inpatient Medicare costs for DRG 467 (odds ratio (OR) 0.593, 95% confidence intervals (CI) 0.374 to 0.941, p = 0.026) and DRG 468 (OR 0.451, 95% CI 0.297 to 0.687, p <  0.001). Conclusion. While a high-volume hospital is less likely to be a high cost outlier, the higher mean Medicare reimbursements at these facilities may be due to increased case complexity. Further study should focus on measures for cost savings in revision total joint arthroplasties. Cite this article: Bone Joint J 2017;99-B:1611–17

Fungal peri-prosthetic infections of the knee and hip are rare but likely to result in devastating complications. In this study we evaluated the results of their management using a single-stage exchange technique. Between 2001 and 2011, 14 patients (ten hips, four knees) were treated for a peri-prosthetic fungal infection. One patient was excluded because revision surgery was not possible owing to a large acetabular defect. One patient developed a further infection two months post-operatively and was excluded from the analysis. Two patients died of unrelated causes. After a mean of seven years (3 to 11) a total of ten patients were available for follow-up. One patient, undergoing revision replacement of the hip, had a post-operative dislocation. Another patient, undergoing revision replacement of the knee, developed a wound infection and required revision 29 months post-operatively following a peri-prosthetic femoral fracture. . The mean Harris hip score increased to 74 points (63 to 84; p < 0.02) in those undergoing revision replacement of the hip, and the mean Hospital for Special Surgery knee score increased to 75 points (70 to 80; p < 0.01) in those undergoing revision replacement of the knee. . A single-stage revision following fungal peri-prosthetic infection is feasible, with an acceptable rate of a satisfactory outcome. Cite this article: Bone Joint J 2014;96-B:492–6

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are recognised and proven interventions for patients with advanced arthritis. Studies to date have demonstrated a steady increase in the requirement for primary and revision procedures. Projected estimates made for the United States show that by 2030 the demand for primary TKA will grow by 673% and for revision TKA by 601% from the level in 2005. For THA the projected estimates are 174% and 137% for primary and revision surgery, respectively. The purpose of this study was to see if those predictions were similar for England and Wales using data from the National Joint Registry and the Office of National Statistics. . Analysis of data for England and Wales suggest that by 2030, the volume of primary and revision TKAs will have increased by 117% and 332%, respectively between 2012 and 2030. The data for the United States translates to a 306% cumulative rate of increase between 2012 and 2030 for revision surgery, which is similar to our predictions for England and Wales. . The predictions from the United States for primary TKA were similar to our upper limit projections. For THA, we predicted an increase of 134% and 31% for primary and revision hip surgery, respectively. Our model has limitations, however, it highlights the economic burden of arthroplasty in the future in England and Wales as a real and unaddressed problem. This will have significant implications for the provision of health care and the management of orthopaedic services in the future. Cite this article: Bone Joint J 2015;97-B:1076–1081

Peri-prosthetic fracture after joint replacement in the lower limb is associated with significant morbidity. The primary aim of this study was to investigate the incidence of peri-prosthetic fracture after total hip replacement (THR) and total knee replacement (TKR) over a ten-year period using a population-based linked dataset. Between 1 April 1997 and 31 March 2008, 52 136 primary THRs, 8726 revision THRs, 44 511 primary TKRs, and 3222 revision TKRs were performed. Five years post-operatively, the rate of fracture was 0.9% after primary THR, 4.2% after revision THR, 0.6% after primary TKR and 1.7% after revision TKR. Comparison of survival analysis for all primary and revision arthroplasties showed peri-prosthetic fractures were more likely in females, patients aged > 70 and after revision arthroplasty. Female patients aged > 70 should be warned of a significantly increased risk of peri-prosthetic fracture after hip or knee replacement. The use of adjuvant medical treatment to reduce the effect of peri-prosthetic osteoporosis may be a direction of research for these patients

Aims. The diagnosis of periprosthetic joint infection (PJI) remains demanding due to limitations of all the available diagnostic tests. The synovial fluid marker, α-defensin, is a promising adjunct for the assessment of potential PJI. The purpose of this study was to investigate the qualitative assessment of α-defensin, using Synovasure to detect or exclude periprosthetic infection in total joint arthroplasty. Patients and Methods. We studied 50 patients (28 women, 22 men, mean age 65 years; 20 to 89) with a clinical indication for revision arthroplasty who met the inclusion criteria of this prospective diagnostic study. The presence of α-defensin was determined using the qualitative Synovasure test and compared with standard diagnostic methods for PJI. Based on modified Musculoskeletal Infection Society (MSIS) criteria, 13 cases were categorised as septic and 36 as aseptic revisions. One test was inconclusive. Results. The Synovasure test achieved a sensitivity of 69% and a specificity of 94%. The positive and negative likelihood ratios were 12.46 and 0.33, respectively. A good diagnostic accuracy for PJI, with an area under the curve of 0.82, was demonstrated. Adjusted p-values using the method of Hochberg showed that Synovasure is as good at diagnosing PJI as histology (p = 0.0042) and bacteriology with one positive culture (p = 0.0327). Conclusion. With its ease of use and rapid results after approximately ten minutes, Synovasure may be a useful adjunct in the diagnosis of PJI. Cite this article: Bone Joint J 2017;99-B:66–72

We analysed data from the Oxford hip and knee questionnaires collected by the New Zealand Joint Registry at six months and five years after joint replacement, to determine if there was any relationship between the scores and the risk of early revision. Logistic regression of the six-month scores indicated that for every one-unit decrease in the Oxford score, the risk of revision within two years increased by 9.7% for total hip replacement (THR), 9.9% for total knee replacement (TKR) and 12.0% for unicompartmental knee replacement (UKR). Our findings showed that 70% of the revisions within two years for TKR and 67% for THR and UKR would have been captured by monitoring the lowest 22%, 28% and 28%, respectively, of the Oxford scores. When analysed using the Kalairajah classification a score of < 27 (poor) was associated with a risk of revision within two years of 7.6% for THR, 7.0% for TKR and 24.3% for UKR, compared with risks of 0.7%, 0.7% and 1.8%, respectively, for scores > 34 (good or excellent). Our study confirms that the Oxford hip and knee scores at six months are useful predictors of early revision after THR and TKR and we recommend their use for the monitoring of the outcome and potential failure in these patients

We have reviewed retrospectively 68 revisions of the femoral component in arthroplasties of the hip in 65 patients, using impaction bone grafting, at a median of three years (1 month to 6 years). We employed the cemented Exeter X-Change technique in 36 patients and the uncemented Bi-Metric allografting method in 32. The 37 bone defects were grade 3 or grade 4 on the Endo-Klinik classification. The Mayo hip score improved from a mean of 32 (. sd. ± 18) to 62 (. sd. ± 15). Most (25) of the 34 complications occurred in grade-3 and grade-4 defects; nine were intraoperative diaphyseal fractures and eight fractures of the greater trochanter. All the fractures united. The risk of intraoperative fracture was prevented by supporting the bone with wires in 16 hips, with reinforcement mesh in 18 and by a plate in six. Early migration of the stem of more than 10 mm during the first year indicated rotational instability; it occurred in three cases. In difficult revision cases with large defects of the femoral bone, bone-impaction techniques carry a high risk of complications

We report the mid-term results of femoral impaction grafting which was used in 53 patients during the second stage of a two-stage revision for an infected total hip replacement. We reviewed all cases performed between 1989 and 1998. All patients underwent a Girdlestone excision arthroplasty, received local and systemic antibiotics and subsequently underwent reconstruction, using femoral impaction grafting. Four patients had further infection (7.5%), and four died within 24 months of surgery. One patient underwent revision of the stem for a fracture below its tip at ten months. This left 44 patients with a mean follow-up of 53 months (24 to 122). All had improved clinical scores and a satisfactory radiological outcome

Patients with infected arthroplasties are normally treated with a two-stage exchange procedure using polymethylmethacrylate bone cement spacers impregnated with antibiotics. However, spacers may act as a foreign body to which micro-organisms may adhere and grow. In this study it was hypothesised that subclinical infection may be diagnosed with sonication of the surface biofilm of the spacer. The aims were to assess the presence of subclinical infection through sonication of the spacer at the time of a second-stage procedure, and to determine the relationship between subclinical infection and the clinical outcome. Of 55 patients studied, 11 (20%) were diagnosed with subclinical infection. At a mean follow-up of 12 months (interquartile range 6 to 18), clinical failure was found in 18 (32.7%) patients. Of the patients previously diagnosed with subclinical infection, 63% (7 of 11) had failed compared with 25% (11 of 44) of those without subclinical infection (odds ratio 5.25, 95% confidence interval 1.29 to 21.4, p = 0.021). Sonication of the biofilm of the surface of the spacer is useful in order to exclude subclinical infection and therefore contributes to improving the outcome after two-stage procedures.

Aims. 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. Methods. The revision arthroplasty network was established in January 2015 and covered five hospitals in the Nottinghamshire and Lincolnshire areas of the East Midlands of England. This comprises a collaborative weekly multidisciplinary meeting where upcoming rTKA and rTHA procedures are discussed, and a plan agreed. Using the Hospital Episode Statistics database, revision procedures carried out between April 2011 and March 2018 (allowing two-year follow-up) from the five network hospitals were compared to all other hospitals in England. Age, sex, and mean Hospital Frailty Risk scores were used as covariates. The primary outcome was re-revision surgery within one year of the index revision. Secondary outcomes were re-revision surgery within two years, any complication within one and two years, and median length of hospital stay. Results. A total of 57,621 rTHA and 33,828 rTKA procedures were performed across England, of which 1,485 (2.6%) and 1,028 (3.0%), respectively, were conducted within the network. Re-revision rates within one year for rTHA were 7.3% and 6.0%, and for rTKA were 11.6% and 7.4% pre- and postintervention, respectively, within the network. This compares to a pre-to-post change from 7.4% to 6.8% for rTHA and from 11.7% to 9.7% for rTKA for the rest of England. In comparative interrupted time-series analysis for rTKA there was a significant immediate improvement in one-year re-revision rates for the revision network compared to the rest of England (p = 0.024), but no significant change for rTHA (p = 0.504). For the secondary outcomes studied, there was a significant improvement in trend for one- and two-year complication rates for rTHA for the revision network compared to the rest of England. Conclusion. Re-revision rates for rTKA and complication rates for rTHA improved significantly at one and two years with the introduction of a revision arthroplasty network, when compared to the rest of England. Most of the outcomes studied improved to a greater extent in the network hospitals compared to the rest of England when comparing the pre- and postintervention periods. Cite this article: Bone Joint J 2023;105-B(6):641–648

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: Bone Joint J 2024;106-B(10):1084–1092

Aims. 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. Methods. This is a retrospective, single-centre analysis. Patients undergoing primary hip or knee arthroplasty with a prior sleeve gastrectomy were eligible for inclusion (n = 80 patients). A morbidly obese control group was established from the same institutional registry using a 1:2 match, for cases:controls with arthroplasty based on propensity score using age, sex, pre-sleeve gastrectomy BMI, Current Procedural Terminology code to identify anatomical location, and presurgical haemoglobin A1C. Outcomes included 90-day complications, incidence of revision arthroplasty, and patient-reported outcome scores at final follow-up. Multivariable logistic regressions evaluated associations of underlying preoperative demographic and treatment characteristics with outcomes. Results. Complications within 90 days of surgery were increased in the sleeve gastrectomy group relative to the obese control group after controlling for underlying preoperative demographic characteristics (odds ratio (OR) 4.00 (95% CI 1.14 to 13.9); p = 0.030). Postoperative revisions were similar in the sleeve gastrectomy group relative to the obese control group after controlling for underlying preoperative demographic characteristics (OR 17.8 (95% CI 0.64 to 494.3); p = 0.090). Patient-Reported Outcomes Measurement Information System (PROMIS) depression decreased by a greater amount from pre- to postoperative in the obese controls relative to the sleeve gastrectomy group (OR 4.04 (95% CI 0.06 to 8.02); p = 0.047). PROMIS pain interference and physical function change from pre- to postoperative was not associated with sleeve gastrectomy status. Conclusion. We found a higher rate of complications at 90 days in patients who underwent sleeve gastrectomy prior to primary hip or knee arthroplasty relative to a matched, obese control population. Prosthetic revision rates were similar between the two groups, while improvements in PROMIS depression scores were larger in the obese cohort. This study suggests that sleeve gastrectomy to achieve preoperative weight loss prior to arthroplasty surgery may not mitigate early complication risks in obese patient populations. Cite this article: Bone Joint J 2024;106-B(9):935–941