Purpose. Exeter stem was introduced to Japanese market at 1996. Since then, owing to its excellent clinical results, the number of the stem used has been increased year by year and more than 2000 stems have been implanted during the year 2009. The present study aims to prove its efficacy for Japanese patients by evaluating short term results of four major dedicated hip centers. Method. We present the short-term multi-center results of primary THA with Exeter stem combined with modern cementing technique in 881 patients (1000 hips). The average age of the patients at operation was 62.3years (ranging 23 to 89 years). Mean postoperative follow up period was 4.0 (ranging 2 to 9) years. Results. Intraoperative complications such as femoral fracture were observed in 6 hips. Postoperative cementing grade using Barrack's classification was judged as A for 735 hips, as B for 246 hips, and as C for 4 hips, respectively. Twenty-four patients died with unrelated disease and 52 patients were lost during follow-up period. Follow-up ratio was 94.8%. Thirty postoperative complications which include 9 infections, 14 dislocations, 5 deep vein thrombosis, and 2 sciatic nerve palsies were observed. Symptomatic pulmonary embolization or femoral fracture was not observed. Re-operations for infection and dislocation were performed for 8 and 6 hips, respectively. At the final follow-up, no radiolucent line at bone-cement interface was observed. Cortical hypertrophy was observed in 9.6% at Gruen zone 2 to 6. Kaplan-Meier survivorship analysis predicted a rate of survival at 5 years of 100% with radiolucent line at bone-cement interface of the femur as the endpoint, and of 98.8% when re-operation for any reason was used. Conclusion. The present study revealed excellent short-term result was obtained using Exeter stem combined with modern cementing technique for primary THAs in Japan

Aims. Our main aim was to describe the trend in the comorbidities of patients undergoing elective total hip arthroplasties (THAs) and knee arthroplasties (KAs) between 1 January 2005 and 31 December 2018 in England. Methods. We combined data from the National Joint Registry (NJR) on primary elective hip and knee arthroplasties performed between 2005 and 2018 with pre-existing conditions recorded at the time of their primary operation from Hospital Episodes Statistics. We described the temporal trend in the number of comorbidities identified using the Charlson Comorbidity Index, and how this varied by age, sex, American Society of Anesthesiologists (ASA) grade, index of multiple deprivation, and type of KA. Results. We included 696,504 and 833,745 elective primary THAs and KAs respectively, performed for any indication. Between 2005 and 2018, the proportion of elective THA and KA patients with one or more comorbidity at the time of their operation increased substantially (THA: 20% to 38%, KA: 22% to 41%). This was driven by increases in four conditions: chronic obstructive pulmonary disease (COPD) (2018: ~17%), diabetes without complications (2018: THA 10%, KA 14%), myocardial infarction (2018: 4%), and renal disease (2018: ~8%). Notably, renal disease prevalence increased from < 1% in 2005 to ~8% in 2018. Conclusion. Between 2005 and 2018 there were significant changes in the number of comorbidities recorded in patients having elective primary THAs and KAs. Renal disease is now one of the most prevalent comorbidities in this patient population. Future research should explore whether this comorbidity trend has increased the burden on other medical specialities to optimize these patients before surgery and to provide additional postoperative care. Cite this article: Bone Joint J 2022;104-B(9):1052–1059

Aims. Waiting times for arthroplasty surgery in Northern Ireland are among the longest in the NHS, which have been further lengthened by the onset of the COVID-19 global pandemic in March 2020. The Department of Health in Northern Ireland has announced a new Elective Care Framework (ECF), with the framework proposing that by March 2026 no patient will wait more than 52 weeks for inpatient/day case treatment. We aimed to assess the feasibility of achieving this with reference to total hip arthroplasty (THA) and total knee arthroplasty (TKA). Methods. Mathematical modelling was undertaken to calculate when the ECF targets will be achieved for THA and TKA, as well as the time when waiting lists for THA and TKA will be cleared. The number of patients currently on the waiting list and percentage operating capacity relative to pre-COVID-19 capacity was used to determine future projections. Results. As of May 2021, there were 3,757 patients awaiting primary THA and 4,469 patients awaiting primary TKA in Northern Ireland. Prior to April 2020, there were a mean 2,346 (2,085 to 2,610) patients per annum boarded for primary THA, a mean 2,514 (2,494 to 2,514) patients per annum boarded for primary TKA, and there were a mean 1,554 primary THAs and 1,518 primary TKAs performed per annum. The ECF targets for THA will only be achieved in 2030 if operating capacity is 200% of pre COVID-19 pandemic capacity and in 2042 if capacity is 170%. For TKA, the targets will be met in 2034 if capacity is 200% of pre-COVID-19 pandemic capacity. Conclusion. This modelling demonstrates that, in the absence of major funding and reorganization of elective orthopaedic care, the targets set out in the ECF will not be achieved with regard to THA and TKA. Waiting times for THA and TKA surgery in Northern Ireland are likely to remain greater than 52 weeks for most of this decade. Cite this article: Bone Jt Open 2022;3(4):302–306

Aims. Computer-assisted 3D preoperative planning software has the potential to improve postoperative stability in total hip arthroplasty (THA). Commonly, preoperative protocols simulate two functional positions (standing and relaxed sitting) but do not consider other common positions that may increase postoperative impingement and possible dislocation. This study investigates the feasibility of simulating commonly encountered positions, and positions with an increased risk of impingement, to lower postoperative impingement risk in a CT-based 3D model. Methods. A robotic arm-assisted arthroplasty planning platform was used to investigate 11 patient positions. Data from 43 primary THAs were used for simulation. Sacral slope was retrieved from patient preoperative imaging, while angles of hip flexion/extension, hip external/internal rotation, and hip abduction/adduction for tested positions were derived from literature or estimated with a biomechanical model. The hip was placed in the described positions, and if impingement was detected by the software, inspection of the impingement type was performed. Results. In flexion, an overall impingement rate of 2.3% was detected for flexed-seated, squatting, forward-bending, and criss-cross-sitting positions, and 4.7% for the ankle-over-knee position. In extension, most hips (60.5%) were found to impinge at or prior to 50° of external rotation (pivoting). Many of these impingement events were due to a prominent ischium. The mean maximum external rotation prior to impingement was 45.9° (15° to 80°) and 57.9° (20° to 90°) prior to prosthetic impingement. No impingement was found in standing, sitting, crossing ankles, seiza, and downward dog. Conclusion. This study demonstrated that positions of daily living tested in a CT-based 3D model show high rates of impingement. Simulating additional positions through 3D modelling is a low-cost method of potentially improving outcomes without compromising patient safety. By incorporating CT-based 3D modelling of positions of daily living into routine preoperative protocols for THA, there is the potential to lower the risk of postoperative impingement events. Cite this article: Bone Jt Open 2023;4(6):416–423

Aims. Patients with a high comorbidity burden (HCB) can achieve similar improvements in quality of life compared with low-risk patients, but greater morbidity may deter surgeons from operating on these patients. Whether surgeon volume influences total hip arthroplasty (THA) outcomes in HCB patients has not been investigated. This study aimed to compare complication rates and implant survivorship in HCB patients operated on by high-volume (HV) and non-HV THA surgeons. Methods. Patients with Charlson Comorbidity Index ≥ 5 and American Society of Anesthesiologists grade of III or IV, undergoing primary elective THA between January 2013 and December 2021, were retrospectively reviewed. Patients were separated into groups based on whether they were operated on by a HV surgeon (defined as the top 25% of surgeons at our institution by number of primary THAs per year) or a non-HV surgeon. Groups were propensity-matched 1:1 to control for demographic variables. A total of 1,134 patients were included in the matched analysis. Between groups, 90-day readmissions and revisions were compared, and Kaplan-Meier analysis was used to evaluate implant survivorship within the follow-up period. Results. Years of experience were comparable between non-HV and HV surgeons (p = 0.733). The HV group had significantly shorter surgical times (p < 0.001) and shorter length of stay (p = 0.009) than the non-HV group. The HV group also had significantly fewer 90-day readmissions (p = 0.030), all-cause revisions (p = 0.023), and septic revisions (p = 0.020) compared with the non-HV group at latest follow-up. The HV group had significantly greater freedom from all-cause (p = 0.023) and septic revision (p = 0.020) than the non-HV group. Conclusion. The HCB THA patients have fewer 90-day readmissions, all-cause revisions, and septic revisions, as well as shorter length of stay when treated by HV surgeons. THA candidates with a HCB may benefit from referral to HV surgeons to reduce procedural risk and improve postoperative outcomes. Cite this article: Bone Joint J 2024;106-B(3 Supple A):10–16

Aims. The prevalence of obesity is increasing substantially around the world. Elevated BMI increases the risk of complications following total hip arthroplasty (THA). We sought to evaluate trends in BMI and complication rates of obese patients undergoing primary THA over the last 30 years. Methods. Through our institutional total joint registry, we identified 15,455 primary THAs performed for osteoarthritis from 1990 to 2019. Patients were categorized according to the World Health Organization (WHO) obesity classification and groups were trended over time. Cox proportional hazards regression analysis controlling for confounders was used to investigate the association between year of surgery and two-year risk of any reoperation, any revision, dislocation, periprosthetic joint infection (PJI), venous thromboembolism (VTE), and periprosthetic fracture. Regression was stratified by three separate groups: non-obese; WHO Class I and Class II (BMI 30 to 39 kg/m. 2. ); and WHO Class III patients (BMI ≥ 40 kg/m. 2. ). Results. There was a significant increase in the proportion of all obesity classes from 1990 to 2019, and the BMI values within each WHO class significantly increased over time. Risk of any reoperation did not change over time among non-obese or WHO Class I/II patients, but increased for WHO Class III patients (hazard ratio (HR) 1.04; p = 0.044). Risk of dislocation decreased over time for non-obese (HR 0.96; p < 0.001) and WHO Class I/II (HR 0.96; p = 0.002) patients, but did not change over time for WHO Class III (HR 0.94; p = 0.073) patients. Risks of any revision and PJI did not change over time for any group. Conclusion. The proportion of patients undergoing THA who are obese has increased dramatically at our institution between 1990 and 2019. Despite BMI values increasing within all WHO classes over time, two-year complication risks have remained stable or decreased in WHO Class I/II patients. However, continued efforts will be required to mitigate risks in the heaviest WHO Class III patients. Cite this article: Bone Joint J 2024;106-B(11):1223–1230

Aims. Registry studies on modified acetabular polyethylene (PE) liner designs are limited. We investigated the influence of standard and modified PE acetabular liner designs on the revision rate for mechanical complications in primary cementless total hip arthroplasty (THA). Methods. We analyzed 151,096 primary cementless THAs from the German Arthroplasty Registry (EPRD) between November 2012 and November 2020. Cumulative incidence of revision for mechanical complications for standard and four modified PE liners (lipped, offset, angulated/offset, and angulated) was determined using competing risk analysis at one and seven years. Confounders were investigated with a Cox proportional-hazards model. Results. Median follow-up was 868 days (interquartile range 418 to 1,364). The offset liner design reduced the risk of revision (hazard ratio (HR) 0.68 (95% confidence interval (CI) 0.50 to 0.92)), while the angulated/offset liner increased the risk of revision for mechanical failure (HR 1.81 (95% CI 1.38 to 2.36)). The cumulative incidence of revision was lowest for the offset liner at one and seven years (1.0% (95% CI 0.7 to 1.3) and 1.8% (95% CI 1.0 to 3.0)). No difference was found between standard, lipped, and angulated liner designs. Higher age at index primary THA and an Elixhauser Comorbidity Index greater than 0 increased the revision risk in the first year after surgery. Implantation of a higher proportion of a single design of liner in a hospital reduced revision risk slightly but significantly (p = 0.001). Conclusion. The use of standard acetabular component liners remains a good choice in primary uncemented THA, as most modified liner designs were not associated with a reduced risk of revision for mechanical failure. Offset liner designs were found to be beneficial and angulated/offset liner designs were associated with higher risks of revision. Cite this article: Bone Joint J 2022;104-B(7):801–810

Aims. The current study aimed to compare robotic arm-assisted (RA-THA), computer-assisted (CA-THA), and manual (M-THA) total hip arthroplasty regarding in-hospital metrics including length of stay (LOS), discharge disposition, in-hospital complications, and cost of RA-THA versus M-THA and CA-THA versus M-THA, as well as trends in use and uptake over a ten-year period, and future projections of uptake and use of RA-THA and CA-THA. Methods. The National Inpatient Sample was queried for primary THAs (2008 to 2017) which were categorized into RA-THA, CA-THA, and M-THA. Past and projected use, demographic characteristics distribution, income, type of insurance, location, and healthcare setting were compared among the three cohorts. In-hospital complications, LOS, discharge disposition, and in-hospital costs were compared between propensity score-matched cohorts of M-THA versus RA-THA and M-THA versus CA-THA to adjust for baseline characteristics and comorbidities. Results. RA-THA and CA-THA did not exhibit any clinically meaningful reduction in mean LOS (RA-THA 2.2 days (SD 1.4) vs 2.3 days (SD 1.8); p < 0.001, and CA-THA 2.5 days (SD 1.9) vs 2.7 days (SD 2.3); p < 0.001, respectively) compared to their respective propensity score-matched M-THA cohorts. RA-THA, but not CA-THA, had similar non-home discharge rates to M-THA (RA-THA 17.4% vs 18.5%; p = 0.205, and 18.7% vs 24.9%; p < 0.001, respectively). Implant-related mechanical complications were lower in RA-THA (RA-THA 0.5% vs M-THA 3.1%; p < 0.001, and CA-THA 1.2% vs M-THA 2.2%; p < 0.001), which was associated with a significantly lower in-hospital dislocation (RA-THA 0.1% vs M-THA 0.8%; p < 0.001). Both RA-THA and CA-THA demonstrated higher mean higher index in-hospital costs (RA-THA $18,416 (SD $8,048) vs M-THA $17,266 (SD $8,396); p < 0.001, and CA-THA $20,295 (SD $8,975) vs M-THA $18,624 (SD $9,226); p < 0.001, respectively). Projections indicate that 23.9% and 3.2% of all THAs conducted in 2025 will be robotic arm- and computer-assisted, respectively. Projections indicated that RA-THA use may overtake M-THA by 2028 (48.3%) and reach 65.8% of all THAs by 2030. Conclusion. Technology-assisted THA, particularly RA-THA, may provide value by lowering in-hospital early dislocation rates and and other in-hospital metrics compared to M-THA. Higher index-procedure and hospital costs warrant further comprehensive cost analyses to determine the true added value of RA-THA in the episode of care, particularly since we project that one in four THAs in 2025 and two in three THA by 2030 will use RA-THA technology. Cite this article: Bone Joint J 2021;103-B(9):1488–1496

Aims

Modular dual-mobility (DM) articulations are increasingly used during total hip arthroplasty (THA). However, concerns remain regarding the metal liner modularity. This study aims to correlate metal artifact reduction sequence (MARS)-MRI abnormalities with serum metal ion levels in patients with DM articulations.

Aims

Total hip arthroplasties (THAs) are performed by surgeons at various stages in training with varying levels of supervision, but we do not know if this is safe practice with comparable outcomes to consultant-performed THA. Our aim was to examine the association between surgeon grade, the senior supervision of trainees, and the risk of revision following THA.

Aims

Total hip arthroplasty (THA) is one of the most successful surgical procedures. The objectives of this study were to define whether there is a correlation between socioeconomic status (SES) and surgical complications after elective primary unilateral THA, and investigate whether access to elective THA differs within SES groups.

Aims

The aim of this study was to assess medium-term improvements following total hip arthroplasty (THA), and to evaluate what effect different preoperative Oxford Hip Score (OHS) thresholds for treatment may have on patients’ access to THA and outcomes.

Aims. The Exeter V40 femoral stem is the most implanted stem in the National Joint Registry (NJR) for primary total hip arthroplasty (THA). In 2004, the 44/00/125 stem was released for use in ‘cement-in-cement’ revision cases. It has, however, been used ‘off-label’ as a primary stem when patient anatomy requires a smaller stem with a 44 mm offset. We aimed to investigate survival of this implant in comparison to others in the range when used in primary THAs recorded in the NJR. Methods. We analyzed 328,737 primary THAs using the Exeter V40 stem, comprising 34.3% of the 958,869 from the start of the NJR to December 2018. Our exposure was the stem, and the outcome was all-cause construct revision. We stratified analyses into four groups: constructs using the 44/00/125 stem, those using the 44/0/150 stem, those including a 35.5/125 stem, and constructs using any other Exeter V40 stem. Results. In all 328,737 THAs using an Exeter V40 stem, the revision estimate was 2.8% (95% confidence interval (CI) 2.7 to 2.8). The 44/00/125 stem was implanted in 2,158 primary THAs, and the ten-year revision estimate was 4.9% (95% CI 3.6 to 6.8). Controlling for age, sex, year of operation, indication, and American Society of Anesthesiologists grade demonstrated an increased overall hazard of revision for constructs using the 44/00/125 stem compared to constructs using other Exeter V40 femoral stems (hazard ratio 1.8 (95% CI 1.4 to 2.3)). Conclusion. Although the revision estimate is within the National Institute for Health and Care Excellence ten-year benchmark, survivorship of constructs using the 44/00/125 stem appears to be lower than the rest of the range. Adjusted analyses will not take into account ‘confounding by indication’, e.g. patients with complex anatomy who may have a higher risk of revision. Surgeons and patients should be reassured but be aware of the observed increased revision estimate, and only use this stem when other implants are not suitable. Cite this article: Bone Joint J 2023;105-B(5):504–510

Angular proximal femoral deformities increase the technical complexity of primary total hip arthroplasties (THAs). The goals were to determine the long-term implant survivorship, risk factors, complications, and clinical outcomes of contemporary primary THAs in this difficult cohort. Our institutional total joint registry was used to identify 119 primary THAs performed in 109 patients with an angular proximal femoral deformity between 1997 and 2017. The deformity was related to previous femoral osteotomy in 85%, and developmental or metabolic disorders in 15%. 53% had a predominantly varus angular deformity. The mean age was 44 years, mean BMI was 29 kg/m. 2. , and 59% were female. An uncemented metaphyseal fixation stem was used in 30%, an uncemented diaphyseal fixation stem in 28%, an uncemented modular body stem with metaphyseal fixation sleeve in 24%, and a cemented stem in 18%. Simultaneous corrective femoral osteotomy was performed in 18%. Kaplan-Meier survivorships and Harris hip scores were reported. Mean follow-up was 8 years. The 10-year survivorships free of femoral loosening, aseptic femoral revision, any revision, and any reoperation were 95%, 93%, 90% and 88%, respectively. Revisions occurred in 13 hips for: aseptic femoral component loosening (3), stem fracture (2), dislocation (2), aseptic acetabular loosening (2), polyethylene liner exchange (2), and infection (2). Preoperative varus angular deformities were associated with a higher risk of any revision (HR 10, p=0.03), and simultaneous osteotomies with a higher risk of any reoperation (HR 3.6, p=0.02). Mean Harris hip scores improved from 52 preoperatively to 82 at 10 years (p<0.001). In the largest series to date of primary THAs in patients with angular proximal femoral deformities, we found a good 10-year survivorship free from any revision. Varus angular deformities, particularly those treated with a simultaneous osteotomy due to the magnitude or location of the deformity, had a higher reoperation rate. Keywords: Proximal femoral deformity; dysplasia; femoral osteotomy; survivorship; revision. Level of evidence: Level III, comparative retrospective cohort

Background and purpose. Previous publications have reported an increased but levelling out risk of revision for infection after total hip arthroplasty (THA) in Norway. We assessed the changes in risk of major (cup and/or stem, 1- or 2-stage) and minor revisions (debridement, exchange of modular parts, antibiotics and implant retention (DAIR)) for infection after primary THAs reported to the Norwegian Arthroplasty Register (NAR) over the period 2005-2022. Patients and methods. Primary THAs reported to the NAR from 2005 to 2022 were included. Time was stratified into time periods (2005-2009, 2010-2018, 2019-2022) based on a previous publication. Cox regression analyses, adjusted for sex, age and ASA-classification, with the first revision for infection were performed. Results. 140,338 primary THAs met the inclusion criteria. 1.3% (1,785) were revised for infection during the study period. 0.5% (638) had major revisions, whereas 0.8% (1,147) had DAIRs for infection. The risk of revision for infection was 1.2 (95%CI 1.1-1.4) for 2010-2018 and 1.0 (0.8-1.1) for 2019-2022 compared to 2005-2009. Compared to 2010-2018, the risk of revision for infection was 0.8 (0.7-0.9) for 2019-2022. The risk of DAIR for infection was 1.5 (1.3-1.9) for 2010-2018 and 1.2 (1.0-1.4) for 2019-2022 compared to 2005-2009. Compared to 2010-2018, the risk of DAIR for infection was 0.8 (0.7-0.9) for 2019-2022. The risk of major revision for infection was 0.8 (0.7-1.0) for 2010-2018 and 0.8 (0.6-1.0) for 2019-2022 compared to 2005-2009. Interpretation. The overall risk of revision for infection after THA, in Norway, has decreased in the period 2019-2022. The risk for DAIR initially increased in the period 2005-2009, levelled out 2010-2018 before starting to decrease in 2019-2022. The risk of major revision for infection was reduced in the period 2005-2009 before levelling out. This shows changes in revision strategies, but may also reflect a true decrease in periprosthetic joint infection

Aims. The aim of this study was to determine the outcome of all primary total hip arthroplasties (THAs) and their subsequent revision procedures in patients aged under 50 years performed at our institution. Methods. All 1,049 primary THAs which were undertaken in 860 patients aged under 50 years between 1988 and 2018 in our tertiary care institution were included. We used cemented implants in both primary and revision surgery. Impaction bone grafting was used in patients with acetabular or femoral bone defects. Kaplan-Meier analyses were used to determine the survival of primary and revision THA with the endpoint of revision for any reason, and of revision for aseptic loosening. Results. The mean age of the patients at the time of the initial THA was 38.6 years (SD 9.3). The mean follow-up of the THA was 8.7 years (2.0 to 31.5). The rate of survival for all primary THAs, acetabular components only, and femoral components only at 20 years’ follow-up with the endpoint of revision for any reason, was 66.7% (95% confidence interval (CI) 60.5 to 72.2), 69.1% (95% CI 63.0 to 74.4), and 83.2% (95% CI 78.1 to 87.3), respectively. A total of 138 revisions were performed. The mean age at the time of revision was 48.2 years (23 to 72). Survival of all subsequent revision procedures, revised acetabular, and revised femoral components at 15 years’ follow-up with the endpoint of revision for any reason was 70.3% (95% CI 56.1 to 80.7), 69.7% (95% CI 54.3 to 80.7), and 76.2% (95% CI 57.8 to 87.4), respectively. A Girdlestone excision arthroplasty was required in six of 860 patients (0.7%). Conclusion. The long-term outcome of cemented primary and subsequent revision THA is promising in these young patients. We showed that our philosophy of using impaction bone grafting in patients with acetabular and femoral defects is a very suitable option when treating young patients. Surgeons should realize that knowledge of the outcome of subsequent revision surgery, which is inevitable in young patients, must be communicated to this group of patients prior to their initial THA. Cite this article: Bone Joint J 2022;104-B(3):368–375

Periprosthetic femur fracture (PFF) is a major complication following total hip arthroplasty (THA) that carries significant morbidity, mortality, and economic burden. Currently, uncemented stems are highly preferred in primary THA, but have been associated with higher risk of PFF compared to cemented stems. The use of collared stems in uncemented primary THA has shown promise in reducing PFF rates postoperatively. This retrospective study included 2,294 uncemented primary THAs using the posterior approach performed by two attending surgeons from January 2016 to December 2022. Both surgeons switched from a collarless femoral stem design to a collared design in May 2020. Data was collected regarding stem design, frequency of PFF, and requirement for revision surgery. Periprosthetic fractures were identified and confirmed using medical records and/or radiographic imaging. Fracture rates and percentages between collared and collarless stems were then analyzed. A Fisher's Exact Test was performed to determine if there was a significant association between collared and collarless stem use on PFF rates. A total of 2,294 uncemented primary THAs performed by 2 surgeons were eligible for analysis. 903 (39.4%) patients received a collared stem, and 1,391 (60.6%) patients received a collarless stem. In total, 14 (0.6%) PFFs occurred over the study period. There was 1 fracture (0.1%) out of 903 collared stems, and 13 fractures (0.9%) out of 1,391 collarless stems (p = 0.012). Collared stems were associated with a significant decrease in PFF rate when compared to collarless stems in uncemented primary THA. Future studies are encouraged to continue to investigate PFF and other complication rates with the use of a collared stem design

The Exeter V40 femoral stem is the most implanted stem in the NJR for primary THA. In 2004, the 44/00/125 stem was released for use in “cement-in-cement” revision cases. It has however been used ‘off-label’ as a primary stem when, for example, patient anatomy requires a smaller stem with a 44mm offset. We aimed to investigate survival of this stem in comparison to others in the range when used in primary THAs recorded in the NJR. Analyses were performed using a dataset based on that used for the 2020 NJR annual report. Our exposure was the stem; the outcome was all-cause construct revision. Crude analyses were performed using Kaplan-Meier and adjusted using Cox models. The 44/00/125 stem was directly compared to other stems in the Exeter range. We analysed 330,732 primary THAs using the Exeter V40 stem comprising 34.5% of the 958,869 THAs with complete information from the start of the NJR to 31 December 2018. The 44/00/125 stem was implanted in 2,158 primary THAs with 67.5% in female patients and a mean age of 67.8. The 10-year revision estimate for the 44/00/125 stem was 4.9% (95%CI 3.6, 6.8) and in constructs using an Exeter V40 stem was 2.8% (95%CI 2.7, 2.8). Controlling for age, sex and ASA demonstrated an increased overall hazard of revision for constructs using the 44/00/125 stem compared to constructs using other Exeter V40 femoral stems (HR 1.8 (95%CI 1.4, 2.3)). Although the revision estimate is within the NICE 10-year benchmark, survivorship of constructs using the 44/00/125 stem appears to be lower than the rest of the Exeter V40 range. Attempts to control for age, sex and ASA will not take into account confounding by indication i.e. patients with more complex anatomy who may have a higher risk of revision. Surgeons and patients should be reassured by this but should be aware of the observed increased revision estimate and use the stem according to its indications

Aim. Previous publications have suggested that the incidence of revisions due to infection after THA is increasing. We performed updated time-trend analyses of risk and timing of revision due to infection after primary THAs in the Nordic countries during the period 2004–2018. Methods. 569,463 primary THAs reported to the Nordic Arthroplasty Register Association from 2004 through 2018 were studied. We estimated adjusted hazard ratios (aHR) with 95% confidence interval by Cox regression with the first revision due to infection after primary THA as endpoint. The risk of revision was investigated. In addition, we explored changes in the time span from primary THA to revision due to infection. Results. 5,653 (1.0%) were revised due to infection. The risk of revision due to infection increased through the study period. Compared to the period 2004–2008, the aHRs were 1.4 (95%CI 1.3–1.5) for 2009–2013, and 1.9 (1.7–2.0) for 2014–2018. We found an increased risk in all four Nordic countries. Compared to 2004–2008, the aHR due to infection 0–30 days after THA was 2.5 (2.1–2.9) for 2009–2013 and 3.4 (3.0–3.9) for 2013–2018. The aHR of revision due to infection 31–90 days after THA was 1.5 (1.3–1.9) for 2009–2013 and 2.5 (2.1–3.0) for 2013–2018, compared to 2004–2008. Beyond 91 days after THA, the risk of revision due to infection was stable over the whole study period. Interpretation. The risk of revision due to deep infection after THA nearly doubled throughout the period 2004–2018. This increase was mainly due to an increased risk of early revisions. The cause for these changes may be multifactorial (patient selection, diagnostics, revision strategy, completeness of reporting, etc.), are not possible to disclose in the present study, and warrants further research

Aims. Periprosthetic femoral fracture (PPF) is a major complication following total hip arthroplasty (THA). Uncemented femoral components are widely preferred in primary THA, but are associated with higher PPF risk than cemented components. Collared components have reduced PPF rates following uncemented primary THA compared to collarless components, while maintaining similar prosthetic designs. The purpose of this study was to analyze PPF rate between collarless and collared component designs in a consecutive cohort of posterior approach THAs performed by two high-volume surgeons. Methods. This retrospective series included 1,888 uncemented primary THAs using the posterior approach performed by two surgeons (PKS, JMV) from January 2016 to December 2022. Both surgeons switched from collarless to collared components in mid-2020, which was the only change in surgical practice. Data related to component design, PPF rate, and requirement for revision surgery were collected. A total of 1,123 patients (59.5%) received a collarless femoral component and 765 (40.5%) received a collared component. PPFs were identified using medical records and radiological imaging. Fracture rates between collared and collarless components were analyzed. Power analysis confirmed 80% power of the sample to detect a significant difference in PPF rates, and a Fisher’s exact test was performed to determine an association between collared and collarless component use on PPF rates. Results. Overall, 17 PPFs occurred (0.9%). There were 16 fractures out of 1,123 collarless femoral components (1.42%) and one fracture out of 765 collared components (0.13%; p = 0.002). The majority of fractures (n = 14; 82.4%) occurred within 90 days of primary THA. There were ten reoperations for PPF with collarless components (0.89%) and one reoperation with a collared component (0.13%; p = 0.034). Conclusion. Collared femoral components were associated with significant decreases in PPF rate and reoperation rate for PPF compared to collarless components in uncemented primary THA. Future studies should investigate whether new-generation collared components reduce PPF rates with longer-term follow-up. Cite this article: Bone Joint J 2024;106-B(3 Supple A):115–120