Aims

This paper describes the methodology, validation and reliability of a new computer-assisted method which uses models of the patient’s bones and the components to measure their migration and polyethylene wear from radiographs after total hip arthroplasty (THA).

As patient data continues to grow, the importance of efficient and precise analysis cannot be overstated. The employment of Generative Artificial Intelligence (AI), specifically Chat GPT-4, in the realm of medical data interpretation has been on the rise. However, its effectiveness in comparison to manual data analysis has been insufficiently investigated. This quality improvement project aimed to evaluate the accuracy and time-efficiency of Generative AI (GPT-4) against manual data interpretation within extensive datasets pertaining to patients with orthopaedic injuries. A dataset, containing details of 6,562 orthopaedic trauma patients admitted to a district general hospital over a span of two years, was reviewed. Two researchers operated independently: one utilised GPT-4 for insights via prompts, while the other manually examined the identical dataset employing Microsoft Excel and IBM® SPSS® software. Both were blinded on each other's procedures and outcomes. Each researcher answered 20 questions based on the dataset including injury details, age groups, injury specifics, activity trends and the duration taken to assess the data. Upon comparison, both GPT-4 and the manual researcher achieved consistent results for 19 out of the 20 questions (95% accuracy). After a subsequent review and refined prompts (prompt engineering) to GPT-4, the answer to the final question aligned with the manual researcher's findings. GPT-4 required just 30 minutes, a stark contrast to the manual researcher's 9-hour analytical duration. This quality improvement project emphasises the transformative potential of Generative AI in the domain of medical data analysis. GPT-4 not only paralleled the accuracy of manual analysis but also achieved this in significantly less time. For optimal accurate results, data analysis by AI can be enhanced through human oversight. Adopting AI-driven approaches, particularly in orthopaedic data interpretation, can enhance efficiency and ultimately improve patient care. We recommend future investigations on large and more varied datasets to reaffirm these outcomes

The use of routine sampling for histological analysis during revision hip replacement has been standard practice in our unit for many years. It is used to identify the presence of inflammatory processes that may represent peri-prosthetic infection. This study follows up on a smaller study in the same unit in 2019 where an initial 152 cases were scrutinised. In this follow up study we examined 1,361 consecutive patients over a 16-year period whom had undergone revision hip replacement in a tertiary orthopaedic centre for any reason excluding primary bone tumour or malignant metastasis. All patients had tissue sampling for histopathological analysis performed by consultant histopathologists with a specialist interest in musculoskeletal pathology. The presence of bacteria in greater than 50% of samples sent for microbiological analysis in each patient was used as the gold standard diagnostic comparator for infection. This was then compared with the histology report for each patient. After excluding 219 patients with incomplete data and 1 sample rejection, 1,141 cases were examined. Microbiology confirmed infection in 132 cases (prevalence of infection 11.04%) and histopathology analysis suggested infection in 171 cases. Only 64 cases with confirmed infection in more than 50% of microbiology samples had concurrent diagnosis of infection on histological analysis (5.60% of total; PPV 51.20%). Furthermore, microbiology analysis confirmed infection in 62 cases where histological analysis failed to identify infection (5.43% of total; False negative rate 49.21%). Overall, histopathology analysis was seen to have a good specificity of 93.99% but poor sensitivity of 50.79%. We believe that this is the largest series in the literature and is somewhat unique in that all histology analysis was performed by consultant histopathologists with specialist interest in musculoskeletal pathology. Based on the costs incurred by this additional investigation our experience does not support routine sampling for histological analysis in revision hip arthroplasty. This is a substantial paradigm shift from current practice among revision arthroplasty surgeons in the United Kingdom but would equate to a substantial cost saving

Dual Mobility (DM) Total Hip Replacements (THRs) were introduced to reduce dislocation risk, which is the most common cause of early revision. The in-vivo mechanics of these implants is not well understood, despite their increased use in both elective and trauma settings. Therefore, the aim of this study was to comprehensively assess retrieved DM polyethylene liners for signs of damage using visual inspection and semi-quantitative geometric assessment techniques. Retrieved DM liners (n=20) were visually inspected for the presence of seven established modes of polyethylene damage. If embedded debris was identified on the external surface, its material composition was characterised using energy-dispersive x-ray analysis (EDX). Additionally, each liner was geometrically assessed for signs of wear/deformation using a validated methodology. Visual inspection of the liners revealed that scratching and pitting were the most common damage modes on either surface. Burnishing was observed on 50% and 15% of the internal and external surfaces, respectively. In addition, embedded debris was identified on 25% of the internal and 65% of the external surfaces. EDX analysis of the debris identified several materials including iron, titanium, cobalt-chrome, and tantalum. Geometric analysis demonstrated highly variable damage patterns across the liners. The results of this study provide insight into the in-vivo mechanics of DM bearings. For example, the results suggest that the internal bearing (i.e., between the head and liner) acts as the primary articulation site for DM-THRs as evidenced by a higher incidence of burnishing and larger, more concentrated regions of penetration across the liners’ internal surfaces. Furthermore, circumferential, and crescent-shaped damage patterns were identified on the articulating surfaces of the liners thus providing evidence that these components can rotate within the acetabular shell with varying degrees of mobility. The mechanics of DM bearings are complex and may be influenced by several factors (e.g., soft tissue fibrosis, patient activities) and thus further investigation is warranted. Finally, the results of this study suggest that DM liners may be susceptible to ex-vivo surface damage and thus caution is advised when handling and/or assessing these types of components

Finite element analysis (FEA) has been applied for the biomechanical analysis of acetabular dysplasia, but not for biomechanical studies of periacetabular osteotomy (PAO) or those performing analysis taking into consideration the severity of acetabular dysplasia. This study aimed to perform biomechanical evaluation of changes in stress distribution following PAO and to determine the effect of the severity of developmental dysplasia of the hip (DDH) using three-dimensional FEA. A normal model was designed with a 25° center-edge (CE) angle and a 25° vertical-center-anterior margin (VCA) angle. DDH models were designed with CE and VCA angles each of 10, 0, or −10°. Post-PAO models were created by separating each DDH model and rotating the acetabular bone fragment in the anterolateral direction so that the femoral head was covered by the acetabular bone fragment, with CE and VCA angles each at 25°. Compared to the normal hip joint model, the DDH models showed stress concentration in the acetabular edge and contacting femoral head, and higher stress values; stress increased with decreasing CE and VCA angles. Compared to the DDH models, the post-PAO models showed near-normal patterns of stress distribution in the acetabulum and femoral head, with stress concentration areas shifted from the lateral to medial sides. Stress dispersion was especially apparent in the severe acetabular dysplasia models. PAO provided greater decreases in the maximum values of von Mises stress in the load-bearing area of the acetabulum and femoral head when applied to the DDH models of higher degrees of severity, although the values increased with increasing severity of DDH. PAO is expected to provide biomechanical improvement of the hip joint, although the results also suggest a limitation in the applicability of PAO for the patients with severe acetabular dysplasia

Aims. The aim of this study was to compare the cost-effectiveness of cemented hemiarthroplasty (HA) versus hydroxyapatite-coated uncemented HA for the treatment of displaced intracapsular hip fractures in older adults. Methods. A within-trial economic evaluation was conducted based on data collected from the World Hip Trauma Evaluation 5 (WHiTE 5) multicentre randomized controlled trial in the UK. Resource use was measured over 12 months post-randomization using trial case report forms and participant-completed questionnaires. Cost-effectiveness was reported in terms of incremental cost per quality-adjusted life year (QALY) gained from the NHS and personal social service perspective. Methodological uncertainty was addressed using sensitivity analysis, while decision uncertainty was represented graphically using confidence ellipses and cost-effectiveness acceptability curves. Results. The base-case analysis showed that cemented implants were cost-saving (mean cost difference -£961 (95% confidence interval (CI) -£2,292 to £370)) and increased QALYs (mean QALY difference 0.010 (95% CI 0.002 to 0.017)) when compared to uncemented implants. The probability of the cemented implant being cost-effective approximated between 95% and 97% at alternative cost-effectiveness thresholds held by decision-makers, and its net monetary benefit was positive. The findings remained robust against all the pre-planned sensitivity analyses. Conclusion. This study shows that cemented HA is cost-effective compared with hydroxyapatite-coated uncemented HA in older adults with displaced intracapsular hip fractures. Cite this article: Bone Joint J 2022;104-B(8):922–928

3D printing acetabular cups offers the theoretical advantage of enhanced bony fixation due to greater design control of the porous implant surfaces. Analysing retrieved 3D printed implants can help determine whether this design intent has been achieved. We sectioned 14 off-the-shelf retrieved acetabular cups for histological analysis; 7 cups had been 3D printed and 7 had been conventionally manufactured. Some of the most commonly used contemporary designs were represented in both groups, which were removed due to either aseptic loosening, unexplained pain, infection or dislocation. Clinical data was collected for all implants, including their age, gender, and time to revision. Bone ingrowth was evaluated using microscopic assessment and two primary outcome measures: 1) bone area fraction and 2) extent of bone ingrowth. The additively manufactured cups were revised after a median (IQR) time of 24.9 months (20.5 to 45.6) from patients with a median (IQR) age of 61.1 years (48.4 to 71.9), while the conventional cups had a median (IQR) time to revision of 46.3 months (34.7 to 49.1, p = 0.366) and had been retrieved from patients with a median age of 66.0 years (56.9 to 68.9, p = 0.999). The additively and conventionally manufactured implants had a median (IQR) bone area fraction of 65.7% (36.4 to 90.6) and 33.9% (21.9 to 50.0), respectively (p < 0.001). A significantly greater amount of bone ingrowth was measured into the backside of the additively manufactured acetabular cups, compared to their conventional counterparts (p < 0.001). Bone occupied a median of 60.0% and 5.7% of the porous depth in the additively manufactured and conventional cups, respectively. 3D printed components were found to achieve a greater amount of bone ingrowth than their conventionally manufactured counterparts, suggesting that the complex porous structures generated through this manufacturing technique may encourage greater osteointegration

Aims. The risk of mechanical failure of modular revision hip stems is frequently mentioned in the literature, but little is currently known about the actual clinical failure rates of this type of prosthesis. The current retrospective long-term analysis examines the distal and modular failure patterns of the Prevision hip stem from 18 years of clinical use. A design improvement of the modular taper was introduced in 2008, and the data could also be used to compare the original and the current design of the modular connection. Methods. We performed an analysis of the Prevision modular hip stem using the manufacturer’s vigilance database and investigated different mechanical failure patterns of the hip stem from January 2004 to December 2022. Results. Two mechanical failure patterns were identified: fractures in the area of the distal fluted profile (distal stem fracture) and failure of the modular taper (modular fracture). A failure rate of 0.07% was observed for distal stem fracture, and modular fracture rates of 1.74% for the original and 0.013% for the current taper design. Conclusion. A low risk of mechanical failure for both fracture types was observed compared to other known complications in revision hip arthroplasty. In addition, the data show that a design change did significantly reduce the risk of a modular fracture. Cite this article: Bone Joint J 2024;106-B(2):151–157

Aims. Using data from the Hip Fracture Evaluation with Alternatives of Total Hip Arthroplasty versus Hemiarthroplasty (HEALTH) trial, we sought to determine if a difference in functional outcomes exists between monopolar and bipolar hemiarthroplasty (HA). Methods. This study is a secondary analysis of patients aged 50 years or older with a displaced femoral neck fracture who were enrolled in the HEALTH trial and underwent monopolar and bipolar HA. Scores from the Western Ontario and McMaster University Arthritis Index (WOMAC) and 12-Item Short Form Health Survey (SF-12) Physical Component Summary (PCS) and (MCS) were compared between the two HA groups using a propensity score-weighted analysis. Results. Of 746 HAs performed in the HEALTH trial, 404 were bipolar prostheses and 342 were unipolar. After propensity score weighting, adequate balance between the bipolar and unipolar groups was obtained as shown by standardized mean differences less than 0.1 for each covariable. A total of 24 months after HA, the total WOMAC score and its subcomponents showed no statistically significant difference between the unipolar and bipolar groups. Similarly, no statistically significant difference was found in the PCS and MCS scores of the SF-12 questionnaire. In participants aged 70 years and younger, no difference was found in any of the functional outcomes. Conclusion. From the results of this study, the use of bipolar HA over unipolar design does not provide superior functional outcomes at 24 months postoperatively. The theoretical advantage of reduced acetabular wear with bipolar designs does not appear to influence functional outcomes in the first two years postoperatively. Cite this article: Bone Jt Open 2023;4(5):370–377

The 22 year survivorship of metal on metal hip resurfacing arthroplasty (RSA) is reported to be 94.3% with expert surgeons, in males with head sizes greater than 48mm. The 2023 National Joint Registry (NJR) report estimates survivorship of all RSA at 19 years to be 85%. This estimate includes all designs, head sizes and females. Our aim was to estimate the survivorship of RSA currently available for implantation (males only, head size >48mm, MatOrtho Adept or Smith and Nephew Birmingham Hip Resurfacing (BHR)) in those under 55 years, performed by all surgeons, compared to conventional THR. We performed a retrospective analysis of the NJR. We included all males under 55 years who had undergone BHR or Adept RSA with head size greater than 48mm. Propensity score matching was used to produce two comparable groups of patients for RSA or conventional THR. We matched in a 3:1 ratio (THR:RSA) using sex, ASA, BMI group, age at primary procedure, surgeon volume, diagnosis and surgeon grade as covariates. The primary analysis was survivorship at 18 years. Time-to-revision was assessed using Kaplan-Meier curves. Cox's proportional hazard models were used to investigate between group differences. 4839 RSA were available for analysis. After matching the RSA and THR groups were well balanced in terms of covariates. Survivorship at 18 years was 93.7% (95% CI 89.9,96.2) in the RSA group and 93.9% (90.5,96.0) in the THR group. Despite these similar estimates the adjusted hazard ratio was 1.40 (95% CI 1.18, 1.67 p<0.001) in favour of THR. Survivorship of the currently available RSA in males under 55 was 93.7% at 18 years, however THR survivorship was superior to RSA. These results, generalisable to UK practice, should be set against perceived benefits in functional status offered in RSA when counselling patients

Patients with a high comorbidity burden (high-risk) can achieve similar improvements in quality of life compared to low-risk patients, but greater morbidity may deter surgeons from operating on these patients. Whether surgeon volume influences THA outcomes in high-risk patients has not been investigated. This study aimed to compare complication rates and implant survivorship in high-risk patients operated on by high volume (HV) and non-HV THA surgeons. Patients with Charlson Comorbidity Index ≥ 5 and American Society of Anesthesiologist Classification of 3 or 4 undergoing primary, elective THA between 2013 and 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. Ninety day readmissions and revisions were compared between groups, and Kaplan-Meier analysis was used to evaluate implant survivorship within the follow-up period. 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) compared to 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 to 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) compared to the non-HV group. High-risk THA patients have fewer 90-day readmissions, all-cause revisions, septic revisions, as well as shorter length of stay when treated by HV surgeons. THA candidates with a high comorbidity burden may benefit from referral to high-volume surgeons to reduce procedural risk and improve postoperative outcomes

We aimed to use data from a randomized controlled trial (RCT) comparing the sliding hip screw vs. intramedullary nailing (IMN) for trochanteric fractures to examine complication rates between those managed with a short vs. long IMN. This is a secondary analysis using one arm of an RCT of patients ≥18 years with trochanteric fractures. We examined differences in fracture-related (femoral shaft fracture, implant failure, surgical site infection (SSI), nonunion, limb shortening, and pain) and medical (organ failure, respiratory distress, stroke, deep vein thrombosis [DVT] gastrointestinal upset, pneumonia, myocardial infarction, sepsis, or urinary tract infection) adverse events (AE), and readmission between short vs. long IMNs. We included 412 trochanteric fracture patients, 339 (82.2%) of whom received a short (170mm–200mm) nail, while 73 (17.7%) received a long (260mm–460 mm) nail. Patients in the long group were more likely to be admitted from home (vs. an institution), and have comorbidities, or more complex fracture types. Patients in the long group had higher rates of fracture-related AE (12.3%) vs. the short group (3.5%). Specifically, SSI (5.5% vs. 0.3%) and pain (2.7% vs. 0.0%) were significantly higher in the long group. Patients in the long group were also more likely to develop DVT (2.7% vs. 0.3%), and be readmitted to the hospital (28.8% vs. 20.7%). Following covariable adjustment, long nails remained associated with a higher odds of fracture-related AE (5.11, 1.96–13.33) compared to short nails. We found no association between the adjusted odds of readmission and nail length (1.00, 0.52–1.94). Our analyses revealed that trochanteric fracture patients managed with long IMN nails may have a higher odds of fracture-related AE compared to short nails. Future research is required to validate these findings with larger event rates, and further optimize IMN for trochanteric fracture patients

Total hip arthroplasty has been constantly evolving with technological improvements to achieve the best survival rates. Although the new implants are under closer surveillance through processes such as Beyond Compliance, orthopaedic surgeons generally tend to look out for the latest implants with good short-term results and hope for better long-term results for these. We questioned whether such an assumption or bias is valid. We analysed the data of Kaplan-Meier estimates of cumulative revisions of primary hip replacement by fixation, stem/cup brand and bearing combinations from the NJR 19th Annual Report published in September 2022. We performed a univariate linear regression analysis to predict the 10- and 15-year revision rates for these different hip implant combinations from the 3- and 5-year revision rates. Thirty-seven implant combinations had their 15-year revision rates reported and 67 had the 10-year revision rates. The correlation co-efficients were 0.43 and 0.58 for the 3-year and 5-year revision rates against 15-year revision rates. Only 17% of the variance in 15-year revision rates could be predicted by a linear regression model from the 3-year revision rate and 32% from the 5-year revision rate. Corresponding values for the 10-year revision rates were 46% and 67%. 95% prediction intervals for the 15-year revision rate were +/− 3.1% from the 3-year revision rate and +/− 2.8% from the 5-year revision rate. Corresponding values for the 10-year revision rates were +/− 1.3% and +/− 1%. 19 of 37 implant combinations showed 15-year revision rate of more than 4%. Average 3-year and 5-year revision rates for this cohort was 1.0% and 1.42% compared to 1.4% and 1.9% for the rest and the difference was statistically significant. Although average early revision rates showed small but significant difference between the groups with lower and higher 15-year revision rates, the prediction intervals for 15-year revision rates for individual hips based on their 3-year and 5-year revision rates are very wide. Three- and 5-year revision rates for primary total hip replacements are poor predictors of 15-year revision rates

Tranexamic Acid (TXA) is now commonly used in major surgical operations including orthopaedics. The TRAC-24 randomised control trial aimed to assess if an additional 24 hours of TXA post – operatively in primary total hip (THA) and total knee arthroplasty (TKA) reduced blood loss. Contrary to other orthopaedic studies to date this trial included high risk patients. This paper presents the results of a cost analysis undertaken alongside this RTC. TRAC-24 was a prospective randomised controlled trial on patients undergoing TKA and THA. Three groups were included, Group 1 received 1 g intravenous (IV) TXA perioperatively and an additional 24-hour post-operative oral regime, group 2 received only the perioperative dose and group 3 did not receive TXA. Cost analysis was performed out to day 90. Group 1 was associated with the lowest mean total costs, followed by group 2 and then group 3. The difference between groups 1 and 3 −£797.77 (95% CI −1478.22, −117.32) were statistically significant. Extended oral dosing reduced costs for patients undergoing THA but not TKA. The reduced costs in groups 1 and 2 resulted from reduced length of stay, readmission rates, Accident and Emergency (A&E) attendances and blood transfusions. This study demonstrated significant cost savings when using TXA in primary THA or TKA. Extended oral dosing reduced costs further in THA but not TKA

The aim of this study was to compare the relative performance of total hip replacement constructs and discern if there is substantial variability in performance in currently commonly used prostheses. All patients who underwent a primary total hip replacement (THR) registered in the NZJR between 1. st. January 1999 to June 2020 were identified. Using a noninferiority analysis, the performance of hip prostheses were compared with the best performing contemporary construct. Construct failure was estimated using the 1-Kaplan Meier survival function method to estimate net failure. The difference in failure between the contemporary benchmark and other constructs was examined. In total 135 432 THR were recorded comprising 1 035 different THR constructs. Notably 328 constructs were used just once. 48 constructs (62 251 THR) had >500 procedures at risk at 3 years post-primary of which 28 were inferior by at least 20% relative risk of which, 10 were inferior by at least 100% relative risk. 16 constructs were identified with >500 procedures at risk at 10 years with 9 inferior by at least 20%, of which one was inferior by >100% relative risk. There were fewer constructs noninferior to the best practice benchmark when we performed analysis by gender. In females at 10 years, from 5 constructs with >500 constructs at risk, 2 were inferior at the 20% margin. In males at 10 years, there were only 2 eligible constructs of which one was inferior at the 20% margin. We discerned that there is substantial variability in construct performance and at most time points, just over half of constructs are inferior to the best performing construct by at least 20%. These results can facilitate informed decision-making when considering THR surgery

Aims. The burden of revision total hip arthroplasty (rTHA) continues to grow. The surgery is complex and associated with significant costs. Regional rTHA networks have been proposed to improve outcomes and to reduce re-revisions, and therefore costs. The aim of this study was to accurately quantify the cost and reimbursement for a rTHA service, and to assess the financial impact of case complexity at a tertiary referral centre within the NHS. Methods. A retrospective analysis of all revision hip procedures was performed at this centre over two consecutive financial years (2018 to 2020). Cases were classified according to the Revision Hip Complexity Classification (RHCC) and whether they were infected or non-infected. Patients with an American Society of Anesthesiologists (ASA) grade ≥ III or BMI ≥ 40 kg/m. 2. are considered “high risk” by the RHCC. Costs were calculated using the Patient Level Information and Costing System (PLICS), and remuneration based on Healthcare Resource Groups (HRG) data. The primary outcome was the financial difference between tariff and cost per patient episode. Results. In all, 199 revision episodes were identified in 168 patients: 25 (13%) least complex revisions (H1); 110 (55%) complex revisions (H2); and 64 (32%) most complex revisions (H3). Of the 199, 76 cases (38%) were due to infection, and 78 patients (39%) were “high risk”. Median length of stay increased significantly with case complexity from four days to six to eight days (p = 0.006) and for revisions performed for infection (9 days vs 5 days; p < 0.001). Cost per episode increased significantly between complexity groups (p < 0.001) and for infected revisions (p < 0.001). All groups demonstrated a mean deficit but this significantly increased with revision complexity (£97, £1,050, and £2,887 per case; p = 0.006) and for infected failure (£2,629 vs £635; p = 0.032). The total deficit to the NHS Trust over two years was £512,202. Conclusion. Current NHS reimbursement for rTHA is inadequate and should be more closely aligned to complexity. An increase in the most complex rTHAs at major revision centres will likely place a greater financial burden on these units. Cite this article: Bone Jt Open 2023;4(8):559–566

Aims. Highly polished stems with force-closed design have shown satisfactory clinical results despite being related to relatively high early migration. It has been suggested that the minimal thickness of cement mantles surrounding the femoral stem should be 2 mm to 4 mm to avoid aseptic loosening. The line-to-line cementing technique of the femoral stem, designed to achieve stem press-fit, challenges this opinion. We compared the migration of a highly polished stem with force-closed design by standard and line-to-line cementing to investigate whether differences in early migration of the stems occur in a clinical study. Methods. In this single-blind, randomized controlled, clinical radiostereometric analysis (RSA) study, the migration pattern of the cemented Corail hip stem was compared between line-to-line and standard cementing in 48 arthroplasties. The primary outcome measure was femoral stem migration in terms of rotation and translation around and along with the X-, Y-, and Z- axes measured using model-based RSA at three, 12, and 24 months. A linear mixed-effects model was used for statistical analysis. Results. Results from mixed model analyses revealed a lower mean retroversion for line-to-line (0.72° (95% confidence interval (CI) 0.38° to 1.07°; p < 0.001), but no significant differences in subsidence between the techniques (-0.15 mm (95% CI -0.53 to 0.227; p = 0.429) at 24 months. Radiolucent lines measuring < 2 mm wide were found in three and five arthroplasties cemented by the standard and line-to-line method, respectively. Conclusion. The cemented Corail stem with a force-closed design seems to settle earlier and better with the line-to-line cementing method, although for subsidence the difference was not significant. However, the lower rate of migration into retroversion may reduce the wear and cement deformation, contributing to good long-term fixation and implant survival. Cite this article: Bone Joint J 2022;104-B(1):19–26

Until today it is unknown whether preservation of the joint capsule positively affects patient reported outcome (PROs) in DAA-THA. A recent RCT found no clinical difference at 1 year. Since 2015 we preserve the capsule suture it at the end. We here evaluate whether this change had any effect on PROs and revisions, 2 years post-operatively. Two subsequent cohorts operated by the senior author were compared. The capsule was resected in the first cohort (January 2012 – December 2014) and preserved in the second cohort (July 2015 – December 2017). No other technical changes have been introduced between the two cohorts. Patient demographics, Charlson Comorbidity Index (CCI), and surgical data were collected from our clinical information system. 2-years PROs questionnaires (OHS, COMI Hip) were obtained. Data was analyzed with generalized multiple regression analysis. 430 and 450 patients were included in the resected and preserved cohorts, respectively. Demographics, CCI surgical time and length of stay were equal in both groups. Blood loss was less in the preserved cohort (p<.05). Four patients had a revision (1 vs 3, n.s.). Once corrected for demographics, capsule preservation had significant worse PROs: +0.24 COMI (p<.001) and −1.6 OHS points (p<.05), however, effects were much smaller than the minimal clinically important difference (0.95 and 5 respectively). The date of surgery (i.e. surgeon's age) was not a significant factor. In this large retrospective study, we observed statistically significant, but probably clinically not relevant, worse PROs with capsule preservation. It might be speculated that the not resected hypertrophied capsule could have caused this difference

Aims

Two-stage exchange revision total hip arthroplasty (THA) performed in case of periprosthetic joint infection (PJI) has been considered for many years as being the gold standard for the treatment of chronic infection. However, over the past decade, there have been concerns about its safety and its effectiveness. The purposes of our study were to investigate our practice, collecting the overall spacer complications, and then to analyze their risk factors.

Aims

Current diagnostic tools are not always able to effectively identify periprosthetic joint infections (PJIs). Recent studies suggest that circulating microRNAs (miRNAs) undergo changes under pathological conditions such as infection. The aim of this study was to analyze miRNA expression in hip arthroplasty PJI patients.