Aims

This study explored the shared genetic traits and molecular interactions between postmenopausal osteoporosis (POMP) and sarcopenia, both of which substantially degrade elderly health and quality of life. We hypothesized that these motor system diseases overlap in pathophysiology and regulatory mechanisms.

Bone marrow stem cells (BMSCs) represent a collection of different cell types exhibiting stem cell characteristics but with notable heterogeneity. Among these, Skeletal Stem Cells (SSCs) represent a distinct matrix subgroup within BMSC and demonstrate a specialized capacity to facilitate bone formation, recruit chondrocytes, and contribute to hematopoiesis. SSCs play a pivotal role in orchestrating the functions of skeletal organs. Local ischemia has a significant impact on cell survival and function. We hypothesize that bone ischemia induces alterations in the differentiation potential of SSCs, consequently influencing changes in bone structure. We mechanically dissected tissue from the necrotic segment in the femoral head and more normal appearing areas from the femoral neck of specimens from 5 patients diagnosed with osteonecrosis of the femoral head (ONFH). These tissues were enzymatically broken down into individual cell suspensions. Utilizing fluorescence-activated cell sorting (FACS) based on specific surface markers indicative of human skeletal stem cells (hSSC), namely CD45- CD235a- CD31- TIE2- Podoplanin (PDPN)+ CD146- CD73+ CD164+, we isolated a distinct cell population. Subsequent in vitro evaluations, focusing on clonogenicity, osteogenesis, and chondrogenesis were conducted to assess the functional prowess of these SSCs. Moreover, we introduced BMP2 at a concentration of 50ng/ml to SSCs extracted from necrotic regions to potentially reinstate their osteogenic capabilities. We effectively isolated SSCs from both Necrotic and Non-necrotic Zones. We observed an augmented clonal formation capacity and chondrogenesis ability of SSCs isolated from the necrotic region, accompanied by a significant decline in osteogenic ability (P＜0.01), an effect not reversible even with the addition of BMP2. Ischemia adversely affects the proliferation and function of SSCs, resulting in a diminished osteogenic capacity and an insensitivity to BMP2, ultimately leading to structural alterations in bone tissue

Periacetabular Osteotomy (PAO) has become the most important surgical procedure for patients with hip dysplasia, offering significant pain relief and improved joint function. This study focuses on recovery after PAO, specifically the return to sports (RTS) timeline, with the objective of identifying preoperative predictors to optimize patient outcomes. Our prospective, monocentric study from 2019 to 2023 included 698 hips from 606 patients undergoing PAO. Comprehensive preoperative data were collected, including demographic information, clinical assessments (Modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (iHot-12), Hip Disability and Osteoarthritis Outcome Score (HOOS), UCLA Activity Score) and psychological evaluations (Brief Symptom Inventory (BSI) and SF-36 Health Survey). Advanced logistic regression and machine learning techniques (R Core Team. (2016)) were employed to develop a predictive model. Multivariate regression analysis revealed that several preoperative factors significantly influenced the RTS timeline. These included gender, invasiveness of the surgical approach, preoperative UCLA Score, preoperative sports activity level, mHHS, and various HOOS subscales (Sport/Recreation, Symptoms, Pain) as well as psychological factors (BSI and SF-36). The subsequent model, using a decision tree approach, showed that the combination of a UCLA score greater than 3 (p<0.001), non-female gender (p=0.003), preoperative sports frequency not less than twice per week (p<0.001), participation in high-impact sports preoperatively (p=0.008), and a BSI anxiety score less than 2 (p<0.001) had the highest likelihood of early RTS with a probability of 71.4% at three months. Using a decision tree approach, this model provides a nuanced prediction of RTS after PAO, highlighting the synergy of physical, psychological, and lifestyle influences. By quantifying the impact of these variables, it provides clinicians with a valuable tool for predicting individual patient recovery trajectories, aiding in tailored rehabilitation planning and predicting postoperative satisfaction

Recently, some smart media devices including portable accelerometers have been used to measure objective physical activity (OPA) after total hip arthroplasty (THA). The aim of this study was to longitudinally assess OPA changes in patients who underwent THA using a compact triaxial accelerometer and to investigate the impact of this recovery process on patient-reported outcomes. This prospective cohort study involved 163 consecutive patients who had unilateral osteoarthritis of the hip and were followed up for 12 months after THA. There were 132 women and 31 men with average age of 66 years. OPA was measured using a compact triaxial accelerometer preoperatively and at 1, 3, 6, and 12 months postoperatively. This study investigated the recovery process of OPA in four patient groups classified by the median of age and preoperative activity levels (younger and higher activity (YH), younger and lower activity (YL), older and higher activity (OH), and older and lower activity (OL)), and examined its impact on patient-reported outcomes, including forgotten joint score-12 (FJS-12). The target period for regaining preoperative activity levels was approximately 3 months for patients with lower preoperative activity, and about 6 months for those with higher preoperative activity. The OPA at 12 months postoperatively was higher in the patients with higher preoperative activity levels than in those with lower preoperative activity levels. In patients with higher preoperative activity levels, FJS-12 scores significantly increased between 6 and 12 months postoperatively (p=0.018). FJS-12 at 12 months postoperatively was best in YH (81.7±18.9), followed by YL (73.5±22.9), OH (73.2±17.4), and OL (66.3±21.8). Differences in the recovery process of postoperative activity levels impacted the duration required for improvement in FJS-12 scores. These results can serve as indicators for setting activity goals in patients undergoing THA

The increased demand for total hip arthroplasty (THA) is having a significant impact on healthcare resources, resulting in increased interest in outpatient care pathways to reduce resource consumption. This study compared costs between patients who underwent outpatient THA using a Direct Anterior (DA) approach compared to a Direct Lateral (DL) approach to understand the effect of surgical approach on resource use. We conducted a prospective randomized controlled trial for DA patients undergoing primary THA. We compared patients in the outpatient arm of the trial to a prospective cohort of outpatient DL approach THAs. We recorded all costs including: equipment, length of stay in hospital, and laboratory or other medical tests. Following discharge, participants also completed a self-reported cost diary recording resource utilization such as emergency department visits or subsequent hospitalizations, tests and procedures, consultations or follow-up, healthcare professional services, rehabilitation, use of pain medications, informal care, productivity losses and out of pocket expenditures. We report costs from both Canadian public health care payer (HCP) and a societal perspective. The HCP perspective includes any direct health costs covered by the publicly funded system. In addition to the health care system costs, the societal perspective also includes additional costs to the patient (e.g. physiotherapy, medication, or assistive devices), as well as any indirect costs such as time off paid employment for patients or caregivers. We included 127 patients in the DA group (66.6 years old) and 51 patients in the DL group (59.4 years old) (p<0.01). There were no statistically significant differences in costs between groups from both the healthcare payer (DA= 7910.19, DL= 7847.17, p=0.80) and societal perspectives (DA= 14657.21, DL= 14581.21, p=0.96). In patients undergoing a successful outpatient hip replacement, surgical approach does not have an effect on cost from in hospital or societal perspectives

The stem design in total hip arthroplasty (THA) is constantly evolving. The impact of the collar on the risk of periprosthetic fracture remains controversial. This study aimed to determine whether adding a collar to the femoral stem impacts the early periprosthetic fracture risk within 90 days of surgery. This retrospective study included 1,623 patients who underwent primary total hip arthroplasty in a single orthopedic department between January 2010 and December 2020. The inclusion criteria were uncemented stem with or without a collar, in a primary intention, without previous hip surgery with a similar “corail like” design. The assessed data were demographic characteristics (age, gender, number of obese (BMI > 30)), single or dual mobility, the surgical approach, the early complication, particularly the periprosthetic femoral fractures. Of the 1,623 patients, 1,380 received a collared stem (85%), and 243 received a collarless stem (15%). A multivariate analysis was performed to determine the collar's effect on the risk of early periprosthetic fracture (<90 days). Nine (0.55%) early periprosthetic fractures were identified in the whole cohort. There were four fractures (1.65%) in the collarless stem group and five fractures (0.36%) in the collared stem group (p=0,005). One patient required revision surgery in the collared stem group, while two patients required revision surgery in the collarless stem group. The multinomial logistic regression model indicated a statistically significant lower (p<0.05) risk of early periprosthetic fracture within 90 days of surgery in the collared stems group. No other risk factor for early periprosthetic fractures has been identified. Using collared stems in cementless THA protects early periprosthetic femoral fractures within 90 days of surgery

Hip resurfacing arthroplasty (HRA) is a bone conserving alternative to total hip arthroplasty. We present the early 2-year clinical and radiographic follow-up of a novel ceramic-on-ceramic (CoC) HRA in an international multi-centric cohort. Patients undergoing HRA between September 2018 and January 2021 were prospectively included. Patient-reported outcome measures (PROMS) in the form of the Forgotten Joint Score (FJS), HOOS Jr, WOMAC, Oxford Hip Score (OHS) and UCLA Activity Score were collected preoperatively and at 1- and 2-years post-operation. Serial radiographs were assessed for migration, component alignment, evidence of osteolysis/loosening and heterotopic ossification formation. 200 patients were identified to have reached 2-year follow-up. Of these, 185 completed PROMS follow-up at 2 years. There was significant improvement in HOOS (p< 0.001) and OHS (p< 0.001) and FJS (p< 0.001) between the pre-operative and 2-year outcomes. Patients reported improved pain (p<0.001), function (p<0.001) and reduced stiffness (p<0.001) as measured by the WOMAC score. Patients had improved activity scores on the UCLA Active Score (P<0.001) with 53% reporting return to impact activity at 2 years. There was no osteolysis and the mean acetabular cup inclination angle was 41deg and the femoral component shaft angle was 137deg. No fractures were reported over but there was one sciatic nerve palsy with partial recovery. Two patients were revised; one at 3 months for pain due to a misdiagnosed back problem and another at 33 months for loosening of the acetabular component with delamination of the titanium ingrowth surface. CoC resurfacing at 2-years post-operation demonstrate promising results with satisfactory PROMS

The purpose of this study was to assess the variability in implant position between sides in patients who underwent staged, bilateral THA and whether variation from one side to the other affected patient-reported outcomes. A retrospective review was conducted on 207 patients who underwent staged, bilateral THA by the same surgeon from 2017–2022. Leg length, acetabular height, cup version, and coronal and sagittal stem angles were assessed radiographically and compared to the contralateral THA. Surgical approach and technology utilization were further assessed for their impact on variability. Linear regression was used to model the relationship between side-to-side variability and patient-reported outcome measures (PROMS). Between sides, mean radiographic leg length varied by 4.6mm (0.0–21.2), acetabular height varied by 3.3mm (0.0–13.7), anteversion varied by 8.2° (0.0 to 28.7), coronal stem alignment varied by 1.1° (0.0 to 6.9), and sagittal angulation varied by 2.3° (0.0 to 10.5). The anterior approach resulted in more variability in stem angle position in both the coronal (1.3° vs. 1.0°, p=0.036) and sagittal planes (2.8° vs. 2.0° p=0.012) compared to the posterior approach. The posterior approach generally led to more anteversion than the anterior approach. Use of robotics or navigation for acetabular positioning did not increase side-to-side variability in cup-related position or leg length. Despite considerable side-to-side variability, Hip dysfunction and osteoarthritis outcome scores (HOOS JR) were not affected by higher levels of position inconsistency. Staged, bilateral THA results in considerable variability in component position between sides. The anterior approach leads to more side-to-side variability in sagittal stem angle and cup anteversion than the posterior approach. Navigation and robotics do not improve the consistency of component position in bilateral THA. Variation in implant position was not associated with differences in PROMs, suggesting that despite variability, patients can tolerate these differences between sides

While obesity is associated with an increased risk of complications after total hip arthroplasty (THA) the relationship between body mass index (BMI) and the risk of early postoperative complications has not been fully characterized. This study sought to describe the relationship between BMI and the risk of early postoperative complications, including periprosthetic joint infection (PJI), composite surgical, and composite medical complications. Primary, elective THAs performed from 2016–2021 were identified using the Premier Healthcare Database (PHD). The study's primary outcome was the diagnosis of PJI within 90 days of THA. Using BMI as a continuous variable, logistic regression was used to develop restricted cubic splines (RCSs) to determine the impact of BMI on PJI risk. Bootstrap simulation was used to identify an inflection point in the final RCS model. The same technique was used to characterize the effects of BMI on composite medical and surgical complications. We found that PJI risk increased exponentially beyond a BMI cutpoint of 37.4 kg/m. 2. Relative to the cutpoint, patients with a BMI of 40 or 50 kg/m. 2. were at a 1.22- and 2.55-fold increased risk of developing PJI, respectively. Surgical complications increased at a BMI of 32 kg/m. 2. and medical complications increased at a BMI of 39 kg/m. 2. Relative to these cutpoints, patients with a BMI of 50 kg/m. 2. were at a 1.36- and 2.07-fold increased risk of developing medical and surgical complications, respectively. The results of this study indicate a non-linear relationship between patient BMI and early postoperative risk of PJI, composite medical complications, and composite surgical complications following THA. The identified cutpoints with associated odds ratios can serve as tools to help risk-stratify and counsel patients seeking primary THA

Controversy persists over whether cemented or uncemented fixation is more effective in reducing revision and mortality risks following primary total hip arthroplasty (THA). Despite a shift towards uncemented THA in Europe, Australia, and the US, no consensus exists on superior outcomes. This ambiguity in evidence from randomized controlled trials (RCTs) and observational studies necessitates advanced research methodologies to derive more definitive conclusions. This study investigates the causal impact of THA fixation type on 2-year and 5-year revision rates, along with 90-day mortality, utilizing a regression discontinuity (RD) design in scenarios where fixation choice is guided by patient age. Employing data from the Dutch Arthroplasty Register, we conducted a cohort study on primary THAs for osteoarthritis from 2007 to 2019. A “fuzzy” RD design was executed to compute the Local Average Treatment Effect for subjects around the age-based selection threshold for fixation type. The main outcome of interest was the revision rate at 2 years post-operation. Analysis for the 2-year revision endpoint, covering any cause, included 2,344 females and 1,671 males across 5 hospitals each, with no significant variation in revision rates observed. For the 5-year mark, 1,058 females in 3 hospitals and 214 males in 1 hospital were examined, similarly showing no significant differences. Mortality within 90 days post-operation was also investigated in 5 female and 7 male cohorts, with 2,180 and 2,145 surgeries respectively, yielding no substantial disparities. In conclusion, the RD analysis revealed no notable differences in revision rates at 2 and 5 years or in early mortality based on the fixation method used in THA. These outcomes suggest that the age-based preference for THA fixation may not influence the revision or mortality risk, underscoring the value of RD design in deriving causal insights from observational data

A: - determine the incidence of intraoperative periprosthetic femoral fracture (PFF). B: - determine the incidence of, and the reoperation rate for postoperative PFF. When using either CC or PTS femoral components. Retrospective review of a consecutive series of 11,018 THAs over a ten-year period. All PFFs were identified using regional radiograph archiving and electronic care systems. Of the 11,018 THAs 4,952 were CC and 6,066 were PTS. Between groups, age, sex, and BMI did not differ. A: - 55 (0.5%) had an intraoperative PFF. 44 CC and 11 PTS (p<0.001). 3 patients in each group had a femoral shaft fracture, remaining fractures were either the calcar (20 CC and 2 group) or the greater trochanter (11 CC and 6 PTS). B: - 91(0.8%) sustained a postoperative PFF. Of those 15 were managed conservatively, 15 were revised and 61 (80.3%) had an ORIF. The CC group had both a lower overall rate of postoperative PFFs (0.7% (36/4,952) vs 0.9% (55/6,066); p = 0.341), and a lower rate of return to theatre (0.4% (22/4,952) vs 0.9% (54/6,066); p = 0.005). 1.3% of male PTS (36/2,674) had a reoperation compared to 0.3% of male CC (7/2,121) (p<0.001). With regard to stem fracture there were none in the Corail group and 5 in the Exeter group. Of these 2 were sub trunnion and 3 were basal neck. A: - There were significantly more intraoperative PFFs with CC 44 (0.8%) than PTS 11 (0.2%). However, the majority of fractures were either of the calcar or greater trochanter with no impact on early recovery or one year Oxford scores. B: - Male PTS were five times more likely to have a reoperation for postoperative PFF. Females had the same incidence of reoperation with either component type. There were 5 stem fractures in the Exeter group and none in the Corail. These results represent robust estimates, which are likely to be more accurate than revision only studies typically generated from registry data

Dislocations have impact on quality of life, but it is difficult to quantify this impact for each patient. The Quality-of-Life Time Trade-Off assesses the percentage of a patient's remaining life that the patient would be willing to trade for perfect health [1]. This technique has been used for non-unions [2], but never proposed for dislocation. 154 patients (with 3 recurrent dislocations) undergoing revision were asked to choose between living with their associated dislocation risk or trading a portion of their life expectancy for a period of perfect health without dislocation, thus determining their Quality-of-Life score. This score may range from 0.1 (willing to trade nine years among 10) to 1.0 (unwilling to trade any years). Additionally, patients were assessed on their willingness to trade implant survival time for a reduced risk of dislocation, considering various implant options that might offer lower (but not necessary) survival time before revision than the theoretical best (for the surgeon) “standard” implant, thus determining a “Survival Implant Quality” score. Patients diagnosed with 3 hip dislocations have a low health-related quality of life. The score of our “dislocation” cohort was average 0.77 with patients willing to trade average 23% of remaining lifespan for perfect health (range 48% to 12%). This score is below that (0.88) of illnesses type-I diabetes mellitus [3] and just higher than tibial non-union (0.68) score [2]. The mean “Survival Implant Quality” score of our recurrent dislocation cohort was 0.71 (range 0.59 to 0.78) which means that patients accept to trade average 3 years (range 2 to 4 years) among 10 theoretical years of survival of the implant. Hip dislocation has a devastating impact that can be quantified for each patient when discussing revision and choice of implants for instability. For references, please contact the author directly

Total hip arthroplasty (THA) is often performed in symptomatic patients with developmental dysplasia of the hip (DDH) who do not qualify for periacetabular osteotomy (PAO). The impact of osteoarthritis (OA) severity on postoperative outcomes in DDH patients who undergo THA is not well described. We hypothesized that DDH patients who undergo THA with mild OA have slower initial recovery postoperatively, but similar one-year patient reported outcome measures (PROMs) when compared to DDH patients with severe OA. We performed a retrospective review at a single academic institution over a six-year period of patients with DDH who underwent primary THA and compared them to patients without DDH who underwent THA. Within the DDH cohort, we compared PROMs stratified by DDH severity and OA severity. Diagnosis of DDH was verified using radiographic lateral center edge angle (LCEA). Minimum one-year follow-up was required. PROMs were collected through one-year postoperatively. Logistic and linear regression models were used adjusting for age, sex, body mass index, and Charlson Comorbidity Index. 263 patients with DDH were compared to 1,225 THA patients without DDH. No significant differences were found in postoperative PROMs or revision rates (p=0.49). When stratified by DDH severity, patients with LCEA<10° had worse preoperative pain (p=0.01), mental health (p<0.01) and physical function (p=0.03) scores but no significant difference in postoperative PROMs. Within the DDH group, when stratified by OA severity, patients with Grade 3 Tonnis score had worse preoperative pain (p=0.04) but no significant difference in postoperative PROMs. Recovery curves in DDH patients based upon severity of DDH and OA were not significantly different at 2-weeks, 6-weeks and 1-year. DDH patients who have mild OA have similar recovery curves compared to those with severe OA. THA is reasonable in symptomatic DDH patients who have mild arthritis and do not qualify for PAO

We report the impact of implementing a new short-stay hip and knee arthroplasty pathway in a National Health Service (NHS) hospital. This was enacted due to existing concerns with a long length of stay (LOS) and reduced elective operating capacity each winter due to emergency bed pressures. The overnight introduction of this pathway was aimed to reduce LOS, alleviate bed pressures, minimise readmission rates and generate financial savings, all combining to facilitate full elective activity during the winter. We conducted a prospective study at a regional tertiary arthroplasty centre. The new pathway was introduced across the service overnight. It includes rigorous preoperative optimisation, specific anaesthetic protocols and uniform changes in surgical practice to allow a focus on early mobilization and discharge on the day of surgery where possible. Data collection spanned 17 months, including the initial six months post implementation of the short-stay pathway. LOS data was collected for the full period and data was compared pre- and post-implementation of the new pathway. Patient satisfaction and 30-day readmission data were also collected. There was an immediate and significant decrease in median LOS from 4 days pre-implementation to 1 day post-implementation. Patient satisfaction was high, and the 30-day readmission rate was unchanged (5.95%), with no readmissions directly related to decreased inpatient stay. Financial analyses revealed substantial cost savings due to reduced LOS and the elimination of routine post-operative blood tests, estimated at over £1.6m per year. Elective activity over winter was significantly higher (79%) than in the same time period in the previous year. An acute introduction of a carefully planned and coordinated short-stay hip and knee pathway is safe, cost-effective and popular with patients, but also contributes to increased efficiency in the delivery of elective healthcare in the context of increasing demand and financial constraints in the NHS

Hypermobility Spectrum Disorder (HSD or hEDS) is attributed to a collagen abnormality associated with excessive joint flexibility. Approximately 90% of females with hip dysplasia have hypermobility. Manifestations of hypermobility in various body systems are unique to every patient, affecting different tissues of the body with varying degrees of severity. Our purposes were to identify the manifestations of hypermobility across multiple body systems and to study the recognition of hypermobility in the medical literature of multiple specialties over multiple decades. A literature search of the major medical disciplines for key words associated with HSD was performed. These specialties included gastroenterology, gynecology, neurology, psychiatry, oral-maxillofacial surgery, cardiology, and orthopaedic surgery. A specialty-specific impact factor (IF) score was calculated as the percentage of research articles that referenced hypermobility as a comorbidity over all articles within that specialty. Statistical differences were identified using single factor ANOVA with significance determined at p<0.05. We reviewed many published, specialty-specific manifestations of hypermobility, and describe them. All six non-orthopaedic specialties demonstrated a continually increasing relative IF ratio throughout the study period with a peak impact average of 0.22 (p<0.05 compared with other time ranges). There was a 93.3% overall increase in IF scores from the 1992–1998 period to the most recent period examined (p<0.05). Hypermobility is increasingly recognized as a significant health issue in multiple disciplines. Since dysplasia is associated with approximately 40% of all primary total hip arthroplasty cases, understanding the multi-system manifestations, and broad impact of hypermobility on patients, is relevant for every hip surgeon. We are expanding our research into other medical disciplines, including urology, ophthalmology, dermatology, clinical psychology, and others

Aims

Sagittal plane imbalance (SPI), or asymmetry between extension and flexion gaps, is an important issue in total knee arthroplasty (TKA). The purpose of this study was to compare SPI between kinematic alignment (KA), mechanical alignment (MA), and functional alignment (FA) strategies.

It is not unusual for patients prior to their total hip arthroplasty (THA) to indicate that their symptoms worsen with certain meteorological conditions. However, the prevalence and evolution of weather-related pain (WRP) following THA remain poorly understood. The aim of this study was to investigate the prevalence of WRP both before and after primary THA, to assess the impact of THA on pre-existing WRP, and to identify potential risk factors associated with WRP. An in-person survey was conducted on 442 primary THAs, in 327 consecutive patients at the time of their postoperative follow-up. Each patient was assessed using a questionnaire specifically designed to address weather-related joint pain before and after their THA. The clinical evaluation included patient-reported outcome scores (PROMS). Preoperatively, 17% of THA hips experienced WRP, with 71% achieving complete resolution postoperatively (p < 0.001). In patients with WRP in multiple joints and their hip, the THA failed to alleviate the WRP in 31% of the cases. In addition, 8% of the THA patients developed de-novo WRP after surgery. Although the overall prevalence of WRP in hips post-THA was 12%, the prevalence was 29% in hips with WRP preoperatively and 31% in the hips of patients with WRP in multiple joints as well as their hip. WRP in other joints, the initial diagnosis, body mass index (BMI), and age were correlated with WRP following THA. WRP is not uncommon prior to and after THA. Although THA can effectively alleviate WRP in specific patient populations, it does not universally eliminate preoperative WRP or prevent the emergence of new WRP after surgery

Aims. This aim of this study was to analyze the detection rate of rare pathogens in bone and joint infections (BJIs) using metagenomic next-generation sequencing (mNGS), and the impact of mNGS on clinical diagnosis and treatment. Methods. A retrospective analysis was conducted on 235 patients with BJIs who were treated at our hospital between January 2015 and December 2021. Patients were divided into the no-mNGS group (microbial culture only) and the mNGS group (mNGS testing and microbial culture) based on whether mNGS testing was used or not. Results. A total of 147 patients were included in the no-mNGS group and 88 in the mNGS group. The mNGS group had a higher detection rate of rare pathogens than the no-mNGS group (21.6% vs 10.2%, p = 0.016). However, the mNGS group had lower rates of antibiotic-related complications, shorter hospital stays, and higher infection control rates compared with the no-mNGS group (p = 0.017, p = 0.003, and p = 0.028, respectively), while there was no significant difference in the duration of antibiotic use (p = 0.957). In culture-negative cases, the mNGS group had lower rates of antibiotic-related complications, shorter hospital stays, and a higher infection control rate than the no-mNGS group (p = 0.036, p = 0.033, p = 0.022, respectively), while there was no significant difference in the duration of antibiotic use (p = 0.748). Conclusion. mNGS improves detection of rare pathogens in BJIs. mNGS testing reduces antibiotic-related complications, shortens hospital stay and antibiotic use duration, and improves treatment success rate, benefits which are particularly evident in culture-negative cases. Cite this article: Bone Joint Res 2024;13(8):401–410

Aims

Precise implant positioning, tailored to individual spinopelvic biomechanics and phenotype, is paramount for stability in total hip arthroplasty (THA). Despite a few studies on instability prediction, there is a notable gap in research utilizing artificial intelligence (AI). The objective of our pilot study was to evaluate the feasibility of developing an AI algorithm tailored to individual spinopelvic mechanics and patient phenotype for predicting impingement.

Aims. The escalating demand for medical resources to address spinal diseases as society ages is an issue that requires careful evaluation. However, few studies have examined trends in spinal surgery, especially unscheduled hospitalizations or surgeries performed after hours, through large databases. Our study aimed to determine national trends in the number of spine surgeries in Japan. We also aimed to identify trends in after-hours surgeries and unscheduled hospitalizations and their impact on complications and costs. Methods. We retrospectively investigated data extracted from the Diagnosis Procedure Combination database, a representative inpatient database in Japan. The data from April 2010 to March 2020 were used for this study. We included all patients who had undergone any combination of laminectomy, laminoplasty, discectomy, and/or spinal arthrodesis. Results. This investigation included 739,474 spinal surgeries and 739,215 hospitalizations in Japan. There was an average annual increase of 4.6% in the number of spinal surgeries. Scheduled hospitalizations increased by 3.7% per year while unscheduled hospitalizations increased by 11.8% per year. In-hours surgeries increased by 4.5% per year while after-hours surgeries increased by 9.9% per year. Complication rates and costs increased for both after-hours surgery and unscheduled hospitalizations, in comparison to their respective counterparts of in-hours surgery and scheduled hospitalizations. Conclusion. This study provides important insights for those interested in improving spine care in an ageing society. The swift surge in after-hours spinal surgeries and unscheduled hospitalizations highlights that the medical needs of an increasing number of patients due to an ageing society are outpacing the capacity of existing medical resources. Cite this article: Bone Jt Open 2024;5(8):662–670