Aims. Spinopelvic characteristics influence the hip’s biomechanical behaviour. However, to date there is little knowledge defining what ‘normal’ spinopelvic characteristics are. This study aims to determine how static spinopelvic characteristics change with age and ethnicity among asymptomatic, healthy individuals. Methods. This systematic review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines to identify English studies, including ≥ 18-year-old participants, without evidence of hip or spine pathology or a history of previous surgery or interventional treatment, documenting lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI). From a total of 2,543 articles retrieved after the initial database search, 61 articles were eventually selected for data extraction. Results. When all ethnicities were combined the mean values for LL, SS, PT, and PI were: 47.4° (SD 11.0°), 35.8° (SD 7.8°), 14.0° (SD 7.2°), and 48.8° (SD 10°), respectively. LL, SS, and PT had statistically significant (p < 0.001) changes per decade at: −1.5° (SD 0.3°), −1.3° (SD 0.3°), and 1.4° (SD 0.1°). Asian populations had the largest age-dependent change in LL, SS, and PT compared to any other ethnicity per decade at: −1.3° (SD 0.3°) to −0.5° (SD 1.3°), –1.2° (SD 0.2°) to −0.3° (SD 0.3°), and 1.7° (SD 0.2°) versus 1.1° (SD 0.1°), respectively. Conclusion. Ageing alters the orientation between the spine and pelvis, causing LL, SS, and PT to modify their orientations in a compensatory mechanism to maintain sagittal alignment for balance when standing. Asian populations have the largest degree of age-dependent change to their spinopelvic parameters compared to any other ethnicity, likely due to their lower PI. Cite this article: Bone Joint Res 2023;12(4):231–244

Aims. Pain is the most frequent complaint associated with osteonecrosis of the femoral head (ONFH), but the factors contributing to such pain are poorly understood. This study explored diverse demographic, clinical, radiological, psychological, and neurophysiological factors for their potential contribution to pain in patients with ONFH. Methods. This cross-sectional study was carried out according to the “STrengthening the Reporting of OBservational studies in Epidemiology” statement. Data on 19 variables were collected at a single timepoint from 250 patients with ONFH who were treated at our medical centre between July and December 2023 using validated instruments or, in the case of hip pain, a numerical rating scale. Factors associated with pain severity were identified using hierarchical multifactor linear regression. Results. Regression identified the following characteristics as independently associated with higher pain score, after adjustment for potential confounders: Association Research Circulation Osseous classification stage IIIa or IIIb, bone marrow oedema, grade 3 joint effusion, as well as higher scores on pain catastrophizing, anxiety, and central sensitization. The final model explained 69.7% of observed variance in pain scores, of which clinical and radiological factors explained 37%, while psychological and neurophysiological factors explained 24% and demographic factors explained 8.7%. Conclusion. Multidimensional characteristics jointly contribute to the severity of pain associated with ONFH. These findings highlight the need to comprehensively identify potential contributors to pain, and to personalize management and treatment accordingly. Cite this article: Bone Joint Res 2024;13(11):673–681

Aim. The localization of sequestrum in chronic osteomyelitis (COM) is crucial in preoperative planning. The identification of sequestrum on plain X-ray could be difficult. CT and MRI were reported to show the sequestrum. We aimed to analyze the sequestrum characteristics on 18F-FDG-PET-CT images. Methods. A prospective study included all patients diagnosed with long-bone chronic osteomyelitis. All patients had preoperative 18F-FDG-PET-CT. Images were analyzed using RadiAnt DICOM Viewer. Axial cuts were used to measure the Standard Uptake Ratio (SUV)max in the Region of Interest (ROI) in the sequestrum, the surrounding area, and the normal bone in the same cut. Surgical debridement was done as standard; samples were taken for microbiology and histopathology, and the intraoperative finding was documented. Results. Nineteen patients (17 males/2 females) were operated on in one center between October/2021 and Jan/2023 at a mean age of 32±18. There were 10 tibias, 7 femurs, one ulna, and one fibula. Ten had postoperative COM, six open fractures, and three hematogenous OM. They all showed sequestrum on PET-CT; the dead bone appeared void, surrounded by a halo of increased uptake. There was a trend of lower uptake in the sequestrum compared to the halo around. The mean SUVmax at the sequestrum was 4.18±3.16, compared to the surrounding halo, 7.08±5.81. The normal bone has a mean SUVmax of 1.61±1.42. Sequestrum was removed successfully in all cases. Conclusion. 18F-FDG-PET-CT can precisely localize the sequestrum preoperatively, it has a lower uptake than tissues around it. This would facilitate planning and improve the quality of debridement

Aims. This study aims to answer the following questions in patients with hip osteoarthritis (OA) who underwent total hip arthroplasty (THA): are patient-reported outcome measures (PROMs) affected by the location of the maximum severity of pain?; are PROMs affected by the presence of non-groin pain?; are PROMs affected by the severity of pain?; and are PROMs affected by the number of pain locations?. Methods. We reviewed 336 hips (305 patients) treated with THA for hip OA from December 2016 to November 2019 using pain location/severity questionnaires, modified Harris Hip Score (mHHS), Hip Outcome Score (HOS), international Hip Outcome Tool (iHOT-12) score, and radiological analysis. Descriptive statistics, analysis of covariance (ANCOVA), and Spearman partial correlation coefficients were used. Results. There was a significant difference in iHOT-12 scores between groups experiencing the most severe pain in the groin and the trochanter (p = 0.039). Additionally, more favourable mHHS scores were related to the presence of preoperative pain in trochanter (p = 0.049), lower back (p = 0.056), lateral thigh (p = 0.034), and posterior thigh (p = 0.005). Finally, the maximum severity of preoperative pain and number of pain locations had no significant relationship with PROMs (maximum severity: HHS: p = 0.928, HOS: p = 0.163, iHOT-12 p = 0.233; number of pain locations: HHS: p = 0.211; HOS: p = 0.801; iHOT-12: p = 0.112). Conclusion. Although there was a significant difference in iHOT-12 scores between patients with the most severe pain in the groin or trochanter, and the presence of pain in the trochanter, lower back, lateral thigh, or posterior thigh was related to higher mHHS scores, the majority of preoperative pain characteristics did not have a significant impact on outcomes. Therefore, a broad array of patients with hip OA might expect similar, favourable outcomes from THA notwithstanding preoperative pain characteristics. Cite this article: Bone Jt Open 2022;3(4):332–339

Aims. The new COVID-19 variant was reported by the authorities of the UK to the World Health Organization (WHO) on 14 December 2020. We aim to describe the clinical characteristics and nosocomial infection rates in major trauma and orthopaedic patients comparing the first and second wave of COVID-19 infection. Methods. A retrospective analysis of a prospectively collected trauma database was reviewed at a level 1 major trauma centre from 1 December 2020 to 18 February 2021 looking at demographics, clinical characteristics, and nosocomial infections and compared to our previously published first wave data (26 January 2020 to 14 April 2020). Results. From 1 December 2020 to 18 February 2021, 522 major trauma patients were identified with a mean age of 54.6 years, and 53.4% (n = 279) were male. Common admissions were falls (318; 60.9%) and road traffic accidents (RTAs; 71 (13.6%); 262 of these patients (50.2%) had surgery. In all, 75 patients (14.4%) tested positive for COVID-19, of which 51 (68%) were nosocomial. Surgery on COVID-19 patients increased to 46 (61.3%) in the second wave compared to 13 (33.3%) in the first wave (p = 0.005). ICU admissions of patients with COVID-19 infection increased from two (5.1%) to 16 (20.5%), respectively (p = 0.024). Second wave mortality was 6.1% (n = 32) compared to first wave of 4.7% (n = 31). Cardiovascular (CV) disease (35.9%; n = 14); p = 0.027) and dementia (17.9%; n = 7); p = 0.030) were less in second wave than the first. Overall, 13 patients (25.5%) were Black, Asian and Minority ethnic (BAME), and five (9.8%) had a BMI > 30 kg/m. 2. The mean time from admission to diagnosis of COVID-19 was 13.9 days (3 to 44). Overall, 12/75 (16%) of all COVID-19 patients died. Conclusion. During the second wave, COVID-19 infected three-times more patients. There were double the number of operative cases, and quadruple the cases of ICU admissions. The patients were younger with less dementia and CV disease with lower mortality. Concomitant COVID-19 and the necessity of major trauma surgery showed 13% mortality in the second wave compared with 15.4% in the first wave. In contrast to the literature, we showed a high percentage of nosocomial infection, normal BMI, and limited BAME infections. Cite this article: Bone Jt Open 2021;2(8):661–670

Aims. This study evaluates risk factors influencing fracture characteristics for postoperative periprosthetic femoral fractures (PFFs) around cemented stems in total hip arthroplasty. Methods. Data were collected for PFF patients admitted to eight UK centres between 25 May 2006 and 1 March 2020. Radiographs were assessed for Unified Classification System (UCS) grade and AO/OTA type. Statistical comparisons investigated relationships by age, gender, and stem fixation philosophy (polished taper-slip (PTS) vs composite beam (CB)). The effect of multiple variables was estimated using multinomial logistic regression to estimate odds ratios (ORs) with 95% confidence intervals (CIs). Surgical treatment (revision vs fixation) was compared by UCS grade and AO/OTA type. Results. A total of 584 cases were included. Median age was 79.1 years (interquartile range 72.0 to 86.0), 312 (53.6%) patients were female, and 495 (85.1%) stems were PTS. The commonest UCS grade was type B1 (278, 47.6%). The most common AO/OTA type was spiral (352, 60.3%). Metaphyseal split fractures occurred only with PTS stems with an incidence of 10.1%. Male sex was associated with a five-fold reduction in odds of a type C fracture (OR 0.22 (95% CI 0.12 to 0.41); p < 0.001) compared to a type B fracture. CB stems were associated with significantly increased odds of transverse fracture (OR 9.51 (95% CI 3.72 to 24.34); p < 0.001) and wedge fracture (OR 3.72 (95% CI 1.16 to 11.95); p = 0.027) compared to PTS stems. Both UCS grade and AO/OTA type differed significantly (p < 0.001 and p = 0.001, respectively) between the revision and fixation groups but a similar proportion of B1 fractures underwent revision compared to fixation (45.3% vs 50.6%). Conclusion. The commonest fracture types are B1 and spiral fractures. PTS stems are exclusively associated with metaphyseal split fractures, but their incidence is low. Males have lower odds of UCS grade C fractures compared to females. CB stems have higher odds of bending type fractures (transverse and wedge) compared to PTS stems. There is considerable variation in practice when treating B1 fractures around cemented stems. Cite this article: Bone Jt Open 2021;2(7):466–475

Objectives. Mesenchymal stem cells (MSCs) are of growing interest in terms of bone regeneration. Most preclinical trials utilize bone-marrow-derived mesenchymal stem cells (bMSCs), although this is not without isolation and expansion difficulties. The aim of this study was: to compare the characteristics of bMSCs and adipose-derived mesenchymal stem cells (AdMSCs) from juvenile, adult, and ovarectomized (OVX) rats; and to assess the effect of human parathyroid hormone (hPTH) 1-34 on their osteogenic potential and migration to stromal cell-derived factor-1 (SDF-1). Methods. Cells were isolated from the adipose and bone marrow of juvenile, adult, and previously OVX Wistar rats, and were characterized with flow cytometry, proliferation assays, osteogenic and adipogenic differentiation, and migration to SDF-1. Experiments were repeated with and without intermittent hPTH 1-34. Results. Juvenile and adult MSCs demonstrated significantly increased osteogenic and adipogenic differentiation and superior migration towards SDF-1 compared with OVX groups; this was the case for AdMSCs and bMSCs equally. Parathyroid hormone (PTH) increased parameters of osteogenic differentiation and migration to SDF-1. This was significant for all cell types, although it had the most significant effect on cells derived from OVX animals. bMSCs from all groups showed increased mineralization and migration to SDF-1 compared with AdMSCs. Conclusion. Juvenile MSCs showed significantly greater migration to SDF-1 and significantly greater osteogenic and adipogenic differentiation compared with cells from osteopenic rats; this was true for bMSCs and AdMSCs. The addition of PTH increased these characteristics, with the most significant effect on cells derived from OVX animals, further illustrating possible clinical application of both PTH and MSCs in bone regenerative therapies. Cite this article:L. Osagie-Clouard, A. Sanghani-Kerai, M. Coathup, R. Meeson, T. Briggs, G. Blunn. The influence of parathyroid hormone 1-34 on the osteogenic characteristics of adipose- and bone-marrow-derived mesenchymal stem cells from juvenile and ovarectomized rats. Bone Joint Res 2019;8:397–404. DOI: 10.1302/2046-3758.88.BJR-2019-0018.R1

Aims. The aim of this study was to identify the effect of the manufacturing characteristics of polyethylene acetabular liners on the survival of cementless and hybrid total hip arthroplasty (THA). Methods. Prospective cohort study using linked National Joint Registry (NJR) and manufacturer data. The primary endpoint was revision for aseptic loosening. Cox proportional hazard regression was the primary analytical approach. Manufacturing variables included resin type, crosslinking radiation dose, terminal sterilization method, terminal sterilization radiation dose, stabilization treatment, total radiation dose, packaging, and face asymmetry. Total radiation dose was further divided into G1 (no radiation), G2 (> 0 Mrad to < 5 Mrad), G3 (≥ 5 Mrad to < 10 Mrad), and G4 (≥ 10 Mrad). Results. A total of 5,329 THAs were revised, 1,290 of which were due to aseptic loosening. Total radiation dose, face asymmetry, and stabilization treatments were found to significantly affect implant survival. G1 had the highest revision risk for any reason and for aseptic loosening and G3 and G4 the lowest. Compared with G1, the adjusted hazard ratio for G2 was 0.74 (95% confidence interval (CI) 0.64 to 0.86), G3 was 0.36 (95% CI 0.30 to 0.43), and G4 was 0.38 (95% CI 0.31 to 0.47). The cumulative incidence of revision for aseptic loosening at 12 years was 0.52 and 0.54 per 100 THAs for G3 and G4, respectively, compared with 1.95 per 100 THAs in G1. Asymmetrical liners had a lower revision risk due to aseptic loosening and reasons other than aseptic loosening compared with symmetric (flat) liners. In G3 and G4, stabilization with vitamin E and heating above melting point performed best. Conclusion. Polyethylene liners with a total radiation dose of ≥ 5 Mrad, an asymmetrical liner face, and stabilization with heating above the melting point demonstrate best survival. Cite this article: Bone Joint J 2020;102-B(1):90–101

Aims. The first death in the UK caused by COVID-19 occurred on 5 March 2020. We aim to describe the clinical characteristics and outcomes of major trauma and orthopaedic patients admitted in the early COVID-19 era. Methods. A prospective trauma registry was reviewed at a Level 1 Major Trauma Centre. We divided patients into Group A, 40 days prior to 5 March 2020, and into Group B, 40 days after. Results. A total of 657 consecutive trauma and orthopaedic patients were identified with a mean age of 55 years (8 to 98; standard deviation (SD) 22.52) and 393 (59.8%) were males. In all, 344 (approximately 50%) of admissions were major trauma. Group A had 421 patients, decreasing to 236 patients in Group B (36%). Mechanism of injury (MOI) was commonly a fall in 351 (52.4%) patients, but road traffic accidents (RTAs) increased from 56 (13.3%) in group A to 51 (21.6%) in group B (p = 0.030). ICU admissions decreased from 26 (6.2%) in group A to 5 (2.1%) in group B. Overall, 39 patients tested positive for COVID-19 with mean age of 73 years (28 to 98; SD 17.99) and 22 (56.4%) males. Common symptoms were dyspnoea, dry cough, and pyrexia. Of these patients, 27 (69.2%) were nosocomial infections and two (5.1%) of these patients required intensive care unit (ICU) admission with 8/39 mortality (20.5%). Of the patients who died, 50% were older and had underlying comorbidities (hypertension and cardiovascular disease, dementia, arthritis). Conclusion. Trauma admissions decreased in the lockdown phase with an increased incidence of RTAs. Nosocomial infection was common in 27 (69.2%) of those with COVID-19. Symptoms and comorbidities were consistent with previous reports with noted inclusion of dementia and arthritis. The mortality rate of trauma and COVID-19 was 20.5%, mainly in octogenarians, and COVID-19 surgical mortality was 15.4%. Cite this article: Bone Joint Open 2020;1-7:330–338

Aims

This study examined the relationship between obesity (OB) and osteoporosis (OP), aiming to identify shared genetic markers and molecular mechanisms to facilitate the development of therapies that target both conditions simultaneously.

Introduction: In children with MMC characteristic kinematic gait patterns and center of mass motion have been identified for different lumbo-sacral levels, which may vary in specific muscle paresis definitions and ambulatory outcome. The goal was to investigate compensatory movements employed in MMC in groups with successive paresis in the following major muscle groups: plantarflexors, dorsiflexors, hip abductors and hip extensors. Patients and Methods: 28 children with MMC (m=10.3 y), walking independently participated in a gait study. A classification based on paresis on the primary muscle groups was established using standard Manual Muscle Test (MMT). Five groups of MMC were established based on successive paresis (0-2 MMT) of the plantarflexors,dor-siflexors, hip abductors, and hip extensors. Subjects were tested in their habitual orthoses, if any. All children underwent full-body three-dimensional gait analysis (VICON, Oxford). Five kinematic cycles from each side were analyzed and group averages were calculated. Results: The most striking compensatory movements were observed in the frontal and transverse planes in the trunk, pelvis, and hips. Trunk sway increased sequentially from Groups 1 to 5, with the largest interval occurring at the onset of hip abductor paresis (Group 4). Trunk and pelvic rotation were observed to completely alter at the onset of hip abductor paresis (Group 4), where an internal position occurs during stance and external during swing. ‘Pelvic hike,’ or the lifting of the pelvis during swing, was observed in as early as Group 2 with plantarflexor paresis, becoming more pronounced in the latter groups. Large hip abduction was observed during stance at the onset of hip abductor paresis (Group 4). The onset of dorsiflexor paresis result in few kinematic changes since all subjects in Groups 2 and 3 wore orthoses. Sagittal plane differences were observed at the onset of hip extensor paresis (Group 5), where the trunk and pelvis were more posteriorly tipped and hips less flexed. Discussion The classification method aids in understanding the specific compensatory mechanisms employed when the muscle functions are successively lost. Plantarflexor paresis is evident in all three planes in even the trunk. Abductor weakness results in large frontal and transverse plane changes. Hip extensor weakness is mostly evident in the sagittal plane. By understand-ingthe characteristic movements employed, an improved basis for evaluation and treatment can be established

Purpose. In children presenting with irritable hip symptoms we wished to determine the incidence of hip septic arthritis, pathogen characteristics and the functional outcome. Methods. Between May 2007 and January 2010, children presenting to our institution with irritable hip symptoms were eligible to participate. Exclusion criteria were history of trauma to the hip, systemic inflammatory diseases. Data collected included; demographics, clinical symptoms, temperature, haematological profile, ultrasound and culture reports, microorganism isolated and outcome. The minimum follow up was 6 months (6–24). Results. Out of 210 children, 199 (135 males) met the inclusion criteria (mean age 5.3 years (0.15–15)). On U/S 72 children had a positive result for hip effusion. 60 children required admission and 41 cases had arthrotomy and washout, with a mean WCC of 10.4 × 10∗9/L (4.85–15.8) and CRP of 118(< 5 to 312). The mean length of hospital stay was 4.4 days (1–32). 25 of the samples cultured showed no growth, 3 of which were positive for gram+cocci on staining. The remaining 16 grew staphylococcus aureus, sensitive to flucloxacillin. 4 cases had positive radiological signs of disease sequelae on follow-up imaging (1 grade II heterotrophic ossification of the hip, 1 minor degenerative changes and 2 major avascular necrosis of the femoral head). Functional sparing was common among this group of cases with preservation of excellent function in all but the 2 cases with major avascular necrosis, which had good/fair function, with 1 and 1.5cm leg length discrepancy. Conclusion. Of 210 consecutive patients, 41 (20.6%) cases required hip arthrotomy and 19 (9.5%) had a positive culture with 2 cases of functional limitation. The most common pathogen isolated was staph. aureous. K. kingae species, which cannot be cultured by standard methods, was isolated from 1 case, highlighting the need for culturing hip aspirates in blood vials in all cases

Introduction: The annual fatalities from the road traffic accidents were relatively stable over the last decade. However over the same period there is noticeable shift in the effect of passenger vehicle rollover crashes on this total. This study looks into the injury characteristics in rollover car crashes utilizing the National Automotive Sampling System (NASS) database. Aim: To describe the regional distribution of the injury pattern in the rollover crashes, and identify the main cause of death in fatal cases according to body region. Methods: Retrospective analysis of the NASS database during the period of 1997–2002 was analysed. Only the car model from year 2002 was included in this study. The regional body distribution was classified as follows. Head and Neck. Thorax. Abdomen. Upper limbs. Lower limbs. The total number of occupants involved, age range of drivers, and detailed descriptions of the injuries sustained were described. Results: There were total of 155 occupants involved in 88 roll over car crashes. The age range of the occupants was 7 months to 84 years. The drivers age range was 15 years – 84 years. There were 50 male drivers, and 38 female drivers. The body region most commonly involved was Head and neck followed by upper extremity. There were 33 fatalities and the main cause of fatality was injury to the brain, accounting for 54.5%. The distributions of injuries were. Head and neck- 93 (60%). Thorax- 37 (23.8%). Abdomen-24 (15.4%). Upper limbs- 73 (47%). Lower limbs- 53 (34%). Conclusion: Rollover crashes are becoming increasingly common due to increase demands of sport utility vehicles. There is a significant number of fatalities. Majority of the occupants sustained multiple injuries. However, the most common body region involved after roll over crashes was head and neck. The young male drivers are more vulnerable group. Improvement of the safety features in new vehicle design should take into account of this body region

Background. The factors that are considered to be associated with successful clinical outcome fallowing cervical arthroplasty surgery are patient selection, absence of facet joint changes and lack of pre-operative kyphosis. Even though many studies have cited the pre-operative demographic details of their patient groups, the effect of associated psychological co-morbidities (Depression/Anxiety), smoking history, gender, social benefits and employment status on the clinical outcome measures have not been reported. The aim of the study was to assess the influence of pre-operative patient characteristics on the clinical outcomes following cervical disc replacement. Methods. We included 126 patients who underwent single or multiple level cervical arthroplasty in our unit were included in the study. The clinical outcome measures such as Visual Analogue Score for neck pain (VAS-NP) and arm pain (VAS-AP); Neck disability Index (NDI), Hospital depression and anxiety scale and Bodily pain component of Short Form 36 questionnaires (SF-36 P) were recorded pre and post operatively. Statistical analysis was completed using SPSS 16.0 statistical package (SPSS Inc, Chicago, IL). Results. There were 60 males and 63 females. Average duration of follow up was 18 months (Range 10–51). Out of 123 patients, 37 patients had a history of anxiety/depression, 25 patients gave history of smoking, 64 were actively working at the time of operation and 27 were receiving social benefits. We have found that gender; smoking status, associated co-morbidities, working and benefit status had no statistically significant contribution to clinical outcome measures in the follow up period. Conclusion. This is has been a first ever attempt to analyse the affect these psychosocial factors on the clinical outcomes following cervical arthroplasty. In our study, contrary to studies related lumbar surgeries, we conclude that there is no statistically significant contribution of associated psychosocial factors on the clinical outcomes in the early follow up period

Aims. Disease transmission, availability and economic costs of allograft have resulted in significant efforts into finding an allograft alternative for use in impaction bone grafting (IBG). Biotechnology offers the combination of skeletal stem cells (SSC) with biodegradable polymers as a potential solution. Recently polymers have been identified with both structural strength and SSC compatibility that offer the potential for clinical translation. The aim of this study was to assess whether increasing the porosity of one such polymer via super critical CO. 2. fluid foaming (SCF) enhanced the mechanical and cellular compatibility characteristics for use as an osteogenic alternative to allograft in IBG. Methods. High molecular weight PLA scaffolds were produced via traditional (solid block) and SCF (porous) techniques, and the differences characterised using scanning electron microscopy (SEM). The polymers were milled, impacted, and mechanical comparison between traditional vs SCD created scaffolds and allograft controls was made using a custom shear testing rig, as well as a novel agitation test to assess cohesion. Cellular compatibility tests for cell number, viability and osteogenic differentiation using WST-1 assays, fluorostaining and ALP assays were determined following 14 day culture with SSC's. Results. SEM showed increased porosity of the SCF produced PLA scaffolds, with pores between 50–100µm. Shear testing showed the SCF polymer exceeded the shear strength of allograft controls (P< 0.001). Agitation testing showed greater cohesion between the particles of the SCF polymer (P< 0.05). Cellular studies showed increased cell number, viability and osteogenic differentiation on the SCF polymer compared to traditional polymer (P< 0.05) and allograft (P< 0.001). Conclusions. The use of supercritical C0. 2. to generate PLA scaffolds significantly improves the cellular compatibility and cohesion compared to traditional non-porous PLA, without substantial loss of mechanical shear strength. The improved characteristics are critical for clinical translation as a potential osteogenic composite for use in IBG

Aim

To analyse the available rotating hinge knee implants available on the market with a view to deriving a rational algorithm for implant selection.

Classification systems for tibial plateau fractures suffer from poor interobserver agreement, and their value in preoperative assessment to guide surgical fixation strategies is limited. For tibial plateau fractures four major characteristics are identified: lateral split fragment, posteromedial fragment, anterior tubercle fragment, and central zone of comminution. These fracture characteristics support preoperative assessment of fractures and guide surgical decision-making as each specific component requires a respective fixation strategy. We aimed to evaluate the additional value of 3D-printed models for the identification of tibial plateau fracture characteristics in terms of the interobserver agreement on different fracture characteristics. Preoperative images of 40 patients were randomly selected. Nine trauma surgeons, eight senior and eight junior registrars indicated the presence or absence of four fracture characteristics with and without 3D-printed models. The Fleiss kappa was used to determine interobserver agreement for fracture classification and for interpretation, the Landis and Koch criteria were used. 3D-printed models lead to a categorical improvement in interobserver agreement for three of four fracture characteristics: lateral split (Kconv = 0.445 versus K3Dprint = 0.620; P < 0.001), anterior tubercle fragment (Kconv = 0.288 versus K3Dprint = 0.449; P < 0.001) and zone of comminution (Kconv = 0.535 versus K3Dprint = 0.652; P < 0.001). The overall interobserver agreement improved for three of four fracture characteristics after the addition of 3D printed models. For two fracture characteristics, lateral split and zone of comminution, a substantial interobserver agreement was achieved. Fracture characteristics seem to be a more reliable way to assess tibial plateau fractures and one should consider including these in the preoperative assessment of tibial plateau fractures compared to the commonly used classification systems

Aims. It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA. Methods. In 52 THAs performed between November 2018 and April 2022, the acoustic parameters of the hammering sound of 224 impacts of successful press-fit fixation, and 55 impacts of unsuccessful press-fit fixation, were analyzed. The successful fixation was defined if the following two criteria were met: 1) intraoperatively, the stability of the cup was retained after manual application of the torque test; and 2) at one month postoperatively, the cup showed no translation on radiograph. Each hammering sound was converted to sound pressures in 24 frequency bands by fast Fourier transform analysis. Basic patient characteristics were assessed as potential contributors to the hammering sound. Results. The median sound pressure (SP) of successful fixation at 0.5 to 1.0 kHz was higher than that of unsuccessful fixation (0.0694 (interquartile range (IQR) 0.04721 to 0.09576) vs 0.05425 (IQR 0.03047 to 0.06803), p < 0.001). The median SP of successful fixation at 3.5 to 4.0 kHz and 4.0 to 4.5 kHz was lower than that of unsuccessful fixation (0.0812 (IQR 0.05631 to 0.01161) vs 0.1233 (IQR 0.0730 to 0.1449), p < 0.001; and 0.0891 (IQR 0.0526 to 0.0891) vs 0.0885 (IQR 0.0716 to 0.1048); p < 0.001, respectively). There was a statistically significant positive relationship between body weight and SP at 0.5 to 1.0 kHz (p < 0.001). Multivariate analyses indicated that the SP at 0.5 to 1.0 kHz and 3.5 to 4.0 kHz was independently associated with the successful fixation. Conclusion. The frequency bands of 0.5 to 1.0 and 3.5 to 4.0 kHz were the key to distinguish the sound characteristics between successful and unsuccessful press-fit cup fixation. Cite this article: Bone Jt Open 2024;5(3):154–161

Aims. It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA. Methods. In 52 THAs performed between November 2018 and April 2022, the acoustic parameters of the hammering sound of 224 impacts of successful press-fit fixation, and 55 impacts of unsuccessful press-fit fixation, were analyzed. The successful fixation was defined if the following two criteria were met: 1) intraoperatively, the stability of the cup was retained after manual application of the torque test; and 2) at one month postoperatively, the cup showed no translation on radiograph. Each hammering sound was converted to sound pressures in 24 frequency bands by fast Fourier transform analysis. Basic patient characteristics were assessed as potential contributors to the hammering sound. Results. The median sound pressure (SP) of successful fixation at 0.5 to 1.0 kHz was higher than that of unsuccessful fixation (0.0694 (interquartile range (IQR) 0.04721 to 0.09576) vs 0.05425 (IQR 0.03047 to 0.06803), p < 0.001). The median SP of successful fixation at 3.5 to 4.0 kHz and 4.0 to 4.5 kHz was lower than that of unsuccessful fixation (0.0812 (IQR 0.05631 to 0.01161) vs 0.1233 (IQR 0.0730 to 0.1449), p < 0.001; and 0.0891 (IQR 0.0526 to 0.0891) vs 0.0885 (IQR 0.0716 to 0.1048); p < 0.001, respectively). There was a statistically significant positive relationship between body weight and SP at 0.5 to 1.0 kHz (p < 0.001). Multivariate analyses indicated that the SP at 0.5 to 1.0 kHz and 3.5 to 4.0 kHz was independently associated with the successful fixation. Conclusion. The frequency bands of 0.5 to 1.0 and 3.5 to 4.0 kHz were the key to distinguish the sound characteristics between successful and unsuccessful press-fit cup fixation. Cite this article: Bone Jt Open 2024;4(3):154–161

Aims. In this study, we aimed to visualize the spatial distribution characteristics of femoral head necrosis using a novel measurement method. Methods. We retrospectively collected CT imaging data of 108 hips with non-traumatic osteonecrosis of the femoral head from 76 consecutive patients (mean age 34.3 years (SD 8.1), 56.58% male (n = 43)) in two clinical centres. The femoral head was divided into 288 standard units (based on the orientation of units within the femoral head, designated as N[Superior], S[Inferior], E[Anterior], and W[Posterior]) using a new measurement system called the longitude and latitude division system (LLDS). A computer-aided design (CAD) measurement tool was also developed to visualize the measurement of the spatial location of necrotic lesions in CT images. Two orthopaedic surgeons independently performed measurements, and the results were used to draw 2D and 3D heat maps of spatial distribution of necrotic lesions in the femoral head, and for statistical analysis. Results. The results showed that the LLDS has high inter-rater reliability. As illustrated by the heat map, the distribution of Japanese Investigation Committee (JIC) classification type C necrotic lesions exhibited clustering characteristics, with the lesions being concentrated in the northern and eastern regions, forming a hot zone (90% probability) centred on the N4-N6E2, N3-N6E units of outer ring blocks. Statistical results showed that the distribution difference between type C2 and type C1 was most significant in the E1 and E2 units and, combined with the heat map, indicated that the spatial distribution differences at N3-N6E1 and N1-N3E2 units are crucial in understanding type C1 and C2 necrotic lesions. Conclusion. The LLDS can be used to accurately measure the spatial location of necrotic lesions and display their distribution characteristics. Cite this article: Bone Joint Res 2024;13(6):294–305