Search Results (182)

Birmingham hip resurfacing (BHR) is an alternative to bone-sparing total hip arthroplasty; however, failures may be associated with the cementing technique. This study aimed to evaluate the characteristics of the cement layer and potential failure mechanisms. BHR explants were analyzed using radiographic evaluation, stereomicroscopy, scanning electron microscopy (SEM), and histopathology. The cement layer was nonuniform, with excessive thickness in the dome regions and insufficient lateral coverage. Increased cement penetration values exceeded recommended thresholds. SEM analysis revealed inhomogeneous cement with cracks, air inclusions, and loosening at the cement–prosthesis interface. BHR failure may be associated with a complex interplay between cementation parameters, cement mantle morphology, and the biological response at the bone–cement interface, as well as interactions at the cement–prosthesis interface. Microscopic evaluation may provide valuable insights into the mechanisms potentially contributing to BHR prosthesis failure. Full article

Background/Objectives: Periprosthetic joint infection (PJI) of the hip remains a challenging complication, particularly in elderly patients who may not tolerate repeated invasive procedures. While two-stage, one-stage, and 1.5-stage revisions are established strategies, an optimal approach for elderly patients with a well-fixed femoral stem remains unclear. This study evaluated the clinical outcomes of partial two-stage revision with femoral stem retention in elderly patients with hip PJI. Methods: A retrospective review was conducted of patients aged 65 years or older who underwent two-stage revision for hip PJI without femoral stem extraction at a single institution and had a minimum follow-up of one year after the final treatment. Patients were treated with aggressive debridement, removal of all components except the femoral stem, and placement of an antibiotic-loaded cement spacer and beads. Clinical outcomes, infection eradication, complications, and functional status were assessed. Results: Twenty-eight patients (28 hips) were included, with a mean age of 79.5 years and a mean follow-up of 46.2 months. The index arthroplasty was hemiarthroplasty in most cases (92.9%). Seventeen patients completed a second-stage revision, while 11 remained with cement spacer retention. Infection control was achieved in all patients (100%) at final follow-up, with initial infection control achieved in 96.4%. No recurrence of infection was observed in either group. Multidrug-resistant organisms were identified in 67.9% of cases. Functional outcomes were acceptable, and no stem-related complications or reinfections occurred. Conclusions: Partial two-stage revision with femoral stem retention provided effective infection control and acceptable functional outcomes in elderly patients with hip PJI. This approach may be considered a reasonable treatment option for elderly patients with a well-fixed femoral stem when reducing surgical invasiveness is an important consideration. Full article

This study presents a fully automatic hybrid framework for circle detection and geometric feature extraction from anteroposterior (AP) X-ray images. Detecting circular structures in X-ray imagery is challenging due to low contrast, noise, and metal-induced artifacts, which often limit the robustness of purely learning-based or purely geometric approaches. To address these challenges, a hybrid deep learning and computer vision pipeline is proposed that combines data-driven region localization with robust geometric fitting. A YOLOv5-based detector is first employed to identify a compact region of interest (ROI) containing circular components. Within this ROI, edge-based processing using Canny detection is applied, followed by an Edge-Snap refinement stage and robust RANSAC-based circle fitting with a Hough-transform fallback to ensure anatomically plausible circle estimation. The resulting circle centers and radii provide stable geometric parameters that can be consistently extracted across images with varying contrast, noise levels, and prosthesis appearances. The applicability of the proposed framework is demonstrated through a case study on hip prosthesis wear analysis, where the automatically detected circle parameters are used to compute medial, superior, and resultant displacement components using established two-dimensional radiographic formulations. Experimental evaluation on AP hip radiographs shows that the YOLOv5 detector achieves high ROI localization performance (mAP@0.5 = 0.971) and that the hybrid pipeline produces consistent circle parameters across longitudinal image sequences. Overall, the proposed method provides an end-to-end automatic solution for robust circle detection in X-ray imagery, with hip prosthesis wear presented solely as a case study without clinical or diagnostic claims. Full article

Background and aim: Artificial intelligence (AI) is gaining increasing relevance in orthopaedic surgery, particularly in prosthetic surgery, due to its ability to support preoperative planning through advanced imaging analysis, implant size prediction, and outcome forecasting. However, recent literature shows considerable variability in employed models, evaluated outcomes, and clinical applicability. The objective of this scoping review is to map AI applications in preoperative planning for orthopaedic arthroplasties and to assess their impact on radiographic and clinical outcomes, also discussing key ethical and medicolegal implications within both Italian and international contexts. Materials and methods: A literature review was conducted following scoping review methodology. The bibliographic search (10 September 2025) was performed in PubMed and Scopus using the query “preoperative planning WITH artificial intelligence AND prosthesis orthopaedic surgery AND outcomes”, restricted to the years 2020–2025, English-language studies, and research focused specifically on real-world AI techniques applied to preoperative planning in prosthetic surgery, reporting radiographic and/or clinical outcomes related to planning. Exclusion criteria included intra/postoperative studies, non-orthopaedic applications, robotic surgery, studies lacking clinical outcomes, case reports, and articles without full-text availability. After PRISMA screening and selection, 42 primary studies were included. Results: Of the 42 studies included, 20 focused on the hip, 19 on the knee, and 3 on the shoulder. Available evidence indicates that AI may improve templating accuracy and prosthetic component positioning, with more robust results in hip and knee arthroplasty, while applications in shoulder arthroplasty remain emerging. Nonetheless, important methodological limitations persist, including algorithm heterogeneity. Discussion: Overall, the findings suggest a promising role for AI in preoperative planning; however, the heterogeneity and variable quality of the evidence call for caution in interpretation and highlight the need for more rigorous prospective research. These considerations also carry relevant medicolegal implications, as the reliability and standardisation of AI-based tools represent essential prerequisites for their safe and conscious integration within diverse regulatory frameworks. Conclusions: AI appears to be a promising tool in the preoperative planning of orthopaedic arthroplasties, although further clinical validation and methodological standardisation are required. The evidence gathered also provides a useful foundation for addressing the associated medicolegal and regulatory implications, particularly in light of evolving Italian and European regulations and their differences from U.S. models. Full article

Background: The objective of this study was to evaluate the short-term clinical and radiological outcomes of a conservative cementless stem (Minima) in total hip arthroplasty (THA) for patients presenting with a narrow femoral canal. Methods: We retrospectively analyzed 18 patients (18 THAs) who received a size 1 Minima stem between 2018 and 2022. Clinical assessment was performed using the Harris Hip Score (HHS). Radiological evaluation focused on stem migration, trabecular bone development, cortical hypertrophy, and the presence of radiolucent or reactive lines. Implant survival was determined using Kaplan–Meier analysis. Results: The mean patient age was 51.6 years, with an average follow-up of 57 months. The mean HHS improved significantly from 38.3 preoperatively to 96.4 at the final evaluation (p < 0.001). Initial stem migration occurred in two hips (11.1%) within the first 6 postoperative months, with no further progression or loosening observed thereafter. Bony trabecular development was identified in Gruen zones 3 (27.8%), 4 (5.5%), and 5 (16.7%). Reactive lines were present around four stems (zones 3–5). One intraoperative complication (5.5%) occurred (acetabular component migration during trial reduction), which required screw fixation. No revisions were performed. Both clinical and radiological implant survival at the final follow-up was 100.0%. Conclusions: At a mean follow-up of 57 months, the use of the size 1 Minima stem in patients with a narrow femoral canal demonstrated excellent clinical and radiological outcomes. These findings suggest that this conservative stem is a reliable option for this specific patient population. Full article

Background and objectives: The increasing volume of total hip and knee arthroplasty created a significant postoperative surveillance burden. While plain radiographs are standard, the detection of aseptic loosening is subjective. This review evaluates the state of the art regarding AI in radiographic analysis for identifying aseptic loosening and mechanical failure in primary hip and knee prostheses. Methods: A systematic search in PubMed, Scopus, Web of Science, and Cochrane was conducted up to November 2025, following PRISMA guidelines. Peer-reviewed studies describing AI tools applied to radiographs for detecting aseptic loosening or implant failure were included. Studies focusing on infection or acute complications were excluded. Results: Ten studies published between 2020 and 2025 met the inclusion criteria. In internal testing, AI models demonstrated high diagnostic capability, with accuracies ranging from 83.9% to 97.5% and AUC values between 0.86 and 0.99. A performance drop was observed during external validation. Emerging trends include the integration of clinical variables and the use of sequential imaging. Conclusions: AI models show robust potential to match or outperform standard radiographic interpretation for detecting failure. Clinical deployment is limited by variable performance on external datasets. Future research must prioritize robust multi-institutional validation, explainability, and integration of longitudinal data. Full article

Background: Accurate microbiological diagnosis of bone and joint infections (BJIs) is frequently hampered by low bacterial load, biofilm formation, and suboptimal tissue processing. This study evaluated the diagnostic performance of mechanical bead-milling using the Ultra-Turrax^® Tube Drive system compared with standard vortex homogenization. Methods: In a prospective cohort of 116 patients undergoing surgery for suspected BJIs, 540 intraoperative samples were processed using both methods. Culture and 16S rRNA PCR results were analyzed using classical and Bayesian statistical approaches. Diagnostic performance was assessed globally and across specimen types and anatomical sites. Results: Ultra-Turrax^® significantly improved sensitivity across all sample types (87.1% vs. 75.2%, p < 0.0001), while maintaining comparable specificity (>99%). Culture positivity increased by 17%, with the greatest gains observed in bone samples and hip prosthesis infections. Quantitative cultures demonstrated a 1.5–2 log₁₀ CFU/mL increase in bacterial yield. In culture-negative specimens, 16S rRNA PCR detection doubled with Ultra-Turrax^® processing (26% vs. 13%, p = 0.04). No increase in contamination was observed. Time to positivity was similar between methods, although Ultra-Turrax^® provided earlier results in 17% of cases. Bayesian modeling confirmed superior sensitivity (posterior probability > 0.995). Conclusions: Ultra-Turrax^® bead-milling markedly enhances microbiological detection in BJIs, particularly in low-biomass and bone-derived specimens. Its simplicity, reproducibility, and compatibility with routine workflows support its integration into diagnostic pathways. This pre-analytical optimization may improve etiological identification and guide more targeted antimicrobial therapy. Full article

Background: Sitting and standing with conventional hip–knee–ankle–foot (HKAF) prostheses are demanding tasks for hip disarticulation (HD) amputees due to the passive nature of current prosthetic hip joints that cannot assist with moment generation. This study developed a sitting and standing control strategy for a motorized hip joint and evaluated whether providing active assistance reduces the intact side demand of these activities. Methods: A dedicated control strategy was developed and implemented for a motorized hip prosthesis (Power Hip) compatible with existing prosthetic knees, feet, and sockets. One HD participant was trained to perform sitting and standing tasks using the Power Hip. Its performance was compared with the participant’s prescribed passive HKAF prosthesis through measurements of ground reaction forces (GRFs), joint moments, and activity durations. GRFs were collected using force plates, kinematics were captured via Theia3D markerless motion capture, and joint moments were computed in Visual3D. Results: The Power Hip enabled more symmetric limb loading and faster stand-to-sit transitions (1.22 ± 0.08 s vs. 2.62 ± 0.41 s), while slightly prolonging sit-to-stand (1.69 ± 0.49 s vs. 1.22 ± 0.40 s) compared to the passive HKAF. The participant exhibited reduced intact-side loading impulses during stand-to-sit (4.97 ± 0.78 N∙s/kg vs. 15.06 ± 2.90 N∙s/kg) and decreased reliance on upper-limb support. Hip moment asymmetries between the intact and prosthetic sides were also reduced during both sit-to-stand (−0.18 ± 0.09 N/kg vs. −0.69 ± 0.67 N/kg) and stand-to-sit transitions (0.77 ± 0.20 N/kg vs. 2.03 ± 0.58 N/kg). Conclusions: The prototype and control strategy demonstrated promising improvements in sitting and standing performance compared to conventional passive prostheses, reducing the physical demand on the intact limb and upper body. Full article

Background: Total hip arthroplasty (THA) is a well-tolerated and effective procedure that can improve a patient’s mobility and quality of life. A main concern, however, is the release of metal ions into the body due to wear and corrosion. Commonly reported ions are Co and Cr, while others, such as Ti, Mo, and Ni, are less frequently studied. The objective of this study was to characterize compartmentalization and time-dependent ion behaviors across serum, whole blood, and urine after hip prosthetic implantation. The goal of using Random Forest (RF) was to determine whether machine learning modeling could support temporal trends across data. Methods: Data was gathered from the literature of clinical studies, and we conducted a pooled analysis of the temporal kinetics from cohorts of patients who received hip prosthetics. Mean ion concentrations were normalized to µg/L across each fluid and weighted by cohort sample size. RF was used as a study-level test of predictive accuracy across ions. Results: For serum and whole blood, Co and Cr displayed one-phase association models, while Ti showed an exponential rise and decay. Ions typically rose quickly within the first 24 months postoperatively. Serum Co and whole blood had similar patterns, tapering off just under 2 µg/L, but serum Cr (~2.02 µg/L) was generally higher than that of whole blood (~0.99 µg/L). Mean urinary Co levels were greater than those of Cr, suggesting a larger, freely filterable fraction for Co. RF was implemented to determine predictive accuracy for each ion, showing a stronger fit for Co (R² = 0.86, RMSE = 0.57) compared to Cr (R² = 0.52, RMSE = 0.50). Conclusions: Sub-threshold exposure was prevalent across cohorts. Serum and whole blood Co and Cr displayed distinct kinetic profiles and, if validated, could support fluid-specific monitoring strategies. We present a methodology for interpreting ion kinetics and show potential for machine learning applications in postoperative monitoring. Full article

Para cross-country (XC) skiing has become a prominent sport since its debut at the Örnsköldsvik Winter Olympic Games in 1976. Nevertheless, the lack of studies focusing on standing para XC skiing highlights the need to provide a comprehensive description of this sport, investigating how different prosthetic devices may influence the athletic outcome. In this exploratory case study, the biomechanics of an elite standing para-athlete, with a right-sided transfemoral amputation, was investigated. Tests were performed during diagonal XC skiing on a treadmill, at different speeds and inclinations. Specifically, two different prosthetic feet were compared: the athlete used an Ottobock Genium X3 prosthetic knee with either the Ottobock Taleo or the Ottobock Evanto prosthetic foot. Inertial Measurement Units (IMUs) were employed to estimate joint angles and detect pole hits and lifts. Additionally, data were collected using embedded sensors in the knee prosthesis. Diagonal stride spatiotemporal parameters were further calculated. Results revealed that the Evanto foot significantly increased swing phase duration and hip range of motion, while generating higher knee torque, ankle torque, and axial loading compared to the Taleo foot. This research represents the first application of the employed testing methodology to para standing XC skiing, and it therefore provides a framework for future studies on this discipline. Full article

Background/Objectives: Unstable intertrochanteric femur fractures (IFFs) in geriatric patients are associated with high rates of morbidity and mortality due to poor bone quality, multiple comorbidities, and limited functional capacity. This study aimed to compare the clinical outcomes of cementless bipolar hemiarthroplasty (BHA) performed via a transtrochanteric approach and proximal femoral nailing (PFN) in elderly patients with unstable IFFs. Methods: This retrospective comparative study included 131 patients aged ≥70 years who underwent surgery for AO/OTA 31-A2 and 31-A3 unstable fractures between January 2021 and July 2025 were retrospectively reviewed. 64 patients received cementless BHA and 67 underwent PFN. Eligible patients were ambulatory prior to fracture (independently or with a cane/walker); patients with pathological fractures/malignancy, alternative procedures (cemented or posterolateral BHA, total hip arthroplasty, tumor prosthesis, or other osteosynthesis methods), incomplete records, or <6 months of follow-up were excluded. Demographics, perioperative variables, mechanical complications, revision requirement, time to mobilization, and 1- and 6-month mortality rates were analyzed. Primary outcomes were mortality and perioperative clinical parameters. Results: The two groups were comparable in age, sex, ASA scores, and fracture patterns. Intraoperative blood loss and transfusion requirements were significantly higher in the BHA group (both p < 0.001). Mobilization was observed earlier in patients treated with BHA (1 [1,2] vs. 3 [2,3] days; p < 0.001). Mechanical complications were more frequently observed after PFN, which was associated with a higher revision requirement (17.9% vs. 4.7%; p = 0.018). Operative time, hospital stay, and 1- and 6-month mortality rates showed no significant differences between the groups. Conclusions: In geriatric patients with unstable IFFs, cementless BHA performed via a transtrochanteric approach may be considered a viable surgical option with appropriate patient selection, taking into account its association with earlier mobilization and the observed mechanical complication profile. PFN offers advantages of reduced blood loss and lower transfusion needs. Surgical decision-making should be individualized based on fracture morphology, bone quality, and the patient’s overall medical condition. Given the heterogeneity of unstable fractures within the AO/OTA classification and the retrospective nature of the present study, larger, multicenter prospective investigations incorporating functional outcomes are warranted to further clarify optimal treatment strategies. Full article

An instrumented total hip replacement (THR) implant capable of remote and continuous monitoring would be an attractive prospect for a surgeon to conveniently track the recovery of their patients. Measuring the relative motion of the prosthesis components would provide insight into joint kinematics and contribute to the detection of adverse events including impingement and subluxation. The aim of this study was to develop a sensing system to measure the relative orientation and translation of the prosthesis components. A tri-axis magnetometer and a permanent magnet were integrated into clinically available THR components, forming a magnetic position and orientation sensing system. A robotic arm was used to articulate the components through controlled motion routines and record the orientation of the components. The output of the robot arm and a camera tracking system were used to validate the performance of the sensing system. The sensing system measured the relative orientation of the components to two degrees of freedom with an RMSE of <4.0° and measured the displacement of the femoral head during an impingement-driven subluxation motion with an RMSE of 0.2 mm. This proof-of-concept work has shown that magnetic sensing technology can track the position and orientation of THR components. With further development, this sensing method could feature within an instrumented THR implant. Full article

Aim: Periprosthetic fracture-related infections (PFRIs) are a serious complication of total arthroplasty, with incidence rates increasing in line with the growing number of joint replacements. PFRI can lead to prolonged hospitalization, multiple surgical procedures and suboptimal functional outcomes. The diagnosis of PFRI remains challenging due to the overlap of clinical symptoms with other post-traumatic conditions, and identification of the pathogen often fails through conventional methods. This study also highlights the importance of a personalized medicine approach in managing PFRI, where diagnostic and therapeutic decisions are tailored to the individual patient’s comorbidities, immune status and bone healing capacity. By integrating clinical, microbiological and imaging data, our findings support precision-based strategies to optimize outcomes and minimize complication. Methods: This retrospective case series was conducted at the Unit of Osteoarticular Infection of the University of Turin, Italy, from January 2018 to December 2023. Patients who developed septic complications after open reduction and internal fixation (ORIF) of periprosthetic fractures involving hip or knee implants were included. The infection was diagnosed in accordance with established guidelines, and treatment decisions were based on clinical, microbiological and radiological findings. Results: In the present study, periprosthetic fractures complicated by infections were identified in nine patients (5.4%), constituting a small but significant subset of cases. The cases were then categorized into four clinical scenarios based on the following variables: joint involvement, fracture healing and infection progression. Scenario A, involving fractures without prosthetic involvement and unhealed fractures, included three patients (33%) and was treated with debridement and change of the fixation device. Scenario B, involving fractures without prosthetic involvement but with healed fractures, involved one patient (11%), where the ongoing infection was confirmed despite the healed fracture and where the device could be removed. The third scenario (C), which pertains to cases involving prosthetic involvement, included three patients (33%) who required replacement or removal of the prosthesis and, in some cases, a second stage. The fourth scenario, involving patients with limited operability, included two patients (22%) for whom no surgery was performed. Despite the significant clinical challenges encountered, the paucity of literature on the management of periprosthetic fractures with septic complications is limited, highlighting the need for further research in this understudied area. Conclusions: PFRI remains a challenging complication that necessitates a multidisciplinary approach to diagnosis and treatment. Despite advances in imaging and microbiological testing, the early detection and identification of pathogens remain challenging, emphasizing the necessity for enhanced diagnostic methods. This study offers valuable insights into the management of PFRI and provides a foundation for future research to develop optimal diagnostic and therapeutic strategies. Full article

Background: Femoral neck fractures (FNFs) in the ageing population carry high risks of postoperative dislocation, with traditional total hip arthroplasty (THA) reporting rates up to 10%. Dual mobility THA (DM-THA) may provide enhanced stability, but evidence for third-generation implants like the Zimmer Biomet G7^® system remains limited. Methods: This retrospective cohort study evaluated 120 patients (mean age 71.6 years; 74% female) with acute displaced intracapsular FNF treated with DM-THA (2021–2023) using the G7^® system. Demographics, surgical details (cemented/uncemented stems), complications, and functional outcomes (Oxford Hip Score (OHS) at one year) were analysed against national benchmarks. Results: Zero dislocations and two peri-prosthetic fracture (0.8%, cemented stem) occurred. Thirty-day mortality was 0.8% (below national averages). Functional recovery was excellent (mean OHS: 41/48; 69% scoring ≥40). Surgical complications were minimal (one deep infection 0.8%). Medical complications (anaemia 6.6%, venous thromboembolism 4.2%) were significantly higher in high ASA groups (III-IV). Radiographs confirmed stable implants without loosening. Conclusions: The G7^® DM-THA system demonstrates exceptional stability and safety in FNF patients, with no dislocation risk and low peri-prosthetic fracture rates—even with cemented stems. These outcomes support its use in high-risk populations, though comparative studies with conventional THA are needed. Full article

Purpose: This study investigates the static mechanical behavior of a non-modular metallic hip prosthesis through Finite Element Method (FEM) simulations, assessing compliance with ASTM F2996-13 standards. The analysis specifically evaluates how key geometric parameters, such as trunnion extension and orientation angles (adduction and flexion), affect stress distributions within the prosthesis. Methodology: A three-dimensional finite element model of a Ti6Al4V alloy hip stem was developed. Boundary and loading conditions were defined according to the standard: the distal portion of the stem was fully constrained 90 mm below the head center, and a static load of 2300 N was applied at the head center along the directions defined by the adduction and flexion angles. A mesh sensitivity analysis was conducted to ensure convergence, and stresses were evaluated. Parametric analyses varying trunnion extension and orientation angles were performed to quantify their impact on local stress concentration. Results: The findings revealed that even minor deviations in the adduction and flexion angles significantly impact the stress distribution, with the potting-level region being particularly sensitive. Additionally, the extension of the trunnion led to notably increased stress concentrations, especially at the prosthesis neck, highlighting its critical influence in implant design. Conclusions: Comparison with existing literature and standard reference data exposed discrepancies primarily attributed to variations in FEM model setups and parameter selections. This emphasizes the necessity of clearly specifying trunnion extension and orientation angles in numerical analyses to ensure consistent stress predictions, supporting the development of safer and longer-lasting hip implants. Future research should extend these analyses to different prosthesis geometries, aiming to develop generalized predictive frameworks applicable to diverse biomechanical scenarios. Full article