Search Results (587)

Background/Objectives: This study was designed to verify the hypothesis that graphical cell differentiation of synovial cell count analysis is helpful for diagnosis of acute periprosthetic joint infection (PJI) and that the additional erythrocyte field has advantages to differentiate PJI from hematoma. Methods: A total of 77 total knee arthroplasties and 31 total hip arthroplasties underwent aspiration within six weeks of primary implantation. The aspirate was analyzed with the cell counter Yumizen H500 and examined by cultivation. Serum CRP was also determined. A total of 43 patients underwent revision and microbiological and histological analysis of the periprosthetic tissue, according to Morowitz and Krenn, was performed. The ICM criteria for diagnosing PJI were used. Results: Thirty-two cases (29.6%) were classified as acute infection. The graphical type differentiation LMNE (leukocyte–monocyte–neutrophil–eosinophil) showed 28 cases with type II (infection type), 63 cases with type IV (indifferent type), 13 cases with type V (hematoma type with a peak in the erythrocyte field) and 4 cases with type VI (mixed infection and hematoma). The LMNE matrix assessment had an accuracy of 98.7%, sensitivity of 96.9%, specificity of 98.7%, positive predictive value of 96.9%, negative predictive value of 98.7%, a positive likelihood ratio of 73.62, and a negative likelihood ratio of 0.03. Only one single non-infectious hematoma sample was misclassified as type VI (mixed infection/hematoma). Conclusions: The graphical type differentiation of the cell count analysis of synovial aspirates is a helpful method for diagnosis of acute periprosthetic joint infection and differentiating between hematoma and real early periprosthetic infections. This report shows that the new erythrocyte field of the Yumizen H500 is a useful additional diagnostic tool. Full article

Background: The primary concern of hip surgeons is restoring the physiological biomechanics of the hip joint through arthroplasty, thereby enabling patients with osteoarthritis to engage better in daily activities. The modularity of the femoral stem-neck head allows surgeons to better restore the hip’s native biomechanics. However, concerns have been raised regarding the potential postoperative complications. This study aims to evaluate patients’ satisfaction and functional outcomes following primary Total Hip Arthroplasty (THA) with modular stem-neck, with a mean follow-up duration of eight years. Methods: We retrospectively reviewed 208 patients who underwent primary THA with modular stem-neck between February 2012 and July 2019. The follow-up period extended from November 2024 to April 2025. Patients who died from unrelated causes were excluded. Patients’ satisfaction was assessed using the SF-36 questionnaire, while functional outcomes were evaluated using the Harris Hip Score (HHS). Intraoperative and postoperative complications were meticulously documented. Results: The average follow-up duration was 95.6 months, with a range from 67.7 to 159.7 months. The mean SF-36 score was 91.2 out of 100, indicating high patient satisfaction. The mean HHS was 90 out of 100, reflecting excellent functional outcomes. Notably, some patients achieved the maximum score of 100 in both SF-36 and HHS assessments, while the lowest recorded scores were 54 and 50, respectively. The mean age of patients at the time of surgery was 67.1 years. One case of periprosthetic fracture was reported; however, no complications related to modular necks, such as trunnionosis or implant failure, were observed. Conclusions: The present study demonstrates that modular neck primary THA could achieve excellent functional and radiological outcomes, high patient satisfaction, and outstanding long-term survivorship, provided that implant selection and surgical technique follow biomechanical principles. 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

Purpose: Revision total hip arthroplasty (RTHA) in the presence of a well-fixed femoral stem is associated with increased risk, as stem removal often results in bone loss, prolonged operative time, and greater blood loss. This problem is particularly relevant for older implants with a 14/16 taper, which is incompatible with most modern femoral heads. The Bioball™ System, a modular head–neck adapter, allows for acetabular or head-only revision while preserving the femoral stem. This study aimed to evaluate long-term clinical and radiological outcomes of RTHA using the Bioball™ System in patients with 14/16 tapers. Methods: A total of 38 patients (23 women, 15 men; mean age 73.5 years) met the inclusion criteria. All procedures were carried out with a well-fixed femoral stem and a 14/16 taper. Revisions were limited to exchange of the acetabular component, liner, or both, avoiding stem removal. The primary indication was acetabular cup loosening (n = 29, 76.3%); liner-only exchange was performed in 9 patients (23.7%). Clinical outcomes were assessed using the modified Merle d’Aubigné and Postel (MAP) score, and radiological evaluation focused on fixation, migration, and loosening. Mean follow-up was 8.44 years. Results: Both the acetabular component and liner were replaced in 76.3% of patients, while 23.7% underwent liner and head exchange only. Longer adapter sizes were most frequently used, and a 7.5° offset adapter was applied in 57.9% of cases. The modified MAP score improved by a mean of 5.7 points (p < 0.05), and VAS pain scores decreased from 7.4 to 2.6 (p < 0.05). No radiological signs of loosening were observed at final follow-up. Conclusions: The Bioball™ System enables effective restoration of hip stability and offset without femoral stem removal, offering favorable long-term clinical and radiological outcomes in revisions involving older 14/16 tapers. Full article

Ceramic-on-ceramic (CoC) bearings are widely used in total hip arthroplasty due to their extremely low wear rate, excellent chemical stability, and good biocompatibility. They are considered one of the most reliable long-term friction bearing systems. Although frictional instability, lubrication regime transitions, and microstructural damage mechanisms have been widely reported at the experimental and retrieval-analysis levels, current clinical evidence, limited by follow-up duration and event incidence, has not demonstrated a definitive negative impact on the clinical performance of fourth-generation ceramic components, including BIOLOX^® delta. Data from national arthroplasty registries consistently demonstrate excellent survivorship and low complication rates for 4th-generation ceramics in both hard-on-soft and hard-on-hard configurations. The most reported causes for revision, such as infection, dislocation, aseptic loosening, and periprosthetic fracture, are not primarily associated with ceramic-related complications, such as ceramic fracture, excessive wear, squeaking, and revision, related to bearing failure; however, these mechanisms remain highly relevant for the design and evaluation of emerging ceramic materials and next-generation implant systems, where inadequate control may potentially impact long-term clinical performance. This review summarizes recent advances in the tribological research of CoC artificial joints, focusing on clinical tribological challenges, material composition and surface characteristics, lubrication mechanisms, wear and microdamage evolution, and third-body effects. Recent progress in ceramic toughening strategies, surface engineering, biomimetic lubrication simulation, and structural optimization is also discussed. Finally, future research directions are outlined to support the performance optimization and long-term reliability assessment of CoC artificial joint systems. Full article

Background and Objectives: Short femoral stems are increasingly used in total hip arthroplasty (THA), yet evidence regarding their performance in elderly femoral neck fracture (FNF) patients is limited. In this study, we compared clinical and radiographic outcomes of the use of a short femoral stem (SFS) versus a conventional standard stem (CSS) in cementless THA. Materials and Methods: This prospective, single-center case–control study (1:2) included patients ≥ 65 years of age with displaced FNF (Garden 3–4) treated with cementless THA. Follow-up lasted a minimum of 2 years. Clinical evaluations included the Harris Hip Score (HHS), Roles and Maudsley satisfaction score, and thigh pain assessment. Radiographic evaluations assessed cup position, osseointegration (Moore signs), radiolucencies (DeLee–Charnley and Gruen zones), subsidence, leg length discrepancy (LLD), and heterotopic ossification. Results: A total of 114 patients were analyzed (38 with SFS versus 76 with CSS). The final follow-up HHS was 87 ± 2.7 (SFS) and 88 ± 2.5 (CSS) (p = 0.231), and satisfaction was excellent in nearly all patients in both groups. Thigh pain was rare and resolved by final follow-up in all SFS patients, and no radiographic loosening was observed. Early subsidence (≤3 mm) occurred in two SFSs and three CSSs without progression, while LLD < 1 cm was present in three SFS and eight CSS cases. No implant-related revisions occurred, and complication rates were low and comparable. Conclusions: Short femoral stems provided clinical and radiographic outcomes equivalent to those of conventional stems in elderly FNF patients treated with cementless THA. Short stems appear to be a safe and effective option in this population, and further studies with longer follow-up are needed to confirm their durability. Full article

Background: This propensity-score-matched retrospective study compared radiographic accuracy and short-term functional outcomes between MAKO robotic-arm-assisted and conventional dual-incision minimally invasive total hip arthroplasty (THA). It was hypothesized that robotic assistance would provide superior radiographic accuracy, primarily smaller absolute deviations from the planned acetabular inclination and anteversion and a higher proportion of cups within the Lewinnek safe zone, without improving early functional outcomes. Methods: Consecutive patients who underwent dual-incision total hip arthroplasty were retrospectively analyzed at two affiliated institutions between March 2023 and March 2025. The study included 52 robotic-arm-assisted cases. The dual-incision technique used an anterolateral incision for acetabular preparation and cup implantation and a posterolateral incision for femoral preparation and stem implantation. Propensity score matching (1:1) generated 52 balanced pairs for age, sex, body mass index (BMI), preoperative Harris Hip Score (HHS), ASA class, and diagnosis. Operative time, blood loss, radiographic accuracy (acetabular anteversion, inclination, leg-length discrepancy [LLD], femoral and combined offsets, and stem subsidence), and functional outcomes (HHS, Oxford Hip Score [OHS], Forgotten Joint Score-12 [FJS-12]) were compared. Results: The robotic group achieved smaller deviations from the planned anteversion (1.15° vs. 3.0°, p < 0.001) and inclination (1.33° vs. 4.5°, p < 0.001), with a higher proportion of cups within the Lewinnek safe zone (98.1% vs. 82.7%, p = 0.016). Significant improvements were also seen in femoral stem subsidence (p = 0.006) and offset restoration, although the reduction in leg-length discrepancy did not reach statistical significance. Operative time was longer (77.8 vs. 65.0 min, p = 0.001), while blood loss and 6-month functional scores were comparable (HHS, p = 0.144; OHS, p = 0.328). Multivariable regression confirmed that greater deviations in acetabular orientation, higher LLD, and increased subsidence were independent predictors of poorer functional outcomes. Conclusions: MAKO robotic-arm assistance was associated with improved radiographic accuracy and biomechanical restoration in dual-incision THA, but no direct short-term functional advantage was observed. Greater radiographic precision was independently associated with better patient-reported outcomes, suggesting that technical precision is a key factor in optimizing early postoperative outcomes, highlighting the importance of technical accuracy in total hip arthroplasty. 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

Total hip arthroplasty (THA) is a transformative procedure for managing severe hip disorders, yet implant longevity remains a critical challenge, particularly for younger, active patients. Wear-related complications are a leading cause of revision surgery, emphasizing the need for optimized design and material performance. This systematic review aims to synthesize evidence on the wear behavior, material properties, and design parameters of hip implants with a focus on finite element analysis (FEA)-based predictive approaches. A comprehensive literature search was conducted across Scopus, PubMed, ScienceDirect, MDPI, and Cochrane databases following PRISMA guidelines. Studies published between 2010 and 2025 were included if they addressed THA biomechanics, wear analysis, or material optimization using FEA, hip simulators, or radiostereometric techniques. Key findings reveal that larger femoral heads, while reducing contact pressure, increase wear due to greater sliding distance. Gravimetric wear rates ranged from 3.15 ± 0.27 mg/Mc to 2.18 ± 0.31 mg/Mc, while linear and volumetric wear reached 0.0375 mm/Mc and 33.6 mm³/Mc, respectively. Stress analysis showed custom stems exhibited markedly lower von Mises stress (194.9 MPa) compared to standard designs (664.3 MPa), and fatigue assessments confirmed a factor of safety > 1 across profiles. Patient-specific factors, such as body weight, significantly influenced wear with a 26% increase in metal wear observed between 100 kg and 140 kg. This systematic review synthesizes current research on total hip arthroplasty, emphasizing biomechanical and material factors critical for implant longevity and patient care. It uniquely integrates FEA-based wear prediction with clinical implications, bridging computational modeling, geometry optimization, and material performance to provide actionable insights for next-generation, patient-specific hip implant design. Full article

Background and Objectives: Organ dysfunctions affect the quality of bone and body fluids. This case report seeks links between the underlying conditions of three patients undergoing hip arthroplasty (HA) with uncemented implants, the quality of their bones, and their Ti-6Al-4V orthopaedic implants, on different time spans. Femoral stems are investigated. A brief review supports our findings. Materials and Methods: Cases: two women (F1 35+, F2 80+), and one man (M 65+), all having diabetes, dyslipidaemia, and kidney dysfunction. Samples: a segment of a broken 7-year-old stem, bone with a metallic layer, soft tissue, segments of one spare stem, and synthetic plasma enriched with glucose and urea according to the biochemistry tests of the respective patients. Vast studies show that cholesterol influences bone quality only. The stem pieces were ultrasonicated for 7 h at 37 °C in synthetic plasma. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and profilometry investigated the Ti-alloy samples, electrochemistry analysed the post-sonication plasma, and histopathology examination was performed on the soft tissue remnants on the broken stem. Results: EDX show that all stem samples are Ti-6Al-4V with minute additions of other elements and hydroxyapatite (HAp) coating. SEM and profilometry analysis are consistent for the roughness in the outer layers of the stems. Electrochemistry on the bone fragment shows migration of vanadium during the 6 months since fracture to revision for M. Conclusions: Stems in altered synthetic plasma are affected by glucose and urea. Metal migration from the prostheses can occur through the chemical interactions between body fluids with abnormal biochemistry and the orthopaedic prostheses, favoured by cracks and concurring with wear following friction during usual movements. Cholesterol influences on the bone quality. Full article

Background: Preoperative templating is an essential step in hip arthroplasty (HA), guiding implant selection and reducing surgical complications. It is typically performed using acetate templates or digital software. These methods, however, depend on the surgeon’s experience and may be limited by cost and availability. This study aimed to develop and validate a deep learning (DL) model using plain radiographs to predict implant sizes in HA. Methods: This retrospective study included patients who underwent primary HA using a cementless CORAIL^® femoral stem and PINNACLE^® acetabular cup. The DL model was trained on 688 preoperative anteroposterior (AP) hip radiographs and validated temporally on 98 additional cases. Implant sizes predicted by the DL model were compared with on-screen templating (acetate templates overlaid on digital images). The actual implanted size was used as the reference standard. Accuracy, mean absolute error (MAE), and root mean square error (RMSE) were calculated. Logistic regression was performed to identify factors influencing prediction accuracy. Results: The DL model showed higher accuracy than the on-screen templating for the acetabular cup (88.9% [77.4% to 95.8%] vs. 83.3% [70.7% to 90.2%]) and femoral stem components (85.7% [77.2% to 92.0%] vs. 81.6% [72.5% to 88.7%]), while the on-screen method performed better for the bipolar head (93.2% [81.3% to 98.6%] vs. 72.7% [57.2% to 85.0%]). MAE and RMSE were comparable between the methods for acetabular and femoral stem components (all p > 0.05), with statistically significant differences observed only in the bipolar head (p < 0.01 and 0.02, respectively). Although logistic regression analysis showed trends toward higher accuracy in acetabular size prediction among women and those with shorter height, no demographic factors were statistically significant predictors of accuracy. Conclusions: A DL model using only plain radiographs can accurately predict implant sizes in HA, particularly for the acetabulum and femoral stem. These findings suggest that the DL-based model could be a useful tool in preoperative planning. With further refinement to improve generalizability, this approach could be useful in a routine clinical setting in the future. Full article

Titanium (Ti) and its alloys are widely used in orthopedic applications, including total hip and knee replacements, bone plates, and dental implants, because of their superior biocompatibility, bioactivity, corrosion resistance, and mechanical robustness. These alloys effectively overcome several limitations of conventional metallic implants, such as 316L stainless steel and Co-Cr alloys, particularly with respect to corrosion, fatigue performance, and biological response. However, dense Ti alloys possess a relatively high elastic modulus, which can cause stress shielding in load-bearing applications. This challenge has motivated significant research toward engineered porous Ti structures that exhibit a reduced and bone-matched modulus while preserving adequate mechanical integrity. This review provides a comprehensive examination of powder metallurgy and additive manufacturing approaches used to fabricate porous Ti and Ti-alloy scaffolds, including additive manufacturing and different powder metallurgy techniques. Processing routes are compared in terms of achievable porosity, pore size distribution, microstructural evolution, mechanical properties, and biological outcomes, with emphasis on the relationship between processing parameters, pore architecture, and functional performance. The reported findings indicate that optimized powder-metallurgy techniques can generate interconnected pores in the 100–500 μm range suitable for osseointegration while maintaining compressive strengths of 50–300 MPa, whereas additive manufacturing enables the precise control of hierarchical architectures but requires careful post-processing to remove adhered powder, stabilize microstructures, and ensure corrosion and wear resistance. In addition, this review integrates fundamental aspects of bone biology and bone implant interaction to contextualize the functional requirements of porous Ti scaffolds. Full article

Background and objectives: Hemiarthroplasty (HA) remains one of the most common treatments for displaced femoral neck fractures in the elderly, providing pain relief, early mobilization and a low reoperation risk. Acetabular erosion is a recognized late complication of this procedure, but early cartilage wear and its potential relationship with infection remain poorly understood. The aim of this study was to describe the clinical and microbiological characteristics of patients who required conversion to total hip arthroplasty (THA) because of acetabular erosion and to analyze the possible role of unexpected infection as a contributing factor. Materials and methods: A retrospective observational study was performed including all patients treated between 2007 and 2019 who underwent conversion of a failed HA to THA due to acetabular erosion after femoral neck fracture. Microbiological analysis was performed in all cases through multiple intraoperative samples. Patients were classified into two groups, with and without infection, according to positive microbiological cultures. Results: Forty-four patients were included, with a median age of 80.5 years (74–85). The median time to acetabular erosion was 25.4 months (10.4–47.4). Infection was identified in six patients (13.6%), all within the first six months after fracture (p = 0.029). The median time to erosion was shorter in infected patients (4.0 versus 29.8 months, p < 0.001). No other demographic, functional, or implant-related variables were associated with infection. There were three re-revisions, two due to recurrent dislocation and one periprosthetic infection in a hip without unexcepted positive culture. All patients with positive intraoperative culture were successfully managed with antibiotherapy. Postoperative functional scores improved significantly in both groups. Fifteen patients (34.1%) died during follow-up. Conclusions: Early acetabular erosion after hemiarthroplasty may represent a manifestation of previously unrecognized low-grade infection, particularly in frail elderly patients. Despite advanced age and multiple comorbidities, conversion to THA achieved significant functional improvement with an acceptable complication rate. Prospective studies with larger populations are warranted to confirm the relationship between infection and early acetabular cartilage loss. 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