Search Results (196)

Background: This study examines current trends in Canada using data from the Canadian Joint Replacement Registry (CJRR) and includes a national survey to understand the varied uptake of cement for femoral stem fixation. Methods: The survey was available online and the website link was distributed to all orthopaedic surgeons through the Canadian Orthopaedic Association between September and December 2022. The CJRR obtained data from the Canadian Institute for Health Information (CIHI), and information pertaining to patients 55 years of age and older who underwent hemiarthroplasty for hip fracture in Canada between April 2017 and March 2022 was used. Results: Most respondents practiced in an academic community setting (52%). Only 53% of respondents reported using cement, and 71% indicated that cemented fixation was the best practice. The main reasons for using uncemented stems were less operative time (23%), cement disease concerns (11%), and surgeons’ comfort (10%). Similarly, CJRR data showed only 51% cemented fixation among 42,386 hemiarthroplasties performed between 2017 and 2022. The proportion of cemented implants varied by province, but overall, the increase in the use of cement from 2017 to 2022 was from 42.9% to 57.7%. Conclusions: This study demonstrates variability in the use of cement for femoral fixation despite solid evidence showing improved outcomes using cement. Some of the main reasons in favour of uncemented stems include operative time, surgical training, and concerns about cement disease. Establishing clear position statements and guidelines supporting cemented fixation may be prudent to build universal consensus on this practice. Full article

Background: Implantation of modularly built-up stems with a tapered and fluted design is currently state of the art in revision total hip arthroplasty (RTHA). Nevertheless, implant-specific major complications like breakage of taper junctions as well as periprosthetic fractures (PPFs) may lead to failure of reconstruction during follow-up. Methods: A cohort of 117 cases receiving femoral RTHA by a modular stem was investigated retrospectively with a mean follow-up of 5.7 (0.5–13.7) years. Cumulative risk and potential factors affecting the occurrence of PPFs were calculated with the Kaplan–Meier method. In addition, cases were presented to discuss operative treatment options. Results: A cumulative risk of PPF of 12.1% (95% CI: 0–24.6%) was calculated at 13.7 years. Female patients had significantly higher risk compared to male patients (0% after 13.5 years for male patients vs. 20.8% (95% CI: 0.5–41.2%) after 13.7 years for female patients; log-rank p = 0.0438) as all five patients sustaining a PPF during follow-up were women. Four fractures were treated by open reduction and internal fixation. Non-union and collapse of the fracture occurred in one patient after closed reduction and internal fixation. Conclusions: Postoperative PPF after femoral revision with a modular stem has shown to be a frequent complication within this mid-term follow-up. Female patients were at a significantly higher risk in this aged cohort, indicating osteoporosis as a risk factor. The surgical treatment of PPF with an integrated long-stemmed prosthesis is challenging and thorough considerations of adequate operative treatment of PPFs are strongly advised in order to limit complication rates. Full article

Background: Short-stem hip replacements are designed to provide improved load distribution and to mimic natural biomechanics. The interplay between implant design, positioning, and resulting bone biomechanics in individual patients remains underexplored, and the relationship between radiographically assessed bone remodeling around short stems and biomechanical predictions has not been previously reported. Methods: This study evaluated three short-stem hip implant designs: Proxima, Collo-MIS, and Minima. Postoperative bone remodeling patterns were analyzed, categorizing remodeling as bone gain, bone loss, or no observable activity, with changes tracked over time. Patient-specific biomechanical models were generated from 6-week postoperative radiographs. Finite element simulations incorporated body weight and gluteal muscle forces to estimate stress and strain distributions within the proximal femur. Strain energy was then applied to a mechanostat-based remodeling algorithm to predict bone remodeling patterns. These biomechanical predictions were compared to observed radiographic remodeling at 2 years post-surgery. A validated biomechanical model was further used to simulate different postoperative positions of the three types of stems. Results: No differences in bone remodeling patterns were observed among the three short-stem designs. Computational modeling demonstrated a statistically significant correlation between predicted remodeling and radiographic measurements at 2 years (p < 0.001). Proxima stems showed a tendency towards increased cortical bone loading under pronounced varus or valgus position in comparison to other two stems, although this observation requires further validation. Conclusions: This exploratory study demonstrates the feasibility of using biomechanical modeling to estimate bone remodeling around short-stem hip implants based on early postoperative radiographs. While the results are promising, they should be interpreted with caution due to the limited cohort size. The proposed modeling approach may offer clinical value in evaluating implant behavior and informing patient-specific treatment strategies. However, further research with larger populations is necessary to refine and validate these predictive tools. Full article

Hip implant optimization is increasingly receiving attention due to the development of manufacturing technology and artificial intelligence interaction in the current research. This study investigates the development of hip implant stem design with the application of lattice structures, and the utilization of the MATLAB regression learner app in finding the best predictive regression model to calculate the mechanical behavior of the implant’s stem based on some of the design parameters. Many cases of latticed hip implants (using 3D lattice infill type) were designed in the ANSYS software, and then 3D printed to undergo simulations and lab experiments. A surrogate model of the implant was used in the finite element analysis (FEA) instead of the geometrically latticed model to save computation time. The model was then generalized and used to calculate the mechanical behavior of new variables of hip implant stem and a database was generated for surgeon so they can choose the lattice parameters for desirable mechanical behavior. This study shows that neural networks algorithms showed the highest accuracy with predicting the mechanical behavior reaching a percentage above 90%. Patients’ weight and shell thickness were proven to be the most affecting factors on the implant’s mechanical behavior. Full article

Periprosthetic femoral fractures (PPFFs) represent the third most frequent indication for revision total hip arthroplasty (THA). Given the steadily increasing number of primary hip replacements, this complication is gaining growing attention among orthopedic surgeons. Clamshell fracture (CF) constitutes a particularly controversial and underrecognized fracture pattern that, for a long time, was not accounted for in the commonly used classification systems for PPFFs. Recent studies suggest that the incidence and clinical relevance of these injury patterns have been underestimated. Therapeutic options are manifold and depend on various patient-specific factors as well as stem stability. Despite this, the current literature remains limited, and standardized therapeutic approaches are still poorly defined. This review aims to provide a comprehensive overview of clamshell fractures as a distinct pattern of periprosthetic injuries. Furthermore, relevant treatment options dependent on biomechanical considerations will be outlined and discussed. Full article

Bone marrow stimulation is a treatment for articular cartilage injuries that promotes cartilage repair by inducing the migration and accumulation of mesenchymal stem cells (MSCs), but often results in fibrocartilage with limited durability. This study aimed to investigate the effect of hypoxic conditions on cartilage repair using a rat osteochondral defect model. Osteochondral defects (1.0 mm in diameter) were created in the femoral trochlear groove, and rats were exposed to hypoxic conditions (12% O₂) for 4 weeks postoperatively. Histological analysis was performed, and protein expression of hypoxia-inducible factor-1α (HIF-1α) and SRY-box transcription factor 9 (SOX9) in the repair tissue was evaluated after 1 week. As a result, after 1 week, protein expression of HIF-1α and SOX9 in the Hypoxia group was significantly increased compared to the Normoxia group. After 4 weeks, the Hypoxia group exhibited a hyaline cartilage-like tissue structure with a significantly lower Modified Wakitani score compared to the Normoxia group. Furthermore, after 4 weeks, the inhibition of HIF-1α suppressed cartilage repair. These findings suggest that hypoxic conditions promote SOX9 expression via HIF-1α during the early phase of MSC chondrogenic differentiation and promote the formation of hyaline cartilage-like repair tissue. In conclusion, bone marrow stimulation under hypoxic conditions may enhance the repair effect on articular cartilage injuries. Full article

Background and objectives: The objective was to validate the Beyond the Vancouver classification. Based on this algorithm, it was hypothesized that cemented polished tapered stems with an intact cement mantle and cementless stable stems with defined criteria could be classified as stable and therefore treated with open reduction and internal fixation (ORIF). Materials and Methods: This retrospective, single-center cohort study re-analyzed patients initially diagnosed with Vancouver type B2 fractures treated with ORIF between 2007 and 2020. Clinical and radiological outcomes were extracted from medical reports. A combined radiological and clinical score was used as the main outcome measure. Patients categorized according to the Beyond the Vancouver classification were compared for functional outcome. Results: 42 patients (25 male, 17 female) with a median (range) age of 83 years (75–88 years) and follow-up time of 25 weeks (12–35 weeks) were reviewed. It was found that ORIF achieved excellent or good results in 81% of cases for stems classified as stable (n = 16) and in 30% of cases for stems classified as loose (n = 23). Successful cases (30%), although classified as loose, all had the same fracture pattern: an intact greater trochanter and a fracture fragment attached laterally to the stem with distal fixation of the stem. Conclusions: This case series suggests that certain Vancouver B2 fractures can be treated with ORIF. The Beyond the Vancouver classification may support the categorization of ‘stable’ and ‘loose’ stems. The validity of the algorithm was supported by the observation that ORIF provided excellent and good results for the majority of stems classified as ‘stable’, but poor results for stems classified as ‘loose’. Furthermore, the fracture pattern has been shown to be a crucial factor that should be considered when treating distally fixed cementless stems. The classification was therefore expanded to include the specific fracture patterns in cementless distally fixed stems that can be successfully treated with ORIF. The Beyond the Vancouver classification can provide further guidance in the identification of ‘loose’ or ‘stable’ stems. Full article

Background: The effectiveness of hip hemiarthroplasty in managing femoral neck fractures in individuals with cerebral palsy has seldom been reported. Objectives: Given the complex neuromuscular issues associated with cerebral palsy (CP), this retrospective study aims to document the outcomes and characterize the complications of hip hemiarthroplasty for fractures of the femoral neck in a series of patients with CP, emphasizing the role of precision medicine in management. Methods: Six cases of hip hemiarthroplasty in six male patients with cerebral palsy and displaced femoral neck fractures have been reviewed in this study. The patients’ mean age at the time of surgery was 55.6 ± 14.1 years (range, 33–71). All the patients were independent indoor ambulators before their femoral neck fracture and had various medical comorbidities. Five patients had intellectual disabilities. Results: The mean clinical and radiographic follow-ups for the patients included in this series were 91.5 and 71.3 months, respectively. All the patients developed significant heterotopic ossification (HO) around the operated hip, which was observed as early as the second week postoperatively on radiographs. HO progressed throughout the follow-up for all the patients. One patient had an early postoperative dislocation with femoral stem loosening, which was managed by implant revision. Another patient had an acetabular protrusion, leading to the loss of their weight-bearing ability and mobility due to pain. Four patients were deceased at a mean of 86.5 months after the index surgery. Conclusions: After considering the preliminary evidence provided with this small case series, this study suggests the overall guarded outcomes of hip hemiarthroplasty in patients with CP. Given the 100% rate of heterotopic ossification, a precision medicine framework with consideration for HO prophylaxis may be recommended after hip hemiarthroplasty in patients with CP. It may also be reasonable to scrutinize a personalized risk assessment approach in this patient subset regarding decision making, surgical approach, and rehabilitation program. The clinical outcomes and the risks of complications following hemiarthroplasty should be sensibly presented to patients with cerebral palsy and their caregivers to achieve reasonable postoperative expectations. Full article

(1) Background: Osteonecrosis of the femoral head (ONFH), caused by insufficient blood supply, leads to bone tissue death. Current treatments lack effective bone regeneration materials to reverse disease progression. This study introduces an injectable and self-setting 3D porous bioceramic scaffold (Mg@Ca), combining MgO + SiO₂ mixtures with α-hemihydrate calcium sulfate, designed to promote bone repair through in situ pore formation and osteoinduction. (2) Methods: In vitro experiments evaluated human bone marrow mesenchymal stem cell (h-BMSC) proliferation, differentiation, and osteogenic marker expression in Mg@Ca medium. Transcriptome sequencing identified bone development-related pathways. In vivo efficacy was assessed in a rabbit model of ONFH to evaluate bone repair. (3) Results: The Mg@Ca scaffold demonstrated excellent biocompatibility and supported h-BMSC proliferation and differentiation, with significant up-regulation of COL1A1 and BGLAP. Transcriptome analysis revealed activation of the PI3K-Akt signaling pathway, critical for osteogenesis. In vivo results confirmed enhanced trabecular density and bone volume compared to controls, indicating effective bone repair and regeneration. (4) Conclusions: The Mg@Ca scaffold offers a promising therapeutic approach for ONFH, providing a minimally invasive solution for bone defect repair while stimulating natural bone regeneration. Its injectable and self-setting properties ensure precise filling of bone defects, making it suitable for clinical applications. Full article

Background: Total hip arthroplasty (THA) remains the standard treatment for advanced osteoarthritis, including for complex deformities. Innovations such as spherical screw-in acetabular components aim to enhance fixation and long-term outcomes. This study evaluated the long-term clinical and radiographic outcomes of cementless THA using such implants. Methods: A retrospective analysis was conducted on 277 patients (293 hips) who underwent THA with a screw-in acetabular cup (Aesculap/BBraun SC, Tuttlingen, Germany) and Antega femoral stem between 2005 and 2024. Patients were evaluated using the modified Merle d’Aubigné and Postel (MAP) score, Visual Analog Scale (VAS), and radiographic classifications, with implant survival assessed via Kaplan–Meier analysis. Results: The mean follow-up was 13.8 years. At the final follow-up, 58.7% of hips achieved excellent MAP scores, and mean VAS pain scores improved from 7.1 to 1.8 (p < 0.05). Implant positioning was within the Lewinnek safe zone in 77.1% of cases. Revision was required in 6.1% of hips, mostly due to aseptic loosening. The five- and ten-year survival rates were 98.3% and 94.0%, respectively. Conclusions: Spherical screw-in acetabular cups provide durable fixation and satisfactory long-term outcomes in THA, particularly for dysplastic hips, supporting their continued use with careful surgical techniques. Full article

Osteoporosis is characterized by an imbalance between bone formation and resorption, leading to decreased bone mass and an increased fracture risk, mainly associated with aging. Current treatments include anti-resorptive and anabolic drugs. However, these often have side effects, leading many patients to seek natural biological alternatives. We have demonstrated previously that hops extract, rich in compounds with estrogenic activity classified as phytoestrogens, exerts osteogenic effects by promoting the osteoblastic differentiation of bone marrow stem cells (BMSCs) while inhibiting osteoclast activity in vitro. In our study, young male Sprague Dawley rats were randomized into two groups: one received hops extract (LPL, 1% w/v in drinking water) for two months, and the other drank water alone (C). The rats were euthanized, and their femurs were dissected and processed for static histomorphometry and bone biomechanics. Additionally, BMSCs were isolated from the humeri to evaluate their osteogenic potential. Our result demonstrated that LPL treatment enhanced the osteogenic potential of humeral BMSCs in ex vivo assays, upregulating osteogenic genes and downregulating pro-resorptive markers. These findings correlated with improved femoral bone microarchitecture and biomechanical parameters. In conclusion, a two-month treatment with LPL enhanced the osteogenic capacity of BMSCs, improving bone microarchitecture and biomechanical properties. These results suggest its potential as a natural alternative for promoting bone health. Full article

Hip replacement is a widespread surgical procedure that eliminates pain and restores motor functions of the pathologically altered hip joint. The issue lies in the lack of pre-operative strength calculations for implant shapes. So, they tend to break after surgery or damage the bone due to the complex stress–strain state. In the present paper, we studied the stress–strain state and ultimate load of S-type canine femoral implants based on titanium alloy Ti6Al4V using finite element analysis for static and cyclic loads. X-ray computed micro tomography data were used to construct the models. Re-engineering and restoration of the 3D geometry of the product were conducted. Strength analysis was performed in the finite element analysis software package Ansys Mechanical was used for various types of implant support. Locations with stress concentrators were identified, and ultimate loads on the implant were obtained. The influence of the rigidity of the support on the prosthesis stem was also studied. For the case of rigid support, the stress–strain state of the prosthesis was studied and the ultimate load was found to be 30.1 kg. Full article

Background/Objectives: Achieving optimal primary stability in cemented total hip arthroplasty remains a critical factor influencing long-term implant success. Variability in cementation techniques can significantly affect biomechanical performance, yet consensus on best practices is lacking. This study investigates the influence of cementation parameters on femoral stem fixation. Methods: This in vitro comparative study evaluated four cementation techniques—Classic (line-to-line), Press-Fit (undersized reaming), Overreaming (oversized reaming), and Valgus Malpositioning (15° deviation). An experimental model using standardized Polyurethane (PU) bone surrogates was developed. Mechanical testing assessed axial deformation and ultimate load capacity to failure. Results: The Press-Fit technique demonstrated significantly greater deformation (17.10 ± 0.89 mm) but a reduced load capacity (6317.47 ± 518.34 N) compared to the Classic approach. Overreaming and Valgus techniques both showed reduced mechanical performance, with Overreaming yielding the lowest structural integrity. Conclusions: Cement mantle thickness emerged as the primary determinant of biomechanical stability, surpassing the impact of implant positioning. While increased mantle thickness improves energy absorption, it may compromise ultimate strength. These findings underscore the importance of optimizing the cementation technique to balance flexibility and mechanical resistance, guiding surgical protocols toward improved implant longevity. This study introduces a novel integrative approach combining fluoroscopic assessment of cement mantle morphology with mechanical testing in a standardized model, providing new evidence on the relative influence of mantle thickness and implant malposition on femoral stem stability. Full article

Introduction: Intertrochanteric femoral fractures (IFFs) are the most common traumatic injuries in elderly people and significantly impact the patient’s health status. The current evidence indicates that short intramedullary nails may be a better choice than dynamic hip screws in IFF management, being less invasive and biomechanically superior, providing a buttress to limit fracture collapse. On the other hand, an unstable fracture may collapse even after adequate reduction and fixation. This paper aims to describe the surgical complexity of the nail-to-total hip arthroplasty (THA) conversion, focusing on the restoration of normal hip geometry. Material and Methods: Patients referred to our level I trauma center with failed cephalomedullary nailing following IFFs and managed with the nail-to-THA conversion were retrospectively recruited. The anteroposterior postoperative pelvis radiographs were analyzed to establish whether the normal biomechanics of the involved hip were restored. The following radiographic parameters were recorded and compared to the contralateral unaffected side: hip offset, cervical–diaphyseal angle, and limb length discrepancy. Clinical assessment was performed using the following scores: the Harris hip score (HHS) and the visual analog scale for pain (VAS). The independent samples t-test and the Pearson correlation test were performed. The tests were two-tailed; a p < 0.05 was considered significant. Results: A total of 31 patients met the inclusion and exclusion criteria (10 males and 21 females; mean age: 76.2 years; range: 66–90 years) and were included in this study. The modes of trochanteric nail failure included the following: cut-out in 22 cases (70.97%), non-union in 4 cases (12.9%), peri-implant fracture in 1 case (3.23%), cut-through in 2 cases (6.45%), and femoral head avascular necrosis (HAN) in 2 cases (6.45%). Long stems were used in 21 patients out of 31 (67.74%), while dual-mobility cups were implanted in 24 patients out of 31 (77.41%). A significant mean neck shaft angle (NSA) increase (p < 0.001) and a significant mean femoral offset reduction (FO, p 0.001) compared to the contralateral hip were recorded; a mean limb length discrepancy (LLD) of 8.35 mm was observed. A significant correlation between HHS and ∆NSA (p = 0.01) and ∆FO (p = 0.003) was recorded. Conclusions: Conversion from a cephalomedullary nail to THA is a complex procedure that should be considered a revision surgery, rather than a primary surgery. Surgeons must be aware that normal hip geometry may not be obtained during this surgical procedure; thus, a patient undergoing the nail-to-THA conversion for intertrochanteric fixation failure may have an increased risk of implant-related complications. Full article

Background: Stress shielding (SS) after total hip arthroplasty (THA) leads to proximal femoral bone loss and increases the risk of complications such as implant loosening and periprosthetic fracture. While various low-stiffness stems have been developed to prevent SS, they often compromise mechanical stability. A novel femoral stem composed of Ti-33.6Nb-4Sn (TNS) alloy offers a gradually decreasing Young’s modulus from proximal to distal regions, potentially improving load distribution and reducing SS. This study aimed to evaluate the mid-term clinical and radiographic outcomes of the TNS stem, with a particular focus on its effectiveness in suppressing SS. Methods: A prospective clinical study was conducted involving 35 patients who underwent THA using the TNS stem, with a minimum follow-up of 7 years. Twenty-one patients with Ti6Al4V metaphyseal-filling stems served as controls. Clinical outcomes were assessed using Japanese Orthopaedic Association (JOA) scores, and radiographic SS was graded using Engh’s classification and analyzed in Gruen zones. Inter-examiner reliability and statistical comparisons between groups were performed using appropriate tests. Results: The TNS group showed significantly higher preoperative JOA scores than the control group, but no significant difference in final scores. Both groups demonstrated significant improvement postoperatively. Third-degree SS occurred in the TNS group, although the overall SS grade distribution was significantly lower than in the control group (p = 0.03). SS frequency was significantly reduced in Gruen Zones 2, 3, and 6 in the TNS group. Conclusions: The TNS stem demonstrated a significant reduction in SS progression compared to conventional titanium stems over a 7-year period, with comparable clinical outcomes. However, the occurrence of third-degree SS indicates that material optimization alone may be insufficient, highlighting the need for further design improvements. Full article