Search Results (37)

Introduction: Neck-preserving total hip arthroplasty (THA) has gained interest for conserving bone stock, restoring biomechanics, and facilitating revision surgery. The Nanos^® femoral stem, designed for metaphyseal fixation while preserving the femoral neck, represents a reliable alternative to conventional THA. This study reports 15-year clinical and radiographic outcomes of the Nanos implant. Materials and Methods: We retrospectively reviewed 53 patients (35 males, 18 females) who underwent THA with the Nanos stem between 2008 and 2010. Patients were stratified into two groups according to age: <50 years (n = 24) and ≥50 years (n = 29). The primary diagnosis was osteoarthritis (95%), with a few cases of avascular necrosis or dysplasia. Clinical evaluation included the Harris Hip Score (HHS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Radiographic assessment focused on implant stability, osteolysis, and heterotopic ossifications. Kaplan–Meier survival analysis was performed with revision for any reason as the endpoint. Results: At 15 years of follow-up, both groups showed significant improvement (p < 0.001). In patients <50 years, HHS increased from 53.3 to 94.8 and WOMAC decreased from 79.9 to 3.5. In patients ≥50 years, HHS improved from 47.5 to 95.2 and WOMAC from 81.5 to 3.2. Radiographs confirmed stable fixation without osteolysis. Complications included two dislocations and one cortical perforation requiring revision. Kaplan–Meier survivorship at 15 years was 100% (<50) and 96.6% (≥50). Conclusions: The Nanos stem provided excellent long-term outcomes with low complication and revision rates. It should be considered one of several reliable short-stem options for younger, active patients, offering durable function while preserving bone stock. Full article

Background: Femoral neck fractures (FNFs) in elderly patients are a growing concern given increased life expectancy and functional demands. Hemiarthroplasty is the standard treatment, but optimal fixation, approach, and perioperative management remain debated. This study aims to describe implant characteristics, perioperative details, survival, and complications of hemiarthroplasty in patients aged ≥75 years. Methods: A descriptive retrospective analysis was performed using the Emilia Romagna arthroplasty registry (RIPO). All patients ≥ 75 years who underwent hemiarthroplasty for FNFs between 2000 and 2021 were included. Data on demographics, implant fixation, surgical approach, complications, and revisions were analyzed. Implant survival was assessed with Kaplan–Meier analysis. Results: A total of 43,657 procedures were identified; the mean age was 85.5 years, and 73.7% were female. Cemented stems were used in ~76% of cases. The lateral approach was most common (52.6%), followed by posterolateral (43.7%) and anterior (2.9%). Overall revision rate was <2% (853 cases). Dislocation was the leading cause of failure (46.9%), followed by periprosthetic fracture, acetabular wear, aseptic loosening, and infection. Heparins were used for thromboprophylaxis in >93% of cases. Ninety-day mortality reached 13.9%. Conclusions: In this large registry study, cemented stems and the lateral approach were predominant. Despite low revision rates, dislocation remained the main cause of failure. High perioperative mortality highlights the vulnerability of this population and the importance of multidisciplinary care. Future high-quality studies, as prospective studies, will be necessary to determine the optimal solutions in this frail elderly population. Full article

Background: The use of tapered fluted revision stems has been shown to be reliable and safe. Primary stability is mandatory for a long-lasting fixation between bone and a prosthesis. Nevertheless, aseptic loosening due to insufficient primary stability occurs and may be related to technically improper preparation of the femoral canal. Instructions of manufacturers are heterogeneous regarding preparation of implant beds. Questions/Purposes: Does speed or the design of the reamer influence the accuracy of the implant bed and, consecutively, primary stability? Materials and Methods: A test foam with an elastic moduli and pressure resistance similar to that of cancellous bone was used. The medullary canal was prepared with the use of reamers of two different straight and tapered femoral revision devices. Three different rotational speeds were used for preparation. After preparation, primary stability was measured and fixating characteristics were derived. Results: Sufficient primary stability was achievable by all three preparation methods but fixating characteristics were different. Significantly higher micro-motions were detected near the tip of the prosthesis compared to those at all more proximal measuring points. Reaming with high velocity resulted in significantly higher micro-motions compared to that with mid- or low-speed burring. Conclusions: Different preparation methods may be one explanation for the range of reported survivorship data of the two devices with aseptic loosening as the end point. The precision of the implant bed and fixating characteristics were best after reaming with lower velocity. Superior but not significantly better fixation characteristics were achieved with the monobloc stem compared to those with the modular device. Full article

Background: NVD003 is an autologous, adipose tissue-derived stem cell-based tissue-engineered bone graft substitute with pro-osteogenic, anti-resorptive, and pro-angiogenic properties. Here, we describe highlights from the NVD003 preclinical development program as well as early clinical experience. Methods: NVD003 is produced in a Good Manufacturing Practice-controlled process from adipose stem cells collected during a minimally invasive liposuction procedure. The final implant is a ready-to-use moldable putty with fixed mineral content and predefined physiologic ranges of osteogenic cells and bioactive growth factors. Preclinical pharmacology studies were conducted in nude rats using a paravertebral implantation model, and subsequently, in a femoral critical-sized bone defect (CSBD) model. In a first-in-human Phase 1b/2a study, NVD003 was used for fracture osteosynthesis with classical fixation material in nine adults with recalcitrant lower limb non-union. NVD003 was also used at the discretion of treating physicians in four pediatric patients surgically treated for congenital pseudarthrosis of the tibia (CPT) with the Masquelet technique. Efficacy was evaluated as clinical healing and in terms of bone formation, bone union, and bone remodeling on radiographs and computed tomography using the extended Lane and Sandhu Scale. Results: Preclinical studies indicated that NVD003 requires cellularity for its bioactivity and moreover facilitates bone union when used as a graft material in femoral CSBD. In the clinical study, nine adult participants were successfully grafted with NVD003 and completed study follow-up to 24 months, with extended safety follow-up to 5 years ongoing. No adverse events were considered related to NVD003. Maximal bone formation occurred between 3 and 12 months post-implantation; the mean time to clinical healing was 6 months and the mean time to radiological union was 17 months. Ultimately, 89% (8/9) of patients achieved bone union without refracture. All four pediatric patients with CPT also achieved lasting bone union following grafting with NVD003. No safety signals were observed over a mean follow-up of 62.1 months. Conclusions: NVD003 represents a safe, autologous bone graft substitute product without side effects of heterotopic ossification or bone resorption. NVD003 facilitated bone union in adult and pediatric patients even under severe pathophysiological conditions. Full article

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 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: 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

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

This paper presents an experimental and numerical analysis of the mechanical behaviour of orthopaedic implants with crack-type defects, considering the principles and advantages of the modern X-FEM method, which was used due to limitations of traditional FEM in terms of crack growth simulation, especially for complex geometries. In X-FEM, the finite element space is enriched with discontinuity functions and asymptotic functions at the crack tip, which are integrated into the standard finite element approximation using the unity division property. Though rare, femoral component failures are well-documented complications that can occur after hip prosthetic implantation. Most stem fractures happen in the first third of the implant due to the loosening of the proximal stem and fixation of the distal stem, leading to bending and eventual fatigue failure. The main goal of this paper was to obtain accurate and representative models of such failures. Experimental analyses of the mechanical behaviour of implants subjected to physiological loads, according to relevant standards, using a new combined approach, including both experiments and numerical simulations was presented. The goal was to verify the numerical results and obtain a novel, effective methodology for assessing the remaining fatigue life of hip implants. For this purpose, the analysis of the influence of Paris coefficients on the total number of cycles was also considered. Hence, this simulation involved defining loads to closely mimic real-life scenarios, including a combination of activities such as ascending stairs, stumbling, and descending stairs. The tensile properties of the titanium alloy were experimentally determined, along with the Paris law coefficients C and m. The finite element software ANSYS 2022R2 version was used to develop and calculate the three-dimensional model with a crack, and the resulting stresses, stress intensity factors, and the number of cycles presented in the figures, tables, and diagrams. The results for the fatigue life of a partial hip implant subjected to various load cases indicated significant differences in behaviour, and this underscores the importance of analysing each case individually, as these loads are heavily influenced by each patient’s specific activities. It was concluded that the use of numerical methods enabled the preliminary analyses of the mechanical behaviour of implants under fatigue loading for several different load cases, and these findings can be effectively used to predict the possibility of Ti-6Al-4V implant failure under variable cyclic loads. Full article

Background: Although tapered and fluted stems are frequently used in revision total hip arthroplasty (RTHA), major complications following the implantation of these implants, like periprosthetic fractures, are less investigated. As epidemiological data do not exist yet, the incidence of PPF in a mid- to long-term follow-up is unknown and potential risk factors have not been detected. Methods: Propensity score matching (PSA) of two retrospectively investigated cohorts after femoral RTHA with either modular (n = 130) or monobloc prosthesis (n = 129) was executed. A total of 186 cases, including 93 of each device, were finally analyzed during a mean follow-up period of 9.1 (0.5–23.1) years. The time-dependent risk of PPF was calculated using a Kaplan–Meier analysis. Results: The cumulative risk for PPF of the whole cohort was 5.7% (95% CI: 1.7–9.8%) at 23.1 years, for the modular device, 13.0% (95% CI: 0–26.0%) after 13.7 years and the monobloc stem, 3.4% (95% CI: 0–7.1%) after 23.1 years, without a significant difference between the two designs (log-rank p = 0.1922). All eight fractures occurred in women and there was one collapse of the fracture after open reduction and internal fixation. The cumulative risk was 10.1% (95% CI: 3.1–17.1%) at 23.1 years compared to 0% after 21.4 years in men (log-rank p = 0.0117). Diabetes was significantly associated with the presence of PPF during follow-up (non-diabetic, 4.4% (95% CI: 0–8.2%) after 21.3 years vs. diabetic, 16.6% (96% CI: 0–34.5%) after 13.3 years; log-rank p = 0.0066). Longer reconstructions showed also a significantly higher fracture risk (equal or longer than median implant length vs. shorter; 10.5% (95% CI: 3.1–17.1%) after 21.4 years vs. 1.0% (95% CI: 0–3.1%) after 23.1 years; log-rank p = 0.0276) but did not correlate with a preoperative defect situation. Conclusions: The cumulative risk for PPF after femoral revision with tapered and fluted devices is a relevant failure reason in this mid- to long-term investigation. There was no difference between the monobloc stem or modular implant. Women and diabetics are at risk, and the choice of a longer implant than necessary is neither prophylactical for PPF nor useful in the case of the operative treatment of a PPF after femoral RTHA with these revision devices. Full article

Background/Objectives: The German Arthroplasty Registry (EPRD) recorded almost 100,000 femoral neck fractures between 2013 and 2023. The aim of this study was to identify survival rates and risk factors for failure in individuals with femoral neck fractures. Methods: A dataset of 97,410 cases from the EPRD was analyzed. We compared hemiarthroplasty (HA) and total hip arthroplasty (THA) using machine learning algorithms (MLAs) and statistical modeling approaches. For the MLA, the dataset was partitioned into training and test sets, with iterative feature selection and hyperparameter search. Predictive models were developed using XGBoost classifiers. Based on the feature importance, we performed LASSO regression to assess the odds ratios for key predictors of implant failure. Results: The failure rate was 3.7% for HAs and 5.6% for THAs, with a peak six weeks after surgery. LASSO regression revealed six risk factors for failure: non-cemented stem fixation (OR: 1.022, 95% CI: 1.019–1.026), treatment type (THA vs. HA; OR: 1.013, 95% CI: 1.010–1.016), time to discharge (OR: 1.006, 95% CI: 1.006–1.006), male sex (OR: 1.003, 95% CI: 1.000–1.005), age (OR: 0.999, 95% CI: 0.999–0.999), and day of surgery (weekday vs. weekend/holiday; OR: 1.004, 95% CI: 1.002–1.008). Conclusions: Longer hospital stays, male sex, and surgeries performed on weekends or holidays were associated with higher failure risks, while cemented fixation and hemiarthroplasty showed protective effects. Given that the overall failure rate was only 4.5%, even a 1–2% change in odds represents a very large clinical effect. Full article

Managing periprosthetic femoral fractures is challenging, particularly in osteoporotic patients with fragile bones. Revision with a long stem is commonly considered but may fail to provide adequate fixation and stability in fragile bones. A novel approach using sandwiched strut allografts and controlled bone crushing with robust cable fixation can offer mechanical support and provide secondary stability to the loosened femoral stem and can be considered a treatment option for low-demand patients. A 73-year-old female with 23 years of hemodialysis experienced pain and instability in her right thigh following a slip. She had extremely low bone mineral density, and radiographs revealed a periprosthetic femoral fracture with a loosened femoral prosthesis, classified as Vancouver type B3. The patient underwent surgical fixation using a long anatomical plate augmented with dual strut allografts sandwiched anterior and posterior femur. Robust cable fixation was performed to partially crush the native cortical bone against the stem to enhance stability. Postoperative imaging at 18 months confirmed successful bone union and implant stability, and the patient regained preoperative functional capacity without pain. This case demonstrates that partially crushing native bone with dual strut allografts may provide stability to the loosened femoral stem and can be an effective alternative to long-stem revision surgery for patients with highly fragile bones. This approach may provide immediate mechanical stability and can be a potential treatment option for managing fragile periprosthetic femoral fractures. Full article

Background and Objectives: The study aimed to evaluate a newly designed semicircular implant for the fixation of Vancouver Type B1 periprosthetic femoral fractures (PFFs) in total hip arthroplasty (THA) patients. To determine its strength and clinical applicability, the new implant was compared biomechanically with conventional fixation methods, such as lateral locking plate fixation and a plate combined with cerclage wires. Materials and Methods: Fifteen synthetic femur models were used in this biomechanical study. A Vancouver Type B1 periprosthetic fracture was simulated by osteotomy 5 mm distal to the femoral stem. The models were divided into three groups: Group I (lateral locking plate fixation), Group II (lateral locking plate with cerclage wires), and Group III (new semicircular implant system). All fixation methods were subjected to axial loading, lateral bending, and torsional force testing using an MTS biomechanical testing device. Failure load and displacement were measured to assess stability. Results: The semicircular implant (Group III) demonstrated a significantly higher failure load (778.8 ± 74.089 N) compared to the lateral plate (Group I: 467 ± 68.165 N) and plate with cerclage wires (Group II: 652.4 ± 65.474 N; p < 0.001). The new implant also exhibited superior stability under axial, lateral bending, and torsional forces. The failure load for Group III was more robust, with fractures occurring at the screw level rather than plate or screw detachment. Conclusions: Compared to traditional fixation methods, the newly designed semicircular implant demonstrated superior biomechanical performance in stabilizing Vancouver Type B1 periprosthetic femoral fractures. It withstood higher physiological loads, offered better structural stability, and could be an alternative to existing fixation systems in clinical practice. Further studies, including cadaveric and in vivo trials, are recommended to confirm these results and assess the long-term clinical outcomes. Full article