Search Results (134)

Background/Objectives: Odontoid fractures—prevalently Anderson–D’Alonzo type II—are clinically relevant for their biomechanical instability and risk of non-union. Posterior C1–C2 fusion yields the highest fusion rates but sacrifices atlantoaxial rotation. Anterior odontoid screw fixation (AOSF) enables direct osteosynthesis while preserving motion. This study aimed to evaluate the radiographic outcomes, fusion rate, and technical considerations of AOSF in a consecutive single-center series, highlighting anatomical and procedural factors influencing bone healing. Methods: Retrospective, single-center case series of patients who underwent AOSF for acute type II odontoid fractures (2018–2024). Inclusion criteria included CT-confirmed fractures with reducible alignment. Radiographic parameters (fracture gap and angulation) were measured on standardized sagittal CT reconstructions. Outcomes were evaluated at 6 weeks, 3 months, and 6 months. Mean follow-up was 24 months. Results: The mean fracture gap decreased from 5.3 mm preoperatively to 0.8 mm postoperatively, and angulation from 27.8° to 3.5° (p < 0.0001). Nine of ten patients (90%) achieved solid fusion; one required secondary posterior fixation. No intra- or postoperative infections, neurovascular injuries, or neurological deficits were observed. Conclusions: AOSF is a safe and effective motion-preserving technique in appropriately selected Grauer IIA/IIB fractures. Precise anatomical reduction (<2 mm gap, <5–10° angulation) is a key predictor of successful fusion, even in elderly patients. Future multicenter studies with larger cohorts and standardized clinical outcome measures are needed to validate radiographic thresholds and optimize patient selection. Full article

Background and Objectives: Unilateral spinal stabilization has emerged as a less invasive alternative to bilateral fixation in the management of lateralized spinal pathologies. While both rigid and dynamic systems are utilized, comparative data regarding their clinical efficacy, radiological outcomes, and complication profiles—particularly in multilevel applications—remain limited. Materials and Methods: A retrospective, two-center analysis was conducted on 113 patients who underwent unilateral posterior spinal stabilization between 2019 and 2023. Patients were divided into unilateral rigid stabilization (URS, n = 41) and unilateral dynamic stabilization (UDS, n = 72) groups. Pathologies of the patients include disc herniations, foraminal and spinal stenosis, tumoral lesions and spondylolisthesis. Clinical outcomes were assessed using the Visual Analogue Scale (VAS) over a 24-month follow-up. Radiological parameters included fusion status, superior adjacent disc height, and foraminal height index. Complication rates, including adjacent segment degeneration (ASD), pseudoarthrosis, and screw loosening, were analyzed according to type-of-stabilization and construct length (two, three, or four levels). Results: Both URS and UDS groups demonstrated significant VAS improvement at final follow-up, with no significant differences between groups (p < 0.001). Fusion rates were significantly higher in the URS group (85.37% vs. 27.78%, p < 0.001), while pseudoarthrosis (39.02% vs. 16.62%, p = 0.081) were more frequent in URS. No cases of rod fracture or infection were observed. Complication rates, particularly ASD, increased with longer constructs (6.56%, 21.21%, vs. 31.58% p = 0.01), independent of stabilization type. Conclusions: Unilateral stabilization—whether rigid or dynamic—offers effective symptom relief with reduced surgical morbidity. However, dynamic systems may provide biomechanical advantages by preserving motion and minimizing adjacent segment stress. While rigid constructs yield higher fusion rates, they are associated with increased complications. These findings support the use of dynamic stabilization, particularly in multilevel constructs, and highlight the need for patient-specific surgical strategies to optimize outcomes and mitigate long-term complications. Full article

Background: Jones fractures of the 5th metatarsal are frequently associated with nonunion due to limited vascularization and repetitive mechanical stress. The aim of the study was to compare the biomechanical performance of T-plate and bicortical screw fixation using standardized 3D models. Methods: Three-dimensional models of the 5th metatarsal were generated from CT images and printed using PolyJet technology (Stratasys J5 DentaJet) using a rigid-elastic composite with properties similar to cortical and cancellous bone. Jones fractures were fixed with either a locked T-plate or a bicortical screw. The samples were tested under axial and oblique static loads (α = 0°, 90°, 180°) and for three values of interfragmentary distance (d = 0.1–1 mm), in a 3 × 2 factorial design. Results: The T-plate fixation recorded a maximum yield force (Fmax) of 149.78 ± 8.53 N (138–161 N), significantly higher compared to the bicortical screw −98.56 ± 2.58 N (96–101 N), (p < 0.05). The ductility index was higher for the plate, indicating a progressive transition to yield. The α and d factors significantly influenced the mechanical behavior, with the polynomial model explaining over 95% of the total variation. Discussion: The plate fixation demonstrated greater strength and superior biomechanical tolerance in imperfect reduction scenarios. The main limitation is the lack of fatigue testing and the inability of 3D models to reproduce the structural heterogeneity of human bone. Conclusions: Implant selection should be individualized based on fracture stability. 3D models provide a reproducible platform for comparative evaluation of osteosynthesis methods, but future studies should include cyclic loading and biological validation. Full article

Background and Objectives: Ankle fractures are common and occur in up to 25% of cases with posterior malleolus (PM) involvement. The gold standard for their treatment considers posterior approaches and plating of both the PM and fibula. However, in elderly and comorbid patients, this strategy remains controversial. The objective of this biomechanical study was to compare a minimally invasive fixation—utilizing a fibula nail and percutaneous anteroposterior (AP) screws—versus double plating. Materials and Methods: An oblique fibula fracture associated with a Haraguchi type 1 PM fracture was reproduced in sixteen human cadaveric specimens randomized to two groups. Eight specimens were treated with a fibula nail plus two AP screws fixing the PM, while the remaining eight specimens underwent double plating. Biomechanical testing was performed under destructive complex cyclic loading applying a staircase protocol. Interfragmentary movements were captured via motion tracking. Results: Initial axial stiffness was similar between nailing (1125.9 ± 341.7 N/mm) and double plating (742.9 ± 600.1 N/mm) (p = 0.129). During cyclic testing, interfragmentary fibula displacement was higher for double plating versus nailing (p = 0.057), whereas PM displacement and syndesmosis diastasis remained comparable between the two techniques (p ≥ 0.197). Conclusions: The minimally invasive fixation of associated PM and fibula fractures utilizing a fibula nail and two anteroposterior screws demonstrated non-inferiority to double plating and presents a viable option in cases where delicate soft tissue management is required. Full article

Adding a fibular strut bone graft to locking plate fixation has been introduced to improve stability and prevent varus collapse. The purpose of this study was to perform finite element analysis (FEA) of the biomechanical characteristics of different insertion angles of the fibular strut graft in proximal humerus fractures. Proximal humerus fractures with metaphyseal comminution and instability were simulated by creating wedge-shaped osteotomies medially and laterally for varus and valgus models, respectively. Three-dimensional finite element models were reconstructed from computed tomography images. A locking compression plate with a length of 90 mm (three holes) was applied to the proximal humerus fracture model. Fibular allografts were inserted at 0° and 30° to the humeral shaft. Axial and traction forces of 70°, 90°, and 110° relative to the vertical axis were applied to each model to simulate stress on the plate and graft. At axial loads, stresses in both the plate and the graft were lower when the graft was inserted at 0° than at 30°. Under traction loads, plate stress was lower with 30° insertion. Graft stress was also lower with 30° in most experimental conditions in both the valgus and varus models. These findings suggest that oblique insertion may provide biomechanical advantages under traction forces in unstable proximal humerus fractures. Full article

Schatzker type V bicondylar tibial plateau fractures present a major challenge due to the difficulty of achieving stable fixation with minimally invasive strategies. This study introduces a dual-thread lag and locking plate (DLLP) design that integrates lag screw compression with unilateral locking plate fixation. A custom-built compression evaluation platform and standardized 3D-printed fracture models were employed to assess biomechanical performance. DLLP produced measurable interfragmentary compression during screw insertion, with a mean displacement of 1.22 ± 0.11 mm compared with 0.02 ± 0.04 mm for conventional single lateral locking plates (SLLPs) (p < 0.05). In static testing, DLLP demonstrated a significantly greater maximum failure force (7801.51 ± 358.95 N) than SLLP (6224.84 ± 411.20 N, p < 0.05) and improved resistance to lateral displacement at 2 mm (3394.85 ± 392.81 N vs. 2766.36 ± 64.51 N, p = 0.03). Under dynamic fatigue loading simulating one year of functional use, all DLLP constructs survived 1 million cycles with <2 mm displacement, while all SLLP constructs failed prematurely (mean fatigue life: 408,679 ± 128,286 cycles). These findings highlight the critical role of lag screw compression in maintaining fracture stability and demonstrate that DLLP provides superior biomechanical performance compared with SLLP, supporting its potential as a less invasive alternative to dual plating in the treatment of complex tibial plateau fractures. Full article

Background: There is no consensus on the best treatment method for calcaneal fractures. The topic of lower limb biomechanics following calcaneal fracture treatment with various fixation methods has not been fully explored. The aim of the study was to assess the balance and load distribution of the lower limbs in patients after various methods of stabilization of calcaneal fractures. Methods: In this two-center study, we retrospectively collected data from 19 patients treated with internal plate fixation at a mean age of 46 years and 27 patients treated with Ilizarov external fixation at a mean age of 50 years. Using the Zebris Medical pedobarophragmatic platform, we assessed the percentage distribution of lower limb loads and balance. Results: There were no significant differences in total load distribution for both the operated (p = 0.489) and non-operated limb (p = 0.46), between the Ilizarov method group and the internal plate group. In the Ilizarov fixation group, total load distribution was 46.89% on the treated limb, and 53.11% on the uninjured limb, p = 0.077. In the internal plate fixation group, the mean total load distribution was 41.57% in the treated limb, and 57.89% in the uninjured limb, p = 0.008. The median CoG (center or gravity) sway path length was 132.41 cm and 170.21 cm in the Ilizarov and internal plate group, respectively, p = 0.023. The median CoG sway areas were 0.84 cm² and 7.57 cm² in the Ilizarov method group and internal plate fixation group, respectively, p < 0.001. Conclusions: The Ilizarov method was associated with more symmetrical load distribution and improved balance performance compared to internal plate fixation. Static biomechanical parameters of calcaneal fracture treatment were better in the Ilizarov group compared to patients with internal plate fixation. Full article

Introduction: Intramedullary nailing is widely used for long bone fractures. Traditional systems are reliable, but they present some complications regarding lack of modularity or possible growth plate damage. Methods: A novel locking rod–screw system featuring a central rod and a grooved screw with a secondary interlocking mechanism was developed and tested. Mechanical testing followed ASTM F543 and ISO 6475 standards using a 3.0 mm steel alloy prototype. Results: The system withstood mechanical testing >200,000 cycles at loads up to 200 N with no rates of failure or loosening, significantly outperforming other implants of the same size (3.0 mm TENS). Conclusions: The proposed implant demonstrates superior biomechanical performance in vitro, enabled by its unique hollow screw and secondary locking configuration. This modular and minimally invasive system shows promise for use in cases of smaller long bones, personalized paediatric fractures, and all types of diaphyseal fractures, but does warrant in vivo validation. Full article

Background/Objectives: The combined effect of femoral neck–shaft angle and lag screw position on unstable intertrochanteric fracture fixation has not been well established. This biomechanical study evaluated the effects of two caput–collum–diaphyseal (CCD) angles and two lag screw positions on construct stability. Methods: Twenty-four synthetic femurs with identical AO/OTA 31-A2.2 fracture gaps (2 mm) were fixed using cephalomedullary nails with CCD angles of either 125° or 130°, each with a central or inferior (calcar) lag screw (n = 6/group). Constructs were tested in a single-leg stance under preloading, cyclic loading (75–750 N, 10,000 cycles, and 2 Hz), and axial loading to failure. Lag screw migration was measured radiographically, and femoral head rotation was recorded using a three-dimensional coordinate-measuring device. Stiffness, failure load, and rotations were compared using the Kruskal–Wallis and Bonferroni post hoc tests. Results: The 125° inferior configuration showed the highest stiffness (188 ± 15 N/mm, p = 0.038) and failure load (1350 ± 97 N, p = 0.047), with the least screw migration (0.54 ± 0.11 mm, p = 0.003), significantly outperforming the 125° central and 130° central constructs. However, it exhibited greater varus collapse (2.25 ± 0.27°, p = 0.013) and axial rotation (~20–30% higher than others, p = 0.025). Screw position had a stronger effect on stability than the CCD angle, although the 130° inferior construct showed slightly less varus deformation. Conclusions: An inferior calcar-guided lag screw improves fixation strength and stiffness in unstable intertrochanteric fractures, particularly in those with a 125° nail. However, this configuration increases varus and rotational displacement, warranting adjunct measures to enhance rotational control in clinical applications. Full article

Carbon fiber-reinforced polyetheretherketone (CFR-PEEK) as an alternative to metallics in orthopedic implants offers biomechanical and radiological advantages. However, the extent of wear particle generation and its clinical impact are unclear. This systematic review evaluates clinical evidence of wear in fracture fixation devices. A systematic search was conducted to identify clinical studies reporting wear of metallic and CFR-PEEK implants used in extremities. Nineteen studies were included: three prospective cohorts, eight retrospective cohorts, one case series, and six case reports. Among 208 fixation plates, 43 were CFR-PEEK and all 93 intramedullary nails were metallic. Risk of bias ranged from low to serious, mainly due to selection bias. Wear-related complications were reported for both materials. Metallic implants showed elevated serum ion levels, metallic debris in tissues, and, in some cases, metallosis. CFR-PEEK implants showed limited evidence of carbon fiber fragments near implants. One comparative study reported higher inflammatory responses in CFR-PEEK explants, though no direct link between debris and implant removal was found. Both metallic and CFR-PEEK fracture fixation devices generate wear particles, which may induce biological responses. However, wear-related complications appear rare, especially with validated implant designs, and clinical significance of wear debris remains limited. Full article

Objectives: Tibial anterior cruciate ligament avulsion fractures (TAFs) are avulsions of the anterior cruciate ligament (ACL) from its insertion at the tibial intercondylar eminence that share the same trauma mechanism as ACL tears. TAFs were initially considered to be a pediatric equivalent to adult ACL ruptures due to the weaker insertion of the ACL on the immature tibial spine. Recent literature suggests that adult TAFs may be more common than previously thought. The incidence, possible concomitant injuries, and other differences between pediatric and adult TAFs remain a topic of ongoing debate in the literature. This systematic review provides a descriptive synthesis of the symptoms, biomechanics, and treatment outcomes of TAFs in pediatric and adult populations. This study highlights notable trends but avoids formal comparisons or meta-analysis due to heterogeneity in the literature. Methods: A systematic review was conducted on human-related studies involving tibial anterior cruciate ligament avulsion fractures, identified in PubMed^®® and EMBASE^®® databases between 2000 and 2024. Studies in English or German were included, while editorials, reviews, experimental studies, and papers with insufficient data were excluded. Data were extracted on patient demographics, trauma mechanisms, fracture classification, diagnostic modalities, treatment approaches, and clinical outcomes. Specific outcome parameters included: incidence and type of postoperative complications, return to sport rate, revision surgeries, hardware removal rates, and duration of follow-up. Due to heterogeneity in reporting, a descriptive synthesis approach was used rather than a meta-analysis. Results: The systematic search identified 3938 publications, with 2707 articles screened after duplicate removal. A total of 56 studies met the inclusion criteria. A total of 677 tibial avulsion fractures (TAF) were analyzed, with 208 (30.4%) pediatric and 469 (69.6%) adult patients. Type III fractures were most common in both groups (pediatric: 63.9%, adult: 63.4%). Concomitant injuries were more frequent in adults (35.6%) than children (8.2%). Arthroscopic surgery was the predominant technique (pediatric: 79.1%, adult: 87.8%). Fixation methods differed: pediatric cases more often used screws (40.5%) and sutures (38.2%), while adults favored sutures (49.7%) and suture anchors (23.1%). Complications were more frequent in pediatric patients (35.1% vs. 17.1%). Conclusions: TAFs show age-related differences in injury patterns and outcomes. Pediatric cases are mostly sports-related, while adult cases are commonly due to road traffic accidents. Concomitant injuries are more frequent in adults, whereas pediatric patients experience higher rates of arthrofibrosis and instability. Adults are more prone to malunion and non-union. These findings support the need for age-specific diagnostic and treatment strategies. Full article

Conventional static fixation for distal radius fractures (DRF) is clinically challenging, with methods often leading to complications such as malunion and pressure-related injuries. These issues stem from uncontrolled pressure and a lack of real-time biomechanical feedback, resulting in suboptimal functional recovery. To overcome these limitations, we engineered an intelligent, adaptive orthopedic device. The system is built on a patient-specific, 3D-printed architecture for a lightweight, personalized fit. It embeds an array of thin-film pressure sensors at critical anatomical sites to continuously quantify biomechanical forces. This data is transmitted via an Internet of Things (IoT) module to a cloud platform, enabling real-time remote monitoring by clinicians. The core innovation is a closed-loop feedback controller governed by a robust Interval Type-2 Fuzzy Logic (IT2-FLC) algorithm. This system autonomously adjusts servo-driven straps to dynamically regulate fixation pressure, adapting to changes in limb swelling. In a preliminary clinical evaluation, the group receiving the integrated treatment protocol, which included the smart splint and TCM herbal therapy, demonstrated superior anatomical restoration and functional recovery, evidenced by higher Cooney scores (91.65 vs. 83.15) and lower VAS pain scores. This proof-of-concept study validates a new paradigm for adaptive orthopedic devices, showing high potential for clinical translation. Full article

Background/Objectives: Traumatic dislocation of the lumbosacral facet joints without associated fractures is exceedingly rare in the pediatric population. Due to the unique anatomical and biomechanical features of the pediatric spine, such injuries present diagnostic and therapeutic challenges. This study aims to describe a rare case of bilateral L5–S1 jumped facets without fracture in a 13-year-old boy and to review the existing literature on pediatric traumatic facet dislocations. Methods: We performed a systematic review according to PRISMA guidelines, searching PubMed, Embase, Scopus, and the Cochrane Library up to 16 January 2025. Keywords included “pediatric traumatic spondylolisthesis” and “pediatric traumatic facet joint”. Eligible studies reported traumatic lumbosacral or thoracolumbar facet dislocations in patients aged <18 years. In addition, we report the clinical course, surgical management, and outcome of a representative case from our institution. Results: The systematic review identified 14 pediatric cases across 11 studies. Most patients were male (71.4%), with high-energy trauma as the primary mechanism. The L5–S1 level was most frequently involved (57.1%). Neurological impairment was present in 57.1% of cases. All patients underwent surgical treatment, with posterior fixation being the most common approach. Our case involved bilateral L5–S1 jumped facets without fracture, successfully treated with open reduction and posterior fusion. Postoperative recovery was favorable, with neurological improvement. Conclusions: Traumatic bilateral facet dislocation without fracture is an extremely rare but serious condition in pediatric patients. Early recognition and surgical stabilization are essential to prevent permanent neurological damage. This study reinforces the importance of advanced imaging and prompt multidisciplinary management in optimizing outcomes. Full article

Purpose: Thoracolumbar burst fractures represent a significant proportion of spinal injuries, with management strategies remaining a subject of debate. While four-screw (4S) short-segment posterior fixation is commonly used, recent biomechanical studies suggest that adding pedicle screws at the fractured level (six-screw, 6S, construct) may improve stability and clinical outcomes. However, the clinical relevance of these findings remains uncertain. Methods: A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines. Three databases (Scopus, PubMed/MEDLINE, Cochrane Library) were searched for studies comparing 4S and 6S constructs in thoracolumbar fractures. Inclusion criteria encompassed comparative clinical studies reporting perioperative, functional, and radiological outcomes. Data were extracted and analyzed using Review Manager 5.4.1, applying fixed- or random-effects models based on heterogeneity. Results: Twenty-two studies involving 1595 patients were included. The 6S group showed significantly improved postoperative pain scores (VAS), better short- and long-term sagittal alignment, and a lower implant failure rate. However, this technique was associated with longer operative times, increased intraoperative blood loss, and extended hospital stays. No significant differences in long-term functional disability (ODI) or infection rates were found. Conclusions: The addition of intermediate screws improves radiological outcomes and reduces implant failure but increases surgical burden. Further high-quality studies focusing on patient-reported outcomes and specific fracture subtypes are needed to refine clinical indications. Full article

Background/Objectives: Given the different biomechanical properties and surgical techniques between the L5-S1 and ≥L4-5 levels, it is necessary to explore RF risk factors at ≥L4-5 levels separately from the lumbosacral junction. This study aims to investigate the risk factors for rod fracture (RF) occurring at ≥L4-5 levels following adult spinal deformity (ASD) surgery. RF occurrence was assessed at the segment level. Methods: Patients who underwent ≥ 5-level fusion, including the sacrum or pelvis, with a minimum follow-up of 2 years were included in this study. Presumed risk factors in terms of patient, surgical, and radiographic variables were compared between the non-RF and RF groups at the segment level. Multivariate logistic regression analysis was performed to identify independent risk factors for RF at ≥L4-5 levels. Results: A total of 318 patients (mean age, 69.3 years; 88.4% female) were included, and 1082 segments were evaluated. During the mean follow-up duration of 47.4 months, RF developed in 45 (14.2%) patients for 51 (4.7%) segments. In multivariate logistic regression analysis, several risk factors were identified, as follows: the use of perioperative teriparatide (odds ratio [OR] = 0.26, p = 0.012), operated levels (L2-3 and L3-4 vs. L4-5 level [OR = 0.45, p = 0.022; OR = 0.16, p < 0.001, respectively]), fusion methods (posterior fusion and anterior column realignment vs. posterior lumbar interbody fusion [OR = 8.04, p < 0.001; OR = 5.37, p = 0.002, respectively]), pedicle subtraction osteotomy (PSO) (OR = 3.14, p = 0.020), and number of rods (four-rod configuration vs. dual-rod fixation [OR = 0.34, p = 0.044]). Conclusions: In this study, the factors related to RF at ≥L4-5 levels included the perioperative use of teriparatide, operated levels, fusion methods, performance of PSO, and rod configuration. Considering that surgical procedures vary by each segment, our findings may help establish segment-specific preventive strategies to reduce RF at ≥L4-5 levels. Full article