Search Results (2,594)

Background and Clinical Significance: Multiligamentous knee injuries (MLKIs) are uncommon but severe injuries associated with instability, neurovascular compromise, and long-term functional impairment. Irreducible knee dislocations are a distinct subgroup requiring urgent intervention because soft-tissue interposition may prevent closed reduction and place the limb at risk of skin necrosis and vascular compromise. This report reviews current concepts in MLKI management and presents a complex KD-IV irreducible knee dislocation treated with a staged surgical strategy. Case Presentation: A 56-year-old woman presented 24 h after a skiing injury with a grossly deformed knee, multidirectional instability, and an anteromedial “pucker sign”. Magnetic resonance imaging demonstrated a KD-IV injury with complete rupture of the anterior cruciate ligament, posterior cruciate ligament, and medial collateral ligament, associated with capsular disruption and intra-articular soft-tissue interposition causing irreducibility. Urgent open reduction was performed. The first stage included reduction of the incarcerated capsule, capsular repair, and reconstruction of the posteromedial corner and medial collateral ligament using a semitendinosus autograft. Delayed reassessment at 6 months demonstrated satisfactory stability, minimal residual anterior laxity, and no subjective instability; therefore, anterior cruciate ligament reconstruction was not performed. At final follow-up, the patient had near-full range of motion, no significant valgus instability, and no arthrofibrosis or vascular complications. Conclusions: Management of MLKIs should be individualized according to reducibility, soft-tissue condition, neurovascular status, and functional demands. Irreducible KD-IV dislocations with a pucker sign require urgent open reduction. In selected patients, staged reconstruction may reduce postoperative stiffness and allow selective omission of cruciate ligament reconstruction when satisfactory functional stability is achieved. Full article

Background/Objectives: Musculoskeletal soft-tissue injuries are common among physically active individuals and arise from complex interactions between environmental and biological factors. Genetic variation in genes involved in extracellular matrix (ECM) organization may contribute to individual susceptibility to such injuries. This study investigated whether polymorphisms in aggrecan (ACAN, rs2351491 and rs1042631) and fibromodulin (FMOD, rs7543148) genes are associated with susceptibility to sports-related injuries. Methods: The study included 335 physically active Caucasians, comprising 202 participants with a history of non-contact sports-related musculoskeletal injuries and 133 uninjured controls. Genotyping was performed using real-time polymerase chain reaction. Results: No significant associations were observed between the analyzed polymorphisms and overall injury occurrence after correction for multiple comparisons. A nominal association was observed for ACAN rs2351491 in the overall injury comparison under the overdominant model (p = 0.0457), where CT heterozygotes were more frequent among injured participants. The ACAN rs1042631 variant showed nominal associations with anterior cruciate ligament (ACL) injury under the codominant (p = 0.0179), recessive (p = 0.0243), and overdominant (p = 0.0346) models, with the TT genotype associated with lower odds of ACL injury under the recessive model (OR = 0.15, 95% CI: 0.02–1.22). No significant associations were observed for FMOD rs7543148 or for haplotype analysis of ACAN variants. Conclusions: No robust associations were identified between the investigated variants and susceptibility to musculoskeletal soft-tissue injury after correction for multiple testing. Nominal signals observed for ACAN variants, particularly in ACL-focused analyses, warrant further investigation but should be interpreted cautiously and confirmed in larger, independent cohorts. Full article

Background: The aim of the present study was to investigate whether the use of a tourniquet during anterior cruciate ligament reconstruction affects the length of the hamstring tendon used for autograft. Methods: Adult patients who were referred to the Orthopedics and Traumatology Department of The Malatya Turgut Özal University hospital and were diagnosed with anterior cruciate ligament injury between 30 July 2025 and 30 December 2025 were included in the study. In total, 31 patients from whom the hamstring tendon was harvested without a tourniquet were placed in Group 1, and 36 patients from whom the hamstring tendon was harvested with a tourniquet were placed in Group 2. This study is a prospective, randomized, comparative study. These two groups were compared with respect to the lengths of the hamstring tendons used as autografts. Results: The semitendinosus and gracilis tendon lengths in Group 1 were 29.61 ± 1.76 cm and 27.68 ± 2.02 cm, respectively. In Group 2, the semitendinosus and gracilis tendon lengths were 25.67 ± 1.45 cm and 23.72 ± 1.06 cm, respectively. A statistically significant difference was observed between the semitendinosus and gracilis tendon lengths of the participants in Groups 1 and 2 (p < 0.05). Conclusions: These findings suggest that avoiding tourniquet use during hamstring tendon harvest may represent a simple technical modification that can influence harvested tendon length during anterior cruciate ligament reconstruction. Full article

Background/Objectives: The uprighting of mesially tipped mandibular second molars following first molar loss is a complex surgical and orthodontic challenge. Conventional methods often result in reciprocal anchorage loss. Mini-implants (MIs) have emerged as essential temporary anchorage devices (TADs) that provide absolute anchorage and enable more predictable tooth movements. Methods: Numerical simulations were performed to evaluate the forces required for mandibular second molar uprighting under two conditions: first, only with the second molar present, and second, with both the second and the third molars present. Although the periodontal ligament exhibits nonlinear and viscoelastic behavior in vivo, a linear elastic approximation was adopted to allow for a reliable evaluation of comparative stress distribution and initial displacement patterns within the scope of this exploratory biomechanical study. Stress distribution in the roots, periodontal ligament, and alveolar bone was assessed for each scenario. Two three-dimensional (3D) models of the left mandibular segment were created from scans of a human mandible and its teeth. The first model included the canine, the first and second premolars, and the second molar. A second model additionally incorporated the third molar. A retromolar MI was placed in both models. Molar uprighting was simulated using a spring connecting the implant to a button bonded on the mesial surface of the second molar. A force of 200 g was applied because in clinical orthodontic practice, forces that exceed approximately 2 N may cause pain or undesirable tooth mobility. Displacements along the X, Y, and Z axes, as well as regions of peak stress, were analyzed. Results: Model 1 showed maximum displacements at the furcation/mid-root, distal root apex, and distal crown, with von Mises stresses of 0.470 to 0.371 MPa. In Model 2, peak displacements occurred at the mesial root and crown, with stresses of 0.185 and 0.149 MPa, respectively. The magnitude of displacements was in the order of 10⁻⁵ mm. Such values represent initial mechanical responses rather than clinically observable tooth movements. However, the differences between models (e.g., the stress reduction) are expected to be clinically meaningful. Conclusions: Since clinical measurements regarding the stress distribution on teeth and surrounding tissues during orthodontic molar uprighting movements are impossible to perform, the finite element method (FEM) can offer insight into these aspects. The presence of the third molar significantly modulates the biomechanics of second molar uprighting via retromolar MIs. When the third molar is present, the second molar exhibits a reduced tendency for deformation during distalization, although this leads to a slower displacement. This FEM provides biomechanical insights but does not support direct clinical decision-making. The present findings should be viewed as theoretical biomechanical tendencies that require confirmation through clinical, experimental, and longitudinal studies before translation into clinical practice. Full article

This study presents a predictive manufacturing framework for customizing the biomechanical response of a 3D printed ergonomic armrest based on relaxed Voronoi metamaterials. A double curved armrest geometry was combined with parametric lattice generation, stereolithography printing in BioMed Elastic 50A resin, uniaxial compression testing of cylindrical lattice specimens, and homogenized finite element simulations using a CT derived forearm model under 15, 30, and 45 N loading. The results showed that both cell size and ligament thickness strongly affected compressive behavior, with smaller cells and thicker ligaments producing higher stiffness and earlier densification. Among the uniform configurations selected for simulation, the E-9-1.5 lattice provided the most balanced response, maintaining contact pressure below about 70 kPa up to 45 N, whereas the stiffer E-7-1.5 configuration exceeded 160 kPa and the E-7-1 configuration surpassed 100 kPa at higher load. Based on these findings, a functionally graded Voronoi concept was developed to combine a more compliant central zone with a stiffer peripheral support region while preserving conformity to the complex armrest boundary. Overall, the results show that relaxed Voronoi lattices offer a computationally efficient route toward anatomically conforming and mechanically tunable cushioning interfaces. Full article

Cranial cruciate ligament rupture is a common orthopedic condition in dogs, and tibial tuberosity advancement is a well-established surgical treatment. The aim of this retrospective study was to evaluate the short-term clinical and radiographic outcomes of a cageless tibial tuberosity advancement technique in small-breed dogs. Medical records of 63 dogs (77 stifles) treated using this technique were reviewed. Fixation was achieved using three construct types: a screw–pin construct (the majority of cases), a screw-only construct, or a screw combined with two pins. Due to small subgroup sizes, fixation-type outcomes were primarily analyzed descriptively. Clinical and radiographic evaluations were performed immediately after surgery and at eight weeks postoperatively. Clinical outcomes were graded based on limb function, and radiographic bone healing was scored using a standardized scale. Postoperative complications were recorded and analyzed in relation to patient and procedural variables. No intraoperative complications were observed, while postoperative complications occurred in 27% of dogs and were predominantly minor and implant-related. Lameness scores improved significantly over the follow-up period. All treated stifles demonstrated stable implants, maintained advancement, and satisfactory bone healing. The use of bone graft material appeared to be associated with fewer complications and more favorable clinical outcomes; however, this observation should be interpreted with caution given the retrospective and non-randomized design of the study. In this retrospective case series, cageless tibial tuberosity advancement using screw-based fixation (predominantly screw–pin constructs) was associated with favorable short-term clinical and radiographic outcomes. These findings should be considered preliminary and limited to short-term evaluation, given the retrospective design, absence of a control group, and relatively short follow-up period. Further prospective studies with larger populations, standardized outcome measures, and longer follow-up are warranted to confirm these findings. Full article

A 34-year-old male presented with persistent medial knee pain and mechanical symptoms three months after a rotational injury, with limited knee extension on examination. Magnetic resonance imaging demonstrated the double posterior cruciate ligament (PCL) sign, produced by a displaced bucket-handle tear of the medial meniscus with the fragment lying anterior and parallel to the intact PCL within the intercondylar notch. Coronal sequences confirmed displacement and loss of normal meniscal configuration. Arthroscopy verified the diagnosis, and arthroscopic partial meniscectomy was performed due to chronic displacement and poor healing potential. Following structured rehabilitation, the patient returned to full athletic activity without symptoms at one-year follow-up. This case underscores the importance of recognizing the double PCL sign as a highly specific MRI finding enabling prompt diagnosis and appropriate management of displaced bucket-handle meniscal tears, while also highlighting its radiologic–arthroscopic correlation and the clinical implications of delayed presentation on treatment strategy, and provides a clear illustrative example of this classic imaging sign for educational purposes. Full article

Periodontal disease represents a major global health burden, beginning with gingivitis and progressing to periodontitis, which causes connective tissue breakdown, alveolar bone resorption, and eventual tooth loss. Beyond local pathology, periodontitis is a chronic inflammatory condition with systemic associations, including cardiovascular disease, diabetes, and metabolic disorders. Mesenchymal stem cells (MSCs) and their extracellular vesicles (EVs) have emerged as promising candidates for periodontal regeneration. This review aimed to map the current evidence on MSC-derived EVs (MSC-EVs) in periodontal regeneration, focusing on their mechanisms of action, therapeutic potential, and translational challenges. A comprehensive literature search was conducted across a major biomedical database (PubMed) to identify preclinical and clinical studies investigating MSC-EVs in the context of periodontitis. Data were charted on EV cargo composition, biological functions, regenerative outcomes, and reported limitations. Evidence indicates that MSC-EVs encapsulate bioactive molecules—including antimicrobial peptides, proteins, lipids, and microRNAs—that modulate immune responses, suppress pro-inflammatory signaling, and promote angiogenesis and tissue repair. In periodontal models, MSC-EVs attenuate osteoclast activity, enhance fibroblast proliferation, and stimulate extracellular matrix remodeling, supporting regeneration of periodontal ligament and alveolar bone. Exosome-based approaches demonstrate advantages such as reduced immunogenicity, improved safety, and feasibility for storage and standardization. However, most findings remain preclinical, with limited human data available. To bridge the translational gap, well-designed clinical trials are needed to confirm efficacy and safety while addressing regulatory challenges, GMP standards, and outcome measures. Harnessing their regenerative capacity while mitigating side effects may guide precision-targeted therapies, and continued mechanistic studies with standardized production will be key to advancing MSC-EVs into clinical practice. Full article

Purpose: To critically evaluate the role or effect of platelet-rich plasma (PRP) in anterior cruciate ligament (ACL) reconstruction in terms of clinical and radiological outcomes. Method: We conducted a systematic search of PubMed, Embase, the Cochrane Library, and Web of Science to identify relevant studies. Clinical outcomes included the Visual Analogue Scale (VAS), International Knee Documentation Committee (IKDC) subjective and objective evaluations, Lysholm score, Tegner score, anterior knee laxity, Knee Injury and Osteoarthritis Outcome Score (KOOS), Kujala score, Victorian Institute of Sport Assessment (VISA) scale, proprioception, isokinetic strength, and physical examination tests (anterior drawer, Lachman, and pivot-shift tests). Radiological outcomes encompassed measures obtained via magnetic resonance imaging (MRI), computed tomography (CT), X-ray, and ultrasound. Statistical significance was defined as a p value < 0.05, and all analyses were performed using R software (version 4.1.3). Results: A total of 23 studies, including 19 randomized controlled trials, met the inclusion criteria, encompassing 1072 patients overall. The meta-analysis showed significant differences between PRP group and non-PRP group with regard to VAS score at 6- and 12-month follow-up, Lysholm score at 6-month follow-up, and Tegner score at 6-month follow-up. Meta-regression showed that the two group differences in VAS score changed significantly with follow-up time (p < 0.01). In terms of radiological findings, about half of the assessments favored PRP to facilitate the graft maturation and integration at 6-month follow-up. Conclusions: PRP application in ACL reconstruction compared with non-PRP, may produce short-term but not long-term clinical outcomes such as VAS score, Lysholm score and Tegner score. While some short-term statistical differences exist, their magnitude and durability do not yet justify routine clinical adoption of PRP in ACL reconstruction. Larger samples and higher-quality studies are needed to support our results and further explore the advantages of PRP in other aspects. Level of evidence: Level II. Full article

Periodontitis represents a primary etiological factor in tooth mobility, with oxidative stress contributing critically to periodontal tissue destruction. Evodiamine (EVO), a quinazolinocarboline alkaloid, exhibits multiple biological activities; however, its antioxidant effects and mechanism in periodontitis have not been elucidated. The aim of this study was to investigate the regulatory effect of EVO on oxidative stress in periodontitis and to explore the associated molecular mechanism. The results indicate that EVO exhibits potent antimicrobial activity against key periodontal pathogens and suppresses pathogen-induced ROS generation as well as the release of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) under periodontitis conditions. EVO binds specifically to the Kelch domain of KEAP1 with a strong binding energy (−11.67 kcal/mol), inhibits KEAP1–NRF2 interaction, and consequently upregulates the expression of antioxidant enzymes (HO-1, NQO1, GCLC, and SOD2), while downregulating the expression of iNOS, COX2, and NOX2. Furthermore, EVO inhibits the pro-apoptotic effect of the JAK2/STAT3 signaling axis and mitigates inflammation, alleviates cell cycle arrest, and promotes the migration and repair of periodontal ligament cells. Collectively, these findings suggest that EVO acts as a potential binder of KEAP1 that alleviates periodontal inflammation through modulation of oxidative stress and regulation of the JAK2/STAT3 pathway. Full article

The rising popularity of sports practiced without adequate preparation has increased the incidence of anterior cruciate ligament (ACL) injuries, particularly among young individuals. Because the ACL has a very limited intrinsic healing capacity, surgical reconstruction—most often using autologous grafts—remains the standard of care. However, current techniques frequently lead to donor-site morbidity and do not consistently restore long-term joint stability, contributing to early post-traumatic osteoarthritis in active patients. Over the past decades, tissue engineering (TE) has opened promising avenues for developing biological substitutes capable of overcoming these limitations. Despite substantial progress, no strategy has yet demonstrated reliable and clinically validated functional regeneration of the human ACL. Meanwhile, artificial intelligence is emerging as a complementary tool for diagnosis, surgical planning, biomechanical assessment, and personalized reconstruction strategies. This review aims to provide a comprehensive overview of current TE-based approaches for ACL repair and reconstruction, analyzes their biological and biomechanical limitations, and discusses emerging concepts that may enhance future clinical outcomes. We first summarize the fundamental principles of tissue engineering, then examine the major strategies proposed for ACL regeneration—highlighting their respective strengths and shortcomings—and finally outline perspectives for a novel approach currently under development. Full article

Background/Objectives: Progressive collapsing foot deformity (PCFD) is driven by multiplanar peritalar instability. This study evaluated the clinical and radiographic outcomes of a standardized four-component reconstruction protocol designed to facilitate immediate postoperative weight-bearing in Stage 1a/1b PCFD. Methods: This single-center retrospective study included 20 patients treated between 2015 and 2023 with medializing calcaneal osteotomy, spring ligament repair, flexor digitorum longus (FDL) tendon transfer with internal brace augmentation, and subtalar arthroereisis. Clinical (VAS, AOFAS) and radiographic parameters (anteroposterior and lateral Meary angles, calcaneal pitch, and talonavicular coverage angle) were assessed longitudinally, with subgroup analysis comparing implant removal versus retention. Results: The protocol yielded significant overall improvements. Mean VAS decreased by 4.37 points (p < 0.001), and final AOFAS reached 84.7 ± 7.6 at the final follow-up. Although subtalar arthroereisis was removed in 45% of patients due to symptomatic irritation, subgroup analysis revealed no significant loss of radiographic correction (p > 0.05). Notably, a significant interaction effect was observed for VAS scores (p = 0.002) and AOFAS scores (p = 0.041), with the removal group demonstrating a pronounced functional recovery trajectory following explantation. No major complications occurred. Conclusions: A standardized four-in-one reconstruction provides reliable multiplanar correction in Stage 1a/1b PCFD. The maintenance of structural alignment despite a high implant removal rate supports the role of arthroereisis as a temporary but valuable adjunct for early mobilization. This strategy offers a reproducible framework for joint-preserving PCFD management. Full article

Background: Multibody models are essential for studying knee joint mechanics, but their reliability and subsequent clinical utility are limited by uncertainties in ligament and contact parameters. Currently, no consensus exists on which parameters to prioritize or which statistical distributions best establish model credibility. Objectives: This scoping review aims to systematize reported uncertainty values for ligament and contact parameters in multibody models of the natural knee to identify trends and research gaps. Methods: Following PRISMA-ScR guidelines, a systematic search was conducted across PubMed, Scopus, and Web of Science. Methodological quality was assessed using a customized 13-item checklist, and the data were synthesized via a narrative approach by charting parameter types, quantification methods, and model structures. Results: In total, 19 articles were included (out of 494 identified), showing a wide variability in uncertain parameter types, values, and modeling approaches. Ligaments were typically represented as deformable cables with quadratic–linear behavior, while articular contact utilized elastic foundation formulations or mechanisms. Standard deviations of 30% of the mean for ligament stiffness and 0.02 for reference strain (typically modeled within Gaussian distributions) were the most frequently quantified uncertain parameters. Geometric uncertainties for ligament attachment points varied widely, ranging from 1.0 to 5.0 mm. Idealized contact geometry also varied within 2.5 mm for linear coordinates and 15° for angular coordinates. Conclusions: Wide variability and inconsistent reports highlight a need for standardized definitions of parameter uncertainty in multibody knee modeling to improve reproducibility of musculoskeletal knee simulations and ensure a reliable transition of these models into clinical practice. Full article

Injuries in elite youth football may disrupt training continuity and long-term development, particularly during the post-peak height velocity (post-PHV) period when training and match demands increase. Therefore, the aim of this study was to determine injury incidence and describe injury patterns in elite U17 football players across six consecutive competitive seasons, including injury type, anatomical location, mechanism, recurrence, and severity. A prospective longitudinal injury-surveillance design was implemented in one elite football academy from 2016/2017 to 2021/2022. Injuries were recorded in the club’s medical database using the international consensus time-loss definition. Injury incidence per 1000 h was calculated for overall exposure, training, and matches, and injuries were analyzed by diagnosis, mechanism, recurrence, and severity. Across the study period, 331 injuries were recorded. Overall injury incidence was 6.95/1000 h, with markedly higher incidence in matches (20.61/1000 h) than training (5.82/1000 h). Seasonal incidence ranged from 4.49/1000 h in 2019/2020 to 9.31/1000 h in 2021/2022. The proportion of injured players ranged from 48% to 76% per season. The most frequent injuries were contusions and muscle cramps/DOMS, followed by ligament injuries, tendinosis, and muscle ruptures. Knee, thigh, ankle, and hip/groin were the most affected regions. Most diagnoses showed a predominantly non-contact pattern. These findings support targeted prevention and load-management strategies in elite youth football. Full article

Background/Objectives: Objective, non-invasive biomarkers are needed to track anterior cruciate ligament (ACL) graft maturation and support individualized return-to-sport decisions. This study evaluated a single-session multiparametric quantitative MRI (qMRI) protocol for longitudinal assessment of ACL graft microstructural evolution and its association with patient-reported outcomes. Methods: Twenty-eight patients undergoing primary ACL reconstruction with hamstring autografts underwent multiparametric qMRI (T1, T2*, R2*, and PD mapping) at 1, 3, 6, and 12 months. The contralateral native ACL served as a within-subject control. IKDC, Lysholm, and VAS scores were recorded at each visit. Linear mixed-effects models were used to test longitudinal changes. Correlations of baseline-normalized changes between adjacent visits were used to evaluate imaging–clinical associations. Results: All qMRI parameters changed significantly over time (all p < 0.001). At 1 month, T1, PD, and T2* were lower and R2* higher than the contralateral native ACL (all p < 0.001). Thereafter, T1, PD, and T2* increased and R2* decreased, with most metrics approaching contralateral values by 3–6 months (all p < 0.05), and changes entered a plateau after 6 months (all p > 0.05). IKDC, Lysholm, and VAS improved over time (all p < 0.001), mainly before 6 months. Greater early T2* increases and R2* decreases (1–3 months) were associated with less pain relief and smaller Lysholm improvement (p < 0.05); no significant associations were observed from 6–12 months. Conclusions: Single-session multiparametric qMRI sensitively captures ACL graft maturation and highlights 3–6 months as a critical remodeling window, providing objective biomarkers to complement clinical assessment for individualized rehabilitation monitoring and return-to-sport timing. Full article