Search Results (1,143)

Background/Objectives: Total knee arthroplasty (TKA) corrects coronal malalignment at the knee, but its effect on the structural status of the ipsilateral ankle is poorly characterised. This prospective study evaluated clinical, radiographic, and MRI-detected changes in the ipsilateral ankle after TKA, and tested whether such changes are related to the magnitude of mechanical axis correction. Methods: Seventy-one consecutive patients (80 operated limbs; mean age 63.9 ± 7.2 years; 83.1% female) undergoing primary TKA with a systematic neutral mechanical alignment strategy were assessed prospectively. Mechanical axis (MA) and talar tilt (TT) were measured on full-length weight-bearing radiographs, ankle-specific status was evaluated with the Foot and Ankle Outcome Score (FAOS), and ipsilateral ankle MRI was performed preoperatively, in the early postoperative period, and at follow-up (median 37 days, interquartile range (IQR) 34–44). Chondral/osteochondral findings and bone marrow oedema were recorded separately at the talus, distal tibia, and subtalar joint. Radiographic and MRI outcomes were analysed at the limb level using linear mixed-effects models and logistic generalised estimating equations with patient as the clustering variable; clinical outcomes were analysed at the patient level. Results: MA improved from 11.62 ± 5.57° to 4.29 ± 4.27° (mean change −7.34°, 95% confidence interval (CI) −8.49 to −6.18; p < 0.001), whereas TT was unchanged (−0.02 ± 1.87° to −0.22 ± 1.91°; p = 0.256). All FAOS subscales improved significantly (total 66.7 ± 27.6 to 84.4 ± 25.1; p < 0.001). Chondral/osteochondral findings were present in 41.2% of limbs preoperatively and were newly reported during follow-up in 40.4% of previously unaffected limbs. Newly reported bone marrow oedema was most frequent in the distal tibia (16/79 limbs, 20.3%), compared with the talus (8/79, 10.1%) and the subtalar joint (6/70, 8.6%). The magnitude of MA correction was not associated with change in TT (r = −0.040), change in FAOS (r = 0.023), or the development of new MRI findings (odds ratio (OR) 1.021 per degree; p = 0.682), and no dose–response gradient was observed across tertiles of correction. Conclusions: Following TKA with neutral mechanical alignment, substantial correction of the mechanical axis and significant clinical improvement occurred without a measurable change in talar tilt. MRI changes in the ipsilateral ankle were modest, concentrated in the distal tibia, and unrelated to the magnitude of alignment correction, suggesting that perioperative rather than alignment-related factors may predominate in the early postoperative period. Given the high preoperative burden of ankle degeneration and the short follow-up interval, the mechanisms and long-term significance of these findings remain uncertain. Full article

Background and Clinical Significance: Local recurrence of extremity leiomyosarcoma after multiple operations and radiotherapy presents a major therapeutic challenge. Adequate oncologic clearance must be balanced against preservation of skeletal stability and reliable wound coverage within a scarred and poorly vascularized tissue bed; Case presentation: A 78-year-old woman presented with a painful recurrent leiomyosarcoma of the anterior proximal third of the right leg after three previous operations and adjuvant radiotherapy. Preoperative magnetic resonance imaging demonstrated a recurrent soft-tissue lesion extending to the anterior surface of the proximal tibia. Staging computed tomography of the chest, abdomen, and pelvis showed no distant metastatic disease before definitive surgery. A one-stage limb-sparing procedure was performed, including resection of the recurrent tumor bed and an approximately 7-cm anterior cortical lamella of the proximal tibia containing an area considered suspicious for neoplastic involvement. A locking tibial plate was applied prophylactically to reduce the risk of pathological fracture. The approximately 12 × 10-cm soft-tissue defect was covered with a muscle flap from the medial head of the gastrocnemius and a free skin graft harvested from the paraumbilical region. Gross pathological examination identified an 8-cm subcutaneous tumor formation. Histopathological examination demonstrated well-differentiated leiomyosarcoma; the spindle cells expressed vimentin, actin, and desmin. All examined resection lines were free of tumor infiltration. No pathogenic microorganism was isolated, and no early postoperative complication was documented. The patient mobilized with walking aids and protected weight bearing for 30 days. At approximately 16 months, the flap and skin graft provided stable coverage, no postoperative tibial fracture or clinically apparent implant-related complication had occurred, and the patient was independently ambulatory. Postoperative MRI demonstrated expected postoperative changes and a small indeterminate subcutaneous focus without diffusion restriction, requiring continued surveillance; Conclusions: This case illustrates the feasibility of combining oncologic resection, prophylactic tibial stabilization, and vascularized soft-tissue reconstruction in a previously irradiated extremity. The documented early functional and reconstructive outcome supports this individualized limb-sparing approach, although longer oncologic surveillance is required. Full article

Background and Objectives: The aim of this study was to investigate the effects of local melatonin application on osseointegration of machined (MAC), resorbable blast material (RBM), and sandblasted and acid-etched (SLA) surface implants placed in rat tibiae, utilizing the reverse torque analysis. Materials and Methods: A total of 72 female Sprague-Dawley rats, weighing between 270 and 300 g, were included in the study. The rats were divided into six groups, and samples in which the implants were not properly placed were excluded from the study: control groups consisting of MAC-CNT (n = 12), RBM-CNT (n = 11), and SLA-CNT (n = 12), and local melatonin (MLT)-treated groups consisting of MAC-MLT (n = 12), RBM-MLT (n = 10), and SLA-MLT (n = 10). The implants were surgically placed into the tibiae of the rats under general anesthesia. Following a four-week experimental period, the biomechanical bone–implant connection level was evaluated using reverse torque analysis. Results: The lowest mean biomechanical bone–implant connection value was observed in the MAC-CNT group, whereas the highest value was recorded in the SLA-MLT group. Compared with the MAC-CNT group, all other groups demonstrated statistically significantly higher biomechanical connection values (p < 0.05). The SLA-MLT group showed significantly higher osseointegration levels than both the MAC-MLT and RBM-MLT groups (p < 0.05). In contrast, no significant difference was detected between the MAC-MLT and RBM-MLT groups (p > 0.05). Both MAC-MLT and SLA-MLT groups exhibited statistically significantly higher biomechanical bone-implant connection values compared to control groups (p < 0.05). Conclusions: Local melatonin application positively affected osseointegration in SLA and MAC surfaced implants. In contrast, local melatonin application did not provide any additional contribution to osseointegration in RBM surfaced implants. Full article

In this study, the effect of data augmentation on machine learning (ML) models that predict the natural frequency of human long bones from the spectrogram of bone-conducted sound was investigated. Bone-conducted sound was recorded from the tibia of 45 healthy university students using a custom-developed hammering device. Short-Time Fourier Transform (STFT) was applied to the recorded sounds to generate spectrograms, from which six ML models were examined to predict the natural frequency. Ground-truth natural frequency was defined as peak values identified from Fast Fourier Transform (FFT) spectra obtained by recorded waveforms of sounds. Data augmentation was performed by shifting bone-conducted sound waveforms, expanded to 5 levels, i.e., 3-fold (3×) to 11-fold (11×). All models showed improved accuracy by data augmentations compared to the original dataset, with a particularly substantial improvement observed in many models when the dataset was expanded from the original to the 3× level. Among the ML models examined here, DenseNet-121 with 11× data augmentation achieved the lowest MAE and the highest R² (10.00 ± 2.27 Hz; R² = 0.927 ± 0.046), followed by PeleeNet, which is constructed on a lightweight DenseNet architecture, with 7× data augmentation (MAE = 10.37 ± 2.91 Hz, R² = 0.920 ± 0.059). Full article

Quantitative assessment of vascularization is important in bone regeneration research, but CD31-immunohistochemically stained sections are often evaluated manually or semi-quantitatively, limiting reproducibility and comparability. The aim of this study was to establish and validate a reproducible, open-source workflow for semi-automated quantification of CD31-positive area fraction in bone sections using Fiji/ImageJ and Trainable Weka Segmentation (TWS). CD31-immunohistochemically stained rat bone sections from defect/regenerating tissue, femur, tibia, and spine were analyzed. The workflow combined standardized image acquisition, predefined regions of interest, pixel-based TWS classification, extraction of the CD31-positive class, and CD31-positive area normalized to tissue area (CD31.Ar/T.Ar). Manual reference measurements were performed by two independent observers in repeated runs. Manual CD31.Ar/T.Ar measurements showed good retest reliability, with mean coefficients of variation (CV) of 7.17% and 6.84% for observer 1 and observer 2, respectively, and good interobserver agreement. Independently trained TWS classifiers produced highly stable CD31.Ar/T.Ar values, with an overall mean CV of 1.98%. Manual assessment required 3:17 ± 1:35 min per section, whereas the TWS-based workflow separated an initial classifier training step from rapid repeated analysis of larger image sets. This study provides a transparent, reproducible, and time-efficient open-source workflow for semi-automated quantification of CD31-positive vascular area fraction in bone sections and supports its use as a scalable method for vascular histomorphometry in preclinical bone regeneration research. Full article

A novel fungal phytase (NFP) was evaluated for its effects on growth performance, phosphorus (P) metabolism, tibia development, and nutrient digestibility in broilers. A total of 420 one-day-old Arbor Acres broilers were randomly assigned to seven treatments: a negative control (basal diet without phytase), a positive control (500 U/kg commercial phytase), and five groups supplemented with NFP at 250, 500, 1000, 1500, or 2000 U/kg. Increasing inclusion of dietary NFP linearly improved average daily gain and feed conversion ratio (FCR) during days 22–42 and overall, with NFP outperforming commercial phytase at equivalent doses in FCR reduction. NFP increased the digestibility of crude fiber and P, linearly increased crude protein digestibility, and dose-dependently enhanced ileal digestibility of several amino acids (especially at 1000–2000 U/kg). NFP dose-dependently increased plasma inorganic P while reducing alkaline phosphatase and parathyroid hormone. Tibia weight, midshaft width, bone density, breaking strength, and P content increased linearly with NFP, peaking at 1000–2000 U/kg. NFP also upregulated tibial mRNA expression of the phosphate-regulating gene with homology to endopeptidase on the X chromosome, dentin matrix protein 1, and osteocalcin. In conclusion, NFP optimizes broiler growth, nutrient utilization, and skeletal development via dose-dependent modulation of P metabolism and osteogenic pathways. Full article

This study evaluated the effects of four LED lighting sources—full spectrum (FS), white (White), battery-powered lantern (Lantern), and monochromatic green (Green)—on Pekin duck growth performance, eye development, fear responses, stress susceptibility, gut health, and skeletal parameters. A total of 432 day-of-hatch Pekin ducklings were assigned to one of four light treatments (n = 9 replicate pens per treatment) and reared from d 0 to 35. Body weight, feed intake, and mortality-corrected feed conversion ratio were recorded, and on d 35, tonic immobility, inversion, physical asymmetry, heterophil-to-lymphocyte ratio, plasma corticosterone, ileal histomorphology, and tibia bone parameters were assessed. Green and White treatments produced greater body weight (3.28 and 3.27 kg; p = 0.002) and feed intake (145.2 and 143.3 g/d; p = 0.002) than FS and Lantern treatments, while feed conversion ratio did not differ (p = 0.73). Green and White ducks exhibited shorter tonic immobility latency to right (p = 0.02), lower composite asymmetry scores (p < 0.001), lower plasma corticosterone (p = 0.002), greater ileal villus-height-to-crypt-depth ratio (p = 0.002), and greater tibia-breaking strength (p = 0.001) compared with FS and Lantern ducks. These results demonstrate that monochromatic green and standard white LED lighting improve growth performance and multiple welfare indicators over full-spectrum and lantern-style LED sources in commercial Pekin duck production. Full article

Background: Premature consolidation of the regenerated bone is a relevant and underreported complication of limb lengthening in achondroplasia, with a reported incidence of 7–15% in the international literature. The gain-of-function fibroblast growth factor receptor 3 (FGFR3) mutation paradoxically enhances bone-healing capacity, predisposing patients to accelerated callus maturation during distraction osteogenesis and exposing patients to a risk of invasive procedures to treat this issue. This study reports the incidence and clinical features of premature consolidation in a cohort of achondroplastic patients treated with external fixation. Methods: A retrospective analysis was conducted on patients with achondroplasia who underwent lower limb lengthening (femur and/or tibia–fibula) between 2017 and 2024 at IRCCS Ospedale Galeazzi–Sant’Ambrogio (Milan, Italy). Inclusion criteria were ages 7–18 years, confirmed achondroplasia, and a clinical–radiological diagnosis of premature consolidation. Key parameters included the healing index (HI), length gained, proportional increase, and fixator duration. Results: Among 39 patients (112 segments: 46 femora and 66 tibia–fibula units), premature consolidation occurred in 7 patients (10 segments), yielding an overall incidence of 8.9%. The fibula was predominantly affected (6/10 segments). The mean HI was 33.47 days/cm for the tibia and 30.1 days/cm for the femur; the mean length gained was 8.1 cm and 8.2 cm, respectively. Conclusions: Premature consolidation affects approximately 9% of lengthened segments in achondroplastic patients, with a predilection for the fibula due to its passive indirect distraction mechanism. Early radiographic recognition and dynamic adjustment of the distraction protocol are essential to prevent surgical calloclasis and optimize outcomes, and further analyses of the FGFR3 mutation are fundamental to understand the biologic features of the bone during the lengthening and consolidation steps. Full article

Background and Objectives: Chronic nonbacterial osteomyelitis (CNO) is a rare pediatric autoinflammatory bone disease with variable presentation and frequent diagnostic delay. Data from Latvia are limited. This study aimed to evaluate demographic data, clinical manifestations, and treatment strategies of CNO in Latvia. Materials and Methods: This is a retrospective case series study of patients under 18 years of age diagnosed with chronic nonbacterial osteomyelitis (CNO) in the only pediatric tertiary hospital in Latvia between 2014 and 2025. Results: Thirteen patients were identified, 8 boys and 5 girls, with a median age at onset of 10 years. The pooled incidence was 0.31 per 100,000 children. The median time from symptom onset to diagnosis was 4.1 months. All patients had localized bone pain; most had fever, swelling, or a reduced range of motion. Multifocal disease occurred in all patients, with a median of 6 bones involved, and 61.5% had axial skeleton involvement. The most affected bones were the femur and tibia. Extraosseous manifestations included rash, central nervous system involvement, and lung granulomas. The most common comorbidities observed were inflammatory bowel disease and juvenile idiopathic arthritis (JIA). Inflammatory markers were moderately to markedly elevated. Whole body MRI with DWIBS was performed in all patients and showed bone marrow edema and STIR/T2 FS hyperintense lesions. All patients received NSAIDs, but only 15.4% had a complete response. Many required escalation to second-line treatment with methotrexate, TNF alpha inhibitors, or bisphosphonates. Conclusions: The incidence was similar to that reported in Europe. The cohort was characterized by multifocal, often severe disease with frequent fever and elevated inflammatory markers. Second-line treatment with methotrexate, TNF alpha inhibitors, or their combination showed a robust treatment response. Full article

Background: Restoration of native distal femoral sagittal morphology is increasingly recognized as an important goal in total knee arthroplasty (TKA). Alterations in anterior femoral offset (AFO), posterior femoral offset (PFO), and anteroposterior (AP) femoral size may affect knee biomechanics and patellofemoral function. This study evaluated whether imageless robotic-assisted TKA performed using a functional alignment (FA) philosophy resulted in statistically significant preoperative-to-postoperative differences in distal femoral sagittal morphology and coronal alignment. Methods: A retrospective analysis of a prospectively collected database included 250 consecutive primary TKAs performed with the imageless ROSA Knee System (Zimmer Biomet) using a tibia-first FA workflow. Preoperative and postoperative radiographic measurements included mechanical hip–knee–ankle angle (mHKA), medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), AP femoral size, AFO, and PFO. Paired comparisons were performed using appropriate statistical tests. Results: While no statistically significant differences were observed between preoperative and postoperative mean values for overall mechanical alignment (mHKA) (177.1 ± 7.7° vs. 177.3 ± 3.2°, p = 0.11), secondary coronal parameters demonstrated statistically significant controlled adjustments reflecting the patient’s individualized functional alignment. No significant differences were observed in sagittal morphology: AP femoral size (70.7 ± 6.3 vs. 71.0 ± 6.2 mm, p = 0.31), AFO (10.7 ± 5.9 vs. 10.8 ± 5.8 mm, p = 0.70), and PFO (34.1 ± 7.6 vs. 34.5 ± 7.2 mm, p = 0.24). Conclusions: Imageless robotic-assisted TKA performed with an FA philosophy and a tibia-first workflow demonstrated minimal mean preoperative-to-postoperative changes in distal femoral sagittal parameters at the cohort level. While overall mean mechanical alignment remained unchanged, secondary coronal parameters showed controlled, statistically significant adjustments, reflecting the implementation of an individualized three-dimensional alignment strategy. These findings support robotic FA as a patient-specific three-dimensional alignment strategy. Further prospective studies are needed to determine whether these radiographic results translate into improved clinical outcomes. Full article

A clinical observation of a previously asymptomatic native knee developing a relevant coronal alignment change after total hip arthroplasty (THA) motivated this research. This raised the question of whether the native knee morphology could influence the response to biomechanical changes elsewhere in the lower limb. First, we developed a simplified finite element model incorporating the Coronal Plane Alignment of the Knee (CPAK) classification. We developed a simplified model of the knee, where we represented the lateral distal femoral angle (LDFA) by physically rotating the femur, and to avoid remodeling the tibia coronal plane for each simulation, we represented the medial proximal tibial angle (MPTA) by adjusting the neutral angle of the joint (the angle at which the joint generates no reaction force). This allowed for quick parametric iteration over the CPAK input space, showing which type of knees were more vulnerable to extreme valgus (CPAK III) and varus (CPAK VII) due to their morphology. The simplicity of this model will also enable users with less technical expertise to quickly obtain insights into specific knee morphologies, without requiring deep knowledge about finite element modeling. This existing model lays the foundation for later work, with a deeper look into how changes to hip morphology build on the pre-existing tendencies to varus and valgus. Full article

Background/Objectives: Forensic age estimation increasingly relies on non-ionizing magnetic resonance imaging (MRI) evaluation of the knee growth plates. The original five-stage classification proposed by Dedouit et al. was developed using spin-echo proton-density-weighted imaging, and its applicability to gradient-echo sequences with different contrast mechanisms has not been fully established. This study aimed to apply the original, unmodified Dedouit classification to a volumetric three-dimensional Multiple Echo Data Image Combination (3D MEDIC) sequence and to generate corresponding age thresholds in a Turkish sample. Methods: Knee MRI examinations of 309 individuals (153 males, 156 females; age range 9.18–25.97 years) were retrospectively evaluated at a 3-Tesla field strength. Two experienced observers independently staged the distal femoral and proximal tibial epiphyses; intra- and inter-observer agreement were assessed using Cohen’s kappa. Spearman’s correlation and the Mann–Whitney U test, with rank-biserial effect sizes and Bonferroni correction, were used to assess the relationship between age and stage and between-sex differences, respectively. To provide forensically applicable thresholds, we additionally modeled the age at which the probability of complete fusion (Stage V) reached 50%, with 95% bootstrap confidence intervals, and calculated the sensitivity, specificity, and area under the curve (AUC) of Stage V for identifying individuals ≥18 years. Results: Agreement was very good for both epiphyses (kappa = 0.808–0.833). Age correlated strongly with stage for both the femur (rho = 0.70–0.76) and tibia (rho = 0.68–0.74). The 50%-probability age for complete fusion ranged from 15.23 years (tibia, females) to 17.43 years (femur, males). Stage V showed high sensitivity (0.96–0.98) but markedly lower and sex-dependent specificity for the 18-year threshold (0.48–0.58 in females versus 0.77–0.85 in males), indicating that Stage V alone is a poor sole criterion for confirming adult status in females. The youngest age at which Stage V was observed was 14.67 years in females and 16.07–16.16 years in males, markedly younger than thresholds reported using spin-echo imaging in the original Dedouit cohort. However, as an extreme-value statistic based on a single individual, this minimum should not be used as a forensic threshold in isolation. Conclusions: The Dedouit classification remains reproducible when applied to a 3D gradient-echo sequence, but the resulting age thresholds may be influenced by acquisition technique, population-specific factors such as socioeconomic status, or both. Consequently, thresholds derived from different MRI sequences or populations should not be assumed to be interchangeable without local validation. Full article

Phytate is a strong chelator of macro- and microminerals in the gastrointestinal tract. Under an environment in which phytate is rapidly hydrolyzed, the digestion and absorption of Ca, P, Zn and other cations from raw materials can be increased. This study investigated the performance, mineral excretion and bone mineralization of broilers fed diets formulated to optimize phytate hydrolysis and supplemented with Zn in the form of a Zn amino acid complex (Zn-AA) or as Zn sulfate (Zn-S). A total of 5040 day-old Ross 308 straight-run broiler chicks were allocated to 84 pens in a complete randomized block design, with 7 treatments and 12 replicates per treatment. Treatments 1 and 2 followed the breed recommendations (RECs) for Ca and P inclusion according to a three-phase feeding program and were supplemented with 90 ppm Zn as Zn-S, with (treatment 1) or without phytase (treatment 2), where treatment 1 is representative of a typical commercial-type diet. The remaining five treatments followed the University of Maryland (UMD) REC for Ca and P inclusion in a five-phase feeding program. The UMD diets were supplemented with either 90 ppm Zn-S (treatment 3) or graded levels of Zn-AA at 20, 40, 60, and 80 ppm (treatments 4–7). Phytase (2000 FTU/kg) was added to all diets except treatment 2. Data were analyzed in JMP 16.0 using one-way ANOVA regression analysis for Zn-AA treatments and Rao–Scott chi-square analysis for categorical data. Broilers fed 80 ppm Zn-AA resulted in heavier (p < 0.05) bodyweight (BW) on d 10, 16, 24, 30, and 37 when compared to all birds fed Zn-S at 90 ppm. On d 10, broilers fed 80 ppm Zn-AA had a higher (p < 0.05) tibia ash and tibia Zn content compared to those fed 90 ppm Zn-S (285.34 vs. 258.53 mg/tibia; and 12.00 vs. 10.62 mg Zn). Breast yield was also higher when comparing 80 ppm Zn-AA and 90 ppm Zn-S using the UMD REC (30.12 vs. 29.32%). Furthermore, broilers fed 40 ppm and above of organic Zn had less severe back scratches at term. It was therefore concluded that supplementation of Zn-AA following the UMD Ca and P REC resulted in increased growth performance and promoted higher breast yield of broilers whilst improving welfare. Full article

Solute Carrier Family 13 Member 5 (SLC13A5) encodes the sodium-dependent citrate cotransporter NaCT, which mediates citrate transport across cell membranes. Pathogenic variants in SLC13A5 cause developmental and epileptic encephalopathy 25 with amelogenesis imperfecta, DEE25; OMIM #615905, a debilitating autosomal recessive disorder. To better define the role of NaCT in ameloblast function and enamel mineralization, we used CRISPR/Cas9 genome editing to generate Slc13a5^R337* knock-in mice that terminate NaCT translation at the Arg337 codon, which is homologous to the human SLC13A5^R333* variant associated with DEE25. We compared enamel phenotypes among wild-type, Slc13a5^+/+; heterozygous, Slc13a5^+/R337*; and homozygous, Slc13a5^R337*/R337* mice using light microscopy, in situ hybridization, immunohistochemistry, backscattered scanning electron microscopy (bSEM); and focused ion beam–scanning electron microscopy (FIB-SEM) with quantitative imaging of organelles and matrix. Citrate bioassays were performed on serum, long bones, such as the femur and tibia, and developing mouse first molars, including enamel organ epithelium, mineralized tooth matrix, and pulp mesenchyme, to assess citrate levels during the presecretory, secretory, and maturation stages of enamel formation. In addition, first molars collected at postnatal days 0, 3, 5, and 12 were analyzed to characterize glycolytic and TCA cycle-related metabolic signatures. Homozygous Slc13a5^R337*/R337* mice exhibited severe defects during the secretory and maturation stages of amelogenesis. Most notably, Slc13a5^R337*/R337* ameloblasts failed to develop a Tomes’ process, detached from the enamel matrix surface, and produced a thin, poorly mineralized crust on the dentin surface rather than organized enamel ribbons. Despite the absence of normal enamel deposition, ameloblasts initially appeared viable and did not become dysplastic until the late secretory stage. Cellular and subcellular analyses revealed increased secondary lysosomes and intracellular accumulation of enamel matrix proteins, consistent with impaired matrix processing or secretion. Citrate concentrations were elevated in serum and long bones at both 7 and 35 weeks of age. Citrate was elevated in secretory-stage Slc13a5^R337*/R337* molars at days 0 and 3, the enamel organ epithelium (including ameloblasts), the pulp mesenchyme (including odontoblasts), and mineralizing dentin and enamel matrices. These levels gradually declined at day 5 and into the enamel maturation stage (day 12). GC-MS-based analysis of central carbon metabolites revealed increased intracellular accumulation of citrate, malate, and pyruvate, suggesting altered energy metabolism and reduced metabolic efficiency in Slc13a5^R337*/R337* mice. Together, these findings indicate that loss of NaCT function in the ameloblasts causes citrate accumulation, which impairs hydroxyapatite formation. Consequently, only a thin, structurally defective mineral crust forms on the dentin surface, while mineral nodules develop ectopically within the maturation-stage enamel organ epithelium. We conclude that regulating citrate concentration is essential for proper appositional growth of enamel. Full article

Background: Osteochondroma is the most common benign bone tumor in childhood. Although most lesions are asymptomatic, surgical treatment is indicated in patients with pain, mechanical symptoms, cosmetic concerns, restricted range of motion, or neurovascular compression. This study evaluated the clinical characteristics and surgical outcomes of osteochondromas in children and adolescents treated at a single tertiary pediatric surgery center. Methods: This retrospective study included 75 pediatric patients who underwent surgical excision of osteochondroma between January 2015 and January 2026. Demographic, clinical, radiological, operative, histopathological, and follow-up data were analyzed. Lesion-related variables were assessed at the level of individual exostoses. The primary outcome was surgical treatment outcome, while secondary outcomes included lesion localization, symptoms, hospital stay, postoperative complications, recurrence, and associations between clinical and morphological variables. Results: A total of 75 patients with 76 solitary osteochondromas were included. The median age was 13 years, and 64.0% of patients were male. Most lesions were located distally (73.7%), with the femur being the most common site (48.7%), followed by the tibia (22.4%). Pain was the most frequent symptom, present in 63.2% of exostoses, followed by cosmetic concern in 32.9%. Standard radiography was used in nearly all cases (98.7%). Radiographic measurements significantly underestimated lesion size compared with intraoperative measurements, with median diameters of 3.0 cm and 4.0 cm, respectively (p < 0.001). A strong positive correlation was observed between radiographic and intraoperative lesion diameter (ρ = 0.77; p < 0.001), while symptom duration showed a weak but significant correlation with lesion diameter (ρ = 0.28; p = 0.013). No significant association was found between lesion diameter and symptomatic presentation, and logistic regression did not identify age, sex, lesion location, or diameter as significant predictors of symptoms. Postoperative outcomes were favorable: 94.6% of patients had no complications, wound infection and hematoma occurred in 2.7% each, and no recurrences or reoperations were recorded during a median follow-up of 63 months. Histopathological examination confirmed osteochondroma in all cases. Conclusions: Surgical excision of symptomatic pediatric osteochondromas was associated with favorable postoperative outcomes, a low complication rate, and no observed recurrence during follow-up. Standard radiography correlates well with intraoperative findings but may underestimate true lesion size, likely due to limited visualization of the cartilaginous cap. Symptom development appears multifactorial and cannot be reliably predicted by lesion size or location alone. Full article