Evaluation of the long-term effect of selective tibial neurotomy for the treatment of spastic foot using a personal goal-centered approach.

OBJECTIVE: The objective of this study was to evaluate the long-term effectiveness of selective tibial neurotomy (STN) for the treatment of the spastic foot using a goal-centered approach. METHODS: Between 2011 and 2018, adult patients with a spastic foot (regardless of etiology) who received STN followed by a rehabilitation program were included. The primary outcome was the achievement of individual goals defined preoperatively (T0) and compared at 1-year (T1) and 5-year (T5) follow-up by using the Goal Attainment Scaling methodology (T-score). The secondary outcomes were the presence of spastic deformities (equinus, varus, and claw toes), modified Ashworth scale (MAS) score for the targeted muscles, and modified Rankin Scale (mRS) score at T0, T1, and T5. RESULTS: Eighty-eight patients were included. At T5, 88.7% of patients had achieved their goals at least "as expected." The mean T-score was significantly higher at T1 (62.5 ± 9.5) and T5 (60.6 ± 11.3) than at T0 (37.9 ± 2.8) (p < 0.0001), and the difference between T1 and T5 was not significant (p = 0.2). Compared to T0, deformities (equinus, varus, and claw toes; all p < 0.0001), MAS score (p < 0.0001), and mRS score (p < 0.0001) were significantly improved at T1 and T5. Compared to T1, MAS score increased slightly only at T5 (p = 0.05) but remained largely below the preoperative value. There was no difference between T1 and T5 regarding other clinical parameters (e.g., deformities, walking abilities, mRS score). CONCLUSIONS: This study found that STN associated with a postoperative rehabilitation program can enable patients to successfully achieve personal goals that are sustained within a 5-year follow-up period.

Biofunctionalized hydrogel composed of genipin-crosslinked gelatin/hyaluronic acid incorporated with lyophilized platelet-rich fibrin for segmental bone defect repair.

Segmental bone defects can arise from trauma, infection, metabolic bone disorders, or tumor removal. Hydrogels have gained attention in the field of bone regeneration due to their unique hydrophilic properties and the ability to customize their physical and chemical characteristics to serve as scaffolds and carriers for growth factors. However, the limited mechanical strength of hydrogels and the rapid release of active substances have hindered their clinical utility and therapeutic effectiveness. With ongoing advancements in material science, the development of injectable and biofunctionalized hydrogels holds great promise for addressing the challenges associated with segmental bone defects. In this study, we incorporated lyophilized platelet-rich fibrin (LPRF), which contains a multitude of growth factors, into a genipin-crosslinked gelatin/hyaluronic acid (GLT/HA-0.5 % GP) hydrogel to create an injectable and biofunctionalized composite material. Our findings demonstrate that this biofunctionalized hydrogel possesses optimal attributes for bone tissue engineering. Furthermore, results obtained from rabbit model with segmental tibial bone defects, indicate that the treatment with this biofunctionalized hydrogel resulted in increased new bone formation, as confirmed by imaging and histological analysis. From a translational perspective, this biofunctionalized hydrogel provides innovative and bioinspired capabilities that have the potential to enhance bone repair and regeneration in future clinical applications.

Gene expression and immune infiltration analysis comparing lesioned and preserved subchondral bone in osteoarthritis.

Background: Osteoarthritis (OA) is a degenerative disease requiring additional research. This study compared gene expression and immune infiltration between lesioned and preserved subchondral bone. The results were validated using multiple tissue datasets and experiments. Methods: Differentially expressed genes (DEGs) between the lesioned and preserved tibial plateaus of OA patients were identified in the GSE51588 dataset. Moreover, functional annotation and protein-protein interaction (PPI) network analyses were performed on the lesioned and preserved sides to explore potential therapeutic targets in OA subchondral bones. In addition, multiple tissues were used to screen coexpressed genes, and the expression levels of identified candidate DEGs in OA were measured by quantitative real-time polymerase chain reaction. Finally, an immune infiltration analysis was conducted. Results: A total of 1,010 DEGs were identified, 423 upregulated and 587 downregulated. The biological process (BP) terms enriched in the upregulated genes included "skeletal system development", "sister chromatid cohesion", and "ossification". Pathways were enriched in "Wnt signaling pathway" and "proteoglycans in cancer". The BP terms enriched in the downregulated genes included "inflammatory response", "xenobiotic metabolic process", and "positive regulation of inflammatory response". The enriched pathways included "neuroactive ligand-receptor interaction" and "AMP-activated protein kinase signaling". JUN, tumor necrosis factor α, and interleukin-1ß were the hub genes in the PPI network. Collagen XI A1 and leucine-rich repeat-containing 15 were screened from multiple datasets and experimentally validated. Immune infiltration analyses showed fewer infiltrating adipocytes and endothelial cells in the lesioned versus preserved samples. Conclusion: Our findings provide valuable information for future studies on the pathogenic mechanism of OA and potential therapeutic and diagnostic targets.

Tibial Axis-to-Talus Distance: A Clinically Reliable Measurement for Sagittal Translation of the Talus in Total Ankle Arthroplasty.

Background: Sagittal talar translation is an important factor influencing the sagittal alignment of total ankle arthroplasty (TAA). Thus, accurate measurement of sagittal talar translation is crucial. This study proposes a simple method (tibiotalar distance [TTD]) that can quantify talar translation without being affected by the ankle and subtalar joint condition or the talar component position in patients with TAA. Methods: We enrolled 280 eligible patients (296 ankles) who underwent primary TAA between 2005 and 2019 and retrospectively reviewed them for sagittal talar translation. The TTD was measured for each patient on weight-bearing lateral ankle radiographs by 3 raters. In addition, we analyzed interrater and intrarater reliability for the TTD method. Results: We found that the TTD method could quantify the talar translation and was not affected by the preoperative condition of the ankle joint surface, subtalar joint pathologies, or the postoperative talar component position. The TTD method showed an excellent intraclass correlation coefficient (> 0.9) in all interrater and intrarater reliability analyses. In the analysis of 157 healthy, unoperated contralateral ankles, we identified that TTD showed a Gaussian distribution (p = 0.284) and a mean of 38.91 mm (normal range, 29.63-48.20 mm). Conclusions: The TTD method is a simple and reliable method that could be applied to patients with TAA to assess the sagittal talar translation regardless of the pre-and postoperative joint condition and implantation status.

Guided Growth to Treat Anterolateral Tibial Bowing Associated with Congenital Pseudarthrosis of the Tibia.

BACKGROUND: Anterolateral tibial bowing associated with congenital tibial pseudarthrosis occurs often in patients with neurofibromatosis type 1 and results from the inability of the fractured bone to unite, leading to persistent nonunion, abnormal bone growth, and further bowing of the tibia. Current surgical and nonsurgical approaches demonstrate persistent nonunion or refracture, often resulting in amputation. METHODS: This report describes the management of 3 patients with anterolateral tibial bowing and NF1 who underwent distal tibia-guided growth. RESULTS: The patients had an average age of 1.6 years at initial operation, with a total of 3 to 4 surgeries over an average of 2.1 years. The latest follow-up on all patients is included, at a mean of 5.1 years after the initial operation. All 3 patients experienced substantial functional improvement and improved alignment of the mechanical axis of the tibia. One patient has experienced refracture. CONCLUSIONS: Our study indicates that guided growth can serve as an additional surgical option to improve ALTB and potentially reduce the risk of fracture and pseudarthrosis by restoring normal mechanical alignment. LEVEL OF EVIDENCE: Level-IV, Case Series.

The Intermalleolar Method for Intraoperative Rotational Assessment of the Tibia-A Prospective Clinical Validation Study.

OBJECTIVES: To determine the accuracy of the intermalleolar method, an intraoperative fluoroscopic method for assessing tibial rotation in patients undergoing intramedullary nail fixation for tibial shaft fractures, by comparing it with the gold standard computed tomography (CT). DESIGN: Prospective cohort study. SETTING: Academic Level 1 trauma center. PATIENT SELECTION CRITERIA: Consecutive patients, aged 18 years and older, with unilateral tibial shaft fractures who underwent intramedullary fixation from September 2021 to January 2023. OUTCOME MEASURES AND COMPARISONS: Intraoperatively, tibial rotation measurements were obtained using the intermalleolar method on both the uninjured and injured limbs. Postoperatively, patients underwent bilateral low-dose lower extremity rotational CT scans. CT measurements were made by 4 blinded observers. Mean absolute rotational differences and standard errors were calculated to compare the injured and uninjured limbs. Subgroup analysis was performed assessing accuracy relating to injured versus uninjured limbs, body mass index, OTA/AO fracture pattern, tibial and fibular fracture location, and distal articular fracture extension requiring fixation. RESULTS: Of the 20 tibia fractures, the mean patient age was 43.4 years. The intermalleolar method had a mean absolute rotational difference of 5.1 degrees (standard error 0.6, range 0-13.7) compared with CT. Sixty percent (24/40) of the measurements were within 5 degrees, 90% (36/40) of the measurements were within 10 degrees, and 100% (40/40) were within 15 degrees of the CT. No patients were revised for malrotation postoperatively. CONCLUSIONS: The intermalleolar method is accurate and consistently provides intraoperative tibial rotation measurements within 10 degrees of the mean CT measurement for adult patients undergoing intramedullary nail fixation for unilateral tibial shaft fractures. This method may be employed in the operating room to accurately quantify tibial rotation and assist with intraoperative rotational corrections. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Association between the procedure of tibiotalocalcaneal arthrodesis by hindfoot nailing and quality of life in Charcot's joint.

INTRODUCTION: Charcot arthropathy is a progressive disorder of the ankle and foot joints that can lead to foot deformity and instability. Surgical intervention is often necessary for deformity and ulcer management during the chronic phase. The device used for arthrodesis remains a challenge. METHODS: This clinical trial study included diabetic patients aged 40 years or older with Charcot foot. Lateral approach with lateral malleolar osteotomy was used to access the ankle joints and remove the cartilage. A small incision was made on the plantar aspect of the foot to pass an appropriately sized intramedullary nail. Demographic information, medical history, surgical details and Clinical data were collected at 2-week and 1-year follow-ups using the Ankle-Hindfoot Scale (AOFAS) score and the EuroQol 5-Dimensional 5-Level (EQ-5D-5L) health utility score. RESULTS: Twenty-six patients with a mean age of 63 ± 0.23 years were included in the study. The findings showed significant improvements in AOFAS questionnaire items related to pain score, length of the walk, walking surfaces, walking disorders, sagittal alignment, back leg alignment, sustainability, alignment and the total score (P value < 0.001). The EQ-5D-5L questionnaire also showed a significant improvement in the total score (P value = 0.002). CONCLUSION: This study provides evidence supporting the effectiveness of tibiotalocalcaneal arthrodesis by hindfoot nailing in diabetic patients with Charcot foot joints and demonstrated comparable and superior outcomes in terms of patient satisfaction and complication rate when compared to previous studies.

How effective is proximal fibular osteotomy in redistributing joint pressures? Insights from an HTO comparative in-silico study.

BACKGROUND: Knee osteoarthritis (KOA) represents a widespread degenerative condition among adults that significantly affects quality of life. This study aims to elucidate the biomechanical implications of proximal fibular osteotomy (PFO), a proposed cost-effective and straightforward intervention for KOA, comparing its effects against traditional high tibial osteotomy (HTO) through in-silico analysis. METHODS: Using medical imaging and finite element analysis (FEA), this research quantitatively evaluates the biomechanical outcomes of a simulated PFO procedure in patients with severe medial compartment genu-varum, who have undergone surgical correction with HTO. The study focused on evaluating changes in knee joint contact pressures, stress distribution, and anatomical positioning of the center of pressure (CoP). Three models are generated for each of the five patients investigated in this study, a preoperative original condition model, an in-silico PFO based on the same original condition data, and a reversed-engineered HTO in-silico model. RESULTS: The novel contribution of this investigation is the quantitative analysis of the impact of PFO on the biomechanics of the knee joint. The results provide mechanical evidence that PFO can effectively redistribute and homogenize joint stresses, while also repositioning the CoP towards the center of the knee, similar to what is observed post HTO. The findings propose PFO as a potentially viable and simpler alternative to conventional surgical methods for managing severe KOA, specifically in patients with medial compartment genu-varum. CONCLUSION: This research also marks the first application of FEA that may support one of the underlying biomechanical theories of PFO, providing a foundation for future clinical and in-silico studies.

Femoral anteversion linked to the inability to squat: Analysis of CT images in the patient and control groups.

Many patients who cannot squat well in a neutral toe position can only squat in an excessively out-toeing position. This excessive out-toeing squat is thought to be caused by rotational problems of the lower extremities. In this study, we aimed to identify the cause for the inability to squat by measuring and comparing femoral and tibial torsion between an excessive out-toeing squat patient group and a control group representing the general population. Between 2008 and 2022, a patient group comprising 50 lower extremities with excessive out-toeing squats was established. A control group representing the general population was selected from patients aged 0 to 29 years, who underwent lower-extremity CT angiography between 2012 and 2022, using the Clinical Data Warehouse with exclusion criteria applied. A total of 94 lower extremities were included in the control group. The femoral torsional angle (FTA) and tibial torsional angle (TTA) of both groups were measured and compared using Student t test. Additionally, 30 each of those with the highest and lowest 30 FTA values were selected from the patient and control groups, and the TTA was compared between the high- and low-FTA groups using Student t test. The mean FTA was 0.34° (SD, 11.11°) in the patient group and 10.14° (SD, 11.85°) in the control group, with a mean difference of 9.8° and P < .001. The mean TTA was 27.95° (SD, 7.82°) in the patient group and 32.67 ° (SD, 7.58°) in the control group, with a mean difference of 4.72° (P = .001). The mean TTA was 34.3° (SD, 7.72°) in the high-FTA group and 28.17° (SD, 8.35°) in the low-FTA group, with a mean difference of 6.13° (P = .005). Patients with excessive out-toeing squat showed lower FTA and TTA values than the general population. Furthermore, although a correlation between FTA and TTA was not established through Pearson correlation analysis, a tendency was observed where a decrease in FTA was associated with a decrease in TTA. Based on these results, decreased FTA was demonstrated to be one of the major causes of excessive out-toeing squats.

Improvement of absorbability, osteoconductivity, and strength of a ß-tricalcium phosphate spacer for opening wedge high tibial osteotomy: clinical evaluations with 106 patients.

BACKGROUND: An ideal synthetic spacer for medial opening wedge high tibial osteotomy (MOWHTO) has not yet been developed. The authors have developed a new ß-tricalcium phosphate (ß-TCP) spacer with 60% porosity (N-CP60) by modifying the micro- and macro-pore structures of a conventional ß-TCP spacer (CP60) that is widely used in clinical practice. The purpose of this study was to compare the absorbability, osteoconductivity, and in vivo strength of the N-CP60 spacer with those of the CP60 spacer, when used in MOWHTO. METHODS: First, the porosity, diameter distribution of macro- and micropores, and compressive strength of each ß-TCP block were examined using methodology of biomaterial science. Secondly, a clinical study was performed using a total of 106 patients (106 knees) with MOWHTO, who were followed up for 18 months after surgery. In these knees, the N-CP60 and CP-60 spacers were implanted into 49 tibias and 57 tibias, respectively. The absorbability and osteoconductivity were radiologically evaluated by measuring the area of the implanted spacer remaining unabsorbed and assessing with the Hemert's score, respectively. The incidence of cracking in the implanted spacers was determined using computed radiography. Statistical comparisons were made with non-parametric tests. The significance level was set at p = 0.05. RESULTS: The N-CP60 and CP60 blocks had almost the same porosity (mean, 61.0% and 58.7%, respectively). The diameter of macropores was significantly larger (p < 0.0001) in the N-CP60 block than in the CP60 block, while the diameter of micropores was significantly smaller (p = 0.019) in the N-CP60 block. The ultimate strength of the N-CP60 block (median, 36.8 MPa) was significantly greater (p < 0.01) than that of the CP60 block (31.6 MPa). As for the clinical evaluations, the absorption rate of the N-CP60 spacer at 18 months after implantation (mean, 48.0%) was significantly greater (p < 0.001) than that of the CP60 spacer (29.0%). The osteoconductivity of the N-CP60 spacer was slightly but significantly higher (p = 0.0408) than that of the CP60 spacer only in zone 1. The incidence of in vivo cracking of the posteriorly located N-CP60 spacer at one month (mean, 75.5%) was significantly lower (p = 0.0035) than that of the CP60 spacer (91.2%). CONCLUSIONS: The absorbability, osteoconductivity, and compressive strength of the new N-CP60 spacer were significantly improved by modifying the macro- and micro-pore structures, compared with the conventional CP60 spacer. The N-CP60 spacer is more clinically useful than the CP60 spacer. TRIAL REGISTRATION NUMBER: H29-0002.

Metal-backed or all-poly tibial components: which are better for medial unicompartmental knee arthroplasty? A propensity-score-matching retrospective study at the 5-year follow-up.

BACKGROUND: This retrospective medium-term follow-up study compares the outcomes of medial fixed-bearing unicompartmental knee arthroplasty (mUKA) using a cemented metal-backed (MB) or an all-polyethylene (AP) tibial component. MATERIALS AND METHODS: The database of our institution was mined for primary mUKA patients implanted with an MB or an AP tibial component (the MB-UKA and AP-UKA groups, respectively) from 2015 to 2018. We compared patient demographics, patient-reported outcome measures (PROMs), and motion analysis data obtained with the Riablo™ system (CoRehab, Trento, Italy). We conducted propensity-score-matching (PSM) analysis (1:1) using multiple variables. RESULTS: PSM analysis yielded 77 pairs of MB-UKA and AP-UKA patients. At 5 years, the physical component summary (PCS) score was 52.4 ± 8.3 in MB-UKA and 48.2 ± 8.3 in AP-UKA patients (p < 0.001). The Forgotten Joint Score (FJS-12) was 82.9 ± 18.8 in MB-UKAs and 73.4 ± 22.5 in AP-UKAs (p = 0.015). Tibial pain was reported by 7.8% of the MB-UKA and 35.1% of the AP-UKA patients (p < 0.001). Static postural sway was, respectively, 3.9 ± 2.1 cm and 5.4 ± 2.3 (p = 0.0002), and gait symmetry was, respectively, 92.7% ± 3.7 cm and 90.4% ± 5.4 cm (p = 0.006). Patient satisfaction was 9.2 ± 0.8 in the MB-UKA and 8.3 ± 2.0 in the AP-UKA group (p < 0.003). CONCLUSIONS: MB-UKA patients experienced significantly better 5-year static sway and gait symmetry outcomes than AP-UKA patients. Although the PROMs of the two groups overlapped, MB-UKA patients had a lower incidence of tibial pain, better FJS-12 and PCS scores, and were more satisfied.

Clinical relevance of positive intraoperative bacterial culture in tibial plateau leveling osteotomy in dogs: a retrospective study.

BACKGROUND: Tibial plateau leveling osteotomy (TPLO) belongs to the most frequently used surgical method for the treatment of cranial cruciate ligament rupture in dogs. Surgical site infection (SSI) is one of the possible postoperative complications. The aim of this study was to evaluate the diagnostic value of intraoperative bacterial culture as a tool for the detection of intraoperative bacterial contamination progressing to infection development in canine TPLO. Electronic patient records from dogs who underwent TPLO between January 2018 to December 2020 were retrospectively reviewed. Intraoperative bacterial culture results, used antimicrobial drugs and presence of SSI were recorded. RESULTS: Ninety-eight dogs were included in the study. SSI rate was 10.2%. All dogs who developed SSI (n = 10) had negative intraoperative bacterial cultures. None of the dogs with positive intraoperative bacterial culture (n = 6) developed SSI. The most cultured bacteria causing SSI was Staphylococcus pseudintermedius (n = 4). CONCLUSIONS: Intraoperative bacterial culture in dogs undergoing TPLO is not suitable as a predictor of surgical site infection.

Total knee arthroplasty following lateral closing-wedge high tibial osteotomy versus primary total knee arthroplasty: a propensity score matching study.

BACKGROUND: The disparity in patient-reported outcomes between total knee arthroplasty (TKA) following high tibial osteotomy (HTO) and primary TKA has yet to be fully comprehended. This study aims to compare the patient-reported outcomes, radiological parameters and complication rates between TKA following HTO and primary TKA. METHODS: Sixty-five patients who underwent TKA following lateral closing-wedge HTO were compared to a matched group of primary TKA at postoperative 6-months and 1-year. Between-group confounders of age, gender, smoking status, Body Mass index, preoperative Numeric Rating Scale (NRS) pain in rest, Knee injury and Osteoarthritis Outcome Score-Physical function Shortform (KOOS-PS), EuroQol five-dimensional (EQ-5D) overall health score, and Oxford Knee Score (OKS) were balanced by propensity score matching. Patient-reported outcome measures were NRS pain in rest, KOOS-PS, EQ-5D overall health score, and OKS. Radiological parameters were femorotibial angle, medial proximal tibial angle, anatomical lateral distal femoral angle, posterior tibial slope, and patellar height assessed by Insall-Salvati ratio. The complication rates of TKA were compared between the two groups. The HTO survival time, the choice of staple removal before or during TKA in patients who underwent TKA following HTO patients, and the rate of patellar resurfacing were assessed. The p value < 0.0125 indicates statistical significance after Bonferroni correction. RESULTS: After propensity score matching, no significant between-group differences in the patient-reported outcome measures, radiographical parameters and complication rates were found (p > 0.0125). In the TKA following HTO group, with an average HTO survival time of 8.7 years, staples were removed before TKA in 46 patients (71%) and during TKA in 19 patients, and 11 cases (17%) had patella resurfacing. In the primary TKA group, 15 cases (23%) had patella resurfacing. CONCLUSION: The short-term assessment of TKA following HTO indicates outcomes similar to primary TKA. A previous HTO does not impact the early results of subsequent TKA, suggesting that the previous HTO has minimal influence on TKA outcomes. LEVEL OF EVIDENCE: III, cohort study.

Superior Pain Reduction with Anteromedialization Tibial Tubercle Osteotomy Versus Non-Operative Management for Patellofemoral Osteoarthritis.

PURPOSE: The purpose of this study was to compare the clinical outcomes of patients with patellofemoral osteoar-thritis (PFOA) treated non-operatively with those treated operatively with an unloading anteromedialization tibial tubercle osteotomy (TTO). METHODS: A retrospective chart review was performed to identify patients with isolated PFOA who were either managed non-operatively or surgically with a TTO and who had a minimum follow-up of 2 years. Patients were surveyed with the visual analog scale (VAS) for pain, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR), Anterior Knee Pain scale (Kujala), and Tegner Activity scale. Statistical analysis included two-sample t-testing, one-way ANOVA, and bivariate analysis. RESULTS: The clinical outcomes of 49 non-operatively managed patients (mean age: 52.7 ± 11.3 years; mean follow-up: 1.7 ± 1.0 years) and 35 operatively managed patients (mean age: 31.8 ± 9.4 years; mean follow-up: 3.5 ± 1.7 years) were assessed. The mean VAS improved sig-nificantly in both groups [6.12 to 4.22 (non-operative), p < 0.0001; 6.94 to 2.45 (TTO); p < 0.0001], with operatively treated patients having significantly lower postoperative pain than non-operatively managed patients at the time of final follow-up [2.45 (TTO) vs. 4.22 (non-operative), p < 0.001]. The mean KOOS-JR score was significantly greater in the operative group at time of final follow-up [78.7 ± 11.6 (TTO) vs. 71.7 ± 17.8 (non-operative), p = 0.035]. There was no significant difference in Kujala or Tegner scores between the treatment groups. Additionally, there was no sig-nificant relationship between the number of intra-articular injections, duration of NSAID use, and number of physical therapy sessions on clinical outcomes in the non-operatively treated group (p > 0.05). CONCLUSIONS: An unloading anteromedialization TTO provides significantly better pain relief and restoration of function compared to non-operative management in the treatment of symptomatic PFOA.

A numerical investigation for the development of functionally graded Ti/HA tibial implant for total ankle replacement: Influence of material gradation law and volume fraction index.

Stress shielding is one of the major concerns for total ankle replacement implants nowadays, because it is responsible for implant-induced bone resorption. The bone resorption contributes to the aseptic loosening and failure of ankle implants in later stages. To reduce the stress shielding, improvements can be made in the implant material by decreasing the elastic mismatch between the implant and the tibia bone. This study proposes a new functionally graded material (FGM) based tibial implant for minimizing the problem of stress shielding. Three-dimensional finite element (FE) models of the intact tibia and the implanted tibiae were created to study the influence of material gradation law and volume fraction index on stress shielding and implant-bone micromotion. Different implant materials were considered that is, cobalt-chromium, titanium (Ti), and FGM with Ti at the bottom and hydroxyapatite (HA) at the top. The FE models of FGM implants were generated by using different volume fractions and the rule of mixtures. The rule of mixtures was used to calculate the FGM properties based on the local volume fraction. The volume fraction was defined by using exponential, power, and sigmoid laws. For the power and sigmoid law varying volume fraction indices (0.1, 0.2, 0.5, 1, 2, and 5) were considered. The geometry resembling STAR® ankle system tibial implant was considered for the present study. The results indicate that FGMs lower stress shielding but also marginally increase implant-bone micromotion; however, the values were within the acceptable limit for bone ingrowth. It is observed that the material gradation law and volume fraction index influence the performance of FGM tibial implants. The tibial implant composed of FGM using power law with a volume fraction index of 0.1 was the preferred option because it showed the least stress shielding.

Impaired bone mineral density and microarchitecture in female adolescents with IgE-mediated cow's milk allergy.

This study compared the bone parameters of adolescents with persistent cow's milk allergy (CMA) with those of healthy adolescents. Adolescents with CMA had compromised bone parameters (lower bone mineral density, impaired trabecular microarchitecture, and lower bone strength). Partial exclusion diet was associated with better bone parameters than total exclusion diet. BACKGROUND: Persistent immunoglobulin E (IgE)-mediated cow's milk allergy (CMA) may impair bone parameters and increase the risk of fractures. High-resolution peripheral quantitative computed tomography (HR-pQCT) is a novel methodology that not only assesses trabecular and cortical bone compartments and volumetric density measurements, but also evaluates bone microarchitecture and estimates biomechanical properties through finite element analysis (FEA). Both HR-pQCT and bone strength parameters derived from FEA have shown a strong correlation with fracture risk. PURPOSE: To assess the bone density, microarchitecture, and bone strength of adolescents with persistent IgE-mediated CMA (IgE-CMA). METHODS: This was an observational, cross-sectional study with female adolescents with persistent IgE-CMA and healthy control participants matched by female sex and sexual maturation. Bone parameters were assessed by areal bone mineral density (aBMD) through dual-energy X-ray absorptiometry (DXA), bone microarchitecture by HR-pQCT at the radius and tibia, and laboratory markers related to bone metabolism. RESULTS: The median age of adolescents with persistent IgE-CMA (n = 26) was 13.0 years (interquartile range (IQR) 11.4-14.7) and of healthy control participants (n = 28) was 13.6 years (IQR 11.9-14.9). Adolescents with IgE-CMA ingested 27.4% less calcium (p = 0.012) and 28.8% less phosphorus (p = 0.009) than controls. Adolescents with IgE-CMA had lower bone mineral content (BMC) (38.83 g vs. 44.50 g) and aBMD (0.796 g/cm2 vs. 0.872 g/cm2) at lumbar spine, and lower BMC (1.11 kg vs. 1.27 kg) and aBMD (0.823 g/cm2 vs. 0.877 g/cm2) at total body less head (TBLH) (p < 0.05). However, Z-scores BMC and Z-scores aBMD at lumbar spine and TBLH, when adjusted for Z-score height/age, were not significantly different between the groups. Moreover, CMA adolescents had lower bone strength at the distal tibia (S 169 kN/mm vs. 194 kN/mm; F Load 8030 N vs. 9223 N) (p < 0.05). Pairing of groups by the presence of menarche showed compromised parameters at the tibia-lower total volumetric BMD (Tt.vBMD) (293.9 mg HA/cm3 vs. 325.9 mg HA/cm3) and trabecular vBMD (Tb.vBMD) (170.8 mg HA/cm3 vs. 192.2 mg HA/cm3), along with lower cortical thickness (Ct.th) (1.02 mm vs. 1.16 mm) and bone strength (S 174 kN vs. 210 kN; F Load 8301 N vs. 9950 N)-and at the radius (S 61 kN/mm vs. 71 kN/mm; F Load 2920 N vs. 3398 N) (p < 0.05) among adolescents with IgE-CMA. Adolescents with IgE-CMA on a total exclusion diet (n = 12) showed greater impairment of bone features than those on a partial exclusion diet (n = 14), with lower lumbar spine Z-score BMC (- 0.65 vs. 0.18; p = 0.013), lumbar spine trabecular bone score (TBS) (1.268 vs. 1.383; p = 0.005), Z-score TBS (0.03 vs. 1.14; p = 0.020), TBLH Z-score BMC (- 1.17 vs. - 0.35; p = 0.012), TBLH Z-score aBMD (- 1.13 vs. - 0.33; p = 0.027), Tt.vBMD at the tibia (259.0 mg HA/cm3 vs. 298.7 mg HA/cm3; p = 0.021), Ct.th at the tibia (0.77 mm vs. 1.04 mm; p = 0.015) and Ct.th at the radius (0.16 mm vs. 0.56 mm; p = 0.033). CONCLUSION: Adolescents with persistent IgE-CMA had lower aBMD and compromised microarchitecture (impaired trabecular microarchitecture and lower bone strength). Adolescents on a partial exclusion diet had better bone parameters than those on a total exclusion diet.

Impact of infrasound exposure and streptozotocin-induced glucose intolerance on bone composition in Wistar rats.

The elemental composition of chemical elements can vary between healthy and diseased tissues, providing essential insights into metabolic processes in physiological and diseased states. This study aimed to evaluate the calcium (Ca) and phosphorus (P) levels in the bones of rats with/without streptozotocin-induced diabetes and/or exposure to infrasound. X-ray fluorescence spectroscopy was used to determine the concentrations of Ca and P in Wistar rat tibiae samples.The results showed a significant decrease in bone P concentration in streptozotocin-induced diabetic rats compared to untreated animals. Similarly, the Ca/P ratio was higher in the streptozotocin-induced diabetic group. No significant differences were observed in bone Ca concentration between the studied groups or between animals exposed and not exposed to infrasound.Moreover, streptozotocin-induced diabetic rats had lower bone P concentration but unaltered bone Ca concentration compared to untreated rats. Infrasound exposure did not impact bone Ca or P levels. The reduced bone P concentration may be associated with an increased risk of bone fractures in diabetes.

Finite element analysis of the effect of tibial osteotomy on the stress of polyethylene liner in total knee arthroplasty.

AIM: To explore the effects of tibial osteotomy varus angle combined with posterior tibial slope (PTS) on the stress of polyethylene liner in total knee arthroplasty (TKA) by building finite element model (FEM). METHODS: Established the FEM of standard TKA with tibial osteotomy varus angle 0° to 9° were established and divided into 10 groups. Next, each group was created 10 FEMs with 0° to 9° PTS separately. Calculated the stress on polyethylene liner in each group in Abaqus. Finally, the relevancy between tibial osteotomy angle and polyethylene liner stress was statistically analyzed using multiple regression analysis. RESULTS: As the varus angle increased, the area of maximum stress gradually shifted medially on the polyethylene liner. As the PTS increases, the percentage of surface contact forces on the medial and lateral compartmental of the polyethylene liner gradually converge to the same. When the varus angle is between 0° and 3°, the maximum stress of the medial compartmental surfaces of polyethylene liner rises smoothly with the increase of the PTS. When the varus angle is between 4° and 9°, as the increase of the PTS, the maximum stress of polyethylene liner rises first and then falls, forming a trough at PTS 5° and then rises again. Compared to the PTS, the varus angle has a large effect on the maximum stress of the polyethylene liner (p < .001). CONCLUSION: When the varus angle is 0° to 3°, PTS 0° is recommended, which will result in a more equalized stress distribution of the polyethylene liner in TKA.

Assessment of bone ingrowth around beaded coated tibial implant for total ankle replacement using mechanoregulatory algorithm.

The long-term performance of porous coated tibial implants for total ankle replacement (TAR) primarily depends on the extent of bone ingrowth at the bone-implant interface. Although attempts were made for primary fixation for immediate post-operative stability, no investigation was conducted on secondary fixation. The aim of this study is to assess bone ingrowth around the porous beaded coated tibial implant for TAR using a mechanoregulatory algorithm. A realistic macroscale finite element (FE) model of the implanted tibia was developed based on computer tomography (CT) data to assess implant-bone micromotions and coupled with microscale FE models of the implant-bone interface to predict bone ingrowth around tibial implant for TAR. The macroscale FE model was subjected to three near physiological loading conditions to evaluate the site-specific implant-bone micromotion, which were then incorporated into the corresponding microscale model to mimic the near physiological loading conditions. Results of the study demonstrated that the implant experienced tangential micromotion ranged from 0 to 71 µm with a mean of 3.871 µm. Tissue differentiation results revealed that bone ingrowth across the implant ranged from 44 to 96 %, with a mean of around 70 %. The average Young's modulus of the inter-bead tissue layer varied from 1444 to 4180 MPa around the different regions of the implant. The analysis postulates that when peak micromotion touches 30 µm around different regions of the implant, it leads to pronounced fibrous tissues on the implant surface. The highest amount of bone ingrowth was observed in the central regions, and poor bone ingrowth was seen in the anterior parts of the implant, which indicate improper osseointegration around this region. This macro-micro mechanical FE framework can be extended to improve the implant design to enhance the bone ingrowth and in future to develop porous lattice-structured implants to predict and enhance osseointegration around the implant.