Bone & Joint Research最新文献

Aims: Intervertebral disc degeneration (IDD) and sagittal-oriented articular processes can restrict motility and increase stiffness of the motion segment, potentially causing compensatory stress and higher motility in adjacent segments. It is unclear if these factors trigger IDD progression in adjacent segments. This study aimed to elucidate this using functional MRI, and identify biomechanical mechanisms with a validated numerical model.

Methods: Clinical data from 95 patients were retrospectively collected from January 2022 to April 2023. Disc collapse and fibrosis were assessed by disc height ratio and fractional anisotropy (FA) values in the L4-L5 segment. The orientation of articular facet processes in L4-L5 was examined. Annulus fibrosus integrity was investigated using diffusion tensor fibre tractography in cranial (L3-L4) and caudal (L5-S1) segments. Statistical analyses determined differences between patients with and without annulus tears, and regression analyses identified predictors of annulus tears. Numerical models of L3-S1 motion segment were developed, incorporating variations in disc collapse, fibrosis, and facet orientation angles in L4-L5. Stress distribution on cranial and caudal discs was calculated under various loading conditions.

Results: Compared to patients with intact annulus at the cranial segment (L3-L4), those with annulus tears show reduced facet orientation angles and disc height ratios, and elevated FA values. These parameters are independent risk factors for cranial annulus tears, not observed on the caudal side. Models with sagittal-oriented articular processes (facet orientation = 35°), disc collapse, and fibrosis show higher stress on the cranial disc, particularly within the annulus, compared to models with coronal-oriented processes (facet orientation = 65°) and healthy discs.

Conclusion: Sagittal orientation of articular processes and IDD phenotypes may increase the risk of annulus tears in the cranial adjacent segment by compromising the biomechanical environment. This offers a novel perspective for understanding biomechanical interactions in adjacent segments during IDD progression.

Aims: The significance of periosteal vessels in the healing of tibial shaft fractures is well-established. However, the gross anatomical patterns and differential distribution of these vessels on the medial versus lateral surface of the tibial shaft have not been thoroughly described. This study aimed to illustrate the comparative anatomy of periosteal circulation on the medial versus lateral surface of the tibial shaft, where tibial plates are commonly applied.

Methods: Ten adult fresh cadavers underwent aortic injection with coloured silicone to investigate the vascular system of the lower limbs, including the tibial extraosseous circulation. Following material fixation, the medial and lateral tibial surfaces were dissected extraperiosteally from the knee to the ankle joint to visualize the gross anatomy of periosteal vessels running along the medial and lateral surfaces of the tibial shaft.

Results: In all specimens, periosteal vessels on the lateral tibial consisted of six to eight main trunks in 17 out of 20 specimens. These vessels were evenly distributed, horizontally oriented, and exhibited variable side branching. Most of these vessels crossed the anterior tibial crest, terminating on the medial side. The extensor muscles on the lateral tibial surface made negligible contributions to the periosteal circulation. The medial tibial surface received its periosteal blood supply partly from the terminal branches of the traversing vessels from the lateral surface and partly from branches of the posterior tibial artery. These vessels were shorter, smaller, sparsely scattered, randomly distributed, and exhibited greater variability in number and size compared to their lateral counterparts.

Conclusion: Periosteal circulation to the anterior two-thirds of the tibial shaft is mainly delivered through the lateral tibial surface. When periosteal circulation is a concern, lateral plating may be more disruptive compared to medial plating.

Aims: We aim to develop a fully automated deep-learning model to detect and classify benign/malignant bone tumours in full-field limb radiographs using an object detection model. The secondary aim is to identify differences in classification characteristics between the developed automated model, three orthopaedic oncologists, and three general orthopaedic surgeons.

Methods: This retrospective analysis included 642 limb bone tumours with 40 diagnoses confirmed pathologically from three institutions (378 benign, 264 malignant including intermediate types). We employed end-to-end object Detection with transformers with Improved deNoising anchOr boxes (DINO) and You Only Look Once (YOLO) models. We performed five-fold cross validation on the collected radiographs, using the training data to train the models, validation data to optimize the models' parameters, and independent test data for final performance evaluation. Firstly, we confirmed DINO achieves a higher detection rate than YOLO. Secondly, we compared the classification performance of DINO with those of doctors, using various metrics such as accuracy, sensitivity, specificity, precision, and F-measure.

Results: The DINO model achieved a higher mean tumour detection rate (85.7% (95% CI 81.5 to 89.8)) than the YOLO model (80.1% (95% CI 77.2 to 82.9)). For the evaluation of classification performance, we used 113 cases that DINO detected out of 128 randomly selected cases as the evaluation test set. The accuracy and sensitivity of the DINO model, as a superior model, were significantly higher than those of general orthopaedic surgeons. The DINO model correctly classified 78.6% (22 out of 28 cases) of the challenging cases that two or more doctors misclassified. However, DINO's diagnostic errors primarily occurred with tumours that were diagnostically challenging for orthopaedic oncologists or present in unusual sites.

Conclusion: The DINO model automatically detects bone tumours better than the YOLO model, and may assist doctors in detecting tumours and classifying malignant/benign bone tumours in clinical practice.

Aims: Growth rods are the gold standard for treating early-onset scoliosis (EOS), but current treatments often fail to optimally promote spinal growth and require frequent distraction surgeries, leading to complications and significant burdens on patients.

Methods: We designed a novel growth rod (NGR) with unidirectional sliding and external regulation capabilities. Using a 3D model, we simulated the implantation of traditional growth rod (TGR) and NGR, applying a 400 N compressive load and a 1 Nm moment to test stiffness. We assessed spinal joint range of motion and growth rod stress distribution, and calculated axial force, moment, and fatigue life.

Results: The axial compressive and torsional stiffness of the NGR were higher than those of the TGR and the intact group. The Von Mises stress values of the NGR under all conditions were higher than those of the TGR. Additionally, the fatigue life of the NGR met basic daily living requirements. Overall, the NGR demonstrated superior stiffness and stress distribution, with stress primarily concentrated near the screw fixation points and distributed along the titanium rods.

Conclusion: The NGR, based on a distraction implant, includes a unidirectional sliding component and a spring-driven component, providing dynamic correction functionality. Additionally, it features a novel non-invasive lengthening mechanism that reduces the risk of infection. Compared to the current market-leading EOS implants, it offers enhanced stability. The novel device can potentially improve clinical outcomes in the surgical treatment of EOS.

Aims: The osteochondral cement line (OCL) plays a key role in joint integrity by attaching articular calcified cartilage (ACC) to underlying subchondral bone (SCB), whose predominant collagens are type 2 (Col-II) and type 1 (Col-I), respectively. Previous studies report contrasting evidence of the presence of collagen fibrils in the OCL, albeit in different species and joints. If present, collagen fibrils might provide a basis for osteochondral bonding in the organic phase. We aimed to study the morphological variations of the osteochondral cement line, to observe whether cartilage and bone collagen fibrils are present in the OCL, and whether they colocalize in a manner that could help explain how ACC attaches to SCB.

Methods: We used immunofluorescence, confocal microscopy, and deconvolution to image Col-I and Col-II collagen fibrils and measure their overlap and colocalization, in OCL harvested from equine and bovine femoral head, patella, and proximal and distal metatarsal condyles. Large mammalian species were chosen to have size and pathobiology relevant to human anatomy. Thousands to millions of Col-I/-II colocalizing complexes were observed per mm² of OCL over a tissue depth of 1 to 5 µm. Kruskal-Wallis with Dunn's post-hoc tests and Mann-Whitney U tests were conducted for intra- and interspecies statistical analysis.

Results: The areal volume (µm³/mm²) of Col-I/Col-II complexes was up to ten times greater in equine than bovine OCL (p = 0.016 to 0.029). Similarly, the number of Col-I/-II complexes and mean volume per complex differed significantly (p < 0.001 to 0.032 and p < 0.001 to 0.029, respectively) among anatomical sites between equine and bovine OCL. Gaps or tears near OCL were present uniquely in the bovine patella.

Conclusion: Col-I/Col-II overlap and colocalize at OCL, which could be a critical source of bond strength between cartilage and bone that should be considered when cartilage repair is attempted in clinical settings.

Aims: Our study explores the candy box (CB) technique with sutures and Nice knot as a novel treatment for inferior pole patellar fractures, potentially superior to traditional wire fixation.

Methods: CT data from five adult knee joints were extracted to create finite element models for inferior pole patellar fractures and four internal fixation models. These included CB technique combined with high-strength sutures and Nice knot (CB-H), CB technique combined with tendon sutures and Nice knot (CB-T), CB technique combined with steel wires (CB-S), and tension-band wiring combined with cerclage wiring (TBWC). Displacement and stress distribution during knee flexion and extension were compared. Physical models were created using 3D printing technology. These models were then subjected to static tensile test and dynamic fatigue test. Data from 21 patients treated with CB-H and 22 patients treated with TBWC were analyzed to assess the effectiveness.

Results: Finite element analysis (FEA) indicated that displacements for CB-H and CB-T were below the failure threshold in all knee joint states. Stresses on the patella and internal fixation were lower in the CB-H and CB-T groups compared with the CB-S and TBWC groups. Both static and dynamic biomechanical experiments confirmed that displacements of CB-H and CB-T also remained below the failure threshold. In clinical research, the CB-H group outperformed the TBWC group in operating time, intraoperative blood loss, length of incision and time to clinical union, and complication control.

Conclusion: The CB technique combined with sutures and Nice knot can provide sufficient fixation strength for inferior pole patellar fractures. This method enables early functional exercise and avoids the need for secondary surgery. It could be a promising alternative to traditional TBWC surgery.

Aims: Lateral locked plating of distal femoral fractures is widely reported, yet there remains a 9% to 19% incidence of mechanical failure. Obliquely directed "kickstand screws", from the metaphyseal portion of a plate toward far-sided articular subchondral bone, have been shown to improve construct stiffness. This study explores the impact of kickstand screws in a finite element analysis bone defect model, comparing plate and screw maximum stress and maximum locking screw forces either with or without the addition of kickstand screws.

Methods: A finite element analysis model of a lateral based femoral plate and fracture gap simulation was created, with material and construct data parameters regarding bone material, implant, and composite model identified. The addition of the upper, lower, or both kickstand screws in an anatomical precontoured lateral distal femoral plate were selected as the variables compared against the absence of kickstand screws. Screw and plate principal stresses (MPa) and locking screw mechanism force (N) were measured.

Results: The addition of the upper kickstand screw or both kickstand screws led to an approximate 40% reduction of stress in the metaphyseal hole closest to the fracture. The addition of the lower, upper, and both kickstand screws led to a 23%, 32%, and 34% reduction of maximum stress in the metaphyseal screws, respectively. The addition of the lower kickstand screw led to a 19% reduction, while the upper or both kickstand screws led to a 23% reduction of maximum force experienced by the locking mechanism.

Conclusion: The addition of kickstand screws improves the mechanical performance of the construct, with reduced stresses experienced by the plate and metaphyseal screws. Furthermore, the maximum forces on the locking screw mechanism were shown to be significantly reduced, providing a protective effect to the polyaxial locking mechanism of the metaphyseal screw.

Aims: This study aimed to identify and compare the microRNA (miRNA) profiles of exosomes derived from human induced pluripotent stem cells (iPSCs), bone marrow mesenchymal stem cells (BMSCs), and adipose tissue-derived stem cells (ADSCs) (hiPSC-Exos, hBMSC-Exos, and hADSC-Exos), and their functional effects on human articular chondrocytes (hACs).

Methods: hiPSC-Exos, hBMSC-Exos, and hADSC-Exos were collected from the appropriate cells cultured in 10% bovine exosome-depleted fetal bovine serum (de-Exo-FBS) for 48 hours. Next-generation sequencing (NGS) and bioinformatics were used to analyze the small RNA profiles of these exosomes. The biological functions of hACs were examined after a 12-day treatment with exosomes.

Results: hBMSC-Exos and hADSC-Exos had similar miRNA profiles but were largely different from hiPS-Exos. There were 17 highly expressed miRNAs in hiPSC-Exos, 13 miRNAs in hADSC-Exos, and 11 miRNAs in hBMSC-Exos. Among them, seven miRNAs overlapped between the hBMSC-Exos and hADSC-Exos, and only three of them (hsa-miR-16-5p, hsa-miR-25-3p, and hsa-miR-93-5p) overlapped among all three exosomes. The putative target genes of the three overlapping exosomal miRNAs, and high-scoring target genes, including MAN2A1, ZNFX1, PHF19, GPR137C, ENPP5, B3GALT2, FNIP1, PKD2, and FBXW7, were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that these genes are involved in cell growth, bone ossification, and cartilage development/differentiation, possibly via the mitogen-activated protein kinase (MAPK) signalling pathway. Accordingly, we confirmed the biological effect on cartilage differentiation and found that hiPSC-Exos, hBMSC-Exos, and hADSC-Exos maintained hAC viability, prevented senescence, promoted the formation of a normal cartilage matrix (glycosaminoglycan and type II collagen), and downregulated fibrocartilage matrix (type I collagen) in normal hACs. Comparatively, hBMSC-Exos had the greatest effect on hAC function.

Conclusion: Bioinformatics revealed differences and possible mechanisms of action of exosomes derived from pluripotent hiPSCs, multipotent hADSCs, and multipotent hBMSCs, and these exosomes effectively suppressed cell senescence and promoted normal functional extracellular matrix formation in hACs. Further investigations of the different functions of exosomes from pluripotent-hiPSCs other than those from multipotent-hMSCs are needed.