Journal of Orthopaedic Research®最新文献

Anterior shoulder instability with glenoid bone lesion can be treated with the Eden-Hybinette procedure utilizing a tricortical iliac crest bone graft or the Latarjet procedure. This study aimed to evaluate the glenohumeral joint (GHJ) kinematics throughout an external shoulder rotation following the Eden-Hybinette and Latarjet procedures. Nine human specimens were examined with dynamic radiostereometry during a GHJ external rotation with anteriorly directed loads from 0 to 30 N. In 30- and 60-degree GHJ abduction, the kinematics (measured as the humeral head center and contact point) was sequentially recorded for a 15% anterior glenoid bone lesion, the Eden-Hybinette, and the Latarjet procedure. The Latarjet and Eden-Hybinette procedures resulted in up to 9.7 mm (95%CI 0.5; 18.8) more posterior and a 7.4 mm (95%CI 0.3; 14.4) superior humeral head center location compared to the glenoid bone lesion. With 0-20 N anterior directed loads, the Latarjet procedure resulted in a more posterior humeral head center and contact point of up to 7.6 mm (95%CI 3.6; 11.5), especially in 60 degrees of GHJ abduction, compared to the Eden-Hybinette procedure. Opposite, at 30 N anterior-directed load, the Eden-Hybinette procedure resulted in a more posterior humeral head center of up to 7.6 mm (95%CI 0.3; 14.9) in 30 degrees GHJ abduction compared to the Latarjet procedure. The results support considering the Latarjet procedures in patients who need the stabilizing effect with the arm in the abducted and externally rotated position (e.g., throwers) and the Eden-Hybinette procedure in patients exposed to high anterior-directed loads with the arm at lower abduction angles (e.g., epilepsia).

Our aim was to develop a novel approach to identify disease-modifying drugs for osteoarthritis (OA), focusing on stimulating type II collagen anabolism in chondrocytes. As ELISA or western blot are destructive, laborious and time consuming, primary human chondrocytes expressing Gaussia luciferase under the control of the type II collagen promoter were developed and used. We cultured them in 3D cartilage aggregates under physioxia, to temporally screen a natural product library over 3-weeks. Hit compounds were analyzed for their potential targets in silico, first by structure, then by RNA-Seq. Two hit compounds were then further analyzed using biochemical assays, dose-response curves, and histological analyses to confirm their effects on type II collagen expression and chondrogenesis. Aromoline shows promise as a potential disease modifying compound, demonstrating an increase in type II collagen expression within cartilage sourced from chondrocytes of three distinct donors. Aromoline is a bisbenzylisoquinoline alkaloid that has been studied for its antiproliferative, anti-inflammatory, and antimicrobial properties, and we are the first to explore its effects on chondrocytes and chondrogenesis. In silico analysis revealed the dopamine receptor D4 (DRD4) as a potential target, confirmed by type II collagen upregulation after aromoline treatment and with DRD4-specific agonist ABT-724. This novel approach combining in silico and in vitro methods provides a platform for drug discovery in a challenging and under-researched area. In conclusion, a novel drug (aromoline) and target receptor (DRD4) were identified as stimulating type II collagen, with the future goal of treating or preventing OA.

Magnetic resonance imaging (MRI) of the knee is the recommended diagnostic method before invasive arthroscopy surgery. Nevertheless, interpreting knee MRI scans is a time-consuming process that is vulnerable to inaccuracies and inconsistencies. We proposed a multitask learning network MCSNet_att which efficiently introduces segmentation prior features and enhances classification results through multiscale feature fusion and spatial attention modules. The MRI studies and subsequent arthroscopic diagnosis of 259 knees were collected retrospectively. Models were trained based on multitask loss with coronal and sagittal sequences and fused using logistic regression (LR). We visualized the network's interpretability by the gradient-weighted class activation mapping method. The LR model achieved higher area under the curve and mean average precision of medial and lateral menisci than models trained on a single sagittal or coronal sequence. Our multitask model MCSNet_at outperformed the single-task model CNet and two clinicians in classification, with accuracy, precision, recall, F1-score of 0.980, 1.000, 0.952, 0.976 for medial and 0.920, 0.905, 0.905, 0.905 for the lateral, respectively. With the assistance of model results and visualized saliency maps, both clinicians showed improvement in their diagnostic performance. Compared to the baseline segmentation model, our model improved dice similarity coefficient and the 95% Hausdorff distance (HD₉₅) of the lateral meniscus for 2.3% and 0.860 mm in coronal images and 4.4% and 2.253 mm in sagittal images. Our multitask learning network quickly generated accurate clinicopathological classification and segmentation of knee MRI, demonstrating its potential to assist doctors in a clinical setting.

This study's objective was to investigate the extent to which two different levels of low-intensity vibration training (0.6 g or 1.0 g) affected musculoskeletal structure and function after a volumetric muscle loss (VML) injury in male C57BL/6J mice. All mice received a unilateral VML injury to the posterior plantar flexors. Mice were randomized into a control group (no vibration; VML-noTX), or one of two experimental groups. The two experimental groups received vibration training for 15-min/day, 5-days/week for 8 weeks at either 0.6 g (VML-0.6 g) or 1.0 g (VML-1.0 g) beginning 3-days after induction of VML. Muscles were analyzed for contractile and metabolic adaptations. Tibial bone mechanical properties and geometric structure were assessed by a three-point bending test and microcomputed tomography (µCT). Body mass-normalized peak isometric-torque was 18% less in VML-0.6 g mice compared with VML-noTx mice (p = 0.030). There were no statistically significant differences of vibration intervention on contractile power or muscle oxygen consumption (p ≥ 0.191). Bone ultimate load, but not stiffness, was ~16% greater in tibias of VML-1.0 g mice compared with those from VML-noTx mice (p = 0.048). Cortical bone volume was ~12% greater in tibias of both vibration groups compared with VML-noTx mice (p = 0.003). Importantly, cross-section moment of inertia, the primary determinant of bone ultimate load, was 44% larger in tibias of VML-0.6 g mice compared with VML-noTx mice (p = 0.006). These changes indicate that following VML, bones are more responsive to the selected vibration training parameters than muscle. Vibration training represents a possible adjuvant intervention to address bone deficits following VML.

The biological factors that affect healing after rotator cuff repair (RCR) are not well understood. Genetic variants in the extracellular matrix protein Tenascin C (TNC) are associated with impaired tendon healing and it is expressed in rotator cuff tendon tissue after injury, suggesting it may have a role in the repair process. The purpose of the current study was to determine the role of TNC on tendon healing after RCR in a murine model. The supraspinatus tendon was transected and repaired on the left shoulder of wild-type (WT-RCR), Tenascin C null (Tnc^--RCR) and Tnc heterozygous (Tnc^+/--RCR) mice. Controls included the unoperated, contralateral shoulder of WT-RCR, Tnc^-RCR, Tnc^+/--RCR mice and unoperated shoulders from age and genotype matched controls. We performed histologic, activity testing, bulk RNA-seq, and biomechanical analyses. At 8-weeks post-RCR, Tnc^- and Tnc^+/- mice had severe bone and tendon defects following RCR. Tnc^--RCR mice had reduced activity after RCR including reduced wheel rotations, wheel duration, and wheel episode average velocity compared with WT-RCR. Loss of Tnc following RCR altered gene expression in the shoulder, including upregulation of sex hormone and WNT pathways and a downregulation of inflammation and cell cycle pathways. Tnc^- mice had similar biomechanical properties after repair as WT. Further research is required to evaluate tissue specific alterations of Tnc, the interactions of Tnc and sex hormone and inflammation pathways as well as possible adjuvants to improve enthesis healing in the setting of reduced TNC function.

Helical plates used for proximal humeral shaft fracture fixation avoid the radial nerve distally as compared to straight plates. To investigate in a human cadaveric model the biomechanical competence of straight lateral plates versus 45° helical plates used for fixation of proximal comminuted humeral shaft fractures, eight pairs of human cadaveric humeri were instrumented using either a long straight PHILOS plate (Group 1) or a 45° helical plate (Group 2) for treatment of an unstable proximal humeral shaft fracture. All specimens were tested under non-destructive quasi-static loading in axial compression, internal and external rotation, and bending in four directions. Subsequently, progressively increasing cyclic loading in internal rotation was applied until failure and interfragmentary movements were monitored by motion tracking. Axial displacement (mm) was 3.13 ± 0.31 in Group 1 and 2.60 ± 0.42 in Group 2, p = 0.015. Flexion/extension deformation (°) in Group 1 and Group 2 was 0.56 ± 0.42 and 0.43 ± 0.23, p = 0.551. Varus/valgus deformation (°) was 6.39 ± 0.44 in Group 1 and 5.13 ± 0.87 in Group 2, p = 0.012. Shear (mm) and torsional (°) displacement were 5.36 ± 0.76 and 17.75 ± 1.06 in Group 1, and 5.03 ± 0.46 and 16.79 ± 1.36 in Group 2, p ≥ 0.090. Cycles to catastrophic failure were 10000 ± 1401 in Group 1 and 9082 ± 1933 in Group 2, p = 0.708. From a biomechanical perspective, 45° helical plating is associated with lower axial and varus/valgus displacement under axial loading and demonstrates comparable resistance to failure versus straight plating. Therefore, 45° helical plates can be considered as a valid alternative to straight plates for treatment of proximal humeral shaft fractures.

This study investigated joint kinematics and attachment tensile mechanics following resection of the medial meniscus anterior attachment. A secondary objective investigated the repair of the attachment. Yucatan minipigs underwent unilateral surgery for either Injury (en bloc) resection of the anterior attachment of the insertional ligament, (a portion of the cranial medial meniscotibial ligament) or Repair (immediate repair with a suture anchor), with the contralateral knee as Intact control. Evaluation at 6 weeks and 6 months included joint kinematics measured from MRI acquired under knee compression and tensile testing of the attachment. Injury resulted in large levels of meniscus extrusion, despite the development of a fibrovascular scar. At 6 weeks, the meniscus extruded 1.95 mm more than Intact; at 6 months, this extrusion was reduced to 0.77 mm. Under an applied 1× body weight load, the meniscus further extruded and was not different with treatment or time. During attachment tensile testing, elongation was 0.6 mm for Intact, following Injury, elongation was 2.7 mm at 6 weeks and was partially restored to 1.5 mm at 6 months. Despite this, the cartilage wear worsened over time. Repair was inadequate to avoid the extrusion or cartilage wear seen in the injury group at 6 weeks, so it was not continued for the 6-month group. This study demonstrates that while meniscus injury is useful to study cartilage degeneration, a holistic consideration of the role of the meniscus itself, including its changing material properties and its impact on joint mechanics during injury, repair, and rehabilitation, are key factors contributing to overall joint health.