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Background: Despite the movement of the thumb carpometacarpal joint has been studied, many unclarified points remain regarding the movement of this joint. The purpose of this study was to evaluate the in vivo kinematics of the thumb carpometacarpal joint during flexion and abduction using computed tomography images. Methods: The subjects were 9 healthy males. Computed tomography images were obtained in 4 equally-divided positions from maximum extension to maximum flexion, and maximum adduction to maximum abduction of the thumb. A three-dimensional model was constructed from these images, and the models of each position were superimposed with reference to the trapezium. The amount of angular change around the bone axes of first metacarpal bone and rotation axes were evaluated. Results: We found that the first metacarpal bone showed relatively simple behavior during abduction. However, during flexion, it exhibited a particular movement in which the amount of angular change of the metacarpal bone with respect to the trapezium rapidly increased with deep flexion. Conclusions: These results suggest that the thumb carpometacarpal joint exhibits a special movement during flexion, especially deep flexion. [ABSTRACT FROM AUTHOR]

Background: Neurolysis alone or administration of anti-adhesion products after neurolysis is performed to treat peripheral nerve adhesion; however, the recovery of nerve function is poor. This study aimed to investigate the efficacy of adipose-derived stem cells (ADSCs) for peripheral nerve adhesion in a rat model., Methods: As a nerve adhesion procedure, the neural bed was coagulated, and the epineurium of the sciatic nerve was sutured to the coagulated neural bed using nylon. Neurolysis was performed 6 weeks after the nerve adhesion procedure, and saline (control group) or ADSCs (ADSC group) were administered around the nerve where neurolysis was performed. Evaluations were performed 6 weeks after the administration., Results: The wet weight ratio of the tibialis anterior muscle and nerve conduction velocity, which are indicators of nerve regeneration, were significantly better, while tensile strength, which is an indicator of the severity of nerve adhesion, was significantly lower in the ADSC group than in the control group. In the nerve, the expression of interleukin-10 and transforming growth factor-β in the nerve was significantly higher and that of tumor necrosis factor-α was significantly lower in the ADSC group than in the control group. Furthermore, significantly fewer M1 macrophages and significantly more M2 macrophages were observed in the ADSC group than in the control group. In the perineural scar, significantly fewer perineural collagen fibers and significantly more vascularization were observed in the ADSC group than in the control group., Conclusions: ADSCs prevented peripheral nerve adhesion by reducing perineural scarring and enhancing vascularization. Additionally, ADSCs promoted nerve regeneration by decreasing inflammatory cytokine levels and increasing anti-inflammatory cytokine levels, as ADSCs regulated macrophage polarization from M1 to M2 macrophages. These findings hold promise for using ADSCs to treat nerve adhesion., Competing Interests: Declaration of competing interest The authors declare that this study was conducted without any commercial or financial relationships that could be construed as potential conflicts of interest., (Copyright © 2024 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Despite the movement of the thumb carpometacarpal joint has been studied, many unclarified points remain regarding the movement of this joint. The purpose of this study was to evaluate the in vivo kinematics of the thumb carpometacarpal joint during flexion and abduction using computed tomography images. Methods: The subjects were 9 healthy males. Computed tomography images were obtained in 4 equally-divided positions from maximum extension to maximum flexion, and maximum adduction to maximum abduction of the thumb. A three-dimensional model was constructed from these images, and the models of each position were superimposed with reference to the trapezium. The amount of angular change around the bone axes of first metacarpal bone and rotation axes were evaluated. Results: We found that the first metacarpal bone showed relatively simple behavior during abduction. However, during flexion, it exhibited a particular movement in which the amount of angular change of the metacarpal bone with respect to the trapezium rapidly increased with deep flexion. Conclusions: These results suggest that the thumb carpometacarpal joint exhibits a special movement during flexion, especially deep flexion.

Introduction: We previously reported the classification of the scaphoid fracture nonunions as linear, cystic, and sclerotic or displaced types based on radiographic findings. We have been treating the linear and cystic type fractures via screw fixation without bone grafting and the sclerotic or displaced type fractures via screw fixation with bone grafting. In this retrospective study, we report the treatment outcomes of the linear and cystic types of scaphoid fracture nonunions., Methods: Nineteen patients with linear and cystic type scaphoid fracture nonunions were included. Two patients had linear type and 17 had cystic type fractures. All the patients were male, their mean age was 29.2 years. All patients were treated with screw fixation alone by a single surgeon., Results: Bone union was achieved in 17 cases. The mean time to bone union was 3.7 months. Bone union was not achieved in one case of linear type and one case of cystic type fracture. The former was thought to be due to misdiagnosis of displaced type as linear type fracture; however, no obvious reason could be found for the latter., Discussion: Screw fixation alone could help achieve bone union in linear type scaphoid fracture nonunions. However, if the type of the fracture is difficult to diagnose based on plain radiography, evaluation using computed tomography should be performed. The cystic type fractures may need to be subclassified according to the location or size of the cyst as well as the viability of the proximal bone fragment., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper.The authors declared no potential conflicts of interest with respect to the research, authorship, and publication of this article., (© 2020 Delhi Orthopedic Association. All rights reserved.)