Fibrin Scaffolds Perfused with Transforming Growth Factor-ß1 as an In Vitro Model to Study Healthy and Tendinopathic Human Tendon Stem/Progenitor Cells.

A limited understanding of tendon cell biology in healthy and pathological conditions has impeded the development of effective treatments, necessitating in vitro biomimetic models for studying tendon events. We established a dynamic culture using fibrin scaffolds, bioengineered with tendon stem/progenitor cells (hTSPCs) from healthy or diseased human biopsies and perfused with 20 ng/mL of human transforming growth factor-ß1 for 21 days. Both cell types showed long-term viability and upregulated Scleraxis (SCX-A) and Tenomodulin (TNMD) gene expressions, indicating tenogenic activity. However, diseased hTSPCs underexpressed collagen type I and III (COL1A1 and COL3A1) genes and exhibited lower SCX-A and TNMD protein levels, but increased type I collagen production, with a type I/type III collagen ratio > 1.5 by day 14, matching healthy cells. Diseased hTSPCs also showed constant high levels of pro-inflammatory cytokines, such as IL-8 and IL-6. This biomimetic environment is a valuable tool for studying tenogenic and inflammatory events in healthy and diseased tendon cells and identifying new therapeutic targets.

Muscle-Tendon Unit Properties in Mice Bred for High Levels of Voluntary Running: Novel Physiologies, Coadaptation, Trade-Offs, and Multiple Solutions in the Evolution of Endurance Running.

AbstractMuscle-tendon unit (MTU) morphology and physiology are likely major determinants of locomotor performance and therefore Darwinian fitness. However, the relationships between underlying traits, performance, and fitness are complicated by phenomena such as coadaptation, multiple solutions, and trade-offs. Here, we leverage a long-running artificial selection experiment in which mice have been bred for high levels of voluntary running to explore MTU adaptation, as well as the role of coadaptation, multiple solutions, and trade-offs, in the evolution of endurance running. We compared the morphological and contractile properties of the triceps surae complex, a major locomotor MTU, in four replicate selected lines to those of the triceps surae complex in four replicate control lines. All selected lines have lighter and shorter muscles, longer tendons, and faster muscle twitch times than all control lines. Absolute and normalized maximum shortening velocities and contractile endurance vary across selected lines. Selected lines have similar or lower absolute velocities and higher endurance than control lines. However, normalized shortening velocities are both higher and lower in selected lines than in control lines. These findings potentially show an interesting coadaptation between muscle and tendon morphology and muscle physiology, highlight multiple solutions for increasing endurance running performance, demonstrate that a trade-off between muscle speed and endurance can arise in response to selection, and suggest that a novel physiology may sometimes allow this trade-off to be circumvented.

Changes in mechanical properties at the muscle level could be detected by Nakagami imaging during in-vivo fixed-end contractions.

In this study, we investigated the capability of the Nakagami transformation to detect changes in vastus lateralis muscle-tendon stiffness (k) during dynamic (and intense) contractions. k was evaluated in eleven healthy males using the gold-standard method (a combination of ultrasound and dynamometric measurements) during maximal and sub-maximal voluntary fixed-end contractions of the knee extensors (20, 40, 60, 80, and 100% of maximum voluntary force), while Nakagami parameters were analysed using the Nakagami transformation during the same contractions. Muscle-belly behaviour was investigated by means of B-mode ultrasound analysis, while Nakagami parameters were obtained in post-processing using radiofrequency data. k was calculated as the slope of the force-muscle-belly elongation relationship. Three contractions at each intensity were performed to calculate the intra-trial reliability and the coefficient of variation (CV) of the Nakagami parameters. At all contraction intensities, high values of intra-trial reliability (range: 0.92-0.96) and low CV (<9%) were observed. k and Nakagami parameters increased as a function of contraction intensity, and significant positive correlations were observed between these variables. These data suggest that changes in mechanical properties (e.g., stiffness) at the muscle level could be investigated by means of Nakagami parameters.

Beyond pixel: Superpixel-based MRI segmentation through traditional machine learning and graph convolutional network.

BACKGROUND AND OBJECTIVE: Tendon segmentation is crucial for studying tendon-related pathologies like tendinopathy, tendinosis, etc. This step further enables detailed analysis of specific tendon regions using automated or semi-automated methods. This study specifically aims at the segmentation of Achilles tendon, the largest tendon in the human body. METHODS: This study proposes a comprehensive end-to-end tendon segmentation module composed of a preliminary superpixel-based coarse segmentation preceding the final segmentation task. The final segmentation results are obtained through two distinct approaches. In the first approach, the coarsely generated superpixels are subjected to classification using Random Forest (RF) and Support Vector Machine (SVM) classifiers to classify whether each superpixel belongs to a tendon class or not (resulting in tendon segmentation). In the second approach, the arrangements of superpixels are converted to graphs instead of being treated as conventional image grids. This classification process uses a graph-based convolutional network (GCN) to determine whether each superpixel corresponds to a tendon class or not. RESULTS: All experiments are conducted on a custom-made ankle MRI dataset. The dataset comprises 76 subjects and is divided into two sets: one for training (Dataset 1, trained and evaluated using leave-one-group-out cross-validation) and the other as unseen test data (Dataset 2). Using our first approach, the final test AUC (Area Under the ROC Curve) scores using RF and SVM classifiers on the test data (Dataset 2) are 0.992 and 0.987, respectively, with sensitivities of 0.904 and 0.966. On the other hand, using our second approach (GCN-based node classification), the AUC score for the test set is 0.933 with a sensitivity of 0.899. CONCLUSIONS: Our proposed pipeline demonstrates the efficacy of employing superpixel generation as a coarse segmentation technique for the final tendon segmentation. Whether utilizing RF, SVM-based superpixel classification, or GCN-based classification for tendon segmentation, our system consistently achieves commendable AUC scores, especially the non-graph-based approach. Given the limited dataset, our graph-based method did not perform as well as non-graph-based superpixel classifications; however, the results obtained provide valuable insights into how well the models can distinguish between tendons and non-tendons. This opens up opportunities for further exploration and improvement.

Multiaxial 3D MRI of the Ankle: Advanced High-Resolution Visualization of Ligaments, Tendons, and Articular Cartilage.

MRI is a valuable tool for diagnosing a broad spectrum of acute and chronic ankle disorders, including ligament tears, tendinopathy, and osteochondral lesions. Traditional two-dimensional (2D) MRI provides a high image signal and contrast of anatomic structures for accurately characterizing articular cartilage, bone marrow, synovium, ligaments, tendons, and nerves. However, 2D MRI limitations are thick slices and fixed slice orientations. In clinical practice, 2D MRI is limited to 2 to 3 mm slice thickness, which can cause blurred contours of oblique structures due to volume averaging effects within the image slice. In addition, image plane orientations are fixated and cannot be changed after the scan, resulting in 2D MRI lacking multiplanar and multiaxial reformation abilities for individualized image plane orientations along oblique and curved anatomic structures, such as ankle ligaments and tendons. In contrast, three-dimensional (3D) MRI is a newer, clinically available MRI technique capable of acquiring high-resolution ankle MRI data sets with isotropic voxel size. The inherently high spatial resolution of 3D MRI permits up to five times thinner (0.5 mm) image slices. In addition, 3D MRI can be acquired image voxel with the same edge length in all three space dimensions (isotropism), permitting unrestricted multiplanar and multiaxial image reformation and postprocessing after the MRI scan. Clinical 3D MRI of the ankle with 0.5 to 0.7 mm isotropic voxel size resolves the smallest anatomic ankle structures and abnormalities of ligament and tendon fibers, osteochondral lesions, and nerves. After acquiring the images, operators can align image planes individually along any anatomic structure of interest, such as ligaments and tendons segments. In addition, curved multiplanar image reformations can unfold the entire course of multiaxially curved structures, such as perimalleolar tendons, into one image plane. We recommend adding 3D MRI pulse sequences to traditional 2D MRI protocols to visualize small and curved ankle structures to better advantage. This article provides an overview of the clinical application of 3D MRI of the ankle, compares diagnostic performances of 2D and 3D MRI for diagnosing ankle abnormalities, and illustrates clinical 3D ankle MRI applications.

The histone H3K9 methyltransferase G9a regulates tendon formation during development.

G9a is a histone methyltransferase that catalyzes the methylation of histone 3 lysine 9 (H3K9), which is involved in the regulation of gene expression. We had previously reported that G9a is expressed in developing tendons in vivo and in vitro and that G9a-deficient tenocytes show impaired proliferation and differentiation in vitro. In this study, we investigated the functions of G9a in tendon development in vivo by using G9a conditional knockout (G9a cKO) mice. We crossed Sox9Cre/+ mice with G9afl/fl mice to generate G9afl/fl; Sox9Cre/+ mice. The G9a cKO mice showed hypoplastic tendon formation at 3 weeks of age. Bromodeoxyuridine labeling on embryonic day 16.5 (E16.5) revealed decreased cell proliferation in the tenocytes of G9a cKO mice. Immunohistochemical analysis revealed decreased expression levels of G9a and its substrate, H3K9me2, in the vertebral tendons of G9a cKO mice. The tendon tissue of the vertebrae and limbs of G9a cKO mice showed reduced expression of a tendon marker, tenomodulin (Tnmd), and col1a1 genes, suggesting that tenocyte differentiation was suppressed. Overexpression of G9a resulted in enhancement of Tnmd and col1a1 expression in tenocytes in vitro. These results suggest that G9a regulates the proliferation and differentiation of tendon progenitor cells during tendon development. Thus, our results suggest that G9a plays an essential role in tendon development.

Atypical Presentation of Tenosynovial Giant Cell Tumor on the Hallucal Flexor Tendon Sheath: A Case Report.

Tenosynovial giant cell tumor (TGCT) is a rare type of neoplasm that may be locally aggressive but is most often benign and can be divided into two subtypes: localized and diffuse. It tends to develop in the joints, bursae, and tendon sheaths primarily in the digits of the hand and less commonly in the forefoot. This soft-tissue mass has many possible differential diagnoses, including lipoma, ganglion cyst, plantar fibroma, and various sarcomas; surgical excision is usually indicated to reach a definitive diagnosis and rule out malignancy. We report a rare case of a 30-year-old woman with atypical plantar hallucal pain and a palpable mass on the plantar lateral aspect of the left hallux. Surgical excision and histopathologic evaluation confirmed a TGCT of the left hallucal flexor tendon sheath. Although it bears clinical resemblance to several other soft-tissue masses, TGCT has numerous pathognomonic features evident with advanced imaging and histologic analysis that help the physician obtain an accurate diagnosis and proceed with appropriate treatment.

Focal adhesion kinase regulates tendon cell mechanoresponse and physiological tendon development.

Tendons enable locomotion by transmitting high tensile mechanical forces between muscle and bone via their dense extracellular matrix (ECM). The application of extrinsic mechanical stimuli via muscle contraction is necessary to regulate healthy tendon function. Specifically, applied physiological levels of mechanical loading elicit an anabolic tendon cell response, while decreased mechanical loading evokes a degradative tendon state. Although the tendon response to mechanical stimuli has implications in disease pathogenesis and clinical treatment strategies, the cell signaling mechanisms by which tendon cells sense and respond to mechanical stimuli within the native tendon ECM remain largely unknown. Therefore, we explored the role of cell-ECM adhesions in regulating tendon cell mechanotransduction by perturbing the genetic expression and signaling activity of focal adhesion kinase (FAK) through both in vitro and in vivo approaches. We determined that FAK regulates tendon cell spreading behavior and focal adhesion morphology, nuclear deformation in response to applied mechanical strain, and mechanosensitive gene expression. In addition, our data reveal that FAK signaling plays an essential role in in vivo tendon development and postnatal growth, as FAK-knockout mouse tendons demonstrated reduced tendon size, altered mechanical properties, differences in cellular composition, and reduced maturity of the deposited ECM. These data provide a foundational understanding of the role of FAK signaling as a critical regulator of in situ tendon cell mechanotransduction. Importantly, an increased understanding of tendon cell mechanotransductive mechanisms may inform clinical practice as well as lead to the discovery of diagnostic and/or therapeutic molecular targets.

Age-dependence of semitendinosus tendon properties used for anterior cruciate ligament reconstruction differs in males and females.

BACKGROUND: The semitendinosus tendon is one of the most used autografts in anterior cruciate ligament reconstruction. Although recent evidence indicates that young patients, especially in females, may experience high rates of revision and residual instability, the reasons for the inferior outcomes in these patients remain unclear. To address this issue, we aimed to compare the mechanical properties of the semitendinosus tendon used for anterior cruciate ligament reconstruction in male and female patients of various ages. METHODS: The semitendinosus tendons harvested from 31 male and 29 female patients who underwent anterior cruciate ligament reconstruction surgery using the semitendinosus tendon autografts were used in this study. Using the distal part of the harvested semitendinosus tendon, the extent of cyclic loading-induced elongation (i.e., the extent of the increase in slack length) and the Young's modulus were measured during cyclic tensile testing. FINDINGS: Spearman correlation analyses revealed that the Young's modulus (|ρ| = 0.725, P < 0.001), but not elongation (|ρ| ≤ 0.036, P ≥ 0.351) positively correlated with the patient age in male tendon samples. In contrast, for female tendon samples, the elongation (|ρ| ≥ 0.415, P ≤ 0.025), but not the Young's modulus (|ρ| = 0.087, P = 0.655) negatively correlated with the patient age. INTERPRETATION: These results indicate that the semitendinosus tendon used for anterior cruciate ligament reconstruction in young male patients is compliant, whereas that in young female patients is susceptible to elongation induced by cyclic loading.

Deep learning enables accurate soft tissue tendon deformation estimation in vivo via ultrasound imaging.

Image-based deformation estimation is an important tool used in a variety of engineering problems, including crack propagation, fracture, and fatigue failure. These tools have been important in biomechanics research where measuring in vitro and in vivo tissue deformations are important for evaluating tissue health and disease progression. However, accurately measuring tissue deformation in vivo is particularly challenging due to limited image signal-to-noise ratio. Therefore, we created a novel deep-learning approach for measuring deformation from a sequence of images collected in vivo called StrainNet. Utilizing a training dataset that incorporates image artifacts, StrainNet was designed to maximize performance in challenging, in vivo settings. Artificially generated image sequences of human flexor tendons undergoing known deformations were used to compare benchmark StrainNet against two conventional image-based strain measurement techniques. StrainNet outperformed the traditional techniques by nearly 90%. High-frequency ultrasound imaging was then used to acquire images of the flexor tendons engaged during contraction. Only StrainNet was able to track tissue deformations under the in vivo test conditions. Findings revealed strong correlations between tendon deformation and applied forces, highlighting the potential for StrainNet to be a valuable tool for assessing rehabilitation strategies or disease progression. Additionally, by using real-world data to train our model, StrainNet was able to generalize and reveal important relationships between the effort exerted by the participant and tendon mechanics. Overall, StrainNet demonstrated the effectiveness of using deep learning for image-based strain analysis in vivo.

Design and Research of the Grasping Force Feedback Mechanism of Flexible Surgical Robots.

BACKGROUND: Robot-assisted microsurgery (RAMS) is gradually becoming the preferred method for some delicate surgical procedures. However, the lack of haptic feedback reduces the safety of the surgery. Surgeons are unable to feel the grasping force between surgical instruments and the patient's tissues, which can easily lead to grasping failure or tissue damage. METHODS: This paper proposes a tendon-driven grasping force feedback mechanism, consisting of a follower hand and a leader hand, to address the lack of grasping force feedback in flexible surgical robots. Considering the friction in the tendon transmission process, a grasping force estimation model is established for the follower hand. The admittance control model is designed for force/position control of the leader hand. RESULTS: Through experimental validation, it has been confirmed that the grasping force sensing range of the follower hand is 0.5-5 N, with a sensing accuracy of 0.3 N. The leader hand is capable of providing feedback forces in the range of 0-5 N, with a static force accuracy of 0.1 N. CONCLUSIONS: The designed mechanism and control strategy can provide the grasping force feedback function. Future work will focus on improving force feedback performance. TRIAL REGISTRATION: This research has no clinical trials.

Sex-Specific Outcomes After Anterior Cruciate Ligament Reconstruction Using an All-Soft Tissue Quadriceps Tendon Autograft in a Young Active Population.

BACKGROUND: The ideal graft for anterior cruciate ligament (ACL) reconstruction (ACLR) in young athletes has a high return-to-sport (RTS) rate and a low reinjury rate. Quadriceps tendon autografts are being used with increasing frequency for ACLR in this population, despite a paucity of evidence to support their use. PURPOSE: To report the RTS rate, ipsilateral reinjury rate, and contralateral ACL injury rate in a young athletic population undergoing primary ACLR using an all-soft tissue quadriceps tendon (ASTQT) autograft. STUDY DESIGN: Cases series; Level of evidence, 4. METHODS: Patients aged 14 to 22 years who underwent primary ACLR using an ASTQT autograft by a single surgeon between January 1, 2005, and April 30, 2020, were identified via electronic medical records and contacted ≥24 months after ACLR to complete a survey regarding subsequent ipsilateral or contralateral ACL injuries and RTS. Patients who had undergone previous ACLR (ipsilateral or contralateral) were excluded. RESULTS: A total of 656 patients (330 male, 326 female; mean age, 17.9 years) were identified, and 395 patients completed the survey (60.2%; 174 male, 221 female; mean age, 17.8 years) with a mean follow-up of 73 ± 29 months (range, 24-139 months). The RTS rate was high (male: 87.7%; female: 82.8%; P = .19). Male and female patients had similar rates of revision ACLR (male: 12.6%; female: 10.0%; P = .40) and contralateral ACL injuries (male: 13.8%; female: 11.3%; P = .46). CONCLUSION: A high RTS rate and similar rates of ipsilateral and contralateral ACL injuries were found for male and female patients in a young athletic population undergoing primary ACLR using an ASTQT autograft. These results help one to better understand the utility of ASTQT grafts to support successful ACLR in young athletic populations, for which ASTQT grafts appear to yield favorable outcomes.

[Arthroscopic surgery for injuries to the popliteal tendon area of the lateral meniscus].

OBJECTIVE: To investigate the mid-term effect and complications of arthroscopic popliteal tendon suture in the treatment of lateral meniscus injury. METHODS: From January 2016 to December 2020, the data of 57 patients with lateral meniscus popliteal tendon injury treated by arthroscopic popliteal tendon suture fixation were retrospectively analyzed, including 35 males and 22 females, aged from 18 to 47 years old with an average of (32.9±7.9) years old. Knee function was evaluated using the International Knee Documentation Committee (IKDC) and Lysholm scores both before the operation and at the final follow-up. Meniscus healing was evaluated according to the postoperative Barrett standard. Wound healing complications, such as vascular injury, nerve injury, and lower extremity venous thrombosis, were recorded. RESULTS: All 57 patients were followed up for 12 to 58 months with an average of (38.1±14.9) months.The incisions of the patients after the operation were all Grade A healing without infection, popliteal tendon injury, blood vessel injury, nerve injury and lower extremity venous thrombosis.The IKDC score increased from (49.7±3.6) points preoperatively to (88.5±4.4) points in the final follow-up (P<0.05). The Lysholm score increased from (48.8±4.9) points preoperatively to (91.9±3.9) points at the final follow-up (P<0.05). At 3, 6 months and 1 year after operation, according to Barrett's criteria, 54 cases were clinically healed, the healing rate was 94.7% (54/57). CONCLUSION: This study preliminarily confirmed that arthroscopic suture technique can result in clinical stability through suture and fixation of the meniscus in the injured lateral popliteal tendon area. No adverse effects on knee joint function were found in the mid-term follow-up after the operation.

Closed-Loop Force Control by Biorealistic Hand Prosthesis With Visual and Tactile Sensory Feedback.

The ability of a novel biorealistic hand prosthesis for grasp force control reveals improved neural compatibility between the human-prosthetic interaction. The primary purpose here was to validate a virtual training platform for amputee subjects and evaluate the respective roles of visual and tactile information in fundamental force control tasks. We developed a digital twin of tendon-driven prosthetic hand in the MuJoCo environment. Biorealistic controllers emulated a pair of antagonistic muscles controlling the index finger of the virtual hand by surface electromyographic (sEMG) signals from amputees' residual forearm muscles. Grasp force information was transmitted to amputees through evoked tactile sensation (ETS) feedback. Six forearm amputees participated in force tracking and holding tasks under different feedback conditions or using their intact hands. Test results showed that visual feedback played a predominant role than ETS feedback in force tracking and holding tasks. However, in the absence of visual feedback during the force holding task, ETS feedback significantly enhanced motor performance compared to feedforward control alone. Thus, ETS feedback still supplied reliable sensory information to facilitate amputee's ability of stable grasp force control. The effects of tactile and visual feedback on force control were subject-specific when both types of feedback were provided simultaneously. Amputees were able to integrate visual and tactile information to the biorealistic controllers and achieve a good sensorimotor performance in grasp force regulation. The virtual platform may provide a training paradigm for amputees to adapt the biorealistic hand controller and ETS feedback optimally.

A rare mass with atypical localization: Heterotopic ossification associated with flexor hallucis longus.

Heterotopic ossification (HO), characterized by the formation of ectopic bone, is a benign mass observed in soft tissues. Depending on its location, it can cause symptoms beyond compression, such as mechanical blockage when associated with joints, leading to limitations in joint movements. In the majority of cases, involvement of the hip and elbow joints is common, while HO can sometimes be observed in atypical locations. Trauma, head injury, and spinal cord injuries are well-recognized risk factors for HO development. However, on rare occasions, in non-traumatic cases are identified without any known risk factors. Herein, we present a rare non-traumatic HO case associated with the flexor hallucis longus (FHL) tendon in a 58-year-old female patient. She complained of pain under the first toe of her right foot while wearing shoes for a year, and a mass was detected on the plantar surface of the foot along with limitation of movement in the first metatarsophalangeal joint. Further examinations revealed that the identified mass was a mature HO lesion. Surgical treatment was performed, and during one-year follow-up, the pain subsided, and joint movements returned to normal, resulting in a satisfactory outcome. In conclusion, although many cases of HO are associated with traumatic injuries, it can sometimes be idiopathic, as in our case, and rarely it is accompanied tendon such as FHL in the foot.

An extremely rare case of absent extensor digitorum communis of the right index finger.

The hand is a unique structure in human body performing complex activities of daily life making it prone to injuries. While operating on zone VI extensor tendon injury, a surprising entity was observed. The extensor digitorum to the right index finger was absent. This is an extremely rare entity in the literature. Also, all previous studies on the extensor digitorum are cadaveric. Our findings are first of its kind intraoperative, incidental, and confirmed on MRI. Thus, it becomes a case report of special worth mentioning in literature.

Immunomodulatory Behavior of Tendon Magnetic Cell Sheets can be Modulated in Hypoxic Environments under Magnetic Stimulus.

Tissue environments play a crucial role in orchestrating cell behavior, guided by a complex interplay of various factors. Long lasting inflammatory signals compromise tendon homeostasis and promote tissue degeneration, while tissue oxygen levels affect local cells' responses with hypoxic environments influencing apoptosis, inflammatory mediators, and matrix production. Recent works have unveiled the therapeutic potential of pulsed electromagnetic field (PEMF) in modulating inflammatory signals expressed by human tendon cells (hTDCs), and in mitigating the hypoxia-induced effects on the regulation of inflammatory cytokines. Thus, we sought to investigate the role of hypoxic environments, namely, 1 and 2% oxygen tension, in the inflammatory profiles of magnetic cell sheets (magCSs) formed by magnetic nanoparticles internalized in contiguous hTDCs with intact cell-cell junctions and deposited matrix. We also aimed to explore the impact of PEMF over hypoxia-treated magCSs, including IL-1ß-primed-magCSs, with the objective of harnessing magnetic stimulation to guide abnormal inflammatory cell responses toward efficient treatments supporting tendon regenerative potential. Our findings revealed that low oxygen tensions amplified the expression of hypoxia-associated genes and of inflammatory markers in IL-1ß-primed-magCSs with an involvement of the NF-κB signaling pathway. Encouragingly, when PEMF was applied to IL-1ß-primed-magCSs under hypoxic conditions, it successfully modulated inflammatory cues by favoring IL-10 and IL-4, via the NF-κB pathway. These results signify the remarkable potential of PEMF in driving proregenerative strategies and opens up new approaches in tendon therapies, highlighting the transformative impact of immunomodulatory magnetic cell sheets.

Towards higher load capacity: innovative design of a robotic hand with soft jointed structure.

In this paper, the innovative design of a robotic hand with soft jointed structure is carried out and a tendon-driven mechanism, a master-slave motor coordinated drive mechanism, a thumb coupling transmission mechanism and a thumb steering mechanism are proposed. These innovative designs allow for more effective actuation in each finger, enhancing the load capacity of the robotic hand while maintaining key performance indicators such as dexterity and adaptability. A mechanical model of the robotic finger was made to determine the application limitations and load capacity. The robotic hand was then prototyped for a set of experiments. The experimental results showed that the proposed theoretical model were reliable. Also, the fingertip force of the robotic finger could reach up to 10.3 N, and the load force could reach up to 72.8 N. When grasping target objects of different sizes and shapes, the robotic hand was able to perform the various power grasping and precision grasping in the Cutkosky taxonomy. Moreover, the robotic hand had good flexibility and adaptability by means of adjusting the envelope state autonomously.