Cyclic Ruthenium-Peptide Conjugates as Integrin-Targeting Phototherapeutic Prodrugs for the Treatment of Brain Tumors.

To investigate the potential of tumor-targeting photoactivated chemotherapy, a chiral ruthenium-based anticancer warhead, Λ/Δ-[Ru(Ph2phen)2(OH2)2]2+, was conjugated to the RGD-containing Ac-MRGDH-NH2 peptide by direct coordination of the M and H residues to the metal. This design afforded two diastereoisomers of a cyclic metallopeptide, Λ-[1]Cl2 and Δ-[1]Cl2. In the dark, the ruthenium-chelating peptide had a triple action. First, it prevented other biomolecules from coordinating with the metal center. Second, its hydrophilicity made [1]Cl2 amphiphilic so that it self-assembled in culture medium into nanoparticles. Third, it acted as a tumor-targeting motif by strongly binding to the integrin (Kd = 0.061 µM for the binding of Λ-[1]Cl2 to αIIbß3), which resulted in the receptor-mediated uptake of the conjugate in vitro. Phototoxicity studies in two-dimensional (2D) monolayers of A549, U87MG, and PC-3 human cancer cell lines and U87MG three-dimensional (3D) tumor spheroids showed that the two isomers of [1]Cl2 were strongly phototoxic, with photoindexes up to 17. Mechanistic studies indicated that such phototoxicity was due to a combination of photodynamic therapy (PDT) and photoactivated chemotherapy (PACT) effects, resulting from both reactive oxygen species generation and peptide photosubstitution. Finally, in vivo studies in a subcutaneous U87MG glioblastoma mice model showed that [1]Cl2 efficiently accumulated in the tumor 12 h after injection, where green light irradiation generated a stronger tumoricidal effect than a nontargeted analogue ruthenium complex [2]Cl2. Considering the absence of systemic toxicity for the treated mice, these results demonstrate the high potential of light-sensitive integrin-targeted ruthenium-based anticancer compounds for the treatment of brain cancer in vivo.

Carrier-Free ATP-Activated Nanoparticles for Combined Photodynamic Therapy and Chemotherapy under Near-Infrared Light.

The combination of photodynamic therapy (PDT) and chemotherapy (chemo-photodynamic therapy) for enhancing cancer therapeutic efficiency has attracted tremendous attention in the recent years. However, limitations, such as low local concentration, non-suitable treatment light source, and uncontrollable release of therapeutic agents, result in reduced combined treatment efficacy. This study considered adenosine triphosphate (ATP), which is highly upregulated in tumor cells, as a biomarker and developed ingenious ATP-activated nanoparticles (CDNPs) that are directly self-assembled from near-infrared photosensitizer (Cy-I) and amphiphilic Cd(II) complex (DPA-Cd). After selective entry into tumor cells, the positively charged CDNPs would escape from lysosomes and be disintegrated by the high ATP concentration in the cytoplasm. The released Cy-I is capable of producing single oxygen (1 O2 ) for PDT with 808 nm irradiation and DPA-Cd can concurrently function for chemotherapy. Irradiation with 808 nm light can lead to tumor ablation in tumor-bearing mice after intravenous injection of CDNPs. This carrier-free nanoparticle offers a new platform for chemo-photodynamic therapy.

Amphiphilic Metallodrug Assemblies with Red-Light-Enhanced Cellular Internalization and Tumor Penetration for Anticancer Phototherapy.

Metallodrugs are widely used in cancer treatment. The modification of metallodrugs with polyethylene glycol (PEGylation) prolongs blood circulation and improves drug accumulation in tumors; it represents a general strategy for drug delivery. However, PEGylation hinders cellular internalization and tumor penetration, which reduce therapeutic efficacy. Herein, the red-light-enhanced cellular internalization and tumor penetration of a PEGylated anticancer agent, PEGylated Ru complex (Ru-PEG), are reported upon. Ru-PEG contains a red-light-cleavable PEG ligand, anticancer Ru complex moiety, and fluorescent pyrene group for imaging and self-assembly. Ru-PEG self-assembles into vesicles that circulate in the bloodstream and accumulate in the tumors. Red-light irradiation induces dePEGylation and changes the Ru-PEG vesicles to large compound micelles with smaller diameters and higher zeta potentials, which enhance tumor penetration and cellular internalization. Red-light irradiation also generates intracellular 1 O2 , which induces the death of cancer cells. This work presents a new strategy to enhance the cellular internalization and tumor penetration of anticancer agents for efficient phototherapy.

Ru-Se Coordination: A New Dynamic Bond for Visible-Light-Responsive Materials.

Photodynamic bonds are stable in the dark and can reversibly dissociate/form under light irradiation. Photodynamic bonds are promising building blocks for responsive or healable materials, photoactivated drugs, nanocarriers, extracellular matrices, etc. However, reactive intermediates from photodynamic bonds usually lead to side reactions, which limit the use of photodynamic bonds. Here, we report that the Ru-Se coordination bond is a new photodynamic bond that reversibly dissociates under mild visible-light-irradiation conditions. We observed that Ru-Se bonds form via the coordination of a selenoether ligand with [Ru(tpy)(biq)(H2O)]Cl2 (tpy = 2,2':6',2″-terpyridine, biq = 2,2'-biquinoline) in the dark, while the Ru-Se bond reversibly dissociates under visible-light irradiation. No side reaction is detected in the formation and dissociation of Ru-Se bonds. To demonstrate that the Ru-Se bond is applicable to different operating environments, we prepared photoresponsive amphiphiles, surfaces, and polymer gels using Ru-Se bonds. The amphiphiles with Ru-Se bonds showed reversible morphological transitions between spherical micelles and bowl-shaped assemblies for dark/light irradiation cycles. The surfaces modified with Ru-Se-bond-containing compounds showed photoswitchable wettability. Polymer gels with Ru-Se cross-links underwent photoinduced reversible sol-gel transitions, which can be used for reshaping and healing. Our work demonstrates that the Ru-Se bond is a new type of dynamic bond, which can be used for constructing responsive, reprocessable, switchable, and healable materials that work in a variety of environments.

Combining reverse end-to-side neurorrhaphy with rapamycin treatment on chronically denervated muscle in rats.

This preliminary research determines whether a combination of reverse end-to-side neurorrhaphy and rapamycin treatment achieves a better functional outcome than a single application after prolonged peripheral nerve injury. We found that the tibial nerve function of the reverse end-to-side + rapamycin group recovered better, with a higher tibial function index value, higher amplitude recovery rate, and shorter latency delay rate (P < 0.05). The reverse end-to-side + rapamycin group better protected the gastrocnemius muscle with more forceful contractility, tetanic tension, and a higher myofibril cross-sectional area (P < 0.05). Combining reverse end-to-side neurorrhaphy with rapamycin treatment is a practical approach to promoting the recovery of chronically denervated muscle atrophy after peripheral nerve injury.

Red and Near-Infrared Light-Cleavable Polymers.

Photocleavable polymers have attracted much attention in drug delivery, photopatterning, and controlling cell behavior. Photolysis is usually induced by UV light. However, UV light cannot penetrate deeply into biological tissue and may damage biological components. Therefore, conventional UV-light-cleavable polymers are problematic for deep-tissue biomedical applications. In this feature article, red and near-infrared light-cleavable polymers are reviewed, and their potential applications are highlighted. The remaining challenges in the field of photocleavable polymers are discussed.

Photoactivation of Anticancer Ru Complexes in Deep Tissue: How Deep Can We Go?

Activation of anticancer therapeutics such as ruthenium (Ru) complexes is currently a topic of intense investigation. The success of phototherapy relies on photoactivation of therapeutics after the light passes through skin and tissue. In this paper, the photoactivation of anticancer Ru complexes with 671-nm red light through tissue of different thicknesses was studied. Four photoactivatable Ru complexes with different absorption wavelengths were synthesized. Two of them (Ru3 and Ru4) were responsive to wavelengths in the "therapeutic window" (650-900 nm) and could be activated using 671-nm red light after passing through tissue up to 16-mm-thick. The other two (Ru1 and Ru2) could not be activated using red light. Additionally, activated Ru4 caused inhibition of cancer cells. These results suggest that photoactivatable Ru complexes are promising for applications in deep-tissue phototherapy.

Variations in several morphological characteristics and Cd/Pb accumulation capacities among different ecotypes of torpedograss responding to Cd-Pb stresses.

Torpedograss (Panicum repens) has been recognized as an useful plant species for phytoremediation of water-level-fluctuation zones, which is a worldwide challenge. In this study, 10 ecotypes collected from tropical zone and flooded habitats (Group A) and subtropical zone and drought habitats (Group B) were used to clarify their responses to Cd-Pb stresses and effects of long-term adaptation on their morphological features and Cd-Pb accumulation capacities. Branch capacity, shoot and root biomasses of Group A under control were smaller than those of Group B, while the opposite results were observed under Cd-Pb stresses. The average plant shoot Cd concentrations of Group A under L-Cd-Pb and H-Cd-Pb were 24.84 and 52.38 mg kg-1, respectively, significantly lower than those of Group B (36.81 and 67.60 mg kg-1), while the variation among each group was insignificant, suggesting that habitat isolation and long-term adaptation may have led to differentiation in morphological features and metal uptake capacity. Torpedograss possesses high tolerance to Cd-Pb toxicities, and those ecotypes with larger biomass had higher Cd-Pb accumulation capacities. Torpedograss is a potential plant species for Cd phytoremediation and approximately 16 years would be required to clean soil contained by Cd as high as 10 mg kg-1 using the selected torpedograss ecotypes.

Redox poly(ethylene glycol)-b-poly(L-lactide) micelles containing diselenide bonds for effective drug delivery.

Bioreducible polymers have appeared as the ideal drug carriers for tumor therapy due to their properties of high stability in extracellular circulation and rapid drug release in intracellular reducing environment. Recently, the diselenide bond has emerged as a new reduction-sensitive linkage. In this work, the amphiphilic poly(ethylene glycol)-b-poly(L-lactide) containing diselenide bond has been synthesized and used to load anti-tumor drug, docetaxel (DTX), to form the redox micelles. It was found that the redox micelles showed a rapid response to glutataione (GSH), which resulted in a fast release of DTX in the presence of GSH. In contrast, <40 % of DTX was released from the micelles within 72 h under the normal condition (absence of GSH). The DTX-loaded redox micelles showed the significant inhibition effect to MCF-7 cells, and the cytotoxicity was dependent on the intracellular GSH concentrations. Moreover, considering the potentially clinical applications of the micelles through intravenous injection, the blood compatibility was also studied by the hemolysis analysis, activated partial thromboplastin time, prothrombin time and thromboelastography assays. These results confirmed that the redox micelles showed good blood safety, suggesting a potential application in tumor therapy.

Chronic ACLD Knees with Early Developmental Cartilage Lesions Exhibited Increased Posterior Tibial Translation during Level Walking.

OBJECTIVE: Early articular cartilage lesion (CL) is a vital sign in the onset of posttraumatic knee osteoarthritis (PTOA) in patients with anterior cruciate ligament deficiency (ACLD). Researchers have suggested that altered kinematics could accelerate CLs and, therefore, lead to the onset of PTOA. However, little is known about whether specific knee kinematics exist that lead to early CL in chronic ACLD knees. Level walking is the most frequent and relevant in vivo activity, which greatly impacts knee health. We hypothesized that the knee kinematics during level walking in chronic ACLD knees with early tibiofemoral CL would significantly differ from those of chronic ACLD knees without early tibiofemoral CL. METHODS: Thirty patients with a chronic ACLD history, including 18 subjects with CLs and 12 subjects without CLs, and 35 healthy control subjects were recruited for the study from July 2020 to August 2022. The knee kinematic data during level walking were collected using a three-dimensional motion analysis system. The kinematic differences between groups were compared using statistical parametric mapping with one dimension for One-Way ANOVA. The cartilage statuses of the ACLD knees were assessed via MRI examination. The CLs distribution of subjects was evaluated using a modified Noyes scale and analyzed by chi-square tests. RESULTS: ACLD knees with CLs had significantly greater posterior tibial translation (7.7-8.0mm, 12%-18% gait cycle GC, p = 0.014) compared to ACLD knees without CLs during level walking. ACLD knees with CLs had greater posterior tibial translation (4.6-5.5mm, 0%-23% GC, p < 0.001; 5.8-8.0mm, 86%-100% GC, p < 0.001) than healthy controls during level walking. In the group of ACLD knees with CLs, CL is mainly located in the back of the tibia plateau and front of load bearing area of the medial femoral condyle (p < 0.05). CONCLUSION: Chronic anterior cruciate ligament deficient knees with cartilage lesions have increased posterior tibial translation compared to anterior cruciate ligament deficient knees without cartilage lesions and healthy subjects. The posterior tibial translation may play an important role in knee cartilage degeneration in ACLD knees. The increased posterior tibial translation and cartilage lesion characteristics may improve our understanding of the role of knee kinematics in cartilage degeneration and could be a helpful potential reference for anterior cruciate ligament deficient therapy, such as physical training to improve abnormal kinematic behavior.

Whether Patients with Anterior Cruciate Ligament Reconstruction Walking at a Fast Speed Show more Kinematic Asymmetries?

OBJECTIVE: Knee kinematic asymmetries after anterior cruciate ligament reconstruction (ACLR) are correlated with poor clinical outcomes, such as the progression of knee cartilage degenerations or reinjuries. Fast walking in patients with knee conditions may exacerbate knee kinematic asymmetries, but its impact on ACLR patients is uncertain. The aim of this study is to investigate if fast walking induces more knee kinematic asymmetries in unilateral ACLR patients. METHODS: This cross-sectional study enrolled 55 patients with unilateral ACLR from January 2020 to July 2022. There were 48 males and seven females with an average age of 30.6 ± 6.4 years. Knee kinematic data were collected at three walking speeds: self-selected, fast (150% normal), and slow (50% normal). A 3D knee kinematic analysis system measured the data, and self-reported outcomes assessed comfort levels during walking. We used SPM1D for two-way repeated ANOVA and posthoc paired t-tests to analyze kinematic differences in groups. RESULTS: In fast walking, ACLR knees exhibited more transverse kinematic asymmetries than intact knees, including greater external rotation angle (1.8°, 38%-43%; gait cycle [GC], p < 0.05 & 1.8-2.7°, 50%-61% GC, p < 0.05) and increased proximal tibial translation (2.1-2.5 mm, 2%-6% GC, p < 0.05 & 2.5-3.2 mm, 92%-96% GC, p < 0.05). Additionally, ACLR knees showed greater posterior tibial translation than intact knees (3.6-3.7 mm, 7%-8% GC, p < 0.05) during fast walking. No posterior tibial translation asymmetries were observed in slow walking compared to normal walking levels. ACLR knees have the most comfortable feelings in slow walking speed, and the most uncomfortable feelings in fast walking speed levels (29%). CONCLUSIONS: Fast walking induces additional external tibial rotation and proximal and posterior tibial translation asymmetries in ACLR patients. This raises concerns about long-term safety and health during fast walking. Fast walking, not self-selected speed, is beneficial for identifying postoperative gait asymmetries in ACLR patients.

Diet influences knee osteoarthritis osteophyte formation via gut microbiota and serum metabolites.

Osteophyte formation, a key indicator of osteoarthritis (OA) severity, remains poorly understood in its relation to gut microbiota and metabolites in knee osteoarthritis (KOA). We conducted 16S rDNA sequencing and untargeted metabolomics on fecal and serum samples from 20 healthy volunteers, 80 KOA patients in Guangdong, and 100 in Inner Mongolia, respectively. Through bioinformatics analysis, we identified 3 genera and 5 serum metabolites associated with KOA osteophyte formation. Blautia abundance negatively correlated with meat, cheese, and bean consumption. The 5 serum metabolites negatively correlated with dairy, beef, cheese, sugar, and salt intake, yet positively with age and oil consumption. Higher Blautia levels in the gut may contribute to KOA osteophyte formation, with serum metabolites LTB4 and PGD2 potentially serving as biomarkers. KOA patients in Inner Mongolia exhibited lower Blautia levels and reduced expression of 5 serum metabolites, possibly due to cheese consumption habits, resulting in less osteophyte formation.

Reversible Crosslinking of Commodity Polymers via Photocontrolled Metal-Ligand Coordination for High-Performance and Recyclable Thermoset Plastics.

Thermoset plastics, highly desired for their stability, durability, and chemical resistance, are currently consumed in over 60 million tons annually across the globe, but they are difficult to recycle due to their crosslinked structures. The development of recyclable thermoset plastics is an important but challenging task. In this work, recyclable thermoset plastics are prepared by crosslinking a commodity polymer, polyacrylonitrile (PAN), with a small percentage of a Ru complex via nitrile-Ru coordination. PAN is obtained from industry and the Ru complex is synthesized in one step, which enables the production of recyclable thermoset plastics in an efficient way. In addition, the thermoset plastics exhibit impressive mechanical performance, boasting a Young's modulus of 6.3 GPa and a tensile strength of 109.8 MPa. Moreover, they can be de-crosslinked when exposed to both light and a solvent and can then be re-crosslinked upon heating. This reversible crosslinking mechanism enables the recycling of thermosets from a mixture of plastic waste. The preparation of recyclable thermosets from other commodity polymers such as poly(styrene-coacrylonitrile) (SAN) resins and polymer composites through reversible crosslinking is also demonstrated. This study shows that reversible crosslinking via metal-ligand coordination is a new strategy for designing recyclable thermosets using commodity polymers.

Generalized joint hypermobility subjects without knee hyperextension have greater walking anterior tibial translation and flexion angle than those with knee hyperextension.

BACKGROUND: The walking knee kinematic results of generalized joint hypermobility (GJH) subjects were controversial in previous studies. We proposed that this could be related to the knee statuses of GJH subjects with/without knee hyperextension (KH) and assumed that there are significant sagittal knee kinematic differences between GJH subjects with/without KH during gait. RESEARCH QUESTION: Do GJH subjects with KH exhibit significantly different kinematic characteristics than those without KH during walking? METHODS: 35 GJH subjects without KH, 34 GJH subjects with KH, and 30 healthy controls were recruited in this study. A three-dimensional gait analysis system was used to record and compare the knee kinematics of the participants. RESULTS: Significant walking knee kinematics differences were found between GJH subjects with/without KH during walking. GJH subjects without KH had greater flexion angles (4.7-6.0°, 24-53 % gait cycle (GC), p < 0.001; 5.1-6.1°, 65-77 % GC, p = 0.008) and anterior tibial translation (ATT) (3.3-4.1 mm, 0-4 % GC, p = 0.015; 3.8-4.3 mm, 91-100 % GC, p = 0.01) than those with KH. Compared to controls, GJH without KH exhibited increased ATT (4.0-5.7 mm, 0-26 % GC, p < 0.001; 5.1-6.7 mm, 78-100 % GC, p < 0.001), and range of motion of ATT (3.3 mm, p = 0.028) whereas GJH with KH only exhibited increased extension angle (6.9-7.3°, 62-66 % GC, p = 0.015) during walking. SIGNIFICANCE: The findings confirmed the hypothesis and suggested that GJH subjects without KH had more walking ATT and flexion angle asymmetries than those with KH. This may raise concerns about the differences in knee health and risk of knee diseases between GJH subjects with/without KH. However, further investigations should be done to explore the exact influence of walking ATT and flexion angle asymmetries in GJH subjects without KH.

Diagnosis of generalized joint hypermobility with gait patterns using a deep neural network.

Generalized joint hypermobility (GJH) describes the situation that the range of joint motion exceeds the normal range. GJH is found to increase the risk of knee-related injury and osteoarthritis, challenging the athletic ability of the population. Gait signals are directly related to hip and knee athletic conditions, and have been shown to have significant changes with GJH by our previous research. But gait data are noisy, and vary with age, gender, weight, and ethnicity, which makes them hard to analyze with traditional statistical methods. In this study, we proposed an end-to-end deep learning model to recognize the patterns of the gait signals. The model consists of convolutional network blocks, residual network blocks, and attention blocks. Our dataset is composed of 452 samples of gait data obtained by a three-dimension motion capture system, with the six-degree-of-freedom kinematic data of hip, knee, and ankle joints during level walking, downhill, and uphill walking. The model achieves 95.77% accuracy and 98.68% specificity with a recall of 76.84% while is more efficient than traditional machine learning methods. The trained model can be run on economical friendly devices, and provide help for immediate and precise diagnosis of GJH. It is also meaningful to consider its application in large-scale GJH screening, which can contribute to sports medicine.

An adaptive fractional stochastic resonance method based on weighted correctional signal-to-noise ratio and its application in fault feature enhancement of wind turbine.

Stochastic resonance (SR) is an effective tool to enhance weak signal by utilizing noise to reach a certain synergistic effect, which has been widely studied in the field of weak signal detection. Currently, using SR to enhance the weak fault feature of wind turbine faces two challenges: First, it is difficult for SR to select the optimal system parameters, while the traditional adaptive method based on SNR needs to predict the precise frequency of the target signal. Second, the wind turbine load changes frequently, making the vibration and noise large. As a result, the traditional SR cannot effectively highlight the target fault feature by inducing a stable resonance phenomenon at the target frequency. To improve the ability of SR to enhance the weak fault feature of wind turbine under strong noise, this paper proposes an adaptive fractional SR method based on weighted correctional signal-to-noise ratio (WCSNR). Firstly, the proposed method considers the adiabatic approximation applicable condition in the SR system and combines characteristics of the expected output signal to construct the WCSNR evaluation index to quantify the system output response, so that the system can adaptively obtain optimal parameters without predicting the accurate frequency of the target signal. Then, the fractional-order theory is applied to the SR system to overcome the shortcoming that the integer-order SR cannot induce stable resonance phenomenon at the target frequency when enhancing the fault feature of wind turbine, and use WCSNR to search for the optimal fractional order to further enhance the weak fault characteristics. Simulation and engineering actual data analysis results verify the effectiveness and superiority of the proposed method in the fault feature enhancement of wind turbine. The analysis results show that compared with the traditional SR method, the method proposed in this paper can more effectively reduce the interference of background noise and accurately enhance the weak fault feature.

Efficient Subject-Independent Detection of Anterior Cruciate Ligament Deficiency Based on Marine Predator Algorithm and Support Vector Machine.

Anterior cruciate ligament (ACL) deficiency not only reduces knee stability, but also increases the risk of more disease and impairs daily life, thus requiring efficient detection of ACL deficiency. To build an efficient subject-independent ACL deficiency detection model, this study proposes a new method called SVM-MPA that fuses marine predator algorithm (MPA) and support vector machine (SVM) for simultaneous feature selection, hyperparameter optimization and classification. 35ACL-deficient (ACLD) and 35 ACL-intact (ACLI) participants were recruited to collect 6-degree-of-freedom knee kinematic data. Then, 216-dimensional multi-domain features covering time domain, frequency domain, time-frequency domain and nonlinearity were extracted. The error rate of SVM classification based on 5-fold cross-validation was used to construct the fitness of MPA, and MPA served to select features and optimize two hyperparameters for SVM. The majority voting strategy-based post-processing was introduced to convert the gait cycle-level to knee-level ACL deficiency detection. Comparing with 7 well-known meta-heuristic algorithms and running all 20 times, the best average gait cycle-level ACL deficiency detection performance (sensitivity: 96.78±0.4.84%, specificity: 99.43±5.70%, and accuracy: 98.48±1.70%) was obtained using the proposed method. With post-processing, this study improved the best (final) detection performance (sensitivity: 97.78±4.97%, specificity: 100±0.00%, and accuracy: 99.13±1.94%). These results demonstrate the feasibility and effectiveness of the proposed method and shows that an efficient subject-independent ACL deficiency detection model can be constructed using the proposed method, which makes it possible to provide a non-invasive, objective and accurate preoperative auxiliary detection method for diagnosing ACL deficiency clinically.

Changes in 6DOF knee kinematics during gait with decreasing gait speed.

BACKGROUND: Gait speed is recognized to correlate to knee kinematic alterations. Clinically, patients with knee diseases tend to walk slowly compared to healthy controls. Hence, gait speed may serve as a confounding factor in the kinematic characteristics of patients during gait compared to healthy controls. RESEARCH QUESTION: Whether and how gait speed affects six degrees of freedom (6DOF) knee kinematics remains unclear. The current study was designed to explore whether and how decreased gait speeds affect 6DOF knee kinematics. METHODS: Thirty subjects (15 males and 15 females) were recruited for this study. A three-dimensional gait analysis system was used to assess the 6DOF knee kinematics of subjects at gait speeds of 4.0 km/h, 3.5 km/h, 3.0 km/h, 2.5 km/h, 2.0 km/h, 1.5 km/h, and 1.0 km/h. Kinematics of gait cycle (GC) were assessed at all gait speed levels. RESULTS: Decreased adduction angle (0.5-3.2 °, p < 0.05), increased external rotation (0.6-3.3 °, p < 0.05) and decreased flexion angle (1.5-17.4 °, p < 0.05) were found during most GC as gait speed level decreased. Greater anterior tibial translation (0.9-2.6 mm, p < 0.05), greater proximal translation (0.4-2.4 mm, p < 0.05) and decreased lateral tibial translation (0.5-3.0 mm, p < 0.05) were found during most GC as gait speed level decreased. Gender was also found to have great effects on 6DOF knee kinematics (p < 0.05). Interactions between gender and gait speed were also found (p < 0.05). SIGNIFICANCE: Our findings suggest that additional attention should be paid when dealing with kinematic comparisons of GC between controls and patients with significantly different gait speeds or genders than controls. Kinematic alterations induced by gait speed may raise concern for patients with knee diseases who struggle to walk faster than their normal speed. This may enhance our knowledge of the relationship between gait speed and 6DOF knee kinematics.

Kinematic alterations of the ankle in subjects with generalized joint hypermobility compared with the controls: A cross-sectional study.

INTRODUCTION: Generalized joint hypermobility (GJH) is a hereditary connective tissue disease in which the range of motion (ROM) of multiple joints exceeds the normal range, and the ROM varies with age, gender, and ethnicity. At present, the six-degree-of-freedom (6-DOF) of ankle kinematics among people with GJH have not been studied. To investigate the kinematic characteristics in the ankle during treadmill gait of university students with generalized joint hypermobility compared to normal participants. We hypothesized that compared to the participants in the control group, those with GJH would exhibit kinematic characteristics of poorer active motion stability in the ankle during treadmill gait. METHODS: Healthy university student volunteers aged 18-24 (excluding those with a history of ankle trauma, etc.) were recruited and divided into a control group (50 volunteers) and a GJH group (Beighton score ≥4, 50 volunteers). Data of the 6-DOF kinematics of ankle was collected using a 3D gait analysis system. Variables were evaluated using independent t-tests and Wilcoxon signed-rank tests. RESULTS: In the proximal/distal parameter, proximal displacement was significantly increased in the GJH group compared with the control group during 4-9% and 96-97% of the gait phase (loading response and terminal swing phase), with an increase of (0.1-0.2 cm, p < .05). Regarding the proximal/distal, internal/external, plantarflexion/dorsiflexion, and anterior/posterior parameters, the participants with GJH exhibited greater ROM than those in the control group throughout the gait cycle (0.24 ± 0.22 cm vs. 0.19 ± 0.15 cm, p = 0.047, 5.56 ± 2.90° vs. 4.48 ± 3.30°, p = .020, 23.05 ± 5.75° vs. 20.36 ± 4.91°, p < .001, 0.65 ± 0.30 cm vs. 0.55 ± 0.27 cm, p = .018). However, ROM of inversion/eversion translation was found to be decreased in the GJH group compared to the control group (8.92 ± 1.59° vs. 9.47 ± 1.37°, p = .009). In addition, there was no statistical difference between the GJH group and the control group in ROM of medial/lateral translation (0.05 ± 0.06 cm vs. 0.04 ± 0.05 cm, p = .131). CONCLUSION: Our results confirm that our hypothesis is not valid. Although there were a few differences in each gait parameter of the ankle between the GJH group and the control group, the difference was not significant. These results indicate that the presence of GJH has less effect on ankle kinematics and enhance our knowledge of the relationship between GJH and 6-DOF of ankle kinematics.

Simultaneous Measurement of Patellofemoral Joint Kinematics and Contact Mechanics in Intact Knees: A Cadaveric Study.

OBJECTIVE: Patellofemoral kinematics and contact mechanics are important measurements for the assessment of patellofemoral joint (PFJ) problems. Simultaneously measuring PFJ contact pressures and kinematics is a challenging task. The purpose of this study was to simultaneously measure the kinematics and mean/peak contact pressures in the PFJs of cadaveric knees. METHODS: This was a comparative study performed on fresh cadaveric knees. The kinematic data was acquired for nine cadaveric knees using an optical tracking system. Data about the contact pressure and contact area in the PFJ was obtained at knee flexion angles of 0°, 30°, 60°, 90°, and 120° using a pressure sensor. Intraclass correlation coefficients (ICCs) and minimal detectable differences (MDDs) of six degrees of freedom (6 DOF) in the PFJs were calculated. ICCs and the MDDs of contact pressure, peak pressure, and contact area in the PFJs were also analyzed. We also compared the kinematics of the cadaveric knees before and after the insertion of the pressure sensor. RESULTS: All ICC values of 6 DOF in the PFJs were found to be greater than or equal to 0.924. Regarding medial-lateral rotation, the patellar showed a simplified movement pattern that demonstrated progressive lateral rotation of 4.8° ± 3.4° at 120° of knee flexion. While for patellar tilting, the patella showed medial tilting that peaked at 7.2 ± 2.5° at 30° of knee flexion. Whereas no significant differences in PFJ kinematics were found between with and without the placement of the pressure sensor at all knee flexions (P > 0.05). Most of the ICC values for contact pressure, peak contact pressure, and contact area ranged from 0.8 to 0.9. The MDDs for rotational displacement were 0.9° and 0.6 mm for translational displacement. No statistical differences in patellar kinematics were found before and after the insertion of the pressure sensor. CONCLUSIONS: The setup in the present study enables researchers to simultaneously and synchronously collect real-time PFJ kinematics and tibiofemoral joint (TFJ) biomechanical kinematic data with high reliability. The low MDDs enabled the researchers to obtain an accurate interpretation of the kinematic and contact mechanics measurement using the experimental setting used in the present study.