Driving β2- While Suppressing α-Adrenergic Receptor Activity Suppresses Joint Pathology in Inflammatory Arthritis

ObjectiveHypersympathetic activity is prominent in rheumatoid arthritis, and major life stressors precede onset in ~80% of patients. These findings and others support a link between stress, the sympathetic nervous system and disease onset and progression. Here, we extend previous research by evaluating how selective peripherally acting α/β2-adrenergic drugs affect joint destruction in adjuvant-induced arthritis.MethodsComplete Freund’s adjuvant induced inflammatory arthritis in male Lewis rats. Controls received no treatment. Arthritic rats then received vehicle or twice-daily treatment with the α-adrenergic antagonist, phentolamine (0.5 mg/day) and the β2-adrenergic agonist, terbutaline (1200 µg/day, collectively named SH1293) from day (D) of disease onset (D12) through acute (D21) and severe disease (D28). Disease progression was assessed in the hind limbs using dorsoplantar widths, X-ray analysis, micro-computed tomography, and routine histology on D14, D21, and D28 post-immunization.ResultsOn D21, SH1293 significantly attenuated arthritis in the hind limbs, based on reduced lymphocytic infiltration, preservation of cartilage, and bone volume. Pannus formation and sympathetic nerve loss were not affected by SH1293. Bone area and osteoclast number revealed high- and low-treatment-responding groups. In high-responding rats, treatment with SH1293 significantly preserved bone area and decreased osteoclast number, data that correlated with drug-mediated joint preservation. SH1293 suppressed abnormal bone formation based on reduced production of osteophytes. On D28, the arthritic sparing effects of SH1293 on lymphocytic infiltration, cartilage and bone sparing were maintained at the expense of bone marrow adipocity. However, sympathetic nerves were retracted from the talocrural joint.Conclusion and SignificanceOur findings support a significant delay in early arthritis progression by treatment with SH1293. Targeting sympathetic neurotransmission may provide a strategy to slow disease progression.

Estimation of the Continuous Walking Angle of Knee and Ankle (Talocrural Joint, Subtalar Joint) of a Lower-Limb Exoskeleton Robot Using a Neural Network

A lower-limb exoskeleton robot identifies the wearer′s walking intention and assists the walking movement through mechanical force; thus, it is important to be able to identify the wearer′s movement in real-time. Measurement of the angle of the knee and ankle can be difficult in the case of patients who cannot move the lower-limb joint properly. Therefore, in this study, the knee angle as well as the angles of the talocrural and subtalar joints of the ankle were estimated during walking by applying the neural network to two inertial measurement unit (IMU) sensors attached to the thigh and shank. First, for angle estimation, the gyroscope and accelerometer data of the IMU sensor were obtained while walking at a treadmill speed of 1 to 2.5 km/h while wearing an exoskeleton robot. The weights according to each walking speed were calculated using a neural network algorithm programmed in MATLAB software. Second, an appropriate weight was selected according to the walking speed through the IMU data, and the knee angle and the angles of the talocrural and subtalar joints of the ankle were estimated in real-time during walking through a feedforward neural network using the IMU data received in real-time. We confirmed that the angle estimation error was accurately estimated as 1.69° ± 1.43 (mean absolute error (MAE) ± standard deviation (SD)) for the knee joint, 1.29° ± 1.01 for the talocrural joint, and 0.82° ± 0.69 for the subtalar joint. Therefore, the proposed algorithm has potential for gait rehabilitation as it addresses the difficulty of estimating angles of lower extremity patients using torque and EMG sensors.

Identifying Range-of-Motion Deficits and Talocrural Joint Laxity After an Acute Lateral Ankle Sprain

Context Approximately 72% of patients with an ankle sprain report residual symptoms 6 to 18 months later. Although 44% of patients return to activity in less than 24 hours after experiencing a sprain, residual symptoms should be evaluated in the long term to determine if deficits exist. These residual symptoms may be due to the quality of ligament tissue and motion after injury. Objective To compare mechanical laxity of the talocrural joint and dorsiflexion range of motion (DFROM) over time (24 to 72 hours, 2 to 4 weeks, and 6 months) after an acute lateral ankle sprain (LAS). Design Cross-sectional study. Setting Athletic training research laboratory. Patients or Other Participants A total of 108 volunteers were recruited. Fifty-five participants had an acute LAS and 53 participants were control individuals without a history of LAS. Main Outcome Measure(s) Mechanical laxity (talofibular interval and anterior talofibular ligament length) was measured in inversion (INV) and via the anterior drawer test. The weight-bearing lunge test was conducted and DFROM was measured. The data were analyzed using repeated-measures analysis of variance, independent-samples t tests, and 1-way analysis of variance. Results Of the 55 LASs, 21 (38%) were grade I, 27 (49%) were grade II, and 7 (13%) were grade III. Increases were noted in DFROM over time, between 24 and 72 hours, at 2 to 4 weeks, and at 6 months (P < .05). The DFROM was less in participants with grade III than grade I LASs (P = .004) at 24 to 72 hours; INV length was greater at 24 to 72 hours than at 2 to 4 weeks (P = .023) and at 6 months (P = .035) than at 24 to 72 hours. The anterior drawer length (P = .001) and INV talofibular interval (P = .004) were greater in the LAS group than in the control group at 6 months. Conclusions Differences in range of motion and laxity were evident among grades at various time points and may indicate different clinical responses after an LAS.

Statistical shape modeling of the talocrural joint using a hybrid multi-articulation joint approach

Historically, conventional radiographs have been the primary tool to morphometrically evaluate the talocrural joint, which is comprised of the distal tibia, distal fibula, and proximal talus. More recently, high-resolution volumetric imaging, including computed tomography (CT), has enabled the generation of three-dimensional (3D) reconstructions of the talocrural joint. Weightbearing cone-beam CT (WBCT) technology provides additional benefit to assess 3D spatial relationships and joint congruency while the patient is load bearing. In this study we applied statistical shape modeling, a computational morphometrics technique, to objectively quantify anatomical variation, joint level coverage, joint space distance, and congruency at the talocrural joint. Shape models were developed from segmented WBCT images and included the distal tibia, distal fibula, and full talus. Key anatomical variation across subjects included the fibular notch on the tibia, talar trochlea sagittal plane rate of curvature, tibial plafond curvature with medial malleolus prominence, and changes in the fibular shaft diameter. The shape analysis also revealed a highly congruent talocrural joint with minimal inter-individual morphometric differences at the articular regions. These data are helpful to improve understanding of ankle joint pathologies and to guide refinement of operative treatments.

Osteochondroma of talus and coalition of talocrural and intercuneiform joints - surgical management

<p class="abstract">Osteochondroma of talus is rare benign tumour. Tarsal coalition is a condition in which two or more tarsal bones are joined by non-osseous bridges of cartilage or fibrocartilage or by osseous bridges. Association of Talus osteochondroma with coalition of tarsal bones is extremely rare and has not been reported in the literature before. We are herewith reporting a case of osteochondroma of the talus with coalition of intercuneiform and talocrural joint in an 11-year-old male patient. Patient noticed swelling around ankle and pain on strenuous activities. CT scan confirmed the diagnosis. We did complete extraperiosteal excision of the osteochondroma and resection of tarsal coalition. Histopathological examination confirmed the diagnosis of osteochondroma. At one-year follow-up there is no recurrence of the tumour and patient had full range of motion. Complete extraperiosteal excision of the osteochondroma along with resection of tarsal coalition is important for complete eradication and preventing a recurrence.</p>

Reliability of Bi-Axial Ankle Stiffness Measurement in Older Adults

This study involves measurements of bi-axial ankle stiffness in older adults, where the ankle joint is passively moved along the talocrural and subtalar joints using a custom ankle movement trainer. A total of 15 elderly individuals participated in test–retest reliability measurements of bi-axial ankle stiffness at exactly one-week intervals for validation of the angular displacement in the device. The ankle’s range of motion was also compared, along with its stiffness. The kinematic measurements significantly corresponded to results from a marker-based motion capture system (dorsi-/plantar flexion: r = 0.996; inversion/eversion: r = 0.985). Bi-axial ankle stiffness measurements showed significant intra-class correlations (ICCs) between the two visits for all ankle movements at slower (2.14°/s, ICC = 0.712) and faster (9.77°/s, ICC = 0.879) speeds. Stiffness measurements along the talocrural joint were thus shown to have significant negative correlation with active ankle range of motion (r = −0.631, p = 0.012). The ankle movement trainer, based on anatomical characteristics, was thus used to demonstrate valid and reliable bi-axial ankle stiffness measurements for movements along the talocrural and subtalar joint axes. Reliable measurements of ankle stiffness may help clinicians and researchers when designing and fabricating ankle-foot orthosis for people with upper-motor neuron disorders, such as stroke.

Design of a 2DoF Ankle Exoskeleton with a Polycentric Structure and a Bi-Directional Tendon-Driven Actuator Controlled Using a PID Neural Network

Lower limb exoskeleton robots help with walking movements through mechanical force, by identifying the wearer’s walking intention. When the exoskeleton robot is lightweight and comfortable to wear, the stability of walking increases, and energy can be used efficiently. However, because it is difficult to implement the complex anatomical movements of the human body, most are designed simply. Due to this, misalignment between the human and robot movement causes the wearer to feel uncomfortable, and the stability of walking is reduced. In this paper, we developed a two degrees of freedom (2DoF) ankle exoskeleton robot with a subtalar joint and a talocrural joint, applying a four-bar linkage to realize the anatomical movement of a simple 1DoF structure mainly used for ankles. However, bidirectional tendon-driven actuators (BTDAs) do not consider the difference in a length change of both cables due to dorsiflexion (DF) and plantar flexion (PF) during walking, causing misalignment. To solve this problem, a BTDA was developed by considering the length change of both cables. Cable-driven actuators and exoskeleton robot systems create uncertainty. Accordingly, adaptive control was performed with a proportional-integral-differential neural network (PIDNN) controller to minimize system uncertainty.

Bone Bruises of the Ankle and Mid-foot Often Associate with Ankle Sprain

Background: Ankle sprains are one of the most common musculoskeletal injuries. However, they may be more serious than commonly believed since many patients reportedly experience chronic problems afterwards. It is necessary to improve the treatment, such as the method and duration of fixation, of sprained ankles.Methods: Magnetic resonance imaging of 70 patients with acute moderate or advanced ankle sprains presenting consecutively between November 2014 and December 2019 were reviewed for analysis of bone bruising associated with ankle sprains. The patients were treated conservatively with a solid splint or cast until walking pain could be resolved without external fixation. In cases with pain at the time of weight bearing after solid fixation, crutches were prescribed for pain relief. The fixation period ranged from 8 days to 72 days (mean: 29.5 days). Afterwards, 54.0% of patients had walking pain and required the use of crutches. The ankle joint pain disappeared after conservative treatment in all patients.Results: The incidence of bone bruises detected by magnetic resonance imaging in the ankle and midfoot associated with ankle sprain was 81.4%. Bone bruises of the midfoot, including the tarsal bone and Chopart joint, were found in 34.3% of ankle sprains. Bone bruises of the talus were the most common, being present in 60% of ankle sprains. Bone bruises were also evident in the tibia (44.3%), the calcaneus (21.4%), and the tarsal bone (25.7%). There was a significant association between bone bruises of the talocrural joint surface and use of the crutches after fixation (P=0.041). Multiple regression analysis adjusted for age and gender revealed that bone bruises of the talocrural joint surface of the talus was a significant independent predictor of crutch use (P=0.045), with an odds ratio (95% confidence interval) of 3.03 (1.03-8.94).Conclusion: Bone bruises of the ankle and midfoot are often present in ankle sprains. In moderate or advanced cases of ankle sprain, external solid fixation of both the ankle and midfoot should be performed. In cases with pain at weight bearing following solid fixation, crutches are advised for pain relief and proper ligament and bone healing.