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JBJS Essential Surgical Techniques 2023Total talar replacement is a salvage procedure for end-stage osteonecrosis of the talus. A customized total talar implant is designed with use of computed tomography...
BACKGROUND
Total talar replacement is a salvage procedure for end-stage osteonecrosis of the talus. A customized total talar implant is designed with use of computed tomography scans of the healthy opposite side and made of alumina ceramic. The use of such an implant is potentially recommended, with a guarded prognosis, for the treatment of traumatic, steroidal, alcoholic, systemic lupus erythematous, hemophilic, and idiopathic pathologies. The talus is surrounded by the tibia, fibula, calcaneus, and navicular bones, which account for a large portion of the articular surface area. Yoshinaga reported that alumina ceramic prostheses were superior in terms of congruency and durability of articular cartilage compared with 316L stainless steel in an in vivo test in dogs. Therefore, alumina ceramic is an ideal material for replacement of the talus to preserve postoperative hindfoot mobility.
DESCRIPTION
Total talar replacement is performed with the patient in a supine position. The anterior ankle approach is utilized to exteriorize the talus, facilitating dissection of the ligaments and joint capsule attached to talus. The first osteotomy is performed around the talar neck, perpendicular to the plantar surface of the foot. The talar head fragment is then removed. Subsequent talar osteotomies are performed parallel to the first cutting line, at approximately 2-cm intervals. The attaching articular capsule and ligaments are dissected in each step. The removal of the posterior talar bone fragments is succeeded by careful dissection of the ligament and joint capsule under the periosteum. After dissecting the remaining interosseous talocalcaneal ligament, the foot is distally retracted and a customized talar implant is inserted. After testing and confirming the stability and mobility of the implant, the wound is irrigated with use of normal saline solution. A suction drain is placed anterior to the implant, and the skin is closed after repairing the extensor retinaculum.
ALTERNATIVES
In cases with a limited area of necrosis, symptoms may improve with a patellar tendon-bearing brace. However, in many cases of symptomatic osteonecrosis of the talus, nonoperative treatment is not expected to improve symptoms. Alternative surgical procedures include ankle arthrodesis and hindfoot arthrodesis, but there are risks of nonunion, leg-length discrepancy as a result of extensive bone loss, and functional decline because of loss of hindfoot motion.
RATIONALE
Total talar replacement is a fundamentally unique treatment concept in which the entire talus is replaced with an artificial implant. Compared with ankle or hindfoot arthrodesis, this procedure preserves the range of motion of the foot and allows for earlier functional recovery. Postoperative results were satisfactory in the subjective evaluation, with no failure requiring revision. This procedure reduces the risk of postoperative failure in patients who are elderly and/or have underlying diseases, who often require a long recovery time. As the talus is a small bone with uniquely vulnerable vascularity, treatment of talar pathology is usually difficult; however, total talar replacement is a potential treatment option for patients with end-stage osteonecrosis of the talus without obesity.
EXPECTED OUTCOMES
The greatest advantage of total talar replacement is the preservation of ankle and hindfoot mobility. Second, a customized talar prosthesis based on a mirrored model of the contralateral, unaffected talus will allow the smooth transfer of body weight from the lower leg to the heel and forefoot-a requirement for a stable gait. Third, the artificial talar prosthesis has a potential advantage in that it minimizes leg-length discrepancy, preventing daily inconvenience for the patient. Twenty years after the development of the implant, replacement with a total talar prosthesis resulted in a median score of 97 out of 100 on the Japanese Society for Surgery of the Foot (JSSF) Ankle-Hindfoot Scale as an objective evaluation and yielded a significant improvement in the subjective evaluation of the Ankle Osteoarthritis Scale (AOS) in a follow-up study over 10 years. The median ankle joint range of motion was 45°, and complications requiring implant replacement never occurred.
IMPORTANT TIPS
The skin incision should be placed at the center of the inferior tibial articular surface and curved medially to avoid the medial branch of the superficial peroneal nerve.During the resection of the talus, the attaching ligament and joint capsule are recommended to be debrided prior to osteotomy.Bone fragments should be removed as an entire block in order to avoid leaving small fragments.When inserting the artificial talus, pull the entire foot distally by grasping the heel in order to avoid excessive plantar flexion.During wound closure, the extensor retinaculum should be repaired to avoid skin bowstringing.Although favorable long-term results have been reported, postoperative outcomes in patients with high body mass index have not been adequately investigated. This procedure should be carefully selected on the basis of the physical characteristics of the patient.
ACRONYMS AND ABBREVIATIONS
AVN = avascular necrosis (osteonecrosis)SLE = systemic lupus erythematousCAD = computer-aided designCT = computed tomographyJSSF = Japanese Society for Surgery of the FootIQR = interquartile rangeAOS = Ankle Osteoarthritis ScalePWB = partial weight-bearingW = weeks.
PubMed: 38274145
DOI: 10.2106/JBJS.ST.22.00030 -
BMC Infectious Diseases Jan 2024Leprosy is a chronic infectious disease caused by Mycobacterium leprae, predominantly affecting the peripheral nerves, resulting in sensory and motor deficits in the...
BACKGROUND
Leprosy is a chronic infectious disease caused by Mycobacterium leprae, predominantly affecting the peripheral nerves, resulting in sensory and motor deficits in the feet. Foot ulcers and imbalances are frequent manifestations in leprosy, often correlating with diminished sensitivity. While clinical scales and monofilament esthesiometers are conventionally utilized to evaluate foot sensitivity and balance in these patients, their discriminatory power is limited and their effectiveness is greatly dependent on the examiner's proficiency. In contrast, baropodometry and posturography offer a more comprehensive evaluation, aiming to preempt potential damage events. This study aimed was to assess the correlation between baropodometry and force plate measurements in leprosy patients and control participants, to improve the prevention and treatment of foot ulcers and complications associated with leprosy.
METHODOLOGY
This cross-sectional study was conducted during 2022 and enrolled 39 participants (22 patients with multibacillary leprosy and 17 non-leprosy controls). Demographic data were collected, and a monofilament esthesiometer was used to assess sensory deficits. In addition, physical examinations and balance and plantar pressure tests were conducted. The Student's t-test was used to compare mean and maximum plantar pressures between groups. For most COP variables, a Mann-Whitney Wilcoxon test was used, except for AP amplitude which was analyzed with the Student's t-test due to its normal distribution. The relationship between foot pressure and balance control was assessed using Spearman's correlation, focusing on areas with significant pressure differences between groups.
PRINCIPAL FINDINGS
Leprosy patients showed increased pressure in forefoot areas (T1, M1, T2-T5, and M2) and decreased pressure in hindfoot regions (MH and LH) compared to controls. These patients also displayed higher AP and ML amplitudes, suggesting poorer COP control. Correlation analyses between the two groups revealed that foot plantar pressures significantly impact balance control. Specifically, increased T1 region pressures correlated with greater sway in balance tasks, while decreased MH region pressures were linked to reduced COP control.
CONCLUSIONS/SIGNIFICANCE
The findings suggest a joint disturbance of plantar pressure distribution and static balance control in leprosy patients. These alterations may increase the risk of tissue injuries, including calluses and deformities, as well as falls.
Topics: Humans; Cross-Sectional Studies; Diabetic Foot; Leprosy, Multibacillary; Foot; Lower Extremity
PubMed: 38267905
DOI: 10.1186/s12879-023-08749-0 -
Exercise, Sport & Movement 2023The purpose of this study was to determine the following in persons with midportion Achilles tendinopathy (AT): 1) maximal strength and power; 2) neural drive during...
INTRODUCTION/PURPOSE
The purpose of this study was to determine the following in persons with midportion Achilles tendinopathy (AT): 1) maximal strength and power; 2) neural drive during maximal contractions and contractile function during electrically evoked resting contractions; and 3) whether pain, neural drive, and contractile mechanisms contribute to differences in maximal strength.
METHODS
Twenty-eight volunteers (14 AT, 14 controls) completed isometric, concentric, and eccentric maximal voluntary contractions (MVCs) of the plantar flexors in a Biodex dynamometer. Supramaximal electrical stimulation of the tibial nerve was performed to quantify neural drive and contractile properties of the plantar flexors. Pain sensitivity was quantified as the pressure-pain thresholds of the Achilles tendon, medial gastrocnemius, and upper trapezius.
RESULTS
There were no differences in plantar flexion strength or power between AT and controls (isometric MVC: = 0.95; dynamic MVC: = 0.99; power: = 0.98), nor were there differences in neural drive and contractile function ( = 0.55 and = 0.06, respectively). However, the mechanisms predicting maximal strength differed between groups: neural drive predicted maximal strength in controls ( = 0.02) and contractile function predicted maximal strength in AT ( = 0.001). Although pain did not mediate these relationships (i.e., between maximal strength and its contributing mechanisms), pressure-pain thresholds at the upper trapezius were higher in AT ( = 0.02), despite being similar at the calf ( = 0.24) and Achilles tendon ( = 0.40).
CONCLUSIONS
There were no deficits in plantar flexion strength or power in persons with AT, whether evaluated isometrically, concentrically, or eccentrically. However, the mechanisms predicting maximal plantar flexor strength differed between groups, and systemic pain sensitivity was diminished in AT.
PubMed: 38222444
DOI: 10.1249/esm.0000000000000017 -
Nature Nanotechnology Apr 2024One of the critical factors determining the performance of neural interfaces is the electrode material used to establish electrical communication with the neural tissue,...
One of the critical factors determining the performance of neural interfaces is the electrode material used to establish electrical communication with the neural tissue, which needs to meet strict electrical, electrochemical, mechanical, biological and microfabrication compatibility requirements. This work presents a nanoporous graphene-based thin-film technology and its engineering to form flexible neural interfaces. The developed technology allows the fabrication of small microelectrodes (25 µm diameter) while achieving low impedance (∼25 kΩ) and high charge injection (3-5 mC cm). In vivo brain recording performance assessed in rodents reveals high-fidelity recordings (signal-to-noise ratio >10 dB for local field potentials), while stimulation performance assessed with an intrafascicular implant demonstrates low current thresholds (<100 µA) and high selectivity (>0.8) for activating subsets of axons within the rat sciatic nerve innervating tibialis anterior and plantar interosseous muscles. Furthermore, the tissue biocompatibility of the devices was validated by chronic epicortical (12 week) and intraneural (8 week) implantation. This work describes a graphene-based thin-film microelectrode technology and demonstrates its potential for high-precision and high-resolution neural interfacing.
Topics: Rats; Animals; Microelectrodes; Graphite; Nanopores; Prostheses and Implants; Electric Stimulation
PubMed: 38212522
DOI: 10.1038/s41565-023-01570-5 -
Frontiers in Neuroscience 2023It has been shown that estrogen and progesterone receptors are expressed in the spinal cord; therefore, fluctuation in their concentrations may affect the spinal network...
It has been shown that estrogen and progesterone receptors are expressed in the spinal cord; therefore, fluctuation in their concentrations may affect the spinal network and modulate the control of movement. Herein, we assessed the neuro-modulatory effect of sex hormones on the polysynaptic spinal network by using a flexion reflex network as a model system. Twenty-four healthy eumenorrheic women (age 21-37 years) were tested every other day for one menstrual cycle. Serum estradiol and progesterone were acquired at the time of testing. The flexion reflex of the tibialis anterior was elicited by sending an innocuous electrical stimulus directly to the posterior tibial nerve or plantar cutaneous afferent. Analyses were performed for each menstrual cycle phase: the follicular phase and the luteal phase. Increases in estradiol or progesterone concentrations were not associated with reflex duration or root mean squared (RMS) amplitude in either the follicular or luteal phases. In the luteal phase, an increase in the estradiol concentration was associated with a longer latency of the reflex ( = 0.23, = 0.038). The estradiol × progesterone interaction was found towards significance ( = -0.017, = 0.081). These results highlight the potential synergistic effect of estradiol and progesterone and may provide indirect confirmatory evidence of the observed modulatory effect.
PubMed: 38188036
DOI: 10.3389/fnins.2023.1263756 -
International Neurourology Journal Dec 2023Lithotomy position has been widely used in the various urologic surgery. Occasionally sensory and motor problems of the lower extremities are occurred due to the...
PURPOSE
Lithotomy position has been widely used in the various urologic surgery. Occasionally sensory and motor problems of the lower extremities are occurred due to the lithotomy position and these deficits may be related with sciatic nerve injury (SNI). Inflammatory process is a factor to induce functional impairment after SNI. Therefore, we evaluated the role of adenosine A2A receptor agonists, polydeoxyribonucleotide (PDRN) showing anti-inflammatory effect on locomotor function following SNI in rats.
METHODS
Sciatic nerve was compressed with surgical clips for 1 minute after exposing of right sciatic nerve. After 3 days of SNI, PDRN (2, 4, and 8 mg/kg) was applied to the damaged area of sciatic nerve once daily for 10 days. Walking track analysis was conducted for locomotor function and plantar test was performed for thermal pain sensitivity. Level of cyclic adenosine-3´,5´-monophosphate (cAMP) were measured using enzyme-linked immunosorbent assay. Western blot analysis was performed for tumor necrosis factor (TNF)-α, interleukin (IL)-1β, cAMP response element binding protein (CREP), vascular endothelial growth factor (VEGF). Immunofluorescence for neurofilament was also conducted.
RESULTS
Locomotor function was decreased and thermal pain sensitivity was increased by SNI. SNI enhanced proinflammatory cytokines' production, such as TNF-α and IL-1β, while suppressed CREP phosphorylation and cAMP level. SNI also reduced the expression of VEGF and neurofilaments. However, treatment with PDRN inhibited proinflammatory cytokines' production and upregulated CREP phosphorylation and cAMP expression. PDRN also enhanced the expression of VEGF and neurofilaments. As a result, PDRN improved locomotor function and alleviated thermal hyperalgesia after SNI.
CONCLUSION
PDRN has shown potential to be used as an effective treatment for neuropathic pain.
PubMed: 38171324
DOI: 10.5213/inj.2326154.127 -
Physiological Research Dec 2023Methylphenidate is a psychostimulant that increases dopamine and noradrenaline levels. Recent studies have shown that methylphenidate potentiates the effect of morphine...
Methylphenidate is a psychostimulant that increases dopamine and noradrenaline levels. Recent studies have shown that methylphenidate potentiates the effect of morphine and together suppress acute and chronic pain. In clinical practice, methylphenidate has been used as a treatment for ADHD and changes of pain threshold have been noted in these patients. The aim of this study was to determine the effect of methylphenidate in an animal model of peripheral neuropathic pain. Neuropathic pain was modeled by the chronic constriction of the sciatic nerve (CCI) in Wistar rats. We evaluated the effect of methylphenidate (1 mg/kg, s.c.) on evoked pain (reflex tests - plantar test, vonFrey test and operant test - thermal place preference) and on spontaneous pain (conditioned place preference). CCI induced thermal, mechanical and cold hyperalgesia/allodynia. Methyphenidate suppressed mechanical and cold hyperalgesia/allodynia, while had no effect on thermal one. Therefore, methylphenidate seems to be a new potential pharmacotherapy for the treatment of neuropathic pain.
Topics: Humans; Rats; Animals; Hyperalgesia; Methylphenidate; Rats, Wistar; Disease Models, Animal; Neuralgia
PubMed: 38165759
DOI: 10.33549/physiolres.935215 -
Translational Neuroscience Jan 2023Dorsal root injury usually leads to irreversible sensory function loss and lacks effective treatments. (-)-epigallocatechin-3-gallate (EGCG) is reported to exert...
Dorsal root injury usually leads to irreversible sensory function loss and lacks effective treatments. (-)-epigallocatechin-3-gallate (EGCG) is reported to exert neuroprotective roles in the nervous systems. However, the function of EGCG in treating dorsal root injury remains unclear. Hence, we built the dorsal root crush injury (DRCI) rat model to be treated with EGCG, followed by the western blot, Enzyme-linked immunosorbent assay, and sensory behavior tests. We observed that EGCG can upregulate the Lysine acetyltransferase 6A (KAT6A) level and inhibit the pyroptosis, indicated by downregulated gasdermin-D, caspase-1, and interleukin 18 protein levels, and alleviate the neuropathic pain, indicated by the decreased paw withdraw threshold in Plantar test and decreased paw withdraw latency in von Frey test, and downregulated calcitonin gene-related peptide, nerve growth factor, and c-Fos protein levels. But EGCG cannot alleviate the neuropathic pain when the KAT6A was inhibited by CTX-0124143 and pyroptosis was activated by Miltirone. These combined results indicated that EGCG can promote the sensory function recovery in rats after DRCI via upregulating KAT6A and inhibiting pyroptosis, laying the foundation for EGCG to be a novel candidate for the treatment of dorsal root injury.
PubMed: 38152093
DOI: 10.1515/tnsci-2022-0326