Anatomical study of the plantaris tendon: reliability as a tendo-osseous graft

Purpose  The purpose of this study was to investigate the insertion of the plantaris tendon in terms of shape, length, width and size, to define if there is available bony insertion for future use as reconstructive procedure in secondary tendon graft in hand surgery. Methods  In 30 limbs, the plantaris tendon was anatomically dissected to investigate its bony attachments to the calcaneus. Results  The plantaris was present in 29 of 30 dissections and regularly inserted in the calcaneus. Conclusions  The tendo-osseous plantaris graft is, according to this research, amenable to be used as a viable choice in reconstruction of secondary flexor tendon injuries related to its length shape and size and especially due to the bone stock adequate to strong phalanx fixation.     

The arterial anatomy of the Achilles tendon: Anatomical study and clinical implications

The Achilles tendon is the most frequently ruptured tendon in the lower limb and accounts for almost 20% of all large tendon injuries. Despite numerous published studies describing its blood supply, there has been no uniformity in describing its topography. The current study comprises a detailed anatomical study of both the intrinsic and extrinsic arterial supply of the Achilles tendon, providing the detail sought from studies calling for improved planning of surgical procedures where damage to the vascularity of the Achilles tendon is likely. A dissection, microdissection, histological, and angiographic study was undertaken on 20 cadaveric lower limbs from 16 fresh and four embalmed cadavers. The Achilles tendon is supplied by two arteries, the posterior tibial and peroneal arteries. Three vascular territories were identified, with the midsection supplied by the peroneal artery, and the proximal and distal sections supplied by the posterior tibial artery. The midsection of the Achilles tendon was markedly more hypovascular that the rest of the tendon. The Achilles tendon is at highest risk of rupture and surgical complications at its midsection. Individuals with particularly poor supply of the midsection may be at increased risk of tendon rupture, and approaches to the tendon operatively should consider the route of supply by the peroneal artery to this susceptible part of the tendon. Clin. Anat. 22:377–385, 2009. © 2009 Wiley‐Liss, Inc.     

The influence of aging on the insertion of the Achilles tendon: A magnetic resonance study

The aim of this study was to examine the variations of the Achilles tendon (AT) insertion point into the calcaneal bone (CB) in relation to age and sex using magnetic resonance imaging (MRI). A total of 202 foot and ankle MRIs were reviewed and patients were allocated into three age groups: (I) <18, (II) 18-65, and (III) >65 years. All measurements were obtained on a mid-sagittal scan. The mean measurement values were used to assess the relationships among the AT insertion point, sex, and age. Our main findings revealed that (1) the distance between the most inferior point of the CB and the most inferior part of the AT insertion into the CB increases with age, (2) the height of the AT insertion into the posterior aspect of the CB decreases with age, and (3) the length of the AT insertion into the posterior aspect of the CB decreases with age. The terminal insertion point of the AT on the CB in younger subjects was more distal, whereas in older individuals it was more proximal. These results could help in developing novel strategies for the treatment and prophylaxis of AT injuries in particular patient age groups. Anatomical data about the AT insertion are crucial for developing a computer model of the AT and for biomechanical considerations regarding this tendon. Clin. Anat. 33:545–551, 2020. © 2019 Wiley Periodicals, Inc.     

The effect of dry needling and treadmill running on inducing pathological changes in rat Achilles tendon

Achilles tendinopathy is a common degenerative condition without a definitive treatment. An adequate chronic animal model of Achilles tendinopathy has not yet been developed. The purpose of this study was to evaluate the individual and combined effects of dry needling and treadmill running on the Achilles tendon of rats. Percutaneous dry needling, designed to physically replicate microrupture of collagen fibers in overloaded tendons, was performed on the right Achilles tendon of 80 Sprague–Dawley rats. The rats were randomly divided into two groups: a treadmill group, which included rats that underwent daily uphill treadmill running (n?=?40), and a cage group, which included rats that could move freely within their cages (n?=?40). At the end of weeks 1 and 4, 20 rats from each group were sacrificed, and bilateral Achilles tendons were collected. The harvested tendons were subjected to mechanical testing and histological analysis. Dry needling induced histological and mechanical changes in the Achilles tendons at week 1, and the changes persisted at week 4. The needled Achilles tendons of the treadmill group tended to show more severe histological and mechanical changes than those of the cage group, although these differences were not statistically significant. Dry needling combined with free cage activity or treadmill running produced tendinopathy-like changes in rat Achilles tendons up to 4 weeks after injury. Dry needling is an easy procedure with a short induction period and a high success rate, suggesting it may have relevance in the design of an Achilles tendinopathy model.     

Immersion of Achilles tendon in phosphate‐buffered saline influences T1 and T2* relaxation times: An ex vivo study

Robust mapping of relaxation parameters in ex vivo tissues is based on hydration and therefore requires control of the tissue treatment to ensure tissue integrity and consistent measurement conditions over long periods of time. One way to maintain the hydration of ex vivo tendon tissue is to immerse the samples in a buffer solution. To this end, various buffer solutions have been proposed; however, many appear to influence the tissue relaxation times, especially with prolonged exposure. In this work, ovine Achilles tendon tissue was used as a model to investigate the effect of immersion in phosphate‐buffered saline (PBS) and the effects on the T₁ and T₂^* relaxation times. Ex vivo samples were measured at 0 (baseline), 30 and 67 hours after immersion in PBS. Ultrashort echo time (UTE) imaging was performed using variable flip angle and echo train‐shifted multi‐echo imaging for T₁ and T₂^* estimation, respectively. Compared with baseline, both T₁ and T₂^* relaxation time constants increased significantly after 30 hours of immersion. T₂^* continued to show a significant increase between 30 and 67 hours. Both T₁ and T₂^* tended to approach saturation at 67 hours. These results exemplify the relevance of stringently controlled tissue preparation and preservation techniques, both before and during MRI experiments.     

The paratendineous tissues: an anatomical study of their role in the pathogenesis of tendinopathy

The aim of this paper was to examine the macroscopic and microscopic characteristics of the paratendineous tissues (paratenon, epitenon and endotenon) of the calcaneal tendon to better understand their role in the pathogenesis of “tendinopathy”. Ten non-embalmed legs from cadavers were used. Histological and immunohistochemical studies were done at the middle third of the tendon. Magnetic resonance images of the hind foot were made in 60 living subjects to analyze the morphological alterations of tendon and paratenon. The paratenon is a thick fibrous layer with few elastic fibers, continuous with the crural fascia, well vascularized and innervated. It forms a sheath around the tendon similar to a synovial layer, but less organized. Indeed, it has no complete epithelium, but only some cells producing hyaluronan, called fasciacytes. Crural fascia and paratenon can be clearly observed by MRI, appearing as homogeneous, low signal intensity bands, sharply defined in the context of subcutaneous tissue in T1-weighted sequences. The mean thickness of the crural fascia was 1.11 mm in healthy subjects and 1.30 mm in patients (p < 0.005). The mean value of paratenon thickness in patients was 1.34 mm, 0.85 in healthy (p < 0.0001). The paratenon is more highly vascularized and innervated than the tendon, supporting the hypothesis that it is the origin of pain in tendinopathy. The imaging study suggests that, an increase in the thickness of the paratenon more than 1.35 mm is predictive of paratendinopathy, even before tendon damage.     

The role of three-dimensional pure bovine gelatin scaffolds in tendon healing,modeling, and remodeling: an in vivo investigation with potential clinical value

Aim of the study: Large tendon defects involving extensive tissue loss present complex clinical problems. Surgical reconstruction of such injuries is normally performed by transplanting autogenous and allogenous soft tissues that are expected to remodel to mimic a normal tendon. However, the use of grafts has always been associated with significant limitations. Tissue engineering employing artificial scaffolds may provide acceptable alternatives. Gelatin is a hydrolyzed form of collagen that is bioactive, biodegradable, and biocompatible. The present study has investigated the suitability of gelatin scaffold for promoting healing of a large tendon-defect model in rabbits. Materials and methods: An experimental model of a large tendon defect was produced by partial excision of the Achilles tendon of the left hind leg in adult rabbits. To standardize and stabilize the length of the tendon defect a modified Kessler core suture was anchored in the sectioned tendon ends. The defects were either left untreated or filled with three-dimensional gelatin scaffold. Before euthanasia 60 days after injury, the progress of healing was evaluated clinically. Samples of healing tendon were harvested at autopsy and evaluated by gross, histopathologic, scanning, and transmission electron microscopy, and by biomechanical testing. Results: The treated animals showed superior weight-bearing and physical activity compared with those untreated, while frequency of peritendinous adhesions around the healing site was reduced. The gelatin scaffold itself was totally degraded and replaced by neo-tendon that morphologically had significantly greater numbers, diameters, density, and maturation of collagen fibrils, fibers, and fiber bundles than untreated tendon scar tissue. It also had mechanically higher ultimate load, yield load, stiffness, maximum stress and elastic modulus, when compared to the untreated tendons. Conclusion: Gelatin scaffold may be a valuable option in surgical reconstruction of large tendon defects.     

Gliding characteristics of flexor tendon and tenosynovium in carpal tunnel syndrome: a pilot study

The characteristic pathological finding in carpal tunnel syndrome (CTS) is noninflammatory fibrosis of the synovium. How this fibrosis might affect tendon function, if at all, is unknown. The subsynovial connective tissue (SSCT) lies between the flexor tendons and the visceral synovium (VS) of the ulnar tenosynovial bursa. Fibrosis of the SSCT may well affect its gliding characteristics. To investigate this possibility, the relative motion of the flexor tendon and VS was observed during finger flexion in patients undergoing carpal tunnel surgery, and for comparison in hands without CTS, in an in vitro cadaver model. We used a camera to document the gliding motion of the middle finger flexor digitorum superficialis (FDS III) tendon and SSCT in three patients with CTS during carpal tunnel release and compared this with simulated active flexion in three cadavers with no antemortem history of CTS. The data were digitized with the use of Analyze Software (Biomedical Imaging Resource, Mayo Clinic, Rochester, MN). In the CTS patients, the SSCT moved en bloc with the tendon, whereas, in the controls the SSCT moved smoothly and separately from the tendon. The ratio of VS to tendon motion was higher for the patients than in the cadaver controls. These findings suggest that in patients with CTS the synovial fibrosis has altered the gliding characteristics of the SSCT. The alterations in the gliding characteristics of the SSCT may affect the ability of the tendons in the carpal tunnel to glide independently from each other, or from the nearby median nerve. These abnormal tendon mechanics may play a role in the etiology of CTS.     

The arterial supply of the tendon of the long head of the biceps brachii in the human: A combined anatomical and radiological study

PurposeArthroscopic repair of superior labral anterior to posterior (SLAP) lesions is often associated with a prolonged period of pain during the rehabilitation process. This might possibly be due to hypoxia in the biceps tendon anchor caused by sutures. The purpose of the study was to investigate the arterial supply of the long head of the biceps brachii tendon (LHBT) that may be impaired by surgery in the region of the biceps tendon anchor.MethodsOn 20 human formalin-fixed bodies, the anterior circumflex humeral artery (ACHA) was located and followed into the intertubercular groove until it reached the LHBT. On 10 fresh-frozen anatomic specimens of the upper extremities, contrast medium was injected into the axillary artery, a 3D scan was performed, and multiplanar reconstructed (MPR) slices were generated. A set of maximum intensity projection (MIP) reconstructions from 10 computed tomography angiographies (CTA) of the upper extremities was used to confirm the findings of the 3D scan.ResultsAll anatomical dissections and radiological investigations revealed that the proximal portion of the LHBT was consistently supplied by an ascending branch of the ACHA. No artery was found to supply the biceps tendon anchor from the proximal aspect.ConclusionsAs the arterial supply of the LHBT is mainly provided by the ACHA, which enters the glenohumeral joint from the distal aspect, surgery at the bony origin of the LHBT may not interfere with this specific vessel.     

The interface between bone and tendon at an insertion site: a study of the quadriceps tendon insertion

Traumatic avulsions of ligament or tendon insertions rarely occur at the actual interface with bone, which suggests that this attachment is strong or otherwise protected from injury by the structure of the insertion complex. In this study we describe the terminal extent of quadriceps tendon fibres where they insert into the patellae of adult rabbits, humans, dogs and sheep. Specimens were examined by scanning electron microscopy (SEM) and light microscopy (LM). To facilitate tracing of tendon fibres the specimens were decalcified for SEM, and polarised light microscopy (PLM) was used in the LM segment of the study. By SEM it was possible to identify mature bone by the presence of osteocytes and a lamellar organisation. PLM and SEM showed that, unlike tendon fibres elsewhere, those in the calcified fibrocartilage were not crimped. No specific cement line was identified by SEM. Tendon fibres interdigitated among separate bone lamellar systems, (osteons or marrow spaces), but did not merge with the collagen systems of individual lamellae. The interdigitation was more extensive and the margin between tendon and bone was less distinct in the anterior third of the insertion. The segment of calcified tendon which interdigitated with bone stained less intensely blue and was less cellular than the more proximal calcified fibrocartilage zone adjacent to the tidemark. Lamellar collagen fibres of the bony trabeculae in the anterior patella were unusually parallel and longitudinal in orientation, making distinction of interposed tendon fibres difficult on LM and PLM sections. LM, SEM and transmission electron microscopy of rabbit patellae at birth revealed that anterior quadriceps tendon fibres extended over the patella in a fibrous cellular layer. By 2 wk of age, this layer had acquired chondroid features (i.e. cell lacunae and metachromasia) and contained vessels extending from patellar marrow. At 6 wk of age, part of this fibrocartilaginous layer was replaced by mature bone and osteoid. In the young adult animal, the quadriceps tension interdigitates extensively with the patellar bone. This segment of the insertion is perhaps the remnant of calcified fibrocartilage which has been remodelled by bone formation.     

Transient receptor potential vanilloid 1 expression and function in splenic dendritic cells: a potential role in immune homeostasis

Neuro‐immune interactions, particularly those driven by neuropeptides, are increasingly implicated in immune responses. For instance, triggering calcium‐channel transient receptor potential vanilloid 1 (TRPV1) on sensory nerves induces the release of calcitonin‐gene‐related peptide (CGRP), a neuropeptide known to moderate dendritic cell activation and T helper cell type 1 polarization. Despite observations that CGRP is not confined to the nervous system, few studies have addressed the possibility that immune cells can respond to well‐documented ‘neural’ ligands independently of peripheral nerves. Here we have identified functionally relevant TRPV1 on primary antigen‐presenting cells of the spleen and have demonstrated both calcium influx and CGRP release in three separate strains of mice using natural agonists. Furthermore, we have shown down‐regulation of activation markers CD80/86 on dendritic cells, and up‐regulation of interleukin‐6 and interleukin‐10 in response to CGRP treatment. We suggest that dendritic cell responses to neural ligands can amplify neuropeptide release, but more importantly that variability in CGRP release across individuals may have important implications for immune cell homeostasis.     

Effects of sodium-hyaluronate and glucosamine-chondroitin sulfate on remodeling stage of tenotomized superficial digital flexor tendon in rabbits: a clinical,histopathological, ultrastructural,and biomechanical study

This study was designed to evaluate the effects of sodium-hyaluronate (NaH) combined with glucosamine HCl-chondroitin sulfate (GlcN-CS) on the post-surgical repair of tendon rupture on day 84 post injury. Twenty white New Zealand female rabbits were divided randomly into two equal groups of injured treated and injured untreated. After tenotomy and surgical repair, using the modified Kessler technique and running pattern, the injured legs were casted for 14 days. NaH was injected subcutaneously over the lesion on days 3, 7, and 10 and was followed by daily oral administration of GlcN-CS on days 3 to 23 post injury. The control animals received normal saline injection and oral placebo similarly. The weight of the animals, tendon diameter, clinical manifestations, and radiographic and ultrasonographic evaluations were conducted for 12 weeks. The rabbits were euthanized 84 days post injury and the tendons were evaluated at macroscopic, histopathologic, and ultrastructural level and were assessed for biomechanical and percentage dry-weight parameters. Treatment significantly reduced the tendon diameter and ultimate and yield strain, and increased the echogenicity, dry-weight content, ultimate and yield strength, and stress and stiffness of the injured tendons compared to those of the untreated ones. Treatment also significantly enhanced the maturation rate of the tenoblasts, fibrillogenesis, the diameters of the collagen fibrils, and fibrillar density. These findings suggest that a combined treatment of NaH and GlcN-CS could be effective in restoring the morphological and biomechanical properties of injured superficial digital flexor tendon of rabbits and might be helpful for future clinical trial studies in tendon ruptures.     

The role of bacterial colonization of ventilator circuit in development of ventilator-associated pneumonia: a prospective observational cohort study

ObjectivesVentilator-associated pneumonia (VAP) is a significant cause of prolonged hospital stay and increased mortality in mechanically ventilated children. Studies of the relationship between bacterial colonization of ventilator circuits (VCs) and VAP are lacking. This study aimed to investigate the role of bacterial colonization of VCs in the development of VAP, and to provide evidence for preventing VAP.MethodsMechanically ventilated patients admitted to the paediatric intensive care unit of a teaching hospital in China from October 2018 to November 2019 were enrolled. Specimens were collected from the VC and the patient's lower respiratory tract (LRT) for bacterial culture. Paired bacteria isolated from the VC and the patient's LRT, where colonization of the VC preceded that of the LRT, were evaluated for relatedness using pulsed field gel electrophoresis (PFGE).ResultsA total of 114 patients were included; the incidence rate of VAP was 28.1% (32/114). A total of 1368 samples were collected from VCs; 16% had positive bacterial culture. There was no significant difference in bacterial colonization of VCs between VAP and non-VAP. In 13 patients, the LRT and VC were concurrently colonized with the same bacteria, where colonization of the VC occurred before colonization of the patient's LRT. PFGE results demonstrated high correlation between bacteria from the LRT and VC in 11 patients. Among 114 mechanically ventilated children, VAP caused by bacteria from the VC occurred in six patients, accounting for 18.8% (6/32) of the overall VAP rate in this study.DiscussionBacterial colonization of the VC is a significant cause of VAP development in mechanically ventilated children. Preventive strategies for early identification and decontamination measures for contaminated VC may play a key role in preventing VAP.     

The potential of complementary and alternative medicine in promoting well-being and critical health literacy: a prospective, observational study of shiatsu

Background  

The potential contribution of complementary and alternative medicine (CAM) modalities to promote and support critical health literacy has not received substantial attention within either the health promotion or the CAM literature. This paper explores the potential of one CAM modality, shiatsu, in promoting well-being and critical health literacy.     

The role of the patellar tendon angle and patellar flexion angle in the interpretation of sagittal plane kinematics of the knee after knee arthroplasty: A modelling analysis

Background

Many different measures have been used to describe knee kinematics. This study investigated the changes of two measures, the patellar tendon angle and the patellar flexion angle, in response to variations in the geometry of the knee due to surgical technique or implant design.