Normal Tendon Research Articles

Regeneration of a full-thickness defect in rotator cuff tendon with umbilical cord-derived mesenchymal stem cells in a rat model.

Although rotator cuff disease is a common cause of shoulder pain, there is still no treatment method that could halt or reveres its development and progression. The purpose of this study was to investigate the efficacy of umbilical cord-derived mesenchymal stem cells (UC MSCs) on the regeneration of a full-thickness rotator cuff defect (FTD) in a rat model. We injected either UC MSCs or saline to the FTD and investigated macroscopic, histological and biomechanical results and cell trafficking. Treatment with UC MSCs improved macroscopic appearance in terms of tendon thickness at two weeks, and inflammation, defect size, swelling/redness and connection surrounding tissue and slidability at four weeks compared to the saline group. Histologically, UC MSCs induced the tendon matrix formation recovering collagen organization, nuclear aspect ratio and orientation angle of fibroblast as well as suppressing cartilage-related glycosaminoglycan compared to saline group at four weeks. The UC MSCs group also improved ultimate failure load by 25.0% and 19.0% and ultimate stress by 27.3% and 26.8% at two and four weeks compared to saline group. UC MSCs labeled with PKH26 exhibited 5.3% survival at four weeks compared to three hours after injection. This study demonstrated that UC MSCs regenerated the FTD with tendon tissue similar properties to the normal tendon in terms of macroscopic, histological and biomechanical characteristics in a rat model.

Reduced Levels of Aligned Fibrillar Structure Are Not Associated With Achilles and Patellar Tendon Symptoms.

To investigate whether the mean cross-sectional area (mCSA) of aligned fibrillar structure (AFS) was associated with the presence and severity of symptoms. Prospective cohort study. One hundred seventy-five elite male Australian football players completed monthly Oslo Sports Trauma Research Center overuse injury questionnaires for both the Achilles and patellar tendon over the season to ascertain the presence and severity of symptoms. At the start of the preseason, participants underwent ultrasound tissue characterization (UTC) imaging of the Achilles and patellar tendon. Images were classified as normal or abnormal based on gray-scale ultrasound. Based on UTC quantification, the mCSA of AFS was compared between those with and without current symptoms. No difference in the mCSA of AFS was observed between those with or without tendon symptoms (P < 0.05). Similar to previous findings, 80% to 92% of abnormal tendons had similar amounts of mCSA of AFS compared with normal tendon. If reduced mCSA of AFS was present, it was not associated with the presence or severity of symptoms. The prevalence, development, or severity of symptoms was not associated with decreased levels of AFS in the Achilles or patellar tendon. This suggests that a lack of structural integrity is not linked to symptoms and questions the rationale behind regenerative medicine. Most tendons are able to compensate for areas of disorganization and maintain tissue homeostasis.

Role of nutritional supplements in the management of tendinopathies: focus on combination of type 1 collagen, vitamin C and mucopolysaccharides

&lt;p class="abstract"&gt;Tendinopathy is a common disease that is difficult to manage due to its recurrent nature. It is associated with increased healthcare costs and significantly impacts quality of life of patients. Also, according to recent studies patients with high cholesterol and diabetes are at a higher risk of developing tendinopathy. There has been rise in the incidence of tendinopathies due to increase in sport activities, life expectancy and some other factors (environment, diet and some drug therapies). Approximately 30% of visits for musculoskeletal pain in general practice are related to tendon injury. Non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids remain the mainstay of treatment. Despite the use of current therapies, there is need of a supportive therapy that can help in the healing process towards development of physiologically normal tendons. Nutraceuticals have been used as supportive therapy for management of tendinopathies. This review focuses on the management of tendinopathy with special attention on role of nutraceuticals such as type I collagen, mucopolysaccharides and vitamin C in the management of tendinopathy. Clinical data suggests that this combination (type I collagen, mucopolysaccharides and vitamin C) promotes the endogenous synthesis of collagen type I, avoiding the accumulation of collagen type III and aggrecan, thus interfering with the degeneration of tendon tissue. Based on the available clinical data, combination of type I collagen, mucopolysaccharides and vitamin C not only reduce the clinical symptoms but also improve structural evolution of different types of tendinopathies as well as plantar fascitis.&lt;/p&gt;

2020 J. Leonard Goldner Award Winner: Inhibition of HMGB1 by Metformin Prevents Mechanical Overloading-Induced Tendinopathy

Category:Basic Sciences/Biologics; SportsIntroduction/Purpose:Tendinopathy is a debilitating tendon disorder that affects millions of Americans and costs billions of healthcare dollars every year. Mechanical overloading is considered to cause the development of tendinopathy, but the underlying molecular mechanisms of tendinopathy remain unclear. High mobility group box-1 (HMGB1), an upstream potent inflammatory mediator, has been identified in high levels in early stage tendinopathy patients [1]. However, whether HMGB1 mediates tendinopathy development due to mechanical overloading is completely unknown. Metformin (Met), a hypoglycemic drug commonly used for the treatment of type II diabetes, has shown to inhibit the activity of HMGB1 via binding the acidic tail of HMGB1 [2]. In this study, we tested the hypothesis that Met prevents mechanical overloading-induced tendinopathy by inhibiting HMGB1.Methods:A total of 24 mice were divided into 4 groups and treated for 24 weeks as follows: Group 1 (Cage) with cage activities; Group 2 (Met) received daily IP injection of metformin (50 mg/kg body weight); Group 3 (ITR) ran on treadmill at 15 meters/min for 3 h/ day, 5 days a week; Group 4 (ITR+Met) ran the same protocol as that of ITR group but with daily IP injection of metformin. Six mice/group were sacrificed at 24 weeks and the Achilles and patellar tendon tissues were harvested. The tendons from the left legs were used for histochemical staining and the right for immunostaining.Results:We found that mechanical overloading induced HMGB1 release into tendon matrix (Fig. 1G, K, O). Metformin inhibited HMGB1 release (Fig. 1H, L, P). ITR induced degenerative tendinopathy as evidenced by the cell morphological changes from elongated shape in normal tendon (Fig. 2A, E, I, M) to round shape (Fig. 2C, G, K, O) and the accumulation of proteoglycans (Fig. 2K, O) in ITR tendon. Metformin injection inhibited ITR effect, which is shown by less round shaped cells and low proteoglycan levels found in metformin injected ITR tendons (Fig. 2D, H, L, P). ITR promoted the expression of chondrogenic markers (collagen II and SOX-9) in tendon (Fig. 3C, G, K, O), and metformin inhibited the expression of chondrogenic makers (Fig. 3D, H, L, P).Conclusion:Our study demonstrated that mechanical overloading induced degenerative changes in mouse tendons characterized by the presence of chondrocyte-like cells, accumulation of proteoglycans, high levels of chondrogenic marker SOX-9 and Collagen II expression. Administration of metformint reduced the degenerative responses in overloaded tendon and blocked the development of tendinopathy. These findings support the notion that mechanical overloading induces tendinopathy development by initiation of tendon inflammation via HMGB1, which leads to eventual tendon degeneration. Thus, metformin, a commonly prescribed and FDA approved drug that specifically inhibits HMGB1, can be used to prevent tendinopathy development due to mechanical overloading placed on the tendon.

Characteristic of Posterior Tibialis Tendon Dysfunction and Adult Acquired Flatfoot Deformity in Professional Athletes

Flatfoot cause several complications such as foot pain, knee pain, back pain, and postural disturbance. These pain rarely occur on babies and children, but the main cause of pain on runners and increase of sport injury. The purpose of this study was to identify characteristic posterior tibialis tendon dysfunction and adult acquired flatfoot deformity in professional athletes at East Java Indonesia. The sample consisted of 112 sample from 56 athletes (n=112) with complain such as foot pain, and knee pain underwent foot ultrasound and radiographic examination in Radiology Department of Soetomo General Academic Hospital Surabaya. Flatfoot was found in 79 sample (70,5%) while the other 33 sample (29,5%). Tenosynovitis that diagnosed from thickening of posterior tibialis tendon sheath was found in 69 sample (61,6%) and normal posterior tibialis tendon in 37 sample (38,4%). Partial tear in posterior tibialis tendon was found in 7 sample (6,3%), while the other 105 sample (93,7%) are without tear. Type of sport that has the largest percentage of flatfoot was wrestling 24 (21,4%) from all the sample. Most of the samples had bilateral flatfoot deformity (92,8%) and bilateral posterior tibialis tendon dysfunction (88,6%). In this study, amongst the athletes, the practitioners of wrestling and fencing had the largest number of flatfoot and tenosynovitis, whereas the largest percentage is gymnastics. The practitioners of wushu had the largest number and percentage of normal pedis radiographic x-ray and posterior tibialis tendon ultrasound. Majority of athletes had flatfoot deformity and posterior tibialis tendon dysfunction, however only a few that had partial tear in posterior tibialis tendon.

Posterior Tibial Tendon Integrity Can Be Screened With Plain Anteroposterior Foot Radiography.

Posterior tibial tendon integrity is an important consideration when treating adult-acquired flatfoot caused by posterior tibial tendon dysfunction. The condition of this tendon traditionally has been evaluated with ultrasonography or magnetic resonance imaging, but recent advances in radiography have increased the resolution of radiographic soft tissue images. The authors examined whether the posterior tibial tendon could be screened with anteroposterior foot radiographs, based on interobserver agreement and accuracy. The authors retrospectively evaluated consecutive patients who underwent weight-bearing foot radiography and ultrasonography based on suspicion of posterior tibial tendinopathy. The integrity of the posterior tibial tendon was evaluated by 2 orthopedic surgeons with foot radiographs and scored as normal or abnormal. The authors evaluated interobserver agreement and compared the findings of ultrasonography and radiography to evaluate diagnostic accuracy. The study included 21 patients with a mean age of 51.5±15.7 years. Ultrasonography showed that 4 patients had normal tendon integrity, 6 patients had tenosynovitis and no tendinopathy, 8 patients had tendinopathy and tendon continuity, and 3 patients had loss of tendon continuity. The surgeons provided consistent radiographic findings for 81.0% of patients (17 of 21). On the basis of the ultrasonographic findings, the surgeons' accuracy was 76.2% (16 of 21) and 61.9% (13 of 21). The results indicate that weight-bearing anteroposterior foot radiography can be used to evaluate posterior tibial tendon integrity, which may allow orthopedic surgeons to predict the prognosis of patients with posterior tibial tendon dysfunction, determine the extent of surgical treatment, and evaluate tendon integrity postoperatively. [Orthopedics. 2020;43(6):e503-e507.].

Endoscopic Tenolysis of Flexor Hallucis Longus Tendon: Surgical Technique

Flexor hallucis longus tendon release for surgical treatment of functional hallux limitus–associated conditions is described. This release is obtained by arthroscopic correction of the tendon's blockage, which is located at the retrotalar pulley. The procedure restores the ability for dorsiflexion of the first toe in ankle dorsiflexion (positive stretch test result). Such movement was not possible before, causing a modified gait pattern and affecting the biomechanics of the foot and leg. This explains why the procedure creates favorable changes concerning foot dynamics by restoration not only of the normal tendon glide but also of the normal mobility of the subtalar joint.

Effect of partial vs complete circumferential epitendinous suture placement on the biomechanical properties and gap formation of canine cadaveric tendons.

To determine the effect of partial vs complete circumferential epitendinous suture (ES) placement in addition to a core suture on the biomechanical strength and gapping characteristics of repaired canine tendinous constructs. Ex vivo, biomechanical study. Thirty-six canine superficial digital flexor tendons. Superficial digital flexor tendons were randomly assigned to three groups (n = 12), sharply transected and repaired with a core locking-loop suture with Group 1 a partial circumferential ES, 180° on the palmar side; Group 2 a complete circumferential ES, 360° and double knotting technique; or Group 3 a complete circumferential ES, 360° and single knotting technique. After preloading, constructs were distracted to monotonic failure. Failure mode, gap formation, yield, peak, and failure forces were analyzed. Mean yield (group 1 = 68.6 N, group 2 = 106.5 N, group 3 = 114 N, P < .013), peak (group 1 = 92.8 N, group 2 = 134.6 N, group 3 = 147.3 N; P < .001), and failure (group 1 = 88.7 N, group 2 = 133.0 N, group 3 = 145.5 N, P < .001) loads differed between groups. No difference in yield (P = .874), peak (P = .434), or failure load (P = .434) was detected between complete circumferential ES groups. Force to create 1-mm (P < .001) and 3-mm (P < .038) gap formation was greater in specimens with complete vs partial circumferential ES placement. Complete circumferential ES repairs failed primarily by suture pull-through compared with suture breakage in most partial circumferential ES constructs. Addition of a complete circumferential ES with a single or double knotting technique increased the biomechanical strength of normal tendon repairs while reducing gap formation compared with partial ES placement alone. Complete circumferential ES is recommended over partial ES placement.

Elastin levels are higher in healing tendons than in intact tendons and influence tissue compliance.

Elastic fibers containing elastin play an important role in tendon functionality, but the knowledge on presence and function of elastin during tendon healing is limited. The aim of this study was to investigate elastin content and distribution in intact and healing Achilles tendons and to understand how elastin influence the viscoelastic properties of tendons. The right Achilles tendon was completely transected in 81 Sprague-Dawley rats. Elastin content was quantified in intact and healing tendons (7, 14, and 28days post-surgery) and elastin distribution was visualized by immunohistochemistry at 14days post-surgery. Degradation of elastin by elastase incubation was used to study the role of elastin on viscoelastic properties. Mechanical testing was either performed as a cyclic test (20× 10N) or as a creep test. We found significantly higher levels of elastin in healing tendons at all time-points compared to intact tendons (4% in healing tendons 28days post-surgery vs 2% in intact tendons). The elastin was more widely distributed throughout the extracellular matrix in the healing tendons in contrast to the intact tendon where the distribution was not so pronounced. Elastase incubation reduced the elastin levels by approximately 30% and led to a 40%-50% reduction in creep. This reduction was seen in both intact and healing tendons. Our results show that healing tendons contain more elastin and is more compliable than intact tendons. The role of elastin in tendon healing and tissue compliance indicates a protective role of elastic fibers to prevent re-injuries during early tendon healing. PLAIN LANGUAGE SUMMARY: Tendons transfer high loads from muscles to bones during locomotion. They are primarily made by the protein collagen, a protein that provide strength to the tissues. Besides collagen, tendons also contain other building blocks such as, for example, elastic fibers. Elastic fibers contain elastin and elastin is important for the extensibility of the tendon. When a tendon is injured and ruptured the tissue heals through scar formation. This scar tissue is different from a normal intact tendon and it is important to understand how the tendons heal. Little is known about the presence and function of elastin during healing of tendon injuries. We have shown, in animal experiments, that healing tendons have higher amounts of elastin compared to intact tendons. The elastin is also spread throughout the tissue. When we reduced the levels of this protein, we discovered altered mechanical properties of the tendon. The healing tendon can normally extend quite a lot, but after elastin removal this extensibility was less obvious. The ability of the healing tissue to extend is probably important to protect the tendon from re-injuries during the first months after rupture. We therefore propose that the tendons heal with a large amount of elastin to prevent re-ruptures during early locomotion.

Diagnostic accuracy of ultrasound in subscapularis tendon abnormalities and the importance of operator experience.

This study aimed to investigate the reasons behind the compliance, diagnostic success, and failure of ultrasound (US) examinations of two radiologists with reference to magnetic resonance imaging (MRI) in the abnormalities of subscapularis (SSC) tendon, including tendinosis. One less experienced radiologist (operator-1) and one senior radiologist, experienced in the musculoskeletal US (operator-2), performed the shoulder US on 78 patients (mean age: 53.18 ± 10.89 [22-73] years), who had undergone MRI for routine reasons except malignancy, within 1-4 weeks of MRI. Tendinopathy, partial (PT), or full-thickness (FT) tears were recorded in the subscapularis. The thickness of the anterior and lateral soft tissues in the shoulder girdle was measured by MRI. The inter-operator agreement on the US results, the US-MRI compliance for each operator, and the relationship between the US-MRI compliance and tissue thickness were investigated. The inter-operator agreement on the US findings was moderate. The US-MRI compliance was fair for operator-1, but substantial for operator-2. The circumferential soft tissue thickness and US-MRI compliance were not correlated (p>0.05). The interobserver agreement in US was moderate (K: 0.415). The US-MRI compliance was fair for operator-1 (K: 0.344) and substantial for operator-2 (K: 0.616). The accuracy rates for the differentiation of normal tendon, tendinosis, PT, and FT were 59%, 75%, 72%, and 100%, respectively, for operator-1 and 87%, 83%, 85%, and 100%, respectively, for operator-2. However, the respective sensitivity of operator-1 was 46%, 19%, 44%, and 100%; and operator-2 was 91%, 67%, 82%, and 100%. The diagnostic performance of operator-1 was lower, except for FT. The thickness of the surrounding tissue does not affect the US results. The differentiation between tendinosis and PT tear is difficult (more prominent in less experienced user); however, because this would not change the treatment choice, shoulder US is recommended after basic training in subscapularis pathologies. Level II, Diagnostic.

Identification of Differentially Expressed Genes Associated with Extracellular Matrix Degradation and Inflammatory Regulation in Calcific Tendinopathy Using RNA Sequencing.

Calcific tendinopathy (CT), developed due to calcium hydroxyapatite deposition in the rotator cuff tendon, mostly affects women in their 40s and 50s and causes severe shoulder pain. However, the molecular basis of its pathogenesis and appropriate treatment methods are largely unknown. In this study, we identified 202 differentially expressed genes (DEGs) between calcific and adjacent normal tendon tissues of rotator cuff using RNA sequencing-based transcriptome analysis. The DEGs were highly enriched in extracellular matrix (ECM) degradation and inflammation-related processes. Further, matrix metalloproteinase 9 (MMP9) and matrix metalloproteinase 13 (MMP13), two of the enzymes associated with ECM degradation, were found to be highly upregulated 25.85- and 19.40-fold, respectively, in the calcific tendon tissues compared to the adjacent normal tendon tissues. Histopathological analyses indicated collagen degradation and macrophage infiltration at the sites of calcific deposit in the rotator cuff tendon. Our study acts as a foundation that may help in better understanding of the pathogenesis associated with CT, and thus in better management of the disease.

Increased flexor hallucis longus tension decreases ankle dorsiflexion

BackgroundRestricted excursion of the flexor hallucis longus (FHL) is associated with several clinical problems. An FHL excursion measurement device (EMD) was used to objectively assess differences between patients with clinically normal or tight FHL tendons. Methods188 patients (356 feet) were enrolled. The EMD measured maximum ankle dorsiflexion with the great toe in 15°, 30°, and 45° of dorsiflexion. All had clinical assessment of FHL tightness by their provider independently of the EMD measurement. ResultsIncreased hallux DF always caused decreased ankle DF. Patients with clinically tight FHLs demonstrated decreased ankle DF compared to normal subjects at all hallux positions (p<0.01). The EMD measurement was not sensitive enough for detection of FHL tightness in individuals. A clinically tight FHL was seen in almost 50% of feet. ConclusionsTension in the FHL can limit ankle DF. Clinical tightness of the FHL is likely more common than currently recognized.

Ultrashort echo time (UTE) imaging reveals a shift in bound water that is sensitive to sub-clinical tendinopathy in older adults

Use ultrashort echo time (UTE) magnetic resonance imaging to quantify bound water components of asymptomatic older Achilles tendons and investigate the relationship between UTE findings and imaging assessment of sub-clinical tendinopathy. Thirteen young (age 25 ± 4.8) and thirteen older (age 67 ± 4.7) adults were tested. A UTE sequence was used to quantify the transverse relaxation times of bound ([Formula: see text]) and free ([Formula: see text]) water and the bound water fraction (Fs) in the Achilles tendon. Anatomical images were collected and graded by a musculoskeletal radiologist to identify signs of sub-clinical tendinopathy. Two-sample t tests were used to compare [Formula: see text], [Formula: see text], and Fs between age groups and between adults with and without sub-clinical tendinopathy. Older tendons exhibited a 60% longer [Formula: see text] (p = 0.004), similar [Formula: see text] (p = 0.86), and 5% smaller Fs (p = 0.048) than young tendons. Seven older adult tendons exhibited tendon thickening and increased signal intensity indicative of sub-clinical tendinopathy. This subset of tendons exhibited a 7% smaller bound water fraction (p = 0.02) and significantly longer [Formula: see text] (p < 0.001) than the normal tendons from young and older adults. Older adult tendons exhibited unique UTE signatures that are consistent with disruption of the collagen fiber network and changes in macromolecular content. UTE imaging metrics were sensitive to early indicators of tissue degeneration identified on anatomical images and hence could provide a quantitative biomarker by which to track changes in tissue health resulting from injury, disease, and treatment.

Comparison of Hands-On Versus Online Learning in Teaching Ultrasound Skills for Achilles Tendon Rupture: A Pilot Study.

IntroductionIn the emergency department, the diagnosis of an Achilles tendon rupture (ATR) is reportedly missed in greater than 20% of cases. A limited number of studies evaluate the use of cadaver models as a potential ultrasound teaching and training modality. We hypothesize that emergency medicine residents can effectively utilize point-of-care ultrasound (POCUS) on cadaver models and a focused teaching intervention to assess their ability to detect ATRs.MethodsA prospective study of 23 EM residents was performed. All participants in the study were divided into two learner groups: (a) independent and (b) hands-on. The independent learner group received a 30-minute online didactic lecture demonstrating how to diagnose ATRs. The hands-on learner group received direct instruction on cadaver lower leg models with a ruptured and normal Achilles tendon (AT). Both groups then participated in identifying either normal or ruptured ATs on six cadaver lower leg models.ResultsThe sensitivity and specificity were 89% and 82% in the independent learner group 96% and 100% in the hands-on learner group, respectively. The overall sensitivity and specificity were 91% and 88%, respectively. There was a trend toward successful identification with increased years of residency training.ConclusionsIn this study, lower leg and ankle cadaver models were found to be as effective as an independent learner model for potential POCUS teaching and training modality in both novice and more advanced trainees.

Development of a novel in vitro insulin resistance model in primary human tenocytes for diabetic tendinopathy research.

BackgroundType 2 diabetes mellitus (T2DM) had been reported to be associated with tendinopathy. However, the underlying mechanisms of diabetic tendinopathy still remain largely to be discovered. The purpose of this study was to develop insulin resistance (IR) model on primary human tenocytes (hTeno) culture with tumour necrosis factor-alpha (TNF-α) treatment to study tenocytes homeostasis as an implication for diabetic tendinopathy.MethodshTenowere isolated from human hamstring tendon. Presence of insulin receptor beta (INSR-β) on normal tendon tissues and the hTeno monolayer culture were analyzed by immunofluorescence staining. The presence of Glucose Transporter Type 1 (GLUT1) and Glucose Transporter Type 4 (GLUT4) on the hTeno monolayer culture were also analyzed by immunofluorescence staining. Primary hTeno were treated with 0.008, 0.08, 0.8 and 8.0 µM of TNF-α, with and without insulin supplement. Outcome measures include 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (2-NBDG) assay to determine the glucose uptake activity; colourimetric total collagen assay to quantify the total collagen expression levels; COL-I ELISA assay to measure the COL-I expression levels and real-time qPCR to analyze the mRNA gene expressions levels of Scleraxis (SCX), Mohawk (MKX), type I collagen (COL1A1), type III collagen (COL3A1), matrix metalloproteinases (MMP)-9 and MMP-13 in hTeno when treated with TNF-α. Apoptosis assay for hTeno induced with TNF-α was conducted using Annexin-V FITC flow cytometry analysis.ResultsImmunofluorescence imaging showed the presence of INSR-β on the hTeno in the human Achilles tendon tissues and in the hTeno in monolayer culture. GLUT1 and GLUT4 were both positively expressed in the hTeno. TNF-α significantly reduced the insulin-mediated 2-NBDG uptake in all the tested concentrations, especially at 0.008 µM. Total collagen expression levels and COL-I expression levels in hTeno were also significantly reduced in hTeno treated with 0.008 µM of TNF-α. The SCX, MKX and COL1A1 mRNA expression levels were significantly downregulated in all TNF-α treated hTeno, whereas the COL3A1, MMP-9 and MMP-13 were significantly upregulated in the TNF–α treated cells. TNF-α progressively increased the apoptotic cells at 48 and 72 h.ConclusionAt 0.008 µM of TNF-α, an IR condition was induced in hTeno, supported with the significant reduction in glucose uptake, as well as significantly reduced total collagen, specifically COL-I expression levels, downregulation of candidate tenogenic markers genes (SCX and MKX), and upregulation of ECM catabolic genes (MMP-9 and MMP-13). Development of novel IR model in hTeno provides an insight on how tendon homeostasis could be affected and can be used as a tool for further discovering the effects on downstream molecular pathways, as the implication for diabetic tendinopathy.

Efficacy of Single-Dose Radiotherapy in Preventing Posttraumatic Tendon Adhesion.

Background and AimPosttraumatic peritendinous adhesion is the greatest obstacle to achieve normal tendon function following lacerations of extrinsic flexor tendons of the hand. In this study, we aimed to evaluate whether single-dose radiotherapy (RT) has the potential to modulate intrasynovial tendon adhesions.Materials and MethodsA total of 80 tendons from the third to fourth flexor profundus of both hind paws of 20 adult New Zealand rabbits were used in this study. Rabbits in the RT group received 3 Gy of X-irradiation in a single fraction. Histopathological evaluation of longitudinal sections of tendons was made using the Tang grading system for peritendinous adhesions. Intratendinous quality of the healing tissue in the laceration zone was assessed using a modified Movin scale.ResultsAdhesion and inflammatory response were greater in the RT group (p˂0.001). Tendon healing in the radiation group was found to be more uniform and organized compared with the control group. However, this difference was not statistically significant. The nuclei of the tenocytes in the radiation group showed a closer resemblance to normal tendon tissue when compared with the control group (p=0.007).ConclusionsDespite RT’s certain advantages such as extracorporeal use, anti-inflammatory effect, and homogenous tissue penetration, 3-Gy X-irradiation resulted in increased peritendinous posttraumatic adhesion, possibly due to dose imbalance. Increased roundness in the tenocyte nuclei was present in the RT group. Studies with different dosing regimens and a higher number of subjects are necessary to establish an ideal dose suppressing the synovial response without compromising tendon healing.

Microsurgical anatomy of the stapedius muscle in adult cadavers.

This study aimed to establish an extended morphometric dataset regarding the stapedius muscle for anatomists and otologists. The tympanic cavity of ten cadavers (five females, five males) aged with 75.70 ± 13.75years was bilaterally dissected. Morphometric properties of the stapedius muscle (i.e., its muscular belly and tendon) and its relationship with the neighborhood structures including the facial nerve was evaluated. The length of the entire stapedius muscle was found as 4.80 ± 1.13mm. The depth between the entrance of the external auditory canal and stapedius muscle was measured as 18.23 ± 2.30mm. The incudostapedial joint and stapedial tendon were found to be 1.66 ± 0.25mm and 1.18 ± 0.19mm away from the facial nerve, respectively. The stapedial tendon length was standardized as five types: Type 1, extremely short tendon (under 0.5mm), 5% of cases; Type 2, short tendon (between 0.5 and 1mm), 30% of cases; Type 3, normal tendon (between 1 and 2mm), 55% of cases; Type 4, long tendon (between 2 and 2.5mm), 10% of cases; and Type 5, extremely long tendon (above 2.5mm), no cases. Our findings showed that the stapedius tendon size in adults was quite similar to fetuses. Therefore, probably entire muscle dimension does not alter after birth. Considering the concordance between direct anatomic (our findings) and radiologic measurements (literature findings) of the stapedius muscle, preoperative radiological evaluation may be important for otologists in terms of the choice of surgical tools such as diamond burr sizes. Due to the lack of standardization regarding the evaluation of the stapedius tendon size (i.e., extremely short or extremely long), we defined the tendons below 0.5mm as extremely short (Type 1) and above 2.5mm as extremely long (Type 5).

Circular RNA expression pattern and competing endogenous RNA network involved in rotator cuff tendinopathy

To detect the differentially expressed circular RNA (circRNA) in rotator cuff tendinopathy and analyze the potential molecular mechanism of these parental genes. Ten supraspinatus tendons donated from patients who underwent tendon repair surgery between June 2018 and June 2019 were used for RNA-sequence. All rotator cuff tendinopathy and normal tendon samples were confirmed by MRI, histological staining, and observation by arthroscopy. All pathological tendons were matched with tendon samples for patients' age, gender, body mass index, and Bonar score. The bioinformatic analysis was performed based on the differentially expressed circRNA and their parental genes, including gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and competing endogenous RNA (ceRNA) network construction. There were 94 differentially expressed circRNAs, including 31 up-regulated and 63 down-regulated, detected between the rotator cuff tendinopathy and normal tendon samples with |log2 fold change (FC)| >2, P<0.05. GO analysis showed that the genes were mostly enriched in response to cyclic adenosine monophosphate (cAMP). KEGG pathway analysis showed that the most genes were enriched in extracellular matrix-receptor interaction, protein digestion and absorption, cell cycle, and nuclear factor κB signaling pathway. ceRNA networks showed the interactions among circRNAs, mRNAs, and miRNAs. And circRNA.8951-has-miR-6089-DNMT3B was the most sum max energy. This bioinformatic study reveals several potential therapeutic targets for rotator cuff tendinopathy, which paves the way to better treatment and prevention of this disorder.

Prospective study of 80 volar wounds of the hand and wrist: Correlations between clinical examination and intraoperative findings

Hand and wrist volar wounds are a common cause of emergency room (ER) visits. These wounds are explored surgically in the operating room at most hospitals. The main objective of our study was to prospectively assess the correlation between clinical examination in the ER performed by a surgical resident and the tendon, vascular and/or nerve damage found during surgery in hand and wrist volar wounds. The second objective was to describe the lesions based on their mechanism, as well as their topography. Eighty patients from two hand surgery referral centers were included. Patients’ past medical history was obtained, as well as records of their physical examination in the ER and description of lesions found during surgery. In 28% of wounds with a normal clinical examination, tendon, vascular or nerve damage was found on surgical exploration. Out of the cases that tested negative for tendon injury in the ER, 16% had partial tendon injury or digital tunnel wound discovered during surgery. Nerve damage was found during surgery in 12% of cases that had not been detected clinically preoperatively. Based on our findings, we recommend performing surgical exploration for all volar hand and wrist wounds in the operating room, as physical examination does not detect all tendons, vascular or nerve injuries.

Flatfoot Deformity Due to Isolated Spring Ligament Injury

Patients with acquired flatfoot deformity due to isolated injury of the spring ligament, with healthy posterior tibialis tendon, are rarely identified. Between December 2004 and September 2011 (6 years and 9 months), we treated 10 patients with acquired flatfoot deformity due to spring ligament injury without tibialis posterior tendon tear. One patient (10%) was lost to follow-up. The mean age of the patients was 44.33 ± 12.91 years; 4 (44.4%) were female, and 5 (55.56%) were male. Clinical presentation included mild to moderate hindfoot valgus and pain extending from the inferior part of the medial malleolus to the navicular, inferior to tibialis posterior. Forefoot abduction was not always present. Weightbearing radiographs and magnetic resonance imaging (MRI) scans were obtained in all cases. Six patients (66.66%) of the patients had a history of minor trauma. Spring ligament repair was performed in all cases, and 4 patients (44.44%) underwent adjunct procedures. After surgery, a cast was applied, and weightbearing was avoided for 6 weeks. The mean preoperative American Orthopaedic Foot and Ankle Society (AOFAS) score was 39.66 ± 18.55, and this improved to 84.88 ± 12.41 after surgery (p = .023). No statistically significant differences were found between males and females or between isolated repairs and adjunct procedures. The mean duration of follow-up was 45.33 ± 37.11 months (range 15 to 120), and no complications were identified. Isolated injuries of the spring ligament with normal posterior tibialis tendon are rarely described and may be more prevalent than generally appreciated.