Tendon Complex Research Articles

Percutaneous repair of the Achilles tendon with one knot offers equivalent results as the same procedure with two knots. A comparative prospective study.

The present prospective comparative study included patients with acute Achilles tendon rupture (ATR) who underwent percutaneous repair with one knot compared to percutaneous repair with two knots. All patients underwent the procedure under local anesthesia. A total of 29 patients underwent percutaneous repair with two knots (Group A), and 33 patients underwent percutaneous repair with one knot (Group B). All patients were treated by a single surgeon between 2019 and 2021 and were followed prospectively for 24months. Patients' characteristics at baseline were similar between the two groups, except for age [38.0(15.0) vs 32.0(15.0) years, P = 0.028]. The procedure took longer for the two knots technique [19.0(4.0) vs 13.0(3.0) min, P < 0.001]. The Achilles tendon total rupture score was not different between the two techniques (90.7 ± 3.26 vs 90.5 ± 2.18, P = 0.737), as was the elongation of the gastrosoleus-Achilles tendon complex measured by the Achilles tendon resting angle [-1.0(2.0) vs - 1.0(2.0), P < 0.380]. The calf circumference of the injured and non-injured leg did not differ between the groups. Plantarflexion strength of the operated leg was significantly weaker than the non-operated leg in both groups. The European Foot and Ankle Society and patient reported outcome measures score by Piedade etal. scores were not statistically significant different between the two groups. No patient experienced a re-rupture, a venous thrombo-embolism episode, or injury to the sural nerve. The modified technique offered similar objective and subjective outcome measures, in addition to reduced operative time.

Direct Anatomical Reconstruction of the Achilles Tendon and Its Application for Surgical Treatment of Acute Achilles Tendon Ruptures

Background/Objectives: Acute ruptures of the Achilles Tendon (AT) are common injuries in the active population, in particular among men aged 30 to 50. Full functional recovery after this kind of injury is long and challenging and nowadays there is no universal “gold standard” strategy when dealing with them. Methods: When it comes to surgical treatment, various techniques have been described: in case of a typical lesion at the midportion of the tendon (which is the most common type), the basic principle of surgical repair is the end-to-end suture of the tendon stumps. The AT (“calcaneal tendon” according to the International Anatomical Terminology) is the strongest tendon of the human body, it is the conjunct tendon of the two Gastrocnemii Muscles and the Soleus Muscle and has a well-recognizable twisted structure: the subtendon from the Medial Head of the Gastrocnemius attaches postero-laterally on the calcaneal tendon footprint, the subtendon from the Lateral Head of the Gastrocnemius attaches antero-laterally and the subtendon from the Soleus attaches medially, therefore creating a 90° twist of the tendon structure. Results: the twisted structure of the human AT is of central importance to its biomechanics, since it gives the tendon a higher resistance to deformation and concurs in supination of the subtalar joint during gait. Conclusions: given the abovementioned anatomical and biomechanical premises, we believe that the restoration of the subtendons anatomy can lead to a better functional recovery of the Triceps Surae—Achilles Tendon complex, therefore we recently decided to adopt for open surgical repair the Direct Anatomical Reconstruction of the Achilles Tendon, which we describe in the present article.

The Effect of Anesthesia on Passive Ankle Dorsiflexion.

Equinus contractures can commonly be due to contractures of gastrocnemius muscle or combined contractures of the gastrocnemius-soleus Achilles tendon complex. The decision to release part or all of the gastrocnemius-soleus Achilles tendon complex is often assessed intraoperatively while the patient is under anesthesia. It remains unknown whether the administration of general anesthesia affects the measurement of passive ankle dorsiflexion. The unaffected, nonoperative limb on 46 foot and ankle patients underwent a Silfverskiold test measuring passive ankle dorsiflexion preoperatively and intraoperatively after administration of general anesthesia using an instrumented force-angular displacement goniometer. To determine clinical significance, we surveyed experienced surgeons to estimate the perceived minimally detectable clinical accuracy for measuring passive ankle dorsiflexion. Forty-six subjects were included with mean age of 42 ± 14.8 years, mean body mass index of 26.2 ± 4.9, and 52% female. The mean change in dorsiflexion values from before anesthesia to after the administration of general anesthesia was 1.9 degrees with 10 lb of pressure with knee extended (E10), 2.3 degrees with 20 lb of pressure with knee extended (E20), 2.8 degrees with 10 lb of pressure with knee flexed (F10), and 2.3 degrees with 20 lb of pressure with knee flexed (F20) (all P < .001). Thirty-three of 45 (73%) surgeons responded to the survey; all thought their minimally detectable clinical accuracy was 5 degrees or greater. After the administration of general anesthesia, a small but likely not clinically detectable increase in passive ankle dorsiflexion occurs. The common clinical practice of making intraoperative treatment decisions regarding the presence of a gastrocnemius-soleus driven equinus contractures after general anesthesia without use of paralytic agents appears reasonable given the magnitude of the changes identified in this study.

Enhancing tendon-bone integration and healing with advanced multi-layer nanofiber-reinforced 3D scaffolds for acellular tendon complexes

Advancements in tissue engineering are crucial for successfully healing tendon-bone connections, especially in situations like anterior cruciate ligament (ACL) restoration. This study presents a new and innovative three-dimensional scaffold, reinforced with nanofibers, that is specifically intended for acellular tendon complexes. The scaffold consists of a distinct layered arrangement comprising an acellular tendon core, a middle layer of polyurethane/type I collagen (PU/Col I) yarn, and an outside layer of poly (L-lactic acid)/bioactive glass (PLLA/BG) nanofiber membrane. Every layer is designed to fulfill specific yet harmonious purposes. The acellular tendon core is a solid structural base and a favorable environment for tendon cell functions, resulting in considerable tensile strength. The central PU/Col I yarn layer is vital in promoting the tendinogenic differentiation of stem cells derived from tendons and increasing the expression of critical tendinogenic factors. The external PLLA/BG nanofiber membrane fosters the process of bone marrow mesenchymal stem cells differentiating into bone cells and enhances the expression of markers associated with bone formation. Our scaffold's biocompatibility and multi-functional design were confirmed through extensive in vivo evaluations, such as histological staining and biomechanical analyses. These assessments combined showed notable enhancements in ACL repair and healing. This study emphasizes the promise of multi-layered nanofiber scaffolds in orthopedic tissue engineering and also introduces new possibilities for the creation of improved materials for regenerating the tendon-bone interface.

Enhancing prediction of supraspinatus/infraspinatus tendon complex injuries through integration of deep visual features and clinical information: a multicenter two-round assessment study

ObjectiveDevelop and evaluate an ensemble clinical machine learning–deep learning (CML-DL) model integrating deep visual features and clinical data to improve the prediction of supraspinatus/infraspinatus tendon complex (SITC) injuries.MethodsPatients with suspected SITC injuries were retrospectively recruited from two hospitals, with clinical data and shoulder x-ray radiographs collected. An ensemble CML-DL model was developed for diagnosing normal or insignificant rotator cuff abnormality (NIRCA) and significant rotator cuff tear (SRCT). All patients suspected with SRCT were confirmed by arthroscopy examination. The model’s performance was evaluated using sensitivity, specificity, accuracy, and area under the curve (AUC) metrics, and a two-round assessment was conducted to authenticate its clinical applicability.ResultsA total of 974 patients were divided into three cohorts: the training cohort (n = 828), the internal validation cohort (n = 89), and the external validation cohort (n = 57). The CML-DL model, which integrates clinical and deep visual features, demonstrated superior performance compared to individual models of either type. The model’s sensitivity, specificity, accuracy, and area under curve (95% confidence interval) were 0.880, 0.812, 0.836, and 0.902 (0.858–0.947), respectively. The CML-DL model exhibited higher sensitivity and specificity compared to or on par with the physicians in all validation cohorts. Furthermore, the assistance of the ensemble CML-DL model resulted in a significant improvement in sensitivity for junior physicians in all validation cohorts, without any reduction in specificity.ConclusionsThe ensembled CML-DL model provides a solution to help physicians improve the diagnosis performance of SITC injury, especially for junior physicians with limited expertise.Critical relevance statementThe ensembled clinical machine learning–deep learning (CML-DL) model integrating deep visual features and clinical data provides a superior performance in the diagnosis of supraspinatus/infraspinatus tendon complex (SITC) injuries, particularly for junior physicians with limited expertise.Key points1. Integrating clinical and deep visual features improves diagnosing SITC injuries.2. Ensemble CML-DL model validated for clinical use in two-round assessment.3. Ensemble model boosts sensitivity in SITC injury diagnosis for junior physicians.Graphical

Achilles tendon rupture prevention in physical activity and sports: predisposition factors

Objective: to summarize all clinically significant factors determining the Achilles tendon predisposition to rupture.Materials and methods: the basis of this scientific-analytical review was the analysis of data from the electronic portals PubMed-NCBI, Google Academy, and “Scientific electronic e-Library.ru”.Results: the presented literature review indicates that injuries and ruptures of the Achilles tendon can be provoked by numerous factors, among which genetic predisposition, individual anatomico-morphological features of the tendon complex structure, initial connective tissue failure, pathological changes in the Achilles tendon structure itself, foot and ankle deformities are of great importance. Men are more susceptible to this injury. Tendon injuries are most common either in 30–40 years, or in the period from 60 to 80 years. Professional athletes and people who lead sedentary lifestyles and do not exercise properly are at risk of Achilles tendon ruptures. Concomitant metabolic disorders and use of some medications also play an important role in the predisposition to this injury. Local corticosteroid injections pose a particular tendon rupture risk. The combination of several established factors significantly increases the likelihood of this emergency.Conclusions: early detection of predisposition to Achilles tendon rupture will allow timely development of effective measures for its prevention in physical training and sports.

The Incidence of Iliopsoas Tendinopathy and Labral Tears on High Resolution MRI, An Observational Study

Introduction. Labral tears (LT) can present with hip or groin pain. Investigation of LT is typically with Magnetic Resonance Arthrography (MRA). The injection of contrast for MRA can lead to fluid signal intensity/oedema on fluid sensitive sequences within the iliopsoas muscle and tendon complex masking the diagnosis of iliopsoas tendinopathy, which may present with similar symptoms. The aim of this study was to identify the presence of iliopsoas oedema in young adult patients being investigated for LT.Material and methods. We performed a retrospective search of our radiology system for the word ‘labral tear’ in the reports of patients who had MRI between 2012 to 2018. Patients under the age of 40 years who underwent high resolution dedicated hip MRI were included in our study. From this database, we then used a keyword search ‘strain and (o)edema’ to identify cases of iliopsoas pathology and analysed the results. Results. We identified 1151 consecutive cases of high resolution hip MRI with a suspected labral tear. 503 patients under the age of 40 years were included in our study with the average age of 27 years. Of the 503 patients within our cohort, searching for the word ‘strain’ identified 48 (9.5%) cases. Of these, 26 (5.3%) patients had iliopsoas oedema with a labral tear. 22 (4.4%) patients had iliopsoas oedema without a labral tear. Conclusion. Our study shows that 4.4% of patients undergoing MRA have no labral tears but iliopsoas oedema. Patients should undergo MRI to exclude iliopsoas strains before MRA.

Curvature of gastrocnemius muscle fascicles as function of muscle-tendon complex length and contraction in humans.

It has been shown that muscle fascicle curvature increases with increasing contraction level and decreasing muscle-tendon complex length. The analyses were done with limited examination windows concerning contraction level, muscle-tendon complex length, and/or intramuscular position of ultrasound imaging. With this study we aimed to investigate the correlation between fascicle arching and contraction, muscle-tendon complex length and their associated architectural parameters in gastrocnemius muscles to develop hypotheses concerning the fundamental mechanism of fascicle curving. Twelve participants were tested in five different positions (90°/105°*, 90°/90°*, 135°/90°*, 170°/90°*, and 170°/75°*; *knee/ankle angle). They performed isometric contractions at four different contraction levels (5%, 25%, 50%, and 75% of maximum voluntary contraction) in each position. Panoramic ultrasound images of gastrocnemius muscles were collected at rest and during constant contraction. Aponeuroses and fascicles were tracked in all ultrasound images and the parameters fascicle curvature, muscle-tendon complex strain, contraction level, pennation angle, fascicle length, fascicle strain, intramuscular position, sex and age group were analyzed by linear mixed effect models. Mean fascicle curvature of the medial gastrocnemius increased with contraction level (+5 m-1 from 0% to 100%; p = 0.006). Muscle-tendon complex length had no significant impact on mean fascicle curvature. Mean pennation angle (2.2 m-1 per 10°; p < 0.001), inverse mean fascicle length (20 m-1 per cm-1 ; p = 0.003), and mean fascicle strain (-0.07 m-1 per +10%; p = 0.004) correlated with mean fascicle curvature. Evidence has also been found for intermuscular, intramuscular, and sex-specific intramuscular differences of fascicle curving. Pennation angle and the inverse fascicle length show the highest predictive capacities for fascicle curving. Due to the strong correlations between pennation angle and fascicle curvature and the intramuscular pattern of curving we suggest for future studies to examine correlations between fascicle curvature and intramuscular fluid pressure.

Internal Structural Connections in the Popliteus Tendon Complex with Posterior Cruciate Ligament and Clinical Implications

Internal Structural Connections in the Popliteus Tendon Complex with Posterior Cruciate Ligament and Clinical Implications

Menstrual Blood–Derived Mesenchymal Stem Cells Encapsulated in Autologous Platelet-Rich Gel Facilitate Rotator Cuff Healing in a Rabbit Model of Chronic Tears

Background: Successful management of chronic rotator cuff (RC) tears remains a challenge owing to its limited intrinsic healing capacity and unsatisfactory failure rate. Menstrual blood–derived mesenchymal stem cells (MenSCs) have the potential to differentiate into the chondrogenic or osteogenic lineage. Autologous platelet-rich gel (APG), a gel material derived from platelet-rich plasma (PRP), can be applied as a carrier system for cell delivery and also as a releasing system for endogenous growth factors. Purpose: To investigate the effect of human MenSCs encapsulated in APG (MenSCs@APG) on the healing of chronic RC tears in a rabbit model. Study Design: Controlled laboratory study. Methods: After evaluation of the effect of PRP on MenSC proliferation or differentiation, the stem cells were encapsulated in APG for in vivo injection. Supraspinatus tenotomy from the right greater tuberosity was performed on 45 New Zealand White rabbits. After 6 weeks, these rabbits were randomly allocated to 3 supplemental treatments during supraspinatus repair: saline injection (control [CTL] group), APG injection (APG group), and MenSCs@APG injection (MenSCs@APG group). At week 18, these rabbits were sacrificed to harvest the humerus–supraspinatus tendon complexes for micro–computed tomography (CT), histological evaluation, tensile test, and MenSC tracking. Results: In vitro results showed that APG can stimulate MenSC proliferation and enhance chondrogenic or osteogenic differentiation. In vivo results showed that APG can act as a carrier for delivering MenSCs into the healing site, and also as a stimulator for enhancing the in vivo performance of MenSCs. Micro-CT showed that bone volume/total volume and trabecular thickness of the new bone in the MenSCs@APG group presented significantly larger values than those of the APG or CTL group (P < .05 for all). Histologically, compared with the CTL or APG group, significantly more mature fibrocartilage regenerated at the healing site in the MenSCs@APG group. A large number of human nuclei–stained cells were observed in the MenSCs@APG group, presenting a similar appearance to fibrochondrocytes or osteocytes. Biomechanically, the MenSCs@APG group showed significantly higher failure load and stiffness than the APG or CTL group (P < .05 for all). Conclusion: Human MenSCs@APG facilitated RC healing in a rabbit model of chronic tears. Clinical Relevance: Autogenous MenSCs@APG may be a new stem cell–based therapy for augmenting RC healing in the clinic.

Effects of daily static stretch training over 6 weeks on maximal strength, muscle thickness, contraction properties, and flexibility.

Static stretch training (SST) with long stretching durations seems to be sufficient to increase flexibility, maximum strength (MSt) and muscle thickness (MTh). However, changes in contraction properties and effects on muscle damage remain unclear. Consequently, the objective of the study was to investigate the effects of a 6-week self-performed SST on MSt, MTh, contractile properties, flexibility, and acute response of creatine kinase (CK) 3 days after SST. Forty-four participants were divided into a control (CG, n = 22) and an intervention group (IG, n = 22), who performed a daily SST for 5 min for the lower limb muscle group. While isometric MSt was measured in leg press, MTh was examined via sonography and flexibility by functional tests. Muscle stiffness and contraction time were measured by tensiomyography on the rectus femoris. Additionally, capillary blood samples were taken in the pretest and in the first 3 days after starting SST to measure CK. A significant increase was found for MSt (p < 0.001, η 2 = 0.195) and flexibility in all functional tests (p < 0.001, η 2 > 0.310). Scheffé post hoc test did not show significant differences between the rectus femoris muscle inter- and intragroup comparisons for MTh nor for muscle stiffness and contraction time (p > 0.05, η 2 < 0.100). Moreover, CK was not significantly different between IG and CG with p > 0.05, η 2 = 0.032. In conclusion, the increase in MSt cannot be exclusively explained by muscular hypertrophy or the increased CK-related repair mechanism after acute stretching. Rather, neuronal adaptations have to be considered. Furthermore, daily 5-min SST over 6 weeks does not seem sufficient to change muscle stiffness or contraction time. Increases in flexibility tests could be attributed to a stretch-induced change in the muscle-tendon complex.

The Effects of Downhill Running and Maturation on Histological and Morphological Properties of Tendon and Enthesis in Mice.

To date, it remains unclear how overuse affects the tendons and entheses at different stages of maturation. Therefore, we evaluated histological and morphological changes in the tendons and entheses in adolescent (4-week-old) and adult mice (8-week-old) by performing flat-land and downhill running exercises. The mice were divided into the Sedentary, High Flat (flat-land high-speed running; concentric-contraction exercise), Low Down (downhill low-speed running; eccentric-contraction exercise), and High Down (downhill high-speed running; eccentric-contraction exercise) groups. Histological changes and inflammatory factor expressions were compared in the entheses and tendons after 4 weeks of exercise. Downhill, but not flat-land high-speed running, induced muscle-tendon complex hypertrophy in both adolescent and adult mice. Histological enthesis changes were induced in both groups during downhill running but were less pronounced in adult mice. Conversely, no significant cell aggregation or fiber orientation changes were observed in the tendon, but increased inflammatory factors were observed in both groups, with significantly higher expression in the tendons of adult mice. Downhill running induced histological and morphological enthesis changes and inflammatory factor increase in the tendons, regardless of running speed variations. These results may help elucidate the pathogenesis of enthesopathy and tendinopathy, which have different pathophysiologies despite having the same pathogenetic factors.

Biomechanical changes in the gastrocnemius medius-Achilles tendon complex in people with hypermobility spectrum disorders: A cross-sectional compression sonoelastography study.

This study aimed to assess the biomechanical impact of Hypermobility Spectrum Disorders (HSD) on the elasticity of the gastrocnemius medius-Achilles tendon (GM-AT) complex. Using a cross-sectional design, the GM-AT complex elasticity was compared using sonoelastography (SEG) in an HSD group and healthy controls during rest and maximal isometric plantar flexion contraction. The HSD group comprised 28 patients (26 women); mean ± SD age 28.7 ± 8.4 years, compared to 28 controls (26 women); 31.5 ± 8.7 years. During rest, greater elasticity was identified in HSD relative to controls at the GM-AT musculotendinous junction (strain ratio 2.05 ± 1.31 vs. 1.48 ± 0.49), mid-AT (3.60 ± 1.97 vs. 2.66 ± 1.00), and distal AT (4.57 ± 2.69 vs. 3.22 ± 1.94) (all p < 0.05). During contraction, no significant differences were found between groups at the GM-AT musculotendinous junction (3.40 ± 2.16 vs. 2.62 ± 1.07), mid AT (10.75 ± 5.29 vs. 8.49 ± 3.53), or distal AT (8.55 ± 5.39 vs. 8.83 ± 3.51) (all p > 0.05). No significant differences were found between groups in the GM strain ratio during rest (4.05 ± 1.43 vs. 3.62 ± 0.78), or contraction (4.23 ± 1.29 vs. 4.19 ± 1.31). Exploratory Receiver Operator Characteristics curve analysis suggested low sensitivity and specificity of the strain ratio for the diagnosis of HSD. People with HSD have greater GM-AT complex elasticity. Although statistically significant group differences were identified, further research is required to establish the diagnostic, clinical, and research utility of strain ratio measurements.

Primary augmentation of percutaneous repair with flexor hallucis longus tendon for Achilles tendon ruptures reduces tendon elongation andmay improve functional outcome.

Achilles tendon ruptures (ATR) result in loss of strength and function of the gastrosoleus-Achilles tendon complex, probably because of gradual tendon elongation and calf muscle atrophy, even after surgical repair. Flexor hallucis longus (FHL) augmentation not only reinforces the repair and provides new blood supply to the tendon, but also protects the repair, internally splinting the repaired Achilles tendon, maintaining optimal tension. We prospectively compared the clinical outcomes of patients with acute ATR, managed with either percutaneous repair only or percutaneous repair and FHL augmentation. Patients with acute ATR undergoing operative management were divided into two groups. Thirty patients underwent percutaneous repair under local anesthesia, and 32 patients underwent percutaneous repair augmented by FHL tendon, harvested through a 3cm longitudinal posteromedial incision, and transferred to the calcaneus, under epidural anesthesia. All patients were treated by a single surgeon between 2015 and 2019 and were followed prospectively for 24months. The percutaneous only group was younger than the augmented one (35.4 ± 8.0 vs 40.4 ± 6.6years, p = 0.01). In the augmented group, 25 patients stayed overnight and only 5 were day cases, whereas in the percutaneous only group 4 patients stayed overnight and 28 of them were day cases (p < 0.001). The duration of the procedure was significantly longer in the augmented group (38.9 ± 5.2 vs 13.2 ± 2.2min, p < 0.001). At 24months after repair, the Achilles tendon resting angle (ATRA) was better in the augmented group (-0.5 ± 1.7 vs -4.0 ± 2.7, p < 0.001), as was Achilles tendon rupture score (ATRS) (91.7 ± 2.2 vs 89.9 ± 2.4, p = 0.004). Calf circumference of the injured and the non-injured leg did not differ between the groups, as did the time interval to single toe raise and the time interval to walking in tiptoes. Although plantarflexion strength of the operated leg was significantly weaker than the non-operated leg in both groups, the difference in isometric strength of the operated leg between the groups was not significant at 24months (435 ± 37.9 vs 436 ± 39.7N, n.s.). Percutaneous repair and FHL tendon augmentation may have a place in the management of acute Achilles tendon ruptures, reducing tendon elongation and improving functional outcome. Level II.

Satisfactory functional and structural outcomes of anterior cable reconstruction using the proximal biceps tendon for large retracted rotator cuff tears.

Large retracted anterior L-shaped tear characterized by a retracted supraspinatus tendon to the glenoid level combined with a relatively preserved infraspinatus tendon is one of the challenging tear patterns in achieving complete repair to the anatomic footprint. The purpose of this study was to evaluate clinical outcomes and tendon integrity of rotator cuff repair combined with anterior cable reconstruction using the proximal biceps tendon in patients with large retracted anterior L-shaped rotator cuff tear. This study prospectively enrolled patients who underwent arthroscopic anterior cable reconstruction using the proximal biceps tendon for large retracted anterior L-shaped rotator cuff tears between 2018 and 2020 with a minimum 2-year follow-up. The anterior portion of the rotator cable was reconstructed using tenotomized proximal biceps tendon fixed with two suture anchors at the footprint. The retracted supraspinatus tendon was repaired on the biceps tendon without undue tension. The proximal portion of the infraspinatus tendon was repaired with the biceps tendon-supraspinatus tendon complex. Clinical outcomes was assessed during the follow-up period. Tendon integrity and retear size were evaluated by postoperative MRI. A total of 32 consecutive patients were included. The ASES score was significantly improved from 66.6 ± 16.6 preoperatively to 94.1 ± 6.1 postoperatively (P < 0.001), and the VAS for pain was significantly relieved from 2.8 ± 1.9 preoperatively to 0.5 ± 0.4 postoperatively (P < 0.001). All patients were satisfied postoperatively regardless of tendon integrity (P = 0.015). Postoperative ROM was increased continuously during the follow-up period (P < 0.001). The Popeye sign was found in 4 patients (12.5%). Six patients (18.7%) had rotator cuff retears. However, the ASES score of patients with retear was significantly improved from 72.8 ± 13.3 preoperatively to 91.1 ± 6.7 postoperatively (P < 0.001). Relative changes in the retear size compared with the primary tear size were -56.8 ± 14.4% for the anteroposterior diameter and - 70.6 ± 6.1% for the mediolateral diameter. Rotator cuff repair combined with anterior cable reconstruction using the proximal biceps tendon provided satisfactory clinical and radiological outcomes for large retracted anterior L-shaped tears. Anterior cable reconstruction using the proximal biceps tendon is a sound surgical option for the patients with large retracted anterior rotator cuff tear. IV.

Isolated bursal-side infraspinatus tear diagnosed by computed tomography bursography: a case series

BackgroundPartial-thickness rotator cuff tears are commonly found in the articular-side tendon of the supraspinatus; however, isolated lesions, except those occurring in the supraspinatus tendons, are rare. We report three cases of isolated bursal-side infraspinatus tears that were difficult to detect by magnetic resonance imaging but could be visualized by computed tomography bursography.Case presentationThree Asian patients (59–71 years old) with shoulder pain ranging from 1 month to 3 years in duration were each diagnosed with shoulder impingement syndrome. Magnetic resonance imaging studies failed to show a tear of the rotator cuff tendon complex. However, computed tomography bursography showed a longitudinal infraspinatus partial-thickness tear on the bursal side in each case. Arthroscopic decompression of the subacromial space and debridement of the infraspinatus tendon tear successfully alleviated the shoulder pain in two of the three patients; the third patient did not undergo surgery and remained symptomatic at follow-up.ConclusionsIn patients with chronic shoulder pain but normal magnetic resonance imaging findings, computed tomography bursography should be considered, as bursal-side infraspinatus tears may be found in these patients. Furthermore, our findings provide a basis for larger studies to further establish the accuracy of computed tomography bursography for these lesions.

Degradable magnesium alloy suture promotes fibrocartilaginous interface regeneration in a rat rotator cuff transosseous repair model

Despite transosseous rotator cuff tear repair using sutures is widely accepted for tendon-bone fixation, the fibrocartilaginous enthesis regeneration is still hardly achieved with the traditional sutures. In the present work, degradable magnesium (Mg) alloy wire was applied to suture supraspinatus tendon in a rat acute rotator cuff tear model with Vicryl Plus 4–0 absorbable suture as control. The shoulder joint humerus-supraspinatus tendon complex specimens were retrieved at 4, 8, and 12 weeks after operation. The Mg alloy suture groups showed better biomechanical properties in terms of ultimate load to failure. Gross observation showed that hyperplastic response of the scar tissue at the tendon-bone interface is progressively alleviated over time in the both Mg alloy suture and Vicryl suture groups. In the histological analysis, for Mg alloy suture groups, chondrocytes appear to proliferate at 4 weeks postoperatively, and the tendon-bone interface showed an orderly structural transition zone at 8 weeks postoperatively. The collagenous fiber tended to be aligned and the tendon-bone interlocking structures apparently formed, where transitional structure from unmineralized fibrocartilage to mineralized fibrocartilage was closer to the native fibrocartilaginous enthesis. In vivo degradation of the magnesium alloy wire was completed within 12 weeks. The results indicated that Mg alloy wire was promising as degradable suture with the potential to promotes fibrocartilaginous interface regeneration in rotator cuff repair.

A Simple Model to Predict Loads within Muscle-Tendon Complexes of the Shoulder during Fast Motions

The load scenario within the shoulder joint among its muscle–tendon complexes during fast motions is of interest, as it would allow an evaluation of critical, accident-like motions. To enhance knowledge, a modelling approach was carried out and compared to experimental data. Nine subjects were investigated while performing tasks that ranged from easy to demanding. Motions were (1) an easy lift of a small weight, (2) a push against a force measurement device, and (3) a gentle side fall against the immovable force measurement device. Extracted data were the kinematics of the right arm and the contact force on the elbow. A simple direct dynamics shoulder model actuated by Hill-type muscle models was arranged to simulate the three experimental motions. The Hatze-based activation of the muscle models was used without any further simulation of neural regulation. For fast motions, the simple shoulder model predicts well the shoulder angle or contact force values, and data fit well into the variability of the data measured experimentally. Because there was no implementation of more complex neural regulation, slow motions, as performed by the subjects, were, in part, not predicted by the shoulder model. Simple mechanisms can be described by the simple model: When activated, the larger deltoid muscle is able to protect the smaller supraspinatus muscle. Furthermore, in awkward conditions, the gentle side fall against an immovable device alone has enough momentum to damage small muscles.

The effect of combined action observation therapy and eccentric exercises in the treatment of mid-portion Achilles tendinopathy: study protocol for a feasibility pilot randomised controlled trial

BackgroundMid-portion Achilles tendinopathy (AT) is a common overuse injury which can be difficult to successfully rehabilitate. Whilst peripherally directed treatment approaches that strengthen the Achilles tendon complex can be efficacious for some individuals, others will continue to experience long-standing pain and functional deficits. Expanding our rehabilitation approach beyond the tendon mechanical properties to include techniques which target the central neurophysiological changes which can occur in chronic injuries, including mid-portion AT, may improve our rehabilitation outcomes. Action observation therapy (AOT) is one such technique which targets central changes and can enhance motor learning. To our knowledge, there is currently no available information on the combined effect of AOT and eccentric exercises in the rehabilitation of mid-portion AT, nor understanding of the feasibility of conducting randomised controlled trials that investigate this combined centrally and peripherally directed treatment approach. This protocol outlines the design of a remotely conducted parallel-group randomised controlled trial comparing the efficacy of combined AOT and eccentric loading exercises versus eccentric loading exercises alone for mid-portion AT.MethodsParticipants recruited throughout Ireland with mid-portion AT will be randomly assigned to one of the following groups: (i) The AOT group will observe videos of the eccentric exercises prior to the physical performance of the eccentric exercises. (ii) The control group will observe videos of landscapes prior to the performance of the eccentric exercises. This is a 12-week daily intervention as per the Alfredson loading protocol and outcome measures will be assessed at baseline, week 6 and week 12. Primary feasibility outcomes will include data on numbers of eligible participants, recruitment and retention rates, along with exercise compliance and acceptability of treatment. The primary clinical outcome measure will be the Victorian Institution Symptom Assessment-Achilles Questionnaire (VISA-A) assessing disability. Secondary clinical outcomes will address the remaining core domains as outlined by the International Scientific Tendinopathy Symposium consensus (ICON group) including pain, participation, functional, physical function capacity, quality of life and psychological factors. Widespread bodily pain and centralised pain features and patient satisfaction levels will also be evaluated.DiscussionThis study will provide scientific direction for future randomised controlled trials exploring the effect of AOT and eccentric exercises in the treatment of mid-portion AT on pain, centralised pain features, motor and non-motor functions, quality of life and patient satisfaction levels. The feasibility of the conducting a study remotely from participant screening to final follow-up assessment will also be provided.Trial registrationISRCTN58161116

Mesh generation and multi-scale simulation of a contracting muscle–tendon complex

The multi-scale character of skeletal muscle models requires simulations with high spatial resolution to capture all relevant effects. This naturally involves high computational load that can only be tackled by parallel computations. We simulate electrophysiology and muscle contraction using a state-of-the-art, biophysical chemo-electro-mechanical model that requires meshes of the 3D domain with embedded, aligned 1D meshes for muscle fibers. We present novel algorithms to construct highly-resolved meshes with robust properties for real muscle geometries from surface triangulations. We demonstrate their use and suitability in a simulation of the biceps brachii muscle and tendons. In addition, the respective simulations showcase several functional enhancements of our simulation framework OpenDiHu.