Biceps Research Articles

Factors associated with long head of the biceps tendon tear severity and predictive insights for grade II tears in rotator cuff surgery.

In rotator cuff repair, the long head of the biceps tendon (LHB) is commonly used as graft material. However, factors influencing LHB tear severity are poorly understood, and predicting grade II LHB tears is challenging. This study aimed to identify these factors preoperatively. The demographics, medical parameters, and pain severity of 750 patients who underwent arthroscopic surgery from January 2010 to February 2021 were evaluated to determine the factors associated with LHB tear severity and grade II tears. Both overall and largeto-massive rotator cuff tear (RCT) cohorts underwent ordinal and binary logistic regression analyses. Predictive accuracy for grade II LHB tears was determined using the area under the receiver operating characteristic curve (AUC). In the overall cohort, high-sensitivity C-reactive protein (hs-CRP) >1 mg/L (P<0.001), subscapularis tear (P<0.001), hypothyroidism (P=0.031), and the tangent sign (P=0.003) were significantly associated with LHB tear severity, and hs-CRP>1 mg/L, subscapularis tear, and Patte retraction degree were significantly associated with grade II LHB tears (P<0.001). In the large-to-massive RCT cohort, hs-CRP>1 mg/L, hypertension, and age ≥50 years (P<0.05) were significantly associated with LHB tear severity, and hs-CRP>1 mg/L (P<0.001) and hypertension (P=0.026) were significantly associated with grade II LHB tears. In both cohorts, hs-CRP >1 mg/L demonstrated good predictive accuracy for grade II LHB tears (AUCs: 0.72 and 0.70). Serum hs-CRP >1 mg/L is associated with LHB tear severity and serves as a reliable predictor of grade II LHB tears, facilitating preoperative assessment of the LHB as potential graft material in arthroscopic rotator cuff repair. Level of evidence: III.

Biceps tenotomy vs. tenodesis: an ACS-NSQIP analysis of postoperative outcomes and utilization trends

BackgroundWhile studies have assessed comparative rates of restoration of shoulder function and alleviation of symptoms, comparative systemic postoperative complication rates between biceps tenotomy and tenodesis have yet to be assessed. The purpose of the present study was to use a national administrative database to perform a comprehensive investigation into 30-day complication rates after biceps tenotomy versus tenodesis, thus providing valuable insights for informed decision-making by clinicians and patients regarding the optimal surgical approach for pathologies of the long head of the biceps tendon. MethodsThe National Surgical Quality Improvement Program (NSQIP) database was queried to analyze postoperative complication rates and metrics associated with biceps tenotomy and tenodesis. Patient data spanning from 2012-2021 were extracted with relevant variables assessed to identify and compare these two surgical approaches. Adjusted and unadjusted analyses were utilized to analyze patient demographics, comorbidities, operative times, lengths of stay, readmissions, adverse events, and yearly surgical volume, along with trends in usage, across cohorts. ResultsOf 11,527 total patients, 264 (2.29%), 6,826 (59.22%), and 4,437 (38.49%) underwent tenotomy, tenodesis with open repair, and tenodesis with arthroscopic repair, respectively. Tenotomy operative times ([mean ± SD]: 66.25 ± 44.76 minutes) were shorter than those for open tenodesis (78.83 ± 41.82) and arthroscopic tenodesis (75.98 ± 40.16). Conversely, tenotomy patients had longer hospital (0.88 ± 4.86 days) relative to open tenodesis (.08 ± 1.55) and arthroscopic tenodesis (.12 ± 2.70). Multivariable logistic regression controlling for demographics and comorbidities demonstrated that patients undergoing tenodesis were less likely to be readmitted (adjusted odds ratio [AOR]: 0.42, 95% confidence interval [CI]: 0.17-0.98, P =0.050) or sustain serious adverse events (AOR: 0.27, 95% CI: 0.13-0.57, P <.001), but equally likely to sustain minor adverse events (AOR: 0.87, CI: 0.21-3.68, P =.850), compared with patients undergoing tenotomy. Lastly, comparing utilization rates from 2012 to 2021 revealed a significant decrease in the proportion of tenotomy (from 6.2% to 1.0%) compared to open tenodesis (from 41.0% to 57.3%) and arthroscopic tenodesis (52.8% to 41.64%; Ptrend = .001). ConclusionTo our knowledge, this is the first large national database study investigating postoperative complication rates between the various surgical treatments for pathologies of the long head of the biceps tendon. Our results suggest that tenodesis yields fewer serious adverse events and lower readmission rates than tenotomy. We also found a shorter operative time for tenotomy. These findings support the increased utilization of tenodesis relative to tenotomy in recent years.

Difference in Stiffness between Biceps Brachii Muscle Bellies Using Shear Wave Elastography

The Shear Wave Elastography of muscles can provide real-time information on the stiffness of muscles; however, the difference in stiffness between biceps brachii muscle bellies requires more research. Understanding the variables that affect muscle stiffness will assist in the development of Shear Wave Elastography as a diagnostic tool for muscle stiffness pathologies. This study’s aim is to determine the Shear Wave Velocity of the short and long head of biceps brachii and the change in stiffness with elbow flexion to create a reliable protocol for pathological muscle assessment. The muscle belly of the short and long heads of bilateral biceps brachii of 38 healthy participants were scanned supine with the arm at full extension and at 30° and 60° elbow flexion. A log transform of the SWV was used as the response variable in the regression analysis, and the intraclass correlation coefficient was determined for reliability. The Shear Wave Velocity of the short head was lower than the long head on average. By fitting Bayesian mixed effect regression models to the data, the estimated posterior predictive mean velocities for the short head at full extension, 30°, and 60° were 3.14 m/s, 2.65 m/s, and 2.62 m/s, respectively; and 3.91 m/s, 3.02 m/s, and 3.15 m/s, respectively, for the long head of the biceps brachii. The intraclass correlation coefficients (0.64–0.92) were good to excellent. Shear Wave Elastography can detect the consistent difference in the stiffness of the two muscle bellies of the biceps brachii at multiple elbow angles. The assessment of muscle stiffness with Shear Wave Elastography should consider the morphology of the muscles.

Tendinopathies Associated with Statin Therapy in Patients with Dyslipidemia: Case Study Article Sidebar

Statins are considered the initial and first-line treatment in cardiovascular and atherosclerotic diseases, characterized by inhibiting HMG-CoA reductase. Some adverse effects associated with these drugs are injuries to the tendon structure including tenosynovitis, tendon and tendon rupture. The aim of this article is to evaluate the tendon structure by musculoskeletal ultrasound and to raise the question of whether chronic statin consumption in this patient with dyslipidemia is related to the appearance of tendinopathies. Methodology A cross-sectional descriptive observational study was carried out, focused on the evaluation of the incidence of tendinopathies in patients who have been using statins chronically. A case study approach was used, analysing in detail a female patient selected according to the established inclusion and exclusion criteria. The sample consisted of a patient who met the inclusion criteria: age between 45-60 years, chronic use of statins for more than 12 months, presentation of symptoms suggestive of tendinopathy. Patients with a history of musculoskeletal diseases prior to the start of treatment were excluded, and anyone with arthritis, chronic septic inflammatory processes, athletes, young patients, and those who did not want to participate in the study and did not agree to give informed consent were excluded. For data collection, 7 patients were selected, of which 1 only met the inclusion and acceptance criteria for the study, a clinical history was taken with exhaustive clinical evaluations of the selected patients, focused on the identification of tendinopathy symptoms and other possible risk factors, at the end a musculoskeletal ultrasound was carried out where possible tendon injuries were identified and characterized. evaluating tendon structure and its relationship to statin use. This methodology provides a detailed and structured approach to conducting research on the incidence of tendinopathies associated with statin use. Results During the clinical evaluation of this patient, symptoms associated with tendinopathy of the long portion of the biceps brachii on the right side were identified. The results of the musculoskeletal ultrasound confirmed the alterations in the structure of the tendon, finding tenosynovitis, significant peritendinous effusion and microruptures of the long portion of the biceps brachii not only on the affected side, but also on the contralateral side, which was asymptomatic for tendon pathology. In addition, not only was the biceps tendon modified, micro ruptures in the supraspinatus tendon and subacromial bursitis were observed. This patient had been taking atorvastatin 20mg every 24 hours in the mornings for 9 years and was not attributed with any mechanism of overuse injury that triggered multiple tendinopathies at the rotator cuff level.

The test-retest reliability of non-navigated transcranial magnetic stimulation (TMS) measures of corticospinal pathway excitability early after stroke

Purpose Motor evoked potential (MEP) characteristics are potential biomarkers of whether rehabilitation interventions drive motor recovery after stroke. The test-retest reliability of Transcranial Magnetic Stimulation (TMS) measurements in sub-acute stroke remains unclear. This study aims to determine the test-retest reliability of upper limb MEP measures elicited by non-neuronavigated transcranial magnetic stimulation in sub-acute-stroke. Methods In two identical data collection sessions, 1–3 days apart, TMS measures assessed: motor threshold (MT), amplitude, latency (MEP-L), silent period (SP), recruitment curve slope in the biceps brachii (BB), extensor carpi radialis (ECR), and abductor pollicis brevis (APB) muscles of paretic and non-paretic upper limbs. Test-retest reliability was calculated using the intra-class correlation coefficient (ICC) and 95% confidence intervals (CI). Acceptable reliability was set at a lower 95% CI of 0.70 or above. The limits of agreement (LOA) and smallest detectable change (SDC) were calculated. Results 30 participants with sub-acute stroke were included (av 36 days post stroke) reliability was variable between poor to good for the different MEP characteristics. The SDC values differed across muscles and MEP characteristics in both paretic and less paretic limbs. Conclusions The present findings indicate there is limited evidence for acceptable test-retest reliability of non-navigated TMS outcomes when using the appropriate 95% CI for ICC, SDC and LOA values. Clinical Trial Registration Current Controlled Trials: ISCRT 19090862, http://www.controlled-trials.com

High-Density Electromyography Excitation in Front vs. Back Lat Pull-Down Prime Movers.

The current study compared the spatial excitation of the primary muscles during the lat pull-down exercise with the bar passing in front (front-LPD) or behind the neck (back-LPD) using high-density electromyography. Fourteen resistance trained men performed a front-LPD or a back-LPD within a non-fatiguing set with 8-RM as the external load. The muscle excitation centroid of latissimus dorsi, middle trapezius, pectoralis major, biceps brachii, triceps brachii and posterior deltoid muscles were recorded during the ascending and the descending phase. During the descending phase, the front-LPD showed superior excitation of the latissimus dorsi (ES = 0.97) and the pectoralis major (ES = 1.17), while in the ascending phase, the back-LPD exhibited superior excitation of the latissimus dorsi (ES = 0.63), and the front-LPD showed superior excitation of the biceps brachii (ES = 0.41) and the posterior deltoid (ES = 1.77). During the descending phase, the front-LPD showed a more lateral centroid of the latissimus dorsi (ES = 0.60), the biceps brachii (ES = 0.63) and the triceps brachii (ES = 0.98), while the centroid was more medial for the middle trapezius (ES = 0.58). The centroid of the middle trapezius was also more medial in the front-LPD during the ascending phase (ES = 0.85). The pectoralis major centroid was more cranial in the front-LPD for both the descending (ES = 1.58) and the ascending phase (ES = 0.88). The front-LPD appears to provide overall greater excitation in the prime movers. However, distinct spatial excitation patterns were observed, making exercise suitable for the training routine.

The Effects of Hand Tremors on the Shooting Performance of Air Pistol Shooters with Different Skill Levels.

Physiologic hand tremors are a critical factor affecting the aim of air pistol shooters. However, the extent of the effect of hand tremors on shooting performance is unclear. In this study, we aim to explore the relationship between hand tremors and shooting performance scores as well as investigate potential links between muscle activation and hand tremors. In this study, 17 male air pistol shooters from China's national team and the Air Pistol Sports Center were divided into two groups: the elite group and the sub-elite group. Each participant completed 40 shots during the experiment, with shooters' hand tremors recorded using three-axis digital accelerometers affixed to their right hands. Muscle activation was recorded using surface electromyography on the right anterior deltoid, posterior deltoid, biceps brachii (short head), triceps brachii (long head), flexor carpi radialis, and extensor carpi radialis. Our analysis revealed weak correlations between shooting scores and hand tremor amplitude in multiple directions (middle-lateral, ML: r2 = -0.22, p < 0.001; vertical, VT: r2 = -0.25, p < 0.001), as well as between shooting scores and hand tremor complexity (ML: r2 = -0.26, p < 0.001; VT: r2 = -0.28, p < 0.001), across all participants. Notably, weak correlations between shooting scores and hand tremor amplitude (ML: r2 = -0.27, p < 0.001; VT: r2 = -0.33, p < 0.001) and complexity (ML: r2 = -0.31, p < 0.001) were observed in the elite group but not in the sub-elite group. Moderate correlation were found between the biceps brachii (short head) RMS and hand tremor amplitude in the VT and ML directions (ML: r2 = 0.49, p = 0.010; VT: r2 = 0.44, p = 0.025) in all shooters, with a moderate correlation in the ML direction in elite shooters (ML: r2 = 0.49, p = 0.034). Our results suggest that hand tremors in air pistol shooters are associated with the skill of the shooters, and muscle activation of the biceps brachii (long head) might be a factor affecting hand tremors. By balancing the agonist and antagonist muscles of the shoulder joint, shooters might potentially reduce hand tremors and improve their shooting scores.

Comparison of muscle and fat parameters measured by ultrasonography and dual-energy x-ray absorptiometry between older palliative care patients with and without type 2 diabetes mellitus.

There are limited data on the comparison of body compositions between diabetic and non-diabetic patients. We aimed to compare the muscle mass and fat parameters measured by ultrasonography (USG) and dual-energy x-ray absorptiometry (DXA) between older palliative care patients with and without type 2 diabetes mellitus (DM). We conducted a prospective, cross-sectional study. We recorded the demographics, comorbidities, blood pressures, microvascular complications, pressure injuries, ambulation and nutritional status, and laboratory parameters. We measured the handgrip strength with a hand dynamometer and anthropometric parameters. We analyzed the subcutaneous fat thickness, muscle thickness (MT), and cross-sectional area (CSA) of the rectus femoris (RF) and biceps brachii muscles by USG and the total and regional muscle mass and fat parameters by DXA. We performed a regression analysis to examine the independently associated factors of DM. We included 55 patients (mean age: 79.0 ± 8.0 years, 56.4%: female). 43.6% had type 2 DM. The patients with DM had significantly higher glucose and HbA1c levels and lower RFMT and RFCSA values than the patients without DM (p < 0.01, for all). The RFMT was independently associated with DM after adjusting age, sex, and body mass index (Odds ratio = 0.735, 95% confidence interval = 0.565-0.956, p = 0.022). Our study demonstrated that the RFMT might be associated with type 2 DM. This was the first study comparing the body compositions measured by USG and DXA between older diabetic and non-diabetic palliative patients with a wide range of laboratory evaluations. Longitudinal, multi-center studies are warranted to understand the underlying mechanisms.

Detection of pTDP-43 via routine muscle biopsy: A promising diagnostic biomarker for amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease, pathologically characterized by TDP-43 aggregates. Recent evidence has been indicated that phosphorylated TDP-43 (pTDP-43) is present not only in motor neurons but also in muscle tissues. However, it is unclear whether testing pTDP-43 aggregation in muscle tissue would assist in the diagnosis of ALS. We propose three key questions: (i) Is aggregation of pTDP-43 detectable in routine biopsied muscles? (ii) Can detection of pTDP-43 aggregation discriminate between ALS and non-ALS patients? (iii) Can pTDP-43 aggregation be observed in the early stages of ALS? We conducted a diagnostic study comprising 2 groups: an ALS group in which 18 cases underwent muscle biopsy screened from a registered ALS cohort consisting of 802 patients and a non-ALS control group, in which we randomly selected 54 muscle samples from a biospecimen bank of 684 patients. Among the 18 ALS patients, 3 patients carried pathological GGGGCC repeats in the C9ORF72 gene, 2 patients carried SOD1 mutations, and 7 patients were at an early stage with only one body region clinically affected. The pTDP-43 accumulation could be detected in routine biopsied muscles, including biceps brachii, deltoid, tibialis anterior, and quadriceps. Abnormal aggregation of pTDP-43 was present in 94.4% of ALS patients (17/18) compared to 29.6% of non-ALS controls (16/54; p < 0.001). The pTDP-43 aggregates were mainly close to the sarcolemma. Using a semi-quantified pTDP-43 aggregates score, we applied a cut-off value of 3 as a diagnostic biomarker, resulting in a sensitivity of 94.4% and a specificity of 83.3%. Moreover, we observed that accumulation of pTDP-43 occurred in muscle tissues prior to clinical symptoms and electromyographic lesions. Our study provides proof-of-concept for the detection of pTDP-43 accumulation via routine muscle biopsy which may serve as a novel biomarker for diagnosis of ALS.

Botulinum toxin A injection for post-stroke upper limb spasticity and rehabilitation practices from centers across Asian countries.

Describe real-life practice and outcomes in the management of post-stroke upper limb spasticity with botulinum toxin A (BoNT-A) in Asian settings. Subgroup analysis of a prospective, observational study (NCT01020500) of adult patients (≥18 years) with post-stroke upper limb spasticity presenting for routine spasticity management, including treatment with BoNT-A. The primary outcome was goal attainment as assessed using goal-attainment scaling (GAS). Patients baseline clinical characteristics and BoNT-A injection parameters are also described. Overall, 51 patients from Asia were enrolled. Rates of comorbid cognitive and emotional problems were relatively low. Patients tended to have more severe distal limb spasticity and to prioritize active over passive function goals. Most (94.1%) patients in the subgroup were treated with abobotulinumtoxinA. For these patients, the median total dose was 500 units, and the most frequently injected muscles were the biceps brachii (83.3%), flexor carpi radialis (72.9%), and flexor digitorum profundus (66.7%). Overall, 74.5% achieved their primary goal and the mean GAS T score after one treatment cycle was 56.0 ± 13.0, with a change from baseline of 20.9 ± 14.3 (p < 0.001). The majority (96.1%) of Asian patients were rated as having improved. In the Asian treatment setting, BoNT-A demonstrated a clinically significant effect on goal attainment for the real-life management of upper limb spasticity following stroke.

Morphological variability of the pectoralis minor muscle. Study in human fetuses

BackgroundThe pectoralis minor muscle is located in the anterior thoracic wall. Typically, is constituted by a single belly originating from the 3rd to the 5th rib and inserted into the coracoid process near the origins of the biceps brachii shorth head and of the coracobrachialis muscle. The current study, on human fetuses, aims to detect all morphological muscle variants and to create a new classification system. Material and methodsClassical dissection of the thoracic wall and the upper limb was bilaterally performed on 25 (13 male and 12 female) human formalin-fixed fetuses aged 18–38 weeks of gestation. The spontaneously aborted fetuses were donated after parental consent to the Medical University anatomy program. The pectoralis minor muscle’s morphology, the number of the muscle’s bellies, their origins, and insertions, as well as the morphometric details of each belly of the pectoralis minor, were assessed. ResultsThe pectoralis minor was bilaterally found in all fetuses (50 cases). Three types of muscle were identified based on the number of muscle bellies. In type, I (typical anatomy), were classified the cases with a single belly (in 66%). This type was divided into two subtypes (Ia and Ib). In the subtype Ia, the single belly had a typical course, and in Ib, a proximal attachment was characterized by two small bellies connecting together and creating one muscular mass. In type II, two bellies (24%), and in type III, three bellies (10%) were identified. ConclusionsPectoralis minor is morphologically variable in the number of its bellies, its course, its origins, its insertions, and the location of its proximal attachments. The most common type (typical anatomy) was the type I represented by one belly. Other identified variants in the number of bellies by the present study may be hypothetically a result of prematurely terminated embryogenesis.

Differential Modulation of Motor Unit Behavior When a Fatiguing Contraction Is Matched for Torque versus EMG.

When an isometric contraction is sustained at a submaximal torque, activation of the motoneuron pool increases, making it difficult to interpret neural excitability alterations. Thus, more recently, isometric contractions with maintained electromyographic (EMG) activity (matched-EMG) are being used to induce fatigue; however, little is known about the neurophysiological adjustments that occur to satisfy the requirements of the task. For our study, 16 participants performed a 10-min sustained isometric elbow flexion contraction at 20% maximal voluntary contraction (MVC) torque or the level of integrated biceps brachii EMG recorded at 20% MVC torque. Surface EMG was used to assess global median frequency, and four fine-wire electrode pairs were used to obtain motor unit (MU) discharge rate from biceps brachii. Torque or EMG steadiness was also assessed throughout the fatiguing contractions. MU discharge rate increased and torque steadiness decreased during the matched-torque contraction; however, MU discharge rate decreased during the matched-EMG contraction, and no changes occurred for EMG steadiness. Data pooled for the two contractions revealed a decrease in global median frequency. Lastly, a greater loss of MVC torque was observed immediately after the matched-torque compared with matched-EMG contraction. These findings indicate that, during a matched-torque fatiguing contraction, the nervous system increases MU discharge rates at the cost of poorer steadiness to maintain the requisite torque. In contrast, during a matched-EMG fatiguing contraction, a reduction of MU discharge rates allows for maintenance of EMG steadiness.

Radiometry in a comprehensive assessment of the effectiveness of extracorporeal shock wave therapy of calcifying tendinobursopathy of the shoulder

Introduction. Uncomfortable working conditions and excessive professional loads on the shoulder joints cause a high prevalence of degenerative-dystrophic changes in the periarticular tissues. Calcifying tendinitis and bursitis occupy a special place, characterized by multifocal accumulation of calcium phosphate crystals in tendons, mucous bags and muscles. The study is devoted to solving the problem of optimizing the X-ray diagnostics of the evolution of calcifying tendinobursopathy of the shoulder (CTS) in the dynamic assessment of the effectiveness of extracorporeal shock wave therapy.&#x0D; The aims of the study to optimize the X–ray diagnosis of calcifying tendinobursopathy of the shoulder in people working under the influence of adverse production factors.&#x0D; Materials and methods. The authors conducted a comparative retrospective analysis of the results of a comprehensive dynamic clinical and X-ray examination of 155 able-bodied men aged 35-57 years with an average work experience of 14.5±2.7 years (miners, loaders, bricklayers) examined for pain syndrome and dysfunction in the shoulder joint. The main group (65 people) are patients with CTS clinic, the presence of calcifications in the periaricular tissues of the rotator cuff and in the biceps muscle of the shoulder, evaluated in dynamics after shock wave therapy (SWT) of the shoulder in the phases of rest, resorption and recovery. The comparison group (90 people) consisted of patients with the absence of instrumentally detectable signs of multifocal accumulation of calcium phosphate crystals in the periarticular tissues of the shoulder. The study included patients whose routine conservative treatment proved ineffective. The following criteria for the effectiveness of therapy were identified: pain at rest, measured using a visual analog scale (VAS); dimensions (calcification area (in mm2)); optical density and calcification density gradient. Specialists evaluated the data at the initial stage of the study before the use of therapy, immediately after treatment and 12 months after the final SWT session.&#x0D; Results. In patients of the main group with the presence of CTS, the main manifestations of shoulder-scapular periarthritis (SSP) both in the main group and in the comparison group were moderately pronounced, however, the frequency of detection of the main SSP syndromes, primarily rotator cuff lesion, as well as background pathology (arthrosis of the shoulder joint) and acromioclavicular joint) were significantly higher in the main group. The effectiveness of SWT was demonstrated by regression of pain syndrome and positive dynamics of density characteristics of periarticular tissues of shoulder joints in areas of interest (in anatomotopographic projections of localization of tendons, mucous bags and muscles). In all patients of the main group, the decalcification process was characterized by both a visually perceptible pattern of disintegration and a decrease in its area, and a decrease in optical density immediately after the end of treatment. In 36.9% of patients, 12 months after the start of SWT, the X-ray and X-ray densitometric picture confirmed the prolongation of the decalcification process up to complete lysis of foci and calcification sites.&#x0D; Conclusions. In a comprehensive assessment of the effectiveness of CTS therapy, along with traditional X-ray diagnostics, special methodological techniques of radiometry (X-ray diffraction and X-ray densitometry in areas of interest) can be used, allowing for more accurate and more objective reflection of the direction of the dynamics of changes.&#x0D; The use of X-ray calcifications in the arsenal of methodological techniques, such as area, optical density and optical density gradient, can significantly improve the quality of diagnosis and avoid the use of computed tomography and an increase in radiation exposure to the patient.&#x0D; High-energy extracorporeal shockwave therapy is largely able to solve the problem of treating resistant forms of calcifying tendinobursopathy of the shoulder.

Investigation of the pressure value while performing biceps tenodesis for superior capsuler reconstruction

BackgroundTo compare the histopathological results of biceps tenodesis (BT) performed with normal, low, and high pressures for superior capsule reconstruction (SCR) in rabbits with massive rotator cuff tears.Materials and methodsThirty rabbits were divided into three groups. Rabbits 1–10 underwent SCR with BT at the same pressure (Group 1), value measured in the groove; 50% lower (Group 2); 50% higher (Group 3). After the 4-week follow-up, shoulder were en-bloc excised and histopathological evaluation was performed with modified Bonar’s scale. Results were compared between the groups, statistically.ResultsExtracellular matrix were significantly lower in group 2 compared to the other groups (p < 0.05). Cellularity levels were significantly lower in group 2 compared to the other groups (p < 0.05). Group 2 had no difference between the sides (p > 0.05). Group 2 had lower vascularity levels compared to the other groups (p = 0.01).DicsussionWhen the biceps tendon was in the bicipital groove and in a more mobile state with lower pressure exposure. BT performed with a tension that creates less pressure than the biceps in the groove is more successful in SCR.

Implementation and Comparison of Wearable Exoskeleton Arm Design with Fuzzy Logic and Machine Learning Control

In this study, a wearable exoskeleton arm was designed and controlled with different control methods to help people with muscle disorders in their arms and support treatment. The developed robot arm was transferred to Simulink software with the Simmechanics application. Two electromyography (EMG) muscle sensors and the ADXL335 position and acceleration sensors attach to the human arm’s biceps and triceps muscle areas. As the human moved the arm, data were obtained from the EMG muscle sensors and the ADXL335 position and acceleration sensor. The received data were first trained with the fuzzy logic algorithm. The same data were then trained with machine learning algorithms in Simulink software. It has been determined that the best result is the quadratic support vector machine (SVM) algorithm. The fuzzy logic algorithm trained with the PID controller block and the received sensor data have been added to the degrees of freedom regions that will enable rotation in the block diagram of the previously exported system. Later, the fuzzy logic block was removed and the machine learning algorithm, the quadratic SVM algorithm, was added. The designed system was operated with two different control systems, and the control algorithm closest to the human arm movement was determined. In addition, each part of the system, whose design was prepared, was removed and assembled separately with a 3D printer. ESP32 microcontroller development board was used to control the system, and it was run in real-time with EMG muscle sensors and position sensors.

Differences in neuromuscular junctions between intrinsic muscles of the forepaw and biceps muscles in rats.

Motor endplates of the interossei muscles become destabilized, whereas those of the biceps muscles remain stable in a rat model of obstetric brachial plexus palsy. However, it is unclear whether the morphology of the motor endplates of the interossei muscles is different from that of the biceps muscles in normal rat. We hypothesized that the motor endplates in the interossei muscles have specific characteristics different from those in the biceps muscles. The motor endplates were labeled with α-bungarotoxin and synaptophysin. The cross-sectional areas of the muscle fibers, the morphologies of the motor endplates, and the absolute and normalized areas (corrected by muscle fiber diameter) of the motor endplates of the interossei muscles and the biceps muscles were compared in rats at 1, 3, and 5 weeks after birth. The cross-sectional area of the interossei muscles and biceps muscle fibers were found to have increased gradually at 1, 3, and 5 weeks, but that of the biceps muscles was larger than that of the interossei muscles. The motor endplates of the interossei muscles and the biceps muscles gradually develop from crescent to pretzel shape after birth, and those of the interossei muscles have a smaller area. At 1, 3, and 5 weeks postnatally, the area of postnatal normalized motor endplates of the interossei muscles was much smaller than that of the biceps muscles. A better understanding of the morphological differences of the motor endplates between the interossei muscles and the biceps muscles may help to understand their physiological and pathological changes.

A comparison of anesthesia induction by two different administration routes and doses of ketamine and medetomidine in red-eared sliders (Trachemys scripta elegans)

This study aimed to assess the efficiency of ketamine and medetomidine by two different doses and routes on anesthesia depth and cardiac stability in red-eared sliders. Each turtle was anesthetized two times, with seven days wash-out period. Induction of anesthesia consisted of a bolus combination of ketamine (10 mg/kg) and medetomidine (0.2 mg/kg) administered in the left brachial biceps in the intramuscular protocol, or a bolus combination of ketamine (20 mg/kg) and medetomidine (0.2 mg/kg) administered in subcarapacial sinus after clear blood presence confirmation in the intravenous protocol. Vital signs, reaction on the skin palpation, manual mouth opening for endotracheal intubation, palpebral and cloacal reflex, and the withdrawal reflex of the front and hind limbs were measured and recorded every 5 minutes for 60 minutes after anesthesia injection. Atipamezole (1 mg/kg) was administered in the right brachial biceps one hour after ketamine and medetomidine administration. Needle insertion and possible painful reactions to drug administration were also evaluated and recorded. Obtained data were analyzed for normality and paired t-tests, Wilcoxon, or McNamar tests were performed where appropriate. The values of P≤0.05 were considered significant. A significantly less pronounced decrease in heart rate was observed with intravenous anesthesia protocol. Both protocols recorded complete anesthesia recovery 60 minutes after intramuscular atipamezole administration. A ketamine-medetomidine dose combination administered intravenously provides a more stable and consistent anesthetic plane in red-eared sliders than ketamine-medetomidine administered intramuscularly.

Neuromuscular electrical stimulation producing low evoked force elicits the repeated bout effect on muscle damage markers of the elbow flexors

This study examined the repeated bout effect (RBE) on muscle damage markers following two bouts of neuromuscular electrical stimulation (NMES) in untrained individuals. Following familiarization, participants received 45 consecutive NMES to the biceps brachii at an intensity that produced low evoked force for the elbow flexors. Muscle damage markers (maximal voluntary isometric contraction [MVIC], elbow range of motion [ROM], muscle soreness via visual analogue scale [VAS] scores, pressure pain threshold [PPT], and muscle thickness) were measured before (PRE), after (POST), 1 day after (24 POST), and 2 days after (48 POST) NMES. Following 1 week of rest, procedures were replicated. Separate repeated measures two-way ANOVAs examined each measure. There were no interactions or bout main effects for MVIC or ROM. Time main effects indicated PRE MVIC was greater than POST (p ​= ​0.002) and 24-POST (p ​= ​0.024), and PRE ROM was greater than POST (p ​= ​0.036). There was no interaction for muscle thickness. Respective time and bout main effects indicated muscle thickness at PRE was less than POST (p ​= ​0.017), and second-bout muscle thickness (p ​= ​0.050) was less compared to the initial-bout. For PPT, there was an interaction (p ​= ​0.019). Initial-bout PRE PPT was less than POST (p ​= ​0.033). Initial-bout 48-POST PPT was less than second-bout 48-POST (p ​= ​0.037). There was a significant interaction for VAS (p ​= ​0.009). Initial-bout PRE VAS was less than POST (p ​= ​0.033) and 24-POST (p ​= ​0.015). Initial-bout POST and 24-POST VAS were greater than second-bout POST (p ​= ​0.023) and 24-POST (p ​= ​0.006), respectively. The results support RBE on muscle damage markers related to inflammation, but not MVIC and ROM.

Distal biceps tendon repair using a double intracortical button anatomic footprint repair technique

Distal biceps tendon repair is usually performed via a double-incision or single-incision bicortical drilling technique. However, these techniques are associated with specific complications and usually do not allow for anatomic footprint restoration. It was the aim of this study to report the clinical results of a double intracortical button anatomic footprint repair technique for distal biceps tendon tears. We hypothesized that this technique would result in supination strength comparable to the uninjured side with a low rerupture rate and minimal bony or neurologic complications. This was a retrospective, single-surgeon cohort study of a consecutive series of 22 patients with a mean (standard deviation) age of 50.7 (9.4) years and at least 1-year follow-up after distal biceps tendon repair. At final follow-up, complications, range of motion (ROM), the Patient-rated Elbow Evaluation (PREE), Mayo Elbow Performance Score (MEPS), Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, visual analog scale (VAS) for pain, patient satisfaction, and supination strength in neutral as well as 60° of supination were analyzed. Radiographic evaluation was performed on a computed tomography scan. One patient (4.5%) experienced slight paresthesia in the area of the lateral antebrachial cutaneous nerve. Heterotopic ossification was seen in 1 patient (4.5%). All patients recovered full ROM except for 1 who had 10° of loss of flexion and extension. Median PREE score was 4.6 (0-39.6), median MEP was 100 (70-100), and median DASH score was 1.4 (0-16.7). All but 1 patient were very satisfied with the outcome. The affected arm had a mean of 98% (±13%) of neutral supination strength (P=.633) and 94% (±12%) of supination strength in 60° (P=.054) compared with the contralateral, unaffected side. There were 4 cases (18.2%) of cortical thinning due to at least 1 button and 1 case of button pullout (4.5%). The double intracortical button anatomic footprint repair technique seems to provide reliable restoration of supination strength and excellent patient satisfaction while minimizing complications, particularly nerve damage and heterotopic ossification.

Bilateral simultaneous distal biceps tendon rupture repair with both cortical button and interference screw

Bilateral simultaneous distal biceps tendon rupture repair with both cortical button and interference screw