Short Head Research Articles

A rare anomalous muscle in the popliteal region - a case report.

Anomalous muscles are rarely seen in the popliteal region of the lower limb. Some of them are harmless and go unnoticed and some create problems such as neuropathies. We report a novel case of an unusual additional muscle in this region. The additional muscle was closely associated with the short head of the biceps femoris muscle. It took its origin from the lower part of the lateral supracondylar line and the adjoining popliteal surface of the femur. The muscle was 10cm in length, 1cm in breadth and was fleshy throughout. It was oriented parallel to the medial side of the tendon of biceps femoris. It was inserted to the posterior aspect of the head of the fibula, medial to the insertion of the biceps femoris. The additional muscle derived its nerve supply from the sciatic nerve. The common peroneal nerve was closely related to the medial border of the additional muscle.

Dynamics of a slow-fast Leslie-Gower predator-prey model with prey harvesting.

For the Leslie-Gower predator-prey model with Michaelis-Menten type prey harvesting, the known results are on the saddle-node bifurcation and the Hopf bifurcation of codimensions 1, the Bogdanov-Takens bifurcations of codimensions 2 and 3, and on the cyclicity of singular slow-fast cycles. Here, we focus on the global dynamics of the model in the slow-fast setting and obtain much richer dynamical phenomena than the existing ones, such as global stability of an equilibrium; an unstable canard cycle exploding to a homoclinic loop; coexistence of a stable canard cycle and an inner unstable homoclinic loop; and, consequently, coexistence of two canard cycles: a canard explosion via canard cycles without a head, canard cycles with a short head and a beard and a relaxation oscillation with a short beard. This last one should be a new dynamical phenomenon. Numerical simulations are provided to illustrate these theoretical results.

An intense electrical stimulus can elicit a StartReact effect but with decreased incidence and later onset of the startle reflex.

Planned actions can be triggered involuntarily by a startling acoustic stimulus (SAS), resulting in very short reaction times (RT). This phenomenon, known as the StartReact effect, is thought to result from the startle-related activation of reticular structures. However, other sensory modalities also can elicit a reflexive startle response. Here, we assessed the effectiveness of an intense startling electric stimulus (SES) in eliciting the StartReact effect as compared to a SAS. We tested SES intensities at 15 and 25 times the perceptual threshold of each participant, as well as SAS intensities of 114 dB and 120 dB. The electrical stimulation electrodes were placed over short head of the biceps brachii on the arm not involved in the task. Intense electric and acoustic stimuli were presented on 20% of the trials in a simple RT paradigm requiring a targeted ballistic wrist extension movement. The proportion of trials showing short latency (≤ 120 ms) startle reflex-related activation in sternocleidomastoid was significantly lower on intense electrical stimulus trials compared to intense acoustic trials, and the startle response onset occurred significantly later on SES trials compared to SAS. However, when a startle reflex was observed, RTs related to the prepared movement were facilitated to a similar extent for both SES and SAS conditions, suggesting that the accelerated response latency associated with the StartReact effect is independent of stimulus type.

Individual and region-specific hamstring muscles use during a novel Flywheel Russian belt Deadlift exercise

BackgroundDespite the implementation of specific exercises to reduce hamstrings strain injuries (HSI) risk, the incidence has remained unchanged over the past 30 years. Therefore, the purpose of the study was to analyze hamstrings muscle activation induced by a novel Flywheel Russian belt Deadlift (FRD) exercise, together with individual muscle-, region- and limb-specific differences. MethodsThe activation of hamstring muscles before and immediately after a 10 × 10 FRD training session was assessed by the T2 shift technique through functional magnetic resonance imaging, in one international-level filed hockey male player. The individual use of the biceps femoris long head (BFLH) and short head (BFSH), semitendinosus (ST), and semimembranosus (SM) were analyzed, together with the region-specific activation for each muscle. ResultsT2 values significantly increased immediately after exercise in all regions of the hamstring muscles in both dominant and non-dominant lower limb. However, the SM muscle showed a lesser activation, compared to BFLH, BFSH and ST muscles [F(3,106) = 9.557, p < 0.001]. Overall, the most activated muscle by the FRD training session was the biceps femoris (short head +13.8 %, long head, +12.7 %), followed by the ST (+11.3 %), and lastly the SM (+6.9 %). ConclusionThe novel FRD exercise triggers a homogeneous and consistent activation of hamstring muscles. Particularly, the lateral positioning muscles (i.e., BFLH and BFSH) were more activated than the medial positioning muscles (i.e., ST and SM). Therefore, the FRD exercise could enhance training programs to strengthen and activate the hamstring muscles, and specifically, the BFLH, in order to reduce HSI risk.

Muscle morphological changes and enhanced sprint running performance: A 1-year observational study of well-trained sprinters.

Numerous cross-sectional studies have attempted to identify the muscle morphology required to achieve high sprint velocity. Our longitudinal study addressed an unanswered question of cross-sectional studies: whether hypertrophy of the individual trunk and thigh muscles induced by daily training (e.g., sprint, jump, and resistance training) is linked to an improvement in sprint performance within well-trained sprinters. Twenty-three collegiate male sprinters (100-m best time of 11.36±0.44s) completed their daily training for 1year without our intervention. Before and after the observation period, the sprint velocities at 0-100m, 0-10m, and 50-60m intervals were measured using timing gates. The volumes of 14 trunk and thigh muscles were measured using magnetic resonance imaging. Muscle volumes were normalized to the participants' body mass at each time point. Sprint velocities increased at the 0-100m (p<0.001), 0-10m (p=0.019), and 50-60m (p=0.018) intervals after the observation period. The relative volumes of the tensor fasciae latae, sartorius, biceps femoris long head, biceps femoris short head, semitendinosus, and iliacus were increased (all p<0.050). Among the hypertrophied muscles, only the change in the relative volume of the semitendinosus was positively correlated with the change in sprint velocity at the 50-60m interval (p=0.018 and ρ=0.591). These findings suggest that semitendinosus hypertrophy seems to be associated with sprint performance improvement within well-trained sprinters during the maximal velocity phase.

The anatomy of the motor branches of the sciatic nerve: an anatomical study with clinical implications.

The sciatic nerve gave the motor branches supply to: biceps femoris long and short head, semitendinosus, semimembranosus and adductor magnus muscles. The anatomy of these motor branches is highly variable. The aim of this study was to estimate the anatomy and morphometry of hamstring muscles innervation. The motor branches of the sciatic nerve were dissected from both sides from 20 cadaveric specimens (9 left and 11 right) from the 11 cadavers (4 females and 7 males) at the Department of Anatomy, Jagiellonian University Medical College Cracow. The motor branches of the sciatic nerve length, distance from piriformis muscle and number of all branches that exist from tibial nerve and common fibular nerve were measured. In most cases common fibular nerve gave off one branch to the short head of biceps femoris, in most cases the proximal hamstring tendon was innervated only by the first trunk, the highest number of branches were innervating the semimembranosus and the long head of biceps femoris, the longest branches were coming to the semimembranosus and the shortest to the proximal hamstring tendon CONCLUSIONS: The present study shows that there are various innervation types of the posterior group of thigh muscles. Knowledge of possible innervation patterns could be of utmost value to operators performing surgeries on the posterior region of the thigh.

Case Report of Arthroscopic Anatomical Bone Glenoid Augmentation with Subscapularis Tendon Protection with A 24 Months Follow-Up and Literature Review of The Current Concepts of Glenoid Bone Augmentation

Recurrent shoulder instability is known to be a challenge in terms of the success rate of surgical stabilization of the shoulder joint. According to the latest literature the choice of the glenohumeral stabilization surgical treatment is guided by the degree of bone loss. Among the techniques dedicated to significant glenoid bone loss, one will find many already reported, but each has its drawbacks. As we observe currently popular techniques, we conclude that we should continue to look for techniques or some modifications to those already available that are laden with as few complications as possible. In 2019, a new technique called bone block cerclage has been described. It is a new approach, using when metal implants are not used while providing benefits such as maintenance and integrity and function of structures like coracobrachialis, short head of biceps, pectoralis minor and preservation of subscapularis tendon. Currently, there are not many reported cases in the literature after BBC with a longer follow-up time. In this paper, we present the case of our patient operated on 24 months ago with this technique with good results. The patient is still under our observation. Due to the relatively new technique and the small number of described follow- ups, we feel it is relevant to describe our case.

Effect of a graded running race on lower limb muscle damage, jump performance and muscle soreness in men and women.

Delayed structural and functional recovery after a 20 km graded running race was analyzed with respect to the sex effect. Thirteen female and 14 male recreational runners completed the race and three test sessions: one before (PRE) and two after, once on Day 1 or 2 (D1-2) and then on Day 3 or 4 (D3-4). Muscle damage was assessed indirectly using ultrasonography to quantify changes in cross-sectional area (CSA) of 10 lower-limb muscles. Delayed onset of muscle soreness (DOMS) was assessed for three muscle groups. Functional recovery was quantified by kinetic analysis of a squat jump (SJ) and a drop jump (DJ) test performed on a sledge ergometer. Linear mixed models were used to assess control group reproducibility and recovery patterns according to sex. Regardless of sex, DOMS peaked at D1-2 for all muscle groups and resolved at D3-4. CSA was increased in each muscle group until D3-4, especially in the semimembranosus muscle. A specific increase was found in the short head of the biceps femoris in women. Regardless of sex, SJ and DJ performances declined up to D3-4. Depending on the muscle, positive and/or negative correlations were found between structural and functional changes. Some of these were sex-specific. Structural and functional recovery was incomplete in both sexes up to D3-4, although DOMS had disappeared. More emphasis should be placed on hamstring muscle recovery. Highlighting the intermuscular compensations that can occur during multi-joint testing tasks, the structural-functional relationships were either positive or negative, muscle- and sex-dependent.

Comparison of the masses and amounts of intramuscular non-contractile tissue of the lower extremity muscles, mobility and balance ability, and cognitive function between older adults with and without low back pain: A pilot study

IntroductionThis study compared the masses and amounts of intramuscular non-contractile tissue of multiple lower extremity muscles measured using an ultrasound imaging device, as well as the mobility and balance ability and cognitive function between community-dwelling older adults with and without low back pain (LBP). MethodsTwenty-five community-dwelling older adults were classified into control (CTR) (n = 17, asymptomatic) and LBP (n = 8) groups. The current LBP status in the LBP group was as follows: duration period: 99.4 ± 81.3 months, Numerical Rating Scale: 4.8 ± 0.9, and Oswestry Disability Index: 15.3 ± 10.4%. The thicknesses and the echo intensities of various muscles (gluteus maximus, medius, and minimus; rectus femoris; vastus intermedius and lateralis; long and short heads of the biceps femoris; semitendinosus; semimembranosus; tibialis anterior; medial head of the gastrocnemius; soleus; and tibialis posterior) were measured using an ultrasound imaging device. Mobility and balance ability were assessed by measuring the usual and maximal walking speeds, timed up-and-go time, five-chair-stand time, and one-legged stance time. Mini-Mental State Examination scores were also assessed. ResultsThe gluteus medius muscle thickness was significantly lower in the LBP group than in the CTR group. The thicknesses and echo intensities of the other lower extremity muscles did not differ significantly between the CTR and LBP groups. The usual walking speed was also significantly slower in the LBP group than in the CTR group. Balance ability and cognitive function did not differ significantly between the two groups. ConclusionThe results of the present study demonstrated lower gluteus medius muscle mass and slower usual walking speed in community-dwelling older adults with LBP compared to those in older adults without LBP; however, other variables did not differ significantly between these groups.

Innervation patterns of hamstring muscles, including morphological descriptions and clinical implication.

The hamstrings muscles are innervated by sciatic nerve branches. However, previous studies assessing which and how many branches innervate each muscle have yielded discrepant results. This study investigated the innervation patterns of hamstrings. Thirty-five cadaver limbs were investigated. The average age of subjects was 78.6 ± 17.2 years, with 48.6% male and 51.4% female, while 57.1% were right limbs and 42.9% left. The sciatic nerve, hamstrings and associated structures were dissected. The number of nerve branches for each muscle and the level where they penetrated the muscle were recorded. The sciatic nerve was connected by a fibrous band to the long head of the biceps femoris. This muscle was innervated by either one or two branches, which penetrated the muscle into its superior or middle third. The short head of the biceps femoris was innervated by a single nerve that usually penetrated its middle third, but sometimes inferiorly or, less commonly, superiorly. The semitendinosus was always innervated by two branches, the superior branch penetrating its upper third, the inferior mostly the middle third. The semimembranosus usually was innervated by a single nerve branch that penetrated the muscle at its middle or lower third. Four specimens revealed common nerves that innervated than one muscle. We have characterized hamstring innervation patterns, knowledge that is relevant to neurolysis, surgery of the thigh, and other procedures. Moreover, a mechanical connection between the sciatic nerve and biceps femoris long head was identified that could explain certain neuralgias.

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.

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.

Current concepts in the aetiology, assessment and management of partial distal biceps tendon tears

Partial distal biceps tendon tears encompass a spectrum of disease. They can be either traumatic or degenerative in nature. Traumatic tears usually involve the short head. Degenerative tears can involve either or both short and long head components with the tear affecting the lateral fibres first. Chronic tears may be associated with a narrow radioulnar space, distinct head insertions and radial tuberosity hypertrophy. Patient history and clinical examination findings suggestive of partial tearing of the distal biceps tendon should be confirmed with advanced imaging. Magnetic resonance imaging allows assessment of the tear size, morphology and associated pathologies. Non-surgical management, including physiotherapy and injections, is appropriate in selected cases. Surgical management can involve either endoscopic or open techniques. In small tears or low demand patients, a simple debridement of the bursa, tuberosity and tendon may be indicated. In larger tears in higher functioning patients, release of the remaining fibres, debridement and an anatomical repair is indicated. In this review paper, the authors present current concepts on the pathogenesis and management of partial distal biceps tendon tears.

Distal hamstrings tendons mechanical properties at rest and contraction using free-hand 3-D ultrasonography.

Tendon properties impact human locomotion, influencing sports performance, and injury prevention. Hamstrings play a crucial role in sprinting, particularly the biceps femoris long head (BFlh), which is prone to frequent injuries. It remains uncertain if BFlh exhibits distinct mechanical properties compared to other hamstring muscles. This study utilized free-hand three-dimensional ultrasound to assess morphological and mechanical properties of distal hamstrings tendons in 15 men. Scans were taken in prone position, with hip and knee extended, at rest and during 20%, 40%, 60%, and 80% of maximal voluntary isometric contraction of the knee flexors. Tendon length, volume, cross-sectional area (CSA), and anteroposterior (AP) and mediolateral (ML) widths were quantified at three locations. Longitudinal and transverse deformations, stiffness, strain, and stress were estimated. The ST had the greatest tendon strain and the lowest stiffness as well as the highest CSA and AP and ML width strain compared to other tendons. Biceps femoris short head (BFsh) exhibited the least strain, AP and ML deformation. Further, BFlh displayed the highest stiffness and stress, and BFsh had the lowest stress. Additionally, deformation varied by region, with the proximal site showing generally the lowest CSA strain. Distal tendon mechanical properties differed among the hamstring muscles during isometric knee flexions. In contrast to other bi-articular hamstrings, the BFlh high stiffness and stress may result in greater energy absorption by its muscle fascicles, rather than the distal tendon, during late swing in sprinting. This could partly account for the increased incidence of hamstring injuries in this muscle.

Influence of network video film and television communication based on sampling theory

The media landscape has been evolving at a dizzying pace in recent years, with short video platforms emerging as a significant public information conduit; yet, it must be acknowledged that the impact of these platforms on transmission is still rather limited. Both the width and the depth are not up to par. Improving the impact, increasing the reach and impact, and making the most of the Douyin platform for scientific communication activity is an immediate concern. Douyin, China's most popular video-sharing platform, with 400 million daily users. Douyin provides regular individuals with the resources they need to start their own video art careers; it is popular outside of tier 1 cities. There are also inventive contests on the site where individuals can try their hand at being famous overnight. In this study, we look at how social media platforms evaluate short video head accounts online. Research is conducted to separate out the communication features of the head accounts based on popular scientific themes, the length of the form, and the use of other platform functions in the operation process. This study use random theory to pick various sorts of short videos as the final effective analysis samples, with a random sampling range of 15% of the empirical sample size, in order to deal with the temporal dimension and the enormous number of online video samples. Among the topics covered by Douyin's popular scientific short video accounts, the percentages for science, technology, innovations, medical care, health, and nature stand at 18.99%, 16.59%, and 15.38%, respectively, according to the article's sample data. Online video and film may be effectively disseminated in this research's media ecosystem, which is based on sampling theory.

The morphometric parameters of the biceps brachii: cadaveric study.

The biceps brachii (BB) is a fusiform muscle comprising of two muscular bellies located in the anterior compartment of the arm. Its primary function includes elbow flexion and forearm supination. The study aimed to examine the morphometric parameters of the BB in adult cadaveric specimens. This dissection-based study examined the anatomy of the BB in 40 arms taken from 20 Thiel embalmed European cadavers, including 13 males with an average age of 81 years and seven females with an average age of 84 years. The investigation included an observational inspection of the BB morphology and collected 19 parameters, comprising the lengths and widths of the short and long head tendons and muscle bellies. The observation analysis showed that the anatomy of the BB consisted mainly of two muscle bellies: a short head and a long head. An additional third humeral head, originating from the anteromedial aspect of the mid of the humerus and inserted into the common biceps tendon, was observed in four (10%) specimens. The average lengths of the short head and long head were 35.98 ± 3.44cm and 38.90 ± 3.40cm, respectively. There was no difference in the BB parameters according to the arm sides. However, the male specimens showed greater BB parameters than the female specimens. The short head had a greater muscle belly, while the long head had a longer origin and insertion tendons. The BB parameters were correlated positively with the humerus length.

Explorative study using ultrasound time-harmonic elastography for stiffness-based quantification of skeletal muscle function

Time-harmonic elastography (THE) is an emerging ultrasound imaging technique that allows full-field mapping of the stiffness of deep biological tissues. THE's unique ability to rapidly capture stiffness in multiple tissues has never been applied for imaging skeletal muscle. Therefore, we addressed the lack of data on temporal changes in skeletal muscle stiffness while simultaneously covering stiffness of different muscles.Acquiring repeated THE scans every five seconds we quantified shear-wave speed (SWS) as a marker of stiffness of the long head (LHB) and short head (SHB) of biceps brachii and of the brachialis muscle (B) in ten healthy volunteers. SWS was continuously acquired during a 3-min isometric preloading phase, a 3-min loading phase with different weights (4, 8, and 12 kg), and a 9-min postloading phase. In addition, we analyzed temporal SWS standard deviation (SD) as a marker of muscle contraction regulation.Our results (median [min, max]) showed both SWS at preloading (LHB: 1.04 [0.94, 1.12] m/s, SHB: 0.86 [0.78, 0.94] m/s, B: 0.96 [0.87, 1.09] m/s, p < 0.001) and the increase in SWS with loading weight to be muscle-specific (LHB: 0.010 [0.002, 0.019] m/s/kg, SHB: 0.022 [0.017, 0.042] m/s/kg, B: 0.039 [0.019, 0.062] m/s/kg, p < 0.001). Additionally, SWS during loading increased continuously over time by 0.022 [0.004, 0.051] m/s/min (p < 0.01). Using an exponential decay model, we found an average relaxation time of 27 seconds during postloading. Analogously, SWS SD at preloading was also muscle-specific (LHB: 0.018 [0.011, 0.029] m/s, SHB: 0.021 [0.015, 0.027] m/s, B: 0.024 [0.018, 0.037] m/s, p < 0.05) and increased by 0.005 [0.003, 0.008] m/s/kg (p < 0.01) with loading. SWS SD did not change over loading time and decreased immediately in the postloading phase.Taken together, THE of skeletal muscle is a promising imaging technique for in vivo quantification of stiffness and stiffness changes in multiple muscle groups within seconds. Both the magnitude of stiffness changes and their temporal variation during isometric exercise may reflect the functional status of skeletal muscle and provide additional information to the morphological measures obtained by conventional imaging modalities.

Hamstrings passive and active shear modulus: Implications of conventional static stretching and warmup

PurposeThis study compares the acute effects of a static stretching and a warmup protocol on the active and passive shear modulus of the hamstring muscles. MethodsMuscle shear modulus was assessed at rest and during isometric contractions at 20 % of maximal voluntary isometric contraction (MVIC). ResultsAfter stretching, the passive shear modulus pattern was not altered, while at 20 % MVIC the biceps femoris short head (BFsh) and semimembranosus showed a shear modulus increase and decrease, respectively, which resulted on BFsh-SM pair differences (pre: 3.8 ± 16.8 vs. post: 39.3 ± 25.1 kPa; p < 0.001; d = 1.66) which was accompanied by a decrease of 18.3 % on MVIC. Following the warmup protocol, passive shear modulus remained unchanged, while active shear modulus was decreased for the semitendinosus (pre: 65.3 ± 13.5 vs. post: 60.3 ± 12.3 kPa; p = 0.035; d = 0.4). However, this difference was within the standard error of measurement (10.54 kPa), and did not impact the force production, since it increased only 1.4 % after the warmup. ConclusionsThe results of this study suggest that the passive and active shear modulus responses of the individual hamstring muscles to static stretching are muscle-specific and that passive and active hamstring shear modulus are not changed by a standard warmup intervention.

All-endoscopic approach for distal biceps tendon pathology: analysis of long-term outcomes in partial and complete ruptures

Distal biceps tendon (DBT) pathology is a spectrum that ranges from tendinopathy to complete retracted ruptures, and surgical treatment is usually performed via open approaches. The purpose of this study was to analyze safety and long-term outcomes of all-endoscopic surgery for entire spectrum of primary DBT pathology. The hypothesis was that at an all-endoscopic technique would result in satisfactory clinical outcomes and a low complication rate. Consecutive patients who underwent all-endoscopic surgery for primary isolated DBT pathology (bursitis, partial and acute/chronic complete tears) between January 2013 and December 2021 were assessed and analyzed retrospectively. Refractory bursitis and low-grade partial tears underwent endoscopic débridement, and high-grade partial tears and complete ruptures underwent all-endoscopic repair or graft reconstruction. Preoperative and follow-up assessment included functional assessment using Mayo Elbow Performance Score and a Patient-Reported Distal Biceps Score, and radiological assessment was performed using plain biplanar radiographs and sonography. Pre- and postoperative scores for the overall group, and for partial and complete tears, were compared using a paired t test. Overall, 26 male patients underwent an all-endoscopic surgery for DBT tears; the pathology was classified by endoscopic findings into 6 types, and follow-up period ranged from 21 to 125months (mean 79.4months). Nine chronic partial tears (35%) included predominantly bursitis (type I, n=2) and predominantly partial tears (type IIA and B, n=7). The complete tear group (65%) included isolated short or long head tears (type IIIA and IIIB, n=2) and complete tendon ruptures (types IV, V, and VIA-C, n=15). Endoscopic débridement of the bursitis/low-grade tears and repair of the high-grade and complete ruptures resulted in complete resolution of symptoms and significant improvement in both Mayo Elbow Performance Score and Patient-Reported Distal Biceps Score (P<.001). Autografts were necessary in 35% (6/17) of complete tears, and no significant difference was found in functional scores in this group as compared to those where primary repairs were possible. There were 2 minor complications (7.6%) that involved transient lateral antebrachial cutaneous nerve neuropraxia. Follow-up sonography and radiographs showed an intact tendon and absence of heterotopic ossification or synostosis. An all-endoscopic approach for treating DBT pathology was safe and reliable and was associated with significant improvement in subjective and functional outcomes in the long-term. The dual-anchor onlay repair technique showed long-term radiologically demonstrable structural integrity of the tendon and was associated with a low minor complication rate and absence of heterotopic ossification.

Moment arm and torque generating capacity of semitendinosus following tendon harvesting for anterior cruciate ligament reconstruction: A simulation study.

Altered semitendinosus (ST) morphology and distal tendon insertion following anterior cruciate ligament reconstruction (ACLR) may reduce knee flexion torque generating capacity of the hamstrings via impaired ST force generation and/or moment arm. This study used a computational musculoskeletal model to simulate mechanical consequences of tendon harvest for ACLR on ST function by modeling changes in ST muscle tendon insertion point, moment arm, and torque generating capacity across a physiological range of motion. Simulated ST function was then compared between ACLR and uninjured contralateral limbs. Magnetic resonance imaging from 18 individuals with unilateral history of ACLR involving a hamstring autograft was used to analyse bilateral hamstring muscle (ST, semimembranosus, bicep femoris long head and short head) morphology and distal ST tendon insertion. The ACLR cohort was sub-grouped into those with and without ST regeneration. For each participant with ST regeneration (n = 7), a personalized musculoskeletal model was created including postoperative remodeling of ST using OpenSim 4.1. Knee flexion and internal rotation moment arms and torque generating capacities of hamstrings were evaluated. Bilateral differences were calculated with an asymmetry index (%) ([unaffected limb-affected limb]/[unaffected limb + affected limb]*100%). Smaller moment arms or knee torques within injured compared to uninjured contralateral limbs were considered a deficit. Compared to uninjured contralateral limbs, ACLR limbs with tendon regeneration (n = 7) had minor reductions in knee flexion (5.80% [95% confidence interval (CI) = 3.97-7.62]) and internal rotation (4.92% [95% CI = 2.77-7.07]) moment arms. Decoupled from muscle morphology, altered ST moment arms in ACLR limbs with tendon regeneration resulted in negligible deficits in knee flexion (1.20% [95% CI = 0.34-2.06]) and internal rotation (0.24% [95% CI = 0.22-0.26]) torque generating capacity compared to uninjured contralateral limbs. Coupled with muscle morphology, ACLR limbs with tendon regeneration had substantial deficits in knee flexion (19.32% [95% CI = 18.35-20.28]) and internal rotation (15.49% [95% CI = 14.56-16.41]) torques compared to uninjured contralateral limbs. Personalized musculoskeletal models with measures of ST distal insertion and muscle morphology provided unique insights into post-ACLR ST and hamstring function. Deficits in knee flexor and internal rotation moment arms and torque generating capacities were evident in those with ACLR even when tendon regeneration occurred. Future studies may wish to implement this framework in personalized musculoskeletal models following ACLR to better understand individual muscle function for injury prevention and treatment evaluation.