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Objectives: Muscles and their tendons present a considerable diversity of morphological variations. The aim of this study was to explore variants of muscles and tendons from compartments of the thigh and to raise awareness about potential problems during ultrasound examination. Materials and Methods: This comprehensive review of the literature was created on the basis of scientific articles sourced from PubMed. The search included all relevant papers related to the topic, ensuring that the most up-to-date studies were incorporated. In order to achieve these results, we created the exclusion criteria and extracted papers that did not meet the requirements of our review. Relevant papers were incorporated, and tracking of citations was fulfilled. The described method allowed for a broad yet detailed understanding, ensuring that the review of the literature covers all key aspects of the presented research. Results: Various aspects of thigh muscle anomalies were already undertaken; however, as this study has shown, current knowledge, while valuable, is insufficient to draw definitive conclusions regarding the prevalence and clinical implications of these muscle variations. A more robust body of ultrasound-based research is essential to accurately characterize these anomalies, establish their frequency, and assess their impact on clinical decision-making, including diagnostic accuracy, surgical planning, and therapeutic interventions. Conclusions: Numerous anatomical variations of the thigh muscles and tendons that were described in literature over the years might have clinical implications and could lead to mistakes during diagnosis by ultrasound imaging. [ABSTRACT FROM AUTHOR]

Background: The cross-sectional area (CSA) and length of an individual's hamstring tendons are both variable, making it challenging for the operating surgeon to generate an ideal size graft during arthroscopic anterior cruciate ligament (ACL) reconstruction surgery. This study aimed to determine the reliability and accuracy of MRI in predicting quadruple hamstring graft diameter for ACL reconstruction, to determine the statistical correlation between the CSA of hamstring tendons without any graft complications. On MRI and intraoperative quadruple hamstring graft diameter, and to find out the minimum CSA of hamstring tendons (ST+GR) required for an 8 mm quadruple hamstring graft diameter. METHODS: This prospective diagnostic study included 52 patients diagnosed with complete ACL rupture. On MRI, we assessed the CSA of the semitendinosus and gracilis tendons at two levels: one at the joint line and the other at the level where the anteroposterior (AP) diameter of the medial femoral condyle is longest. The cutoff CSA required for a graft of sufficient size was calculated using simple logistic regression analysis. Results: The mean ST+GR CSA on MRI was 19.2mm 2, the minimum CSA was 14.4 mm2, and the maximum CSA was 22.0 mm2. Pearson's correlation between the intraoperative quadruple hamstring graft diameter (mm) and ST+GR CSA on MRI was 0.838 Conclusion: In this prospective diagnostic study, we used radiological imaging for preoperative assessment of hamstring tendons and predicting the Graft size for ACL reconstruction. This study showed that ST+GR CSA on MRI and the intraoperative quadruple hamstring graft diameter had a strong statistical relationship. [ABSTRACT FROM AUTHOR]

Introduction: Conflicting results have been reported on the functional role of the proximal and distal compartments of the semitendinosus (ST) muscle. This study compared the discharge characteristics of motor units (MU) in the two compartments at three knee joint angles (0°: long length; 45°: intermediate length; and 90°: short length). Methods: Twenty men (21.4 ± 2.3 yr) performed steady isometric contractions with the knee flexors at four target forces: 10%, 20%, 40%, and 60% of maximum voluntary contraction. High-density EMG signals were recorded to examine the MU discharge characteristics in the two compartments. Measurements included recruitment threshold, mean discharge rate, coefficient of variation (CoV) for interspike interval, and SD of filtered cumulative spike train (fCST). Additionally, the within- and between-compartment association of the neural drive was calculated. Results: ANOVA indicated that maximal force, absolute EMG amplitude during the maximum voluntary contractions, and force steadiness (CoV for force) were greater at the longest muscle length than the other two lengths (P < 0.05). Linear mixed models showed that both recruitment threshold and CoV for interspike interval were similar between compartments (P > 0.05) at each of the three knee joint angles. However, the mean discharge rate and the variability in neural drive were greater for the proximal than the distal compartment (P < 0.05). The between-compartment association in neural drive (filtered cumulative spike train) was relatively low. Conclusions: There were distinct differences in MU discharge characteristics between the proximal and the distal compartments of ST across its operating range of muscle lengths, and each compartment received a relatively distinct neural drive. These findings emphasize the importance of recognizing differences in neural control of the ST compartments to guide related interventions and to inform rehabilitation strategies. [ABSTRACT FROM AUTHOR]

Abstract Despite the increase in research of hamstring stiffness through the use of ultrasound-based shear wave elastography, the active stiffness of biceps femoris long head (BFlh) and semitendinosus (ST) muscles under fatigue conditions at various contraction intensities has not been sufficiently explored. This study aimed to compare the effects of knee flexor’s isometric contraction until exhaustion performed at 20% vs. 40% of maximal voluntary isometric contraction (MVIC), on the active stiffness responses of BFlh and ST. Eighteen recreationally active males performed two experimental sessions. The knee flexors’ MVIC was assessed before the fatiguing task, which involved a submaximal isometric contraction until failure at 20% or 40% of MVIC. Active muscle stiffness of the BFlh and ST was assessed using shear wave elastography. BFlh active stiffness remained relatively unaltered at 20% of MVIC, while ST active stiffness decreased from ≅ 91% contraction time (55.79 to 44.52 kPa; p 0.05) or ST (63.62 to 53.54 kPa; p > 0.05) at 40% of MVIC session. Intermuscular active stiffness at 20% of MVIC differed until 64% contraction time (p 0.05), but a steeper increase in BFlh/ST ratio was found for 20% (0.004 ± 0.003 ratio/%) compared to 40% (0.001 ± 0.003 ratio/%) of MVIC (p = 0.003). These results suggest that contraction duration could play a major role in inducing changes in hamstrings’ mechanical properties during fatigue tasks compared to contraction intensity.

Background: Posterior sternoclavicular joint (SCJ) dislocations are rare events that can evolve into real emergencies due to the vital structures in the mediastinum. When closed reduction maneuvers fail, open SCJ reconstruction becomes mandatory, with literature proposing several stabilization techniques that either preserve or remove the SCJ's mobility. This study is a narrative review of the most recent literature regarding posterior trauma to the SCJ along with a single institution's experience of this pathology, managed either conservatively or surgically, with a figure-of-eight autologous semitendinosus graft in case of closed reduction failure. Methods: This article provides an overview of posterior traumatic SCJ dislocation, and it describes five cases of patients managed for traumatic posterior SCJ dislocation treated either conservatively or surgically with a figure-of-eight semitendinosus tendon autograft reinforced with high-strength suture tape. A comparison with the most recent literature is performed, focusing on biomechanics. Results: The demographics, the mechanism of injury, the management algorithm and the surgical strategy align with the most recent literature. Despite the final treatment, at one year of follow-up, the ROM was restored with full strength throughout the range of motion of the shoulder with no neurological deficits. The reduced joint successfully healed in imaging, and patients returned to their daily lives. The surgical site wounds and donor harvest sites were perfectly healed. Conclusions: Although recent recommendations for treating posterior traumatic SCJ dislocation have advanced, no universally accepted method of stabilization exists, and the surgical strategy is generally entrusted to the surgeon's experience. The literature still increasingly supports figure-of-eight ligament reconstruction with a biological or synthetic graft. This work further implements the literature by reporting good outcomes at follow-up. [ABSTRACT FROM AUTHOR]

Given the posterior chain configuration, it is anticipated that tibial positioning influences hamstring recruitment; medial hamstrings should be more activated during medial rotation, while lateral hamstrings should be more activated during lateral rotation. However, most studies showing this pattern have focused on concentric or isometric strength, leaving the influence on eccentric strength fairly unknown. Therefore, the aim of this study was to investigate the electromyographic response of the hamstring muscles during Nordic hamstring exercises in three leg positions: internal rotation, external rotation, and neutral. This study encompassed a randomized crossover study and used surface electromyography to analyze the activity of the biceps femoris and semitendinosus muscles during the Nordic hamstring exercise, in the three positions. Results indicated no statistically significant differences in muscle activation between positions or sides (p > 0.05), though small effect sizes were observed for the biceps femoris in different positions (η2 = 0.01–0.03). Furthermore, the internal rotation position generally elicited the highest muscle activations. Notably, biceps femoris muscles exhibited higher activations compared to semitendinosus muscles, with the greatest differences seen in the internal rotation position. This suggests that tibial rotation influences hamstring recruitment patterns; however, it was lower than expected. [ABSTRACT FROM AUTHOR]

Background During sprinting, the biceps femoris long head predominantly gets injured, while hamstring strengthening exercises predominantly activate the semitendinosus more effectively. Understanding how joint dominance influences hamstring activity may offer clarity on appropriate exercise selection in strengthening programs. Purpose This study compared three hip-dominant hamstring exercises: the rocker, perpetuum mobile fast and slow (PMfast and PMslow) and the Nordic Hamstring exercise (NHE) on their potential to simulate sprint-like activity and kinematics. Methods Muscle activity of the posterior kinetic chain (biceps femoris, semitendinosus, gluteus maximus, and medial gastrocnemius) was measured with surface electromyography (sEMG) during the exercises and treadmill running at 75% of the individual maximal sprint velocity in male athletes. sEMG data were normalized to maximal sprinting. 3D-motion capture was employed to assess hip and knee angles. Results Eight male athletes were included (age: 24.0 years ± SD 2.9; body mass: 76.8 kg ± 7.7; height: 1.79 m ± 0.08). Greater activity of the hamstrings occurred during the explosive exercises ranging from 63.9% [95%CI: 56.3-71.5%] (rocker) to 49.0% [95%CI: 40.4-57.6%] (PMfast) vs. 34.0% [95%CI: 29.1-38.9%] (NHE) to 32.1% [95%CI: 26.9-37.3%] (PMslow). The rocker showed greatest hamstring and gluteus maximus activity. Biceps femoris consistently showed greater activity than the semitendinosus across all exercises in peak (mean difference: 0.16, [95%CI: 0.07-0.26]) and average (mean difference: 0.06, [95%CI: 0.01-0.11]) activity. PMfast, PMslow and NHE demonstrated less hip flexion angle at peak hamstring activity than the rocker and high-speed running and every exercise showed less hamstring elongation stress than during high-speed running. Discussion Hamstring activity is comparable to high-intensity treadmill running for NHE and PMslow, and greater for the rocker and PMfast. Gluteus maximus activity varied, with the rocker and PMfast showing greater activity than in sprinting. All examined exercises demonstrated their peak activity at short hamstring muscle length. Level of evidence 3b [ABSTRACT FROM AUTHOR]

Background: Preventing severe arthrogenic muscle inhibition (AMI) after knee injury is critical for better prognosis. The novel Sonnery-Cottet classification of AMI enables the evaluation of AMI severity but requires validation. This study aimed to investigate the electromyography (EMG) patterns of leg muscles in the examination position from the classification during isometric contraction to confirm its validity. We hypothesised that the AMI pattern, which is characterised by quadriceps inhibition and hamstring hypercontraction, would be detectable in the supine position during isometric contraction. Methods: Patients with meniscal or knee ligament injuries were enrolled between August 2023 and May 2024. Surface EMG was assessed during submaximal voluntary isometric contractions (sMVIC) at 0° extension in the supine position for the vastus medialis (VM) and vastus lateralis (VL) muscles and at 20° flexion in the prone position for the semitendinosus (ST) and biceps femoris (BF) muscles. Reference values for normalisation were obtained from the EMG activity during the gait of the uninjured leg. The Kruskal–Wallis test was used to compare the activation patterns of the muscle groups within the same leg, and the post-hoc tests were conducted using the Mann–Whitney U test and Bonferroni correction. Results: Electromyographic data of 40 patients with knee injuries were analyzed. During sMVIC, the extensor and flexor muscles of the injured leg showed distinct behaviours (P < 0.001), whereas the uninjured side did not (P = 0.144). In the injured leg, the VM differed significantly from the ST (P = 0.018), and the VL differed significantly from the ST and BF (P = 0.001 and P = 0.026, respectively). However, there were no statistically significant differences within the extensor muscle groups (VM and VL, P = 0.487) or flexor muscle groups (ST and BF, P = 0.377). Conclusion: AMI was detectable in the examination position suggested by the Sonnery-Cottet classification. The flexor and extensor muscles of the injured leg exhibited distinct activation behaviours, with inhibition predominantly occurring in the quadriceps muscles, whereas the hamstrings showed excitation. [ABSTRACT FROM AUTHOR]

This study aimed to measure the pH of meat from both male and female Aubrac cattle. The study focused on the M. Semitendinosus and M. Longissimus dorsi muscles, comparing the pH values of the meat recorded at 0-, 24-, and 48- hours postmortem. Regarding the acidity of M. Longissimus dorsi in males, significant differences were observed between the average pH values at 0-, 24-, and 48-hours post-slaughter, with a slight decrease in the average from 6.05 at 0 hours to 5.5 at 48 hours. Similarly, significant differences were observed in females between the average pH values of M. Longissimus dorsi at 0-, 24-, and 48-hours post-slaughter. Analysing the acidity of M. Semitendinosus, significant differences were observed in both sexes between the average pH values at 0-, 24-, and 48-hours post-slaughter; for example, in males, average values ranging from 5.99 to 5.50 were obtained. In conclusion, these results highlight that the sex of the cattle influenced the average pH value at 0 hours for both muscle categories, collected from Aubrac cattle. [ABSTRACT FROM AUTHOR]

Background: Changes in electromyographic (EMG) activity of hip extensor muscles and knee flexion angles at peak biceps femoris long head (BFlh) EMG activity by different shank angles during razor curl (RC) exercises are unknown. Aims: We investigated the changes in EMG activity of hip extensor muscles and knee flexion angle at peak BFlh EMG activity with different shank angles during RC and also compared the Nordic hamstring (NH) and RC exercises in the EMG activity of hip extensor muscles. Methods: Twelve male university students randomly performed two repetitions of NH and RC with the lower leg slope angle set at 0° (NH0, RC0) and 40° (NH40, RC40). The EMG activity of hip extensor muscles was measured at the BFlh and related muscles. EMG activity was calculated based on the peak value of the root mean square, normalized as a percentage of the maximum voluntary isometric contraction. Results: The BFlh EMG activity of NH0 was higher than that of RC0 (p = 0.002) and RC40 (p = 0.008). The knee flexion angle at peak BFlh EMG activity of NH0 was larger than that of NH40 (p = 0.003) and RC40 (p = 0.002), and RC0 was larger than that of NH40 (p = 0.002) and RC40 (p = 0.002). Conclusion: NH40, the BFlh EMG activity equivalent to NH0, might be more effective for preventing recurrence of hamstring injury because the knee flexion angle at peak BFlh EMG activity remains within 30°, combined with a high BFlh EMG activity. [ABSTRACT FROM AUTHOR]

Purpose: 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. Materials and methods: 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. Results: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the level of muscle activity during sprint running using T2-weighted magnetic resonance imaging. Methods: Fourteen male sprinters (age 21.2 [4.0] y; height 171.8 [4.2] cm, weight 65.5 [5.3] kg, 100-m personal record 11.01 [0.41] s; mean [SD]) performed 3 sets of three 60-m round-trip sprints. Before and after the round-trip sprints, 3 T magnetic resonance imaging scans were performed to obtain the T2 values of the 14 athletes' lower-extremity muscles. Results: After the 60-m round-trip sprints, the T2 value of the gluteus maximus, long head of biceps femoris, semitendinosus, semimembranosus, adductor brevis, adductor longus, adductor magnus, and gracilis increased significantly. The rate of change in the T2 values before and after the 60-m round-trip sprints was notably higher in the semitendinosus and gluteus maximus than in the other muscles. Conclusions: These findings demonstrate the specific physiological metabolism of the lower-extremity muscles during fast sprinting. There are particularly high levels of muscle activity in the gluteus maximus and semitendinosus during sprint performance. [ABSTRACT FROM AUTHOR]

The ischial origin of the hamstring musculature is complex. While the conjoint tendon and semimembranosus are commonly discussed and understood by radiologists, there is a lesser-known origin of the semitendinosus along the inferior and medial surface of the ischium in the form of a broad direct muscular connection. This secondary origin is infrequently described in the radiology literature and is a potential pitfall during grading of semitendinosus injuries if the interpreting physician is unaware of its presence. In a proximal hamstring tendon tear, the direct muscular origin of the semitendinosus can be spared, torn along with the conjoint tendon, or remain intact and contribute to a vertical shearing injury of the semitendinosus myotendinous junction. Detailed knowledge of this anatomy and its imaging appearance in the setting of injury enables the reader to correctly diagnose these unique hamstring injuries. [ABSTRACT FROM AUTHOR]

Background: Various studies regarding the morphology of the muscles of the hamstring compartment have exhibited anatomical variations in terms of origin or insertion points. However, variation of the semitendinosus muscle is uncommon. In this case we report an accessory head of the semitendinosus muscle. Materials and methods: During routine dissection for medical teaching purposes, a unilateral morphological variant of the semitendinosus muscle was noted on the left side in an 82-year-old female. Results: The accessory head of the semitendinosus muscle originated lateral to the midpoint of the semitendinosus muscle. Fibres of the accessory head originated from the medial border of the long head of biceps femoris as well as the midpoint of the semitendinosus. The accessory head had a common insertion point with the semitendinosus muscle. Conclusions: This case report adds to the existing body of knowledge about the semitendinosus muscle, which is of anatomical and clinical value. Knowledge of the anatomical variants is essential for anatomists and clinicians and may avoid misinterpretation during diagnostic procedures. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to compare the patient‐reported outcomes and return to sports of the conservative and surgical treatment of distal hamstring tendon injuries. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines, two reviewers searched PubMed, Scopus and Virtual Health Library databases in January 2023. Clinical studies evaluating conservative or surgical management outcomes of distal hamstring tendon injuries were considered eligible for this systematic review if predefined criteria were fulfilled: (1) published in English or Spanish; (2) evaluated any of the following: patient‐reported outcomes, return‐to‐sports rate (RTS‐R) or return‐to‐sports time (RTS‐T). Data were presented in tables using absolute values from individual studies and derived pooled percentages. Results: Eighteen studies were included for 67 patients and 68 distal hamstring tendon injuries. Initially, 39 patients (58.2%) underwent surgical treatment, whereas 28 (41.8%) were treated conservatively. Among conservative treatment patients, 15 failed and had to be operated on (53.6%), all with distal semitendinosus tendon injuries. Anchor fixation was the technique of choice in 20 lesions (36.4%), tenodesis in 16 (29.1%), tenectomy in 14 (25.5%) and sutures were preferred in five (9%). Thirteen out of 28 patients (46.4%) undergoing initial conservative treatment returned to sports at a mean of 3.6 months (range 1 week to 12 months), in contrast to surgical treatment, in which 36 out of 39 patients (92.3%) returned at a mean of 4.2 months (range 6 weeks to 12 months). Additionally, 14 of 15 patients (93.3%) converted to surgical treatment after failed conservative treatment returned to sports at a mean of 7.6 months after injury. Conclusion: Initial surgical treatment of distal hamstring tendon injuries yields a high RTS‐R (92.3%) at a mean of 4.2 months. Furthermore, 15 out of 28 patients (53.6%) initially treated conservatively had to be operated on, delaying the RTS‐T (mean 7.6 months after injury) without affecting their RTS‐R. Level of Evidence: IV. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the effect of passive and active knee flexion efforts on the stiffness of the thoracolumbar (TLF), semitendinosus (STF), and semimembranosus fascia (SMF). Fourteen young healthy males participated in this study. Using ultrasound shear‐wave elastography, fascia elastic modulus was measured at rest (passive condition) and during submaximal isometric knee flexion efforts (active condition) with the hip at neutral position and the knee flexed at 0°, 45°, and 90°. Analysis of variance designs indicated that when the knee was passively extended from 90° to 0°, shear modulus of the TLF, SMF, and STF increased significantly (p < 0.05). Similarly, active knee flexion contractions caused a significant increase in TLF, SMF, and STF shear modulus (p < 0.001). Compared to hamstring fascia, the TLF showed greater thickness but a lower shear modulus (p < 0.05) while STF modulus was greater compared that to SMF during active contraction (p < 0.05). These results indicate that exercising the hamstring muscles can remotely influence the stiffness of the fascia which surrounds the lumbar area. [ABSTRACT FROM AUTHOR]

Background: Medial ulnar collateral ligament (mUCL) injury can cause significant pain and alter throwing mechanics. Common autograft options for mUCL reconstruction (UCLR) include the palmaris longus (PL) and hamstring tendons. Allograft use may reduce donor site morbidity and decrease function related to PL autografts. Purpose: To compare varus stability and load to failure between a novel allograft for UCLR—knee medial collateral ligament (kMCL)—and a PL autograft in human donor elbow specimens. Study Design: Controlled laboratory study. Methods: A total of 24 fresh-frozen human elbows were dissected to expose the mUCL. Medial elbow stability was tested with the mUCL intact (native), deficient, and reconstructed utilizing the humeral single-docking technique with either a (1) kMCL allograft (n = 12) or (2) a PL autograft (n = 12). A 3-N·m valgus torque was applied to the elbow, and valgus rotation of the ulna was recorded via motion tracking cameras. The elbow was cycled through a full range of motion 5 times. After kinematic testing, specimens were loaded to failure at 70° of elbow flexion, and failure modes were recorded. Results: The mUCL-deficient elbows demonstrated significantly greater valgus rotation compared with the intact and reconstructed elbows at every flexion angle tested (10°-120°) (P <.001). Both kMCL- and PL-reconstructed elbows exhibited significantly higher mean valgus rotation compared with the intact state between 10° and 40° of flexion (P <.01). There were no significant differences in valgus rotation at any flexion angle between the kMCL and PL graft groups. When loaded to failure, elbows reconstructed with both kMCL and PL grafts failed at similar torque values (18.6 ± 4 and 18.1 ± 3.4 N·m, respectively; P =.765). Conclusion: Fresh-frozen and aseptically processed kMCL allografts demonstrated similar kinematic and failure properties to PL tendon autografts in UCL-reconstructed elbows, although neither graft fully restored kinematics between 10° and 40°. Clinical Relevance: Prepared kMCL ligament allografts may provide a viable graft material when reconstructing elbow ligaments while avoiding the potential complications related to PL autografts— including donor site morbidity. [ABSTRACT FROM AUTHOR]

We examined the effect of maceration frequency on surface area, purge loss, and palatability of eye of round and bottom round steaks. Beef eye of round (n = 12) was cut into 8 steaks each and randomly assigned to 0, 1, 2, or 3 macerations and uncooked or cooked slice shear force (SSF) tenderness determinations. Bottom round muscles (n = 12) were cut into 12 steaks and randomly assigned to 0, 1, 2, or 3 macerations and uncooked or cooked SSF or trained sensory evaluations. Steaks were trimmed to a common size (50 cm2 for eye of round and 80 cm2 for bottom round) prior to maceration with a commercial steak tenderizer. Data were analyzed via mixed ANOVA models using a randomized complete block design. Surface area increased (P < 0.001) by 15.4%, 38.6%, and 62.4% for eye of round steaks and 22.0%, 51.3%, and 70.3% for bottom round steaks after 1, 2, or 3 macerations, respectively. Purge losses did not differ (P ≥ 0.247) for either muscle due to maceration frequency. Uncooked SSF values for eye of round steaks were decreased (P < 0.001) by 6.6%, 19.5%, and 40.0% after 1, 2, and 3 macerations; however, cooked SSF values did not differ (P = 0.077). For bottom round steaks, uncooked SSF values were decreased (P < 0.001) by 32.0%, 45.5%, and 67.2% after 1, 2, and 3 macerations; cooked SSF values for steaks macerated 3 times were 26.6% lower (P = 0.022) than steaks macerated 0, 1, or 2 times. Cooking losses were greater (P < 0.001) for macerated eye of round (5.4% to 7.2%) and bottom round steaks (7.6% to 10.8%). Maceration decreased (P < 0.001) sensory juiciness and connective tissue ratings and increased (P < 0.001) sensory tenderness ratings. Maceration increased surface area and improved tenderness.

Introduction: Fibrotic myopathy of the gracilis, semitendinosus, and semimembranosus is described primarily in working German Shepherd dogs. The purpose of this case series is to describe the rehabilitation modalities and treatments utilized in working dogs with fibrotic myopathy and the time frame they were able to continue working. Methods: Medical records of patients with hindlimb lameness that were presented to the Schwarzman Animal Medical Center in New York City from 2012 to 2023 were retrospectively searched. Signalment, history, clinical evaluation, gait analysis, goniometry of stifles, and follow-up evaluation were compared among patients. Ten male working dogs met inclusion criteria. Extracorporeal Shockwave Therapy (ECSWT) was administered under sedation or general anesthesia. Rehabilitation therapy (RT), including massage, hamstring stretch, photobiomodulation, pulsed electromagnetic field therapy, warm compress, therapeutic ultrasound, underwater treadmill, and therapeutic exercises, were performed once every one to 3 weeks with varying protocols according to patient assessments. Follow-up phone calls and emails were conducted to determine long-term outcome. Results: On average, dogs were able to work full-time for 32.1 months (range 6-82; SD 23.6) from the time of diagnosis. No activity limitation was reported by the owners/handlers. Discussion: This report is the first to describe non-invasive medical treatments that may extend the working ability of dogs diagnosed with fibrotic myopathy. Further prospective randomized controlled studies are needed to demonstrate the efficacy of ECSWT and RT for treating fibrotic myopathy. Conclusion: The results of this retrospective study suggest that the combination of ECSWT and RT may allow working dogs with fibrotic myopathy to continue their working capacity for an extended period of time. [ABSTRACT FROM AUTHOR]

Purpose: This study compares the average speed, knee flexor peak torque and shear modulus of the hamstrings after a repeated sprint task, in football players of different competitive levels and playing positions. Methods: Fifty-four football field players without hamstring strain injury history participated, 15 being categorized as professional (2nd league) and 39 as semi-professional (17 in 3rd and 22 in 4th league). Muscle shear modulus was assessed using ultrasound-based shear wave elastography at rest and at 20% of maximal voluntary isometric effort before and immediately after the repeated sprint protocol. Results: No significant differences were seen in average sprint speed between competitive levels (p = 0.07; η2p = 0.28) and positions (p = 0.052; η2p = 0.29). Moreover, the sprint fatigue index showed no significant differences between competitive levels (p = 0.14; η2p = 0.08) and playing positions (p = 0.89; η2p = 0.05). No significant differences were observed in hamstring shear modulus changes between competitive levels (p = 0.94; η2p = 0.03) and positions (p = 0.92; η2p = 0.03). Peak torque changes also showed non-significant association with competitive levels (p = 0.46; η2p = 0.03) and positions (p = 0.60; η2p = 0.02). Conclusion: The results of this study suggest that the average sprint speed performance parameter and mechanical parameters are not able to distinguish football players of different competitive levels and positions. [ABSTRACT FROM AUTHOR]

This study examined the effects of ultrasound transducer pressure and examiner experience on the biceps femoris long head and semitendinosus muscle active shear modulus in healthy individuals (n = 28). Active shear modulus was assessed using shear wave elastography at 20% of knee flexor maximal voluntary isometric contraction. Examiners with different experience levels measured the muscles' shear modulus with three pressure levels: mild, moderate, and hard. A main effect of transducer pressure was found for both biceps femoris long head (p < 0.001; η2 p = 0.314) and semitendinosus muscles (p < 0.001; η2 p = 0.280), whereas differences were found between mild-moderate (biceps femoris long head: p = 0.013, d = 0.23; semitendinosus: p = 0.024, d = 0.25), and mild-hard pressures (biceps femoris long head: p = 0.001, d = 0.47; semitendinosus: p = 0.002, d = 0.47). Examiners performed similar shear modulus measurements in the biceps femoris long head (p = 0.299; η2 p = 0.041) and semitendinosus (p = 0.177; η2 p = 0.066), although the experienced examiner showed a higher measurement repeatability (biceps femoris long head: ICC = 0.86–0.95, semitendinosus: ICC = 0.89–0.96; vs. biceps femoris long head: ICC = 0.78–0.87, semitendinosus: ICC = 0.66–0.87). Transducer pressure influences the active shear modulus measurement between mild and moderate or hard pressures. Additionally, examiner experience seems to have no influence on muscle active shear modulus measurement when assessed at the same site (using casts). Future studies assessing active muscle shear modulus should use mild transducer pressure and having experienced examiners in order to improve measurement reliability. [ABSTRACT FROM AUTHOR]

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Purpose: The Nordic hamstring exercise (NHE) has been shown to considerably reduce hamstring injuries among soccer players. However, as the load in the NHE is the person's own bodyweight, it is a very heavy exercise and difficult to individualize. The flywheel inertial leg curl (FLC) could be an alternative since the eccentric overload is based on the amount of work produced in the concentric movement. Therefore, the primary aim of this study was to compare the activation in the hamstrings at long muscle lengths in the NHE and the FLC in amateur soccer players. Methods: Fifteen male amateur soccer players performed 5 repetitions in each exercise in a randomized and counterbalanced order. The concentric and eccentric movements were divided into lower and upper phases. Surface EMG was measured distally, proximally, and in the middle, at both muscles. Results: In the lower phase in the eccentric movement, there were no significant differences between the 2 exercises (P =.101–.826). In the lower concentric movement, the FLC led to higher activation in all parts of both the biceps femoris (31%–52%, P <.001) and the semitendinosus (20%–35%, P =.001–.023). Conclusion: Both exercises activated the hamstrings similarly at long muscle lengths during eccentric contractions (Nordic hamstring, nonsignificantly higher). However, when performing concentric contractions, the FLC induced higher activations. Therefore, the FLC could be a useful alternative to the NHE and particularly suitable for weaker athletes before progressing to NHE. [ABSTRACT FROM AUTHOR]

Purpose: This study compares the average speed, knee flexor peak torque and shear modulus of the hamstrings after a repeated sprint task, in football players of different competitive levels and playing positions.Methods: Fifty-four football field players without hamstring strain injury history participated, 15 being categorized as professional (2nd league) and 39 as semi-professional (17 in 3rd and 22 in 4th league). Muscle shear modulus was assessed using ultrasound-based shear wave elastography at rest and at 20% of maximal voluntary isometric effort before and immediately after the repeated sprint protocol.Results: No significant differences were seen in average sprint speed between competitive levels (p = 0.07; η2p = 0.28) and positions (p = 0.052; η2p = 0.29). Moreover, the sprint fatigue index showed no significant differences between competitive levels (p = 0.14; η2p = 0.08) and playing positions (p = 0.89; η2p = 0.05). No significant differences were observed in hamstring shear modulus changes between competitive levels (p = 0.94; η2p = 0.03) and positions (p = 0.92; η2p = 0.03). Peak torque changes also showed non-significant association with competitive levels (p = 0.46; η2p = 0.03) and positions (p = 0.60; η2p = 0.02).Conclusion: The results of this study suggest that the average sprint speed performance parameter and mechanical parameters are not able to distinguish football players of different competitive levels and positions.

IntroductionFibrotic myopathy of the gracilis, semitendinosus, and semimembranosus is described primarily in working German Shepherd dogs. The purpose of this case series is to describe the rehabilitation modalities and treatments utilized in working dogs with fibrotic myopathy and the time frame they were able to continue working.MethodsMedical records of patients with hindlimb lameness that were presented to the Schwarzman Animal Medical Center in New York City from 2012 to 2023 were retrospectively searched. Signalment, history, clinical evaluation, gait analysis, goniometry of stifles, and follow-up evaluation were compared among patients. Ten male working dogs met inclusion criteria. Extracorporeal Shockwave Therapy (ECSWT) was administered under sedation or general anesthesia. Rehabilitation therapy (RT), including massage, hamstring stretch, photobiomodulation, pulsed electromagnetic field therapy, warm compress, therapeutic ultrasound, underwater treadmill, and therapeutic exercises, were performed once every one to 3 weeks with varying protocols according to patient assessments. Follow-up phone calls and emails were conducted to determine long-term outcome.ResultsOn average, dogs were able to work full-time for 32.1 months (range 6–82; SD 23.6) from the time of diagnosis. No activity limitation was reported by the owners/handlers.DiscussionThis report is the first to describe non-invasive medical treatments that may extend the working ability of dogs diagnosed with fibrotic myopathy. Further prospective randomized controlled studies are needed to demonstrate the efficacy of ECSWT and RT for treating fibrotic myopathy.ConclusionThe results of this retrospective study suggest that the combination of ECSWT and RT may allow working dogs with fibrotic myopathy to continue their working capacity for an extended period of time.

Chronic ankle instability is a pathology arising from one of the most common orthopedic injuries, lateral ankle sprains. The gold standard surgical procedure for lateral ankle instability is repair of the anterior talofibular and calcaneofibular ligaments with imbrication of the inferior extensor retinaculum. The senior author's indications for a modified Brostrom versus a modified Chrisman-Snook have evolved over the past decade. Indications for a modified Chrisman-Snook include: revision reconstruction, generalized laxity, collagen vascular disease, BMI greater than 35, and significant hindfoot varus or midfoot cavus. The primary aim of this report is to provide a narrative review of the Chrisman-Snook procedure and overview of our modified technique.

Purpose: To investigate the rate of bacterial contamination of semitendinosus (ST) tendons during graft harvest in anterior cruciate ligament reconstruction (ACLR), in order to precisely specify the underlying pathogens and obtain data on their susceptibility to potential antibiotics. Methods: In a prospective study, a total of 59 consecutive patients undergoing primary ACLR were recruited from one centre. No patient had history of previous surgery to the knee or showed clinical signs of infection. Four tissue samples of harvested ST tendons for anterior cruciate ligament (ACL) autografts (case group; ST) were examined for evidence of bacterial colonisation and compared to four tissue samples of the native ACL as negative controls (control group; ACL). Three of the respective samples were subjected to cultural microbiological examination and one to 16S rRNA-PCR. Antibiotic susceptibility testing was performed for each pathogen that was identified. Results: A total of 342 samples were analysed by culture. Significantly more patients showed a positive culture of the ST (33.9%; n = 20/59) compared to 3.4% of patients (n = 2/59) with positive culturing of the ACL (p < 0.0001). Including 16S rRNA-PCR, in a total of 42.4% (25/59) of patients, bacteria were detected in at least one ST sample either by PCR and/or culture. All species found (n = 33) belong to the typical skin flora with Staphylococcus epidermidis (39.4%; n = 13/33) being the most common species, followed by Staphylococcus capitis (24.2%; n = 8/33). All tested isolates (n = 29) were susceptible to vancomycin (29/29, 100%), 69% (n = 20/29) to oxacillin and 65.5% (n = 19/29) to clindamycin. Conclusion: ST autografts for ACLR were commonly contaminated with skin commensal bacteria during harvest. One-third of the isolates showed resistance to typical perioperative intravenous antibiotics, whereas all isolates were sensitive to vancomycin. Therefore, routine prophylactic decontamination of all hamstring autografts before implantation should be recommended, preferably with topical vancomycin. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]

Background: The effect of 10 × 30 m repeated sprints on passive and active stiffness of semitendinosus (ST) and biceps femoris long head (BFlh), and knee flexor maximal voluntary isometric contraction (MVIC) and rate of force development (RFD), and whether athletes with previous hamstring injury have a different response, is unknown. Hypothesis: Repeated sprints would (1) increase BFlh stiffness and decrease ST stiffness and knee flexors MVIC and RFD in healthy participants; and (2) greater magnitude of response would be seen in athletes with previous hamstring injury. Study Design: Case series (experiment I) and case control (experiment II) study designs. Level of Evidence: Level 3. Methods: Healthy nonathletes attended 2 replicated sessions (experiment I, n = 18), while soccer players with (n = 38) and without (n = 67) previous hamstring injury attended 1 testing session (experiment II). Results: In both experiments, the knee flexors MVIC and RFD decreased after the sprints (P < 0.05). In experiment I, the ST and BFlh passive stiffness reduced after the sprints (P < 0.02), while a small BFlh active stiffness increase was noted (P = 0.02); however, no correlation was observed between the 2 testing sessions for the postsprint muscle stiffness responses (r = -0.07-0.44; P > 0.07). In experiment II, only an ST passive stiffness reduction was observed after the sprints (P < 0.01). No differences were noted between injured and noninjured lower limbs for any variable (P > 0.10). Conclusion: Repeated sprints are likely to decrease the knee flexor's maximal and rapid strength, and to alter the hamstring stiffness in the nonathlete population. Previous hamstring injury does not apparently affect the footballer's hamstring functional and mechanical responses to repeated sprints. Clinical Relevance: The responses of hamstring stiffness and knee flexor strength to repeated sprints are unlikely to be associated with hamstring injury. [ABSTRACT FROM AUTHOR]

Purpose: To compare graft dimensions, functional outcomes, and failure rates following anterior cruciate ligament reconstruction (ACLR) with either five-strand or four-strand hamstring autograft options. Methods: Three databases (MEDLINE, PubMed, and EMBASE) were searched from inception to 22 April 2023 for level I and II studies comparing five- and four-strand hamstring autografts in ACLR. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on demographics, surgical details and rehabilitation, graft diameter, patient-reported outcome measures (PROMs), and rates of positive Lachman test, positive pivot shift test, and graft rupture were extracted. PROMs included Knee Osteoarthritis and Outcome Score (KOOS) subscales, Lysholm, and International Knee Documentation Committee (IKDC). Results: One randomized controlled trial (RCT) and four prospective cohort studies with 572 patients were included. Graft diameters were larger in the five-strand group with a mean difference of 0.93 mm (95% CI 0.61 to 1.25, p < 0.001, I2 = 66%). The five-strand group reported statistically higher KOOS ADL subscale and Lysholm scores with a mean difference of 4.85 (95% CI 0.14 to 9.56, p = 0.04, I2 = 19%) and 3.01 (95% CI 0.48 to 5.53, p = 0.02, I2 = 0%), respectively. There were no differences in KOOS symptoms, pain, quality of life, or sports subscales, or IKDC scores. There were no differences in rates of positive Lachman test, positive pivot shift test, or graft rupture with pooled odds ratios of 0.62 (95% CI 0.13 to 2.91, n.s., I2 = 80%), 0.94 (95% CI 0.51 to 1.75, n.s., I2 = 31%), and 2.13 (95% CI 0.38 to 12.06, n.s., I2 = 0%), respectively. Conclusions: Although five-stranded hamstring autografts had significantly larger graft diameters compared to four-stranded grafts with a mean difference of 0.93 mm, similar graft rupture rates and clinical laxity assessments were identified following ACLR. While some PROMs were statistically superior in the five-stranded hamstring groups, the threshold for the minimal clinical important difference was not reached indicating similar clinical outcomes overall. Level of Evidence: Level II. [ABSTRACT FROM AUTHOR]

Hamstring injuries are among the most common muscle injuries. They have been reported in many different sports, such as running, soccer, track and field, rugby, and waterskiing. However, they are also present among the general population. Most hamstring injuries are mild strains, but also moderate and severe injuries occur. Hamstring injuries usually occur in rapid movements involving eccentric demands of the posterior thigh. Sprinting has been found to mainly affect the isolated proximal biceps femoris, whereas stretching-type injuries most often involve an isolated proximal injury of the semimembranosus muscle. The main cause of severe 2- or 3-tendon avulsion is a rapid forceful hip flexion with the ipsilateral knee extended. Most hamstring injuries are treated non-surgically with good results. However, there are also clear indications for surgical treatment, such as severe 2- or 3-tendon avulsions. In athletes, more aggressive recommendations concerning surgical treatment can be found. For a professional athlete, a proximal isolated tendon avulsion with clear retraction should be treated operatively regardless of the injured tendon. Surgical treatment has been found to have good results in severe injuries, especially if the avulsion injury is repaired in acute phase. In chronic hamstring injuries and recurring ruptures, the anatomical apposition of the retracted muscles is more difficult to be achieved. This review article analyses the outcomes of surgical treatment of hamstring ruptures. The present study confirms the previous knowledge that surgical treatment of hamstring tendon injuries causes good results with high satisfaction rates, both in complete and partial avulsions. Early surgical repair leads to better functional results with lower complication rates, especially in complete avulsions.KEY MESSAGEsSurgical treatment of hamstring tendon ruptures leads to high satisfaction and return to sport rates.Both complete and partial hamstring tendon ruptures have better results after acute surgical repair, when compared to cases treated surgically later.Athletes with hamstring tendon ruptures should be treated more aggressively with operative methods.

Our objective was to test the effects of freezing temperature and frequency on purge loss and tenderness of eye of round steaks. Commercially sourced USDA Choice beef semitendinosus (n=10) were aged 24 d postmortem. Twelve steaks were cut from each muscle and randomly assigned to 1 of 12 treatments in a 4×3 factorial treatment structure(unfrozen control at 2.2°C or initial freezing at −17.8°C, −26.1°C, or −34.4°C followed by secondary freezing at −17.8°C, −26.1°C, or −34.4°C). Steaks were weighed after cutting and after thawing following each freezing treatment to determine purge losses. Tenderness was assessed via Warner-Bratzler shear force (WBSF); all data were analyzed via mixed models. Lower total purge losses (6.27%) were observed for steaks initially unfrozen (P0.501) in WBSF was detected among the freezing treatments. These results suggest that freezing temperature and thus freezing rate impact purge loss of eye of round steaks, but mechanical tenderness was not influenced.

Background: The anterior half of the peroneus longus tendon (AHPLT) has been reported to be a suitable autograft for ligament reconstruction with low donor-site morbidity. However, clinical data on graft size are limited. Purpose: To determine (1) if there is any difference in size between the AHPLT and semitendinosus tendon (ST) and (2) whether anthropometric measurements can predict autograft size. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 128 consecutive patients scheduled for knee ligament reconstruction were prospectively enrolled. Patients were treated with AHPLT (50%) or ST (50%). Data included anthropometric measurements and intraoperatively recorded graft size. A Student t test was used to determine differences between the groups. Bivariate correlation coefficients and multivariate regression analyses were calculated to identify relationships between graft size and anthropometric measurements. Results: The AHPLT and ST groups were equally distributed according to age, sex, height, weight, and body mass index (BMI). The quadrupled graft length for the AHPLT was 7.3 ± 0.6 cm as compared with 7.5 ± 0.7 cm for the ST (P <.05). The quadrupled graft diameter was 7.7 ± 0.8 mm for the AHPLT and 8.0 ± 0.7 mm for the ST (P <.05). Height had a moderate (r = 0.57) to high (r = 0.68) correlation with AHPLT and ST length, respectively (P <.01). Weight had a moderate correlation (r = 0.43) with AHPLT diameter (P <.01) but only a weak correlation (r = 0.19) with ST diameter (P >.05). A significant interaction effect of BMI and thigh circumference on ST graft diameter was found, which showed that the effect of thigh circumference on ST graft diameter decreased significantly as BMI increased (P <.05). This moderating effect of BMI could not be observed for the coefficient of shank circumference on AHPLT graft diameter (P >.05). Conclusion: (1) The peroneus longus split tendon provides a reliable autograft size for knee ligament reconstructions. It was prone to be slightly shorter and thinner than the ST. (2) Patient height was the strongest predictor for AHPLT and ST graft length. However, predicting graft diameter based on thigh or shank circumference was more challenging, with higher BMIs affecting the ability to predict ST more than AHPLT. [ABSTRACT FROM AUTHOR]

Abstract Temporal biomechanical and physiological responses to physical activity vary between individual hamstrings components as well as between exercises, suggesting that hamstring muscles operate differently, and over different lengths, between tasks. Nevertheless, the force-length properties of these muscles have not been thoroughly investigated. The present review examines the factors influencing the hamstrings’ force-length properties and relates them to in vivo function. A search in four databases was performed for studies that examined relations between muscle length and force, torque, activation, or moment arm of hamstring muscles. Evidence was collated in relation to force-length relationships at a sarcomere/fiber level and then moment arm-length, activation-length, and torque-joint angle relations. Five forward simulation models were also used to predict force-length and torque-length relations of hamstring muscles. The results show that, due to architectural differences alone, semitendinosus (ST) produces less peak force and has a flatter active (contractile) fiber force-length relation than both biceps femoris long head (BFlh) and semimembranosus (SM), however BFlh and SM contribute greater forces through much of the hip and knee joint ranges of motion. The hamstrings’ maximum moment arms are greater at the hip than knee, so the muscles tend to act more as force producers at the hip but generate greater joint rotation and angular velocity at the knee for a given muscle shortening length and speed. However, SM moment arm is longer than SM and BFlh, partially alleviating its reduced force capacity but also reducing its otherwise substantial excursion potential. The current evidence, bound by the limitations of electromyography techniques, suggests that joint angle-dependent activation variations have minimal impact on force-length or torque-angle relations. During daily activities such as walking or sitting down, the hamstrings appear to operate on the ascending limbs of their force-length relations while knee flexion exercises performed with hip angles 45–90° promote more optimal force generation. Exercises requiring hip flexion at 45–120° and knee extension 45–0° (e.g. sprint running) may therefore evoke greater muscle forces and, speculatively, provide a more optimum adaptive stimulus. Finally, increases in resistance to stretch during hip flexion beyond 45° result mainly from SM and BFlh muscles.

This study examined the effects of fatigue on hamstring muscles and gluteus maximus passive and active shear modulus in hip extension (HE) and knee flexion (KF) at 20% of maximal voluntary isometric contraction performed until task failure. Measurements were taken before and after the fatigue tasks and the delta (post-pre) was calculated. No differences in the fatigue effects on passive shear modulus were seen between muscles nor between tasks. For the active shear modulus: a task × muscle interaction was seen (p = 0.002; η2 p = 0.401). The results for the tasks separately demonstrated only a significant effect for muscle in KF (p < 0.001; η2 p = 0.598), with different individual contributions identified between BFlh-SM (p = 0.006; d = 1.10), BFlh-ST (p = 0.001; d = 1.35) and SM-ST (p = 0.020; d = 0.91). The comparisons between tasks for each muscle demonstrated significant differences for SM (p = 0.025; d = 0.60) and ST (p = 0.026; d = 0.60); however, no differences were seen for BFlh (p = 0.062; d = 0.46). Therefore, fatigue effects induce different patterns on the hamstring muscles in HE and KF tasks when performed at 20% MVIC. [ABSTRACT FROM AUTHOR]

Background: Hand tendon reconstruction is required in both acute and chronic tendon injuries. A number of donor sites have been described; one such novel donor site is semitendinosus tendon used a graft for hand tendon reconstruction. Based on data reviewed, only a few cases are described up till now. Objective: Utility of semitendinosus tendon graft with adequacy of tendon material for hand tendon reconstruction and minimal donor site morbidity Methods: Semitendinosus tendon was utilized in total of 18 patients undergoing tendon reconstruction for chronic tendon injuries and for tendon transfer to achieve adequate length. All cases were performed during January 2019 To December 2020. Full length uni/bilateral semi-tendinosus tendon was harvested using a tendon harvester. Tendon was used as a single slip or was split into further slips as needed for tendon reconstruction. Post operatively splints were continued as per protocol (keeping splint for 6 weeks, encouraging active physiotherapy at 8 weeks, continuing night splintage for total of 10 weeks and advising patient to avoid lifting heavy weight for at least 12 weeks). Patients were followed with assessment of strength via MRC (Medical Research Council) grading scale, and tendon excursion measurements via tip to palm distance. Results: Patients had a mean age for 27.5±2.3 with a predominant male population (72.2%). Post-operative assessment showed finger strength of MRC 5 in twelve patients and MRC 4 in three and MRC 3 in three patients. Tendon excursion was documented measuring a tip to palm distance. Three patients developed tendon adhesions which were treated with tenolysis. Conclusion: Semitendinosus is a recommended option for hand tendon (both flexor & extensor) reconstruction, providing adequate length & strength for reconstruction with high predictable availability and reliability. Although Palmaris longus remains the recommended option for single tendon reconstruction, it is absent in a few cases or is rudimentary, making it difficult to be utilized. [ABSTRACT FROM AUTHOR]

Hamstring injuries are among the most common muscle injuries. They have been reported in many different sports, such as running, soccer, track and field, rugby, and waterskiing. However, they are also present among the general population. Most hamstring injuries are mild strains, but also moderate and severe injuries occur. Hamstring injuries usually occur in rapid movements involving eccentric demands of the posterior thigh. Sprinting has been found to mainly affect the isolated proximal biceps femoris, whereas stretching-type injuries most often involve an isolated proximal injury of the semimembranosus muscle. The main cause of severe 2- or 3-tendon avulsion is a rapid forceful hip flexion with the ipsilateral knee extended. Most hamstring injuries are treated non-surgically with good results. However, there are also clear indications for surgical treatment, such as severe 2- or 3-tendon avulsions. In athletes, more aggressive recommendations concerning surgical treatment can be found. For a professional athlete, a proximal isolated tendon avulsion with clear retraction should be treated operatively regardless of the injured tendon. Surgical treatment has been found to have good results in severe injuries, especially if the avulsion injury is repaired in acute phase. In chronic hamstring injuries and recurring ruptures, the anatomical apposition of the retracted muscles is more difficult to be achieved. This review article analyses the outcomes of surgical treatment of hamstring ruptures. The present study confirms the previous knowledge that surgical treatment of hamstring tendon injuries causes good results with high satisfaction rates, both in complete and partial avulsions. Early surgical repair leads to better functional results with lower complication rates, especially in complete avulsions. Surgical treatment of hamstring tendon ruptures leads to high satisfaction and return to sport rates. Both complete and partial hamstring tendon ruptures have better results after acute surgical repair, when compared to cases treated surgically later. Athletes with hamstring tendon ruptures should be treated more aggressively with operative methods. [ABSTRACT FROM AUTHOR]

Background: Sports and games have become professional activities. The standard of fitness level is raised. Advancement in arthroscopic anterior cruciate ligament (ACL) reconstruction using free tendon graft is one of the key developments. Autograft with minimal donor site or functional morbidity is the key. The latest is the use of semitendinosus in ACL reconstruction. Preoperative knowledge of graft in terms of size is crucial. The present cadaveric study is an attempt to understand the morphology of the semitendinosus tendon (ST) as tendon graft in the local population. Methodology: A total of 50 male cadaver limbs embalmed with formalin were used for harvesting 50 STs. The exact age and height of the cadavers were not known. The femoral length was used as a measure of body height. Tendon length and quadruple diameters were measured. Anderson–Darling test was used for distribution analysis of all the data. Results: In our study, mean length of the tendon was 27.12 cm which is shorter than the required 28 cm for quadrupling the tendon. The average diameter was 8.14 mm which is slightly more than the minimum required thickness of 8 mm. These two findings suggest that tendons in the Indian population are not long enough for an ideal quadruple graft with more than 8 mm diameter. Conclusion: The result of our study is in conformation with the previous studies on the Indian population and also in the Western population. The height of the individual can be inferred from length of the femur; hence, height can be taken as a good predictor for the length of ST in the Indian population.

Background: Semitendinosus and gracilis muscle tendons are among the most frequently used grafts in anterior cruciate ligament reconstructive surgery. Gracilis is also frequently used in breast reconstruction as well as in upper and lower limb reconstruction as a free graft. Materials and Methods: A total of 60 human cadaver lower limbs were studied of 30 adults (12 men and 18 women) who have been embalmed at a tertiary care institution. Those cadavers whose lower limb had undergone surgery in the past and those with concomitant pathology that would have affected the local anatomy were excluded. Gracilis and semitendinosus tendons were taken out of embalmed remains after the cutaneous and subcutaneous tissues had been carefully dissected. Results: It was observed that the maximum load of all the semitendinosus tendons studied had a mean value of 768.2 ± 130.4 N. The semitendinosus tendon’s maximal load in males ranged from 698.4 to 1133.9 N. However in females, the semitendinosus tendon’s maximal load ranged from 589.5 to 780.0 N. Conclusion: The topographical and morphometric data from this study can be utilized as a database of anthropological parameters for the Semitendinosus and Gracilis muscle tendons of a population in a south Indian setting,

Objective: The aim of this study was to assess force and power exertion during a countermovement jump after anterior cruciate ligament reconstruction using either semitendinosus and gracilis or bone-patellar tendon-bone graft. Design: One hundred-nineteen semitendinosus and gracilis and 146 bone-patellar tendon-bone participants performed a countermovement jump on two force platforms after 3 (T1) and 6–9 mos (T2) from surgery. Twenty-four healthy participants served as control group. Peak force of eccentric and concentric phases and peak power were obtained from the analysis of vertical components of the ground reaction forces. Asymmetry was quantified by means of limb symmetry index. Results: Eccentric peak force was significantly (P < 0.05) lower than concentric peak force in both bone-patellar tendon-bone and semitendinosus and gracilis at T1 and T2. At T1, bone-patellar tendon-bone showed higher peak power, but lower limb symmetry index in eccentric and concentric compared with semitendinosus and gracilis. At T2, bone-patellar tendon-bone showed higher peak power than semitendinosus and gracilis, although there were no differences in limb symmetry index between the two groups, which however was significantly (P < 0.05) lower in both groups when compared with control group. Conclusions: Bone-patellar tendon-bone and semitendinosus and gracilis participants showed asymmetries in eccentric and concentric force during a countermovement jump. Bone-patellar tendon-bone showed greater asymmetries and a higher peak power respect to semitendinosus and gracilis participants. [ABSTRACT FROM AUTHOR]

Background: There are potential drawbacks and complications associated with using the anterior approach to harvest the hamstring tendon as an autograft source for anterior cruciate ligament (ACL) and medial patellofemoral ligament (MPFL) reconstruction. A posterior harvest technique has been described as an alternative to an anterior approach in skeletally mature patients. The 2 approaches have not been compared in adolescents. Purpose: We sought to compare the incision size and harvested tendon length produced by anterior and posterior hamstring harvest techniques in an adolescent population. Methods: After obtaining consent, we prospectively collected data on a consecutive series of 115 adolescents undergoing ACL or MPFL reconstruction, including the length of the incision and of the harvested hamstring tendon. Demographic information including age, sex, and body mass index (BMI) was collected at the time of surgery. Results: The mean age at the time of surgery was 14.3 ± 1.8 years (range: 9–21 years), and 43% (N = 50) of participants were male. Of the 115 hamstring autografts, 26 were harvested anteriorly and 89 were harvested posteriorly. Neither mean semitendinosus length nor mean gracilis length was significantly different when harvested anteriorly versus posteriorly. The posterior harvest group had a mean incision length that was significantly smaller than that of the anterior harvest group. No iatrogenic nerve injuries or neurovascular complications were observed in either group. Conclusion: A posterior incision for hamstring autograft harvest provided an alternative approach in adolescents, which resulted in a 20% smaller incision than an anterior approach. For procedures such as MPFL reconstruction that do not require concomitant anteromedial work, posterior hamstring harvest may be used to improve cosmesis while producing viable hamstring autograft tissue for surgical reconstruction. [ABSTRACT FROM AUTHOR]

Temporal biomechanical and physiological responses to physical activity vary between individual hamstrings components as well as between exercises, suggesting that hamstring muscles operate differently, and over different lengths, between tasks. Nevertheless, the force-length properties of these muscles have not been thoroughly investigated. The present review examines the factors influencing the hamstrings' force-length properties and relates them to in vivo function. A search in four databases was performed for studies that examined relations between muscle length and force, torque, activation, or moment arm of hamstring muscles. Evidence was collated in relation to force-length relationships at a sarcomere/fiber level and then moment arm-length, activation-length, and torque-joint angle relations. Five forward simulation models were also used to predict force-length and torque-length relations of hamstring muscles. The results show that, due to architectural differences alone, semitendinosus (ST) produces less peak force and has a flatter active (contractile) fiber force-length relation than both biceps femoris long head (BFlh) and semimembranosus (SM), however BFlh and SM contribute greater forces through much of the hip and knee joint ranges of motion. The hamstrings' maximum moment arms are greater at the hip than knee, so the muscles tend to act more as force producers at the hip but generate greater joint rotation and angular velocity at the knee for a given muscle shortening length and speed. However, SM moment arm is longer than SM and BFlh, partially alleviating its reduced force capacity but also reducing its otherwise substantial excursion potential. The current evidence, bound by the limitations of electromyography techniques, suggests that joint angle-dependent activation variations have minimal impact on force-length or torque-angle relations. During daily activities such as walking or sitting down, the hamstrings appear to operate on the ascending limbs of their force-length relations while knee flexion exercises performed with hip angles 45–90° promote more optimal force generation. Exercises requiring hip flexion at 45–120° and knee extension 45–0° (e.g. sprint running) may therefore evoke greater muscle forces and, speculatively, provide a more optimum adaptive stimulus. Finally, increases in resistance to stretch during hip flexion beyond 45° result mainly from SM and BFlh muscles. [ABSTRACT FROM AUTHOR]

Aims: MRI has been suggested as an objective method of assessing anterior crucate ligament (ACL) graft “ligamentization” after reconstruction. It has been proposed that the MRI appearances could be used as an indicator of graft maturity and used as part of a return-to-sport assessment. The aim of this study was to evaluate the correlation between MRI graft signal and postoperative functional scores, anterior knee laxity, and patient age at operation. Methods: A consecutive cohort of 149 patients who had undergone semitendinosus autograft ACL reconstruction, using femoral and tibial adjustable loop fixations, were evaluated retrospectively postoperatively at two years. All underwent MRI analysis of the ACL graft, performed using signal-to-noise quotient (SNQ) and the Howell score. Functional outcome scores (Lysholm, Tegner, International Knee Documentation Committee (IKDC) subjective, and IKDC objective) were obtained and all patients underwent instrumented side-to-side anterior laxity differential laxity testing. Results: Two-year postoperative mean outcome scores were: Tegner 6.5 (2 to 10); Lysholm 89.8 (SD 10.4; 52 to 100); and IKDC subjective 86.8 (SD 11.8; 51 to 100). The objective IKDC score was 86% A (128 patients), 13% B (19 patients), and 1% C (two patients). Mean side-to-side anterior laxity difference (134 N force) was 0.6 mm (SD 1.8; -4.1 to 5.6). Mean graft SNQ was 2.0 (SD 3.5; -14 to 17). Graft Howell scores were I (61%, 91 patients), II (25%, 37 patients), III (13%, 19 patients), and IV (1%, two patients). There was no correlation between either Howell score or SNQ with instrumented anterior or Lysholm, Tegner, and IKDC scores, nor was any correlation found between patient age and ACL graft SNQ or Howell score. Conclusion: The two-year postoperative MRI appearances of four-strand, semitendinosus ACL autografts (as measured by SNQ and Howell score) do not appear to have a relationship with postoperative functional scores, instrumented anterior laxity, or patient age at surgery. Other tools for analysis of graft maturity should be developed. Cite this article: Bone Jt Open 2021;2(8):569–575.

INTRODUCTION: Bone-patellar tendon-bone (BPTB) and semitendinosus–gracilis (STG) are the commonest grafts used for ACL reconstruction. However even after having been debated for years, there is no consensus about the ideal graft. Moreover, the literature is deficient about STG graft with preserved tibial insertion (STGPI) which preserves the proprioception. Our aim is to compare the outcome of BPTB, free STG and STGPI grafts after ACL reconstruction in professional sports persons. We compared the outcome in terms of mechanical stability, functional outcome, return to sports activity and degenerative changes. MATERIALS AND METHODS: Professional sports persons aged between 16-50 years operated for ACL tear using BPTB, free STG and STGPI grafts with minimum follow-up of two years were identified from hospital records. Patients with associated knee injuries were excluded. Patients, divided in three groups according to graft used, were compared in terms of mechanical stability (arthrometric examination KT-1000 score), functional outcome (Lysholm Score), return to sports activity (Tegner score and difference in thigh circumference) and degenerative changes (KL grading). RESULTS: BPTB graft group was found to be better than free STG and STGPI graft groups in terms of KT-1000 score. There was no statistically significant difference among the groups in terms of Lysholm score, Tegner score, difference in thigh circumference and KL grading. CONCLUSION: BPTB graft is better than free STG and STGPI grafts in terms of knee stability. When compared for patient reported outcome, return to sports activity, osteoarthritic changes and graft failure there is no significant difference among the three types of grafts.

Introduction: The pes anserinus consists of the sartorius, semitendinosus, and gracilis muscles. They coalesce together with the leg fascia to form the anserine plate. The semitendinosus and gracilis both form the deep layer of this plate and are clinically relevant for ligament reconstruction. The aim of the study is to report a detailed morphometric evaluation of the semitendinosus and gracilis muscles and assess their clinical implications. Methods: Using a rigorous dissection process on 18 cadaveric hips, measurements of both the semitendinosus and gracilis muscles with bone parameters were conducted. We measured the following: (a) total femur, femoral shaft, and neck lengths, (b) total muscle lengths, and (c) intra-muscular and extra-muscular (free) tendon lengths. Correlation values between bone variables, muscle variables, and in-between muscle variables were computed. Results: The total muscle and the distal intra-muscular tendon length of the St and Gr are correlated with the total femur length. When compared to gracilis, the total muscle and distal intra-muscular tendon lengths of the ST are much better correlated with the total femur length. The free distal tendon length for both muscles did not show a significant correlation with any of the femoral bone lengths. Conclusion: The variability of tendon length of the ST/Gr poses a significant challenge to surgeons. This study reports a detailed morphometric evaluation of the ST/Gr hamstring muscle and tendons. It revealed a positive correlation between the femoral length and the ST/Gr graft lengths. This could help orthopedic surgeons in predicting the graft lengths pre-operatively and develop better planning for reconstructive surgeries. [ABSTRACT FROM AUTHOR]

Abstract Background Irreparable rotator cuff tears are common and difficult to treat. Techniques for “filling the loss of substance” require fixation to the rotator cuff stump (tendon augmentation) or to the glenoid (superior capsular reconstruction), which are complicated by the narrow working zone of the subacromial space. The main objective of this study was to determine whether a braided graft of gracilis (GR) and semitendinosus (ST) could fill a loss of tendon substance from an irreparable rupture of the supra- and infraspinatus, by fixing the graft to the greater tuberosity and the spine of the scapula. Methods This was a cadaveric study with the use of ten specimens. The GRA and ST tendons were harvested, braided and reinforced with suture. An experimental tear of the supraspinatus (SS) and upper infraspinatus (IS) retracted at the glenoid was made. The GRAST transplant was positioned over the tear. The transplant was attached to the greater tuberosity by two anchors and then attached to the medial third of the scapular spine by trans-osseous stitching. The percentage of filling obtained was then measured and passive mobility of the shoulder was assessed. We proceeded to the same technique under arthroscopy for a 73 years old patient whom we treated for a painful shoulder with irreparable cuff tear. We inserted a GRAST graft using arthroscopy. Results The Braided-GRAST allowed a 100% filling of the loss of tendon substance. Mobility was complete in all cases. Conclusion This technique simplifies the medial fixation and restores the musculo-tendinous chain where current grafting techniques only fill a tendinous defect. The transplant could have a subacromial “spacer” effect and lower the humeral head. The donor site morbidity and the fate of the transplant in-vivo are two limits to be discussed. This anatomical study paves the way for clinical experimentation.

Purpose: To quantify the effect on strength of semitendinosus (ST) graft harvest by comparing isokinetic and isometric muscle strength. Methods: A cohort of 140 patients underwent anterior cruciate ligament (ACL) reconstruction (ACLR) and were randomized to ipsilateral or contralateral ST graft harvest. Isokinetic and isometric muscle strength testing using a dynamometer were collected for the operated and non-operated leg. Patients were assessed pre-surgery and at 6, 12 and 24 months after reconstruction. Results: ST graft harvest reduced isokinetic flexion muscle strength for 6 months. At 12 months follow up there was no significant difference between the two groups and they were all stronger than pre-injury. No other significant differences were found in any primary or secondary outcome measurements. Conclusion: Solitary ST graft harvest does not appear to result in a permanent reduced isometric or isokinetic quadriceps muscle strength on the side where the graft is harvested. A reduction in hamstring muscle strength of less than 10% can be seen at short-term follow-up with full recovery by 12 months. Most patients report little or no donor site pain. Given these findings, ST autograft is an alternative graft choice that could be used for various reconstructions in terms of donor site morbidity. Level of evidence: Level II. [ABSTRACT FROM AUTHOR]

The study aimed at investigating the effects of neuromuscular electrical stimulation superimposed on functional exercises (NMES+) early after anterior cruciate ligament reconstruction (ACLr) with hamstring graft, on muscle strength, knee function, and morphology of thigh muscles and harvested tendons. Thirtyfour participants were randomly allocated to either NMES+ group, who received standard rehabilitation with additional NMES of knee flexor and extensor muscles, superimposed on functional movements, or to a control group, who received no additional training (NAT) to traditional rehabilitation. Participants were assessed 15 (T1), 30 (T2), 60 (T3), 90 (T4) and at a mean of 380 days (T5) after ACLr. Knee strength of flexors and extensors was measured at T3, T4 and T5. Lower limb loading asymmetry was measured during a sit-to-stand-to-sit movement at T1, T2, T3, T4 and T5, and a countermovement-jump at T4 and T5. An MRI was performed at T5 to assess morphology of thigh muscles and regeneration of the harvested tendons. NMES+ showed higher muscle strength for the hamstrings (T4, T5) and the quadriceps (T3, T4, T5), higher loading symmetry during stand-to-sit (T2, T3, T4, T5), sit-to-stand (T3, T4) and countermovementjump (T5) than NAT. No differences were found between-groups for morphology of muscles and tendons, nor in regeneration of harvested tendons. NMES+ early after ACLr with hamstring graft improves muscle strength and knee function in the short- and long-term after surgery, regardless of tendon regeneration. [ABSTRACT FROM AUTHOR]