Harvesting astrip from the distal rectus femoris tendon as an autograft for ligament reconstruction of the knee or other joints. Ligament reconstructions of the knee, both primary and revision procedures. Relative: athletes in jumping sports requiring rapid recovery of explosive strength. Palpation of the distal quadriceps tendon at the "fusion zone," approximately 5 cm proximal to the superior patellar pole. A3-4 cm longitudinal skin incision is made at the junction of the lateral and middle third or centrally. The quadriceps tendon is exposed and identified proximally. After identification, two parallel incisions create an 8-10 mm wide graft. The tendon strip is mobilized with aclamp just above the fusion zone and separated from the deeper layers. Distal detachment of the graft can be performed either (a)with ascalpel after whipstitching of the free end or (b)with aclosed tendon stripper following proximal release under tension. The preparation is then extended proximally by 7-8 cm with scissors and bluntly separated from deeper layers with the index finger. An open or closed tendon stripper (8-9 mm) is advanced proximally with the knee in 20°flexion until complete graft harvest. Rotational movements should be avoided. Rehabilitation follows the protocol of the corresponding ligament reconstruction. No specific measures are required for the donor site. Radiological assessment demonstrated amean distal rectus femoris tendon length of 39 cm (32-47 cm). In cadaveric studies, the technique was feasible and reproducible. Clinically, the graft was used in 103 patients, with amean graft diameter of 8.3 mm. In afew cases, hamstring augmentation was required. Complications such as arthrofibrosis or donor-site hematoma were rare and successfully treated. External studies confirmed the suitability of the rectus femoris tendon, particularly for revision anterior cruciate ligament reconstruction.

Virtual Reality (VR) has been proposed as a tool in rehabilitation to create more realistic, interactive, and engaging environments that can enhance the sense of embodiment, and thus possibly the effect of the treatment itself. Previous research has shown that combining movement observation with somatosensory stimulation may further improve training outcomes. The present study aimed to examine whether a protocol integrating the observation of human movements within an VR environment with proprioceptive stimulation, thereby establishing a Proprioceptive-Augmented virtual Reality (PAR) paradigm, could enhance participants' ability to imitate the dynamic properties of movements presented in VR. Twenty-three healthy young adults were asked to imitate the features of a flexion-extension forearm movement observed in an immersive VR environment, either while receiving or not receiving 80Hz muscle tendon vibration that induced an illusory sensation of movement congruent with the observed direction (PAR). The imitation task was performed with the stimulated forearm either after the stimulation had ended (OFFLINE imitation) or concurrently with it (ONLINE imitation). Participants' ability to reproduce the avatar's mean and maximal velocities was assessed (reproduction error). Root means square error (RMSE) between avatar and participants' trajectory was calculated. In addition, a questionnaire evaluating the sense of embodiment was administered after the OFFLINE imitation task under both conditions, as well as the evaluation of the vividness evoked by PAR and VR. In the OFFLINE task the reproduction error was lower in PAR than in VR, while the opposite was obtained in the ONLINE task. In the OFFLINE task no difference emerged between PAR and VR RMSE values, whilst in the ONLINE task PAR RMSE was higher than that in VR. PAR evoked a higher sense of embodiment and higher vividness compared to VR when considering all the domain tested (body ownership, sense of agency, location of the body). These findings indicate that proprioceptive stimulation in the PAR condition positively affected movement reproduction during the OFFLINE imitation task, likely benefiting from the heightened sense of embodiment and vividness elicited in this condition. This suggests that muscle tendon vibration can enhance the perception of self-motion in VR, enabling richer interaction strategies and offering promising prospects for sensorimotor rehabilitation.

Surgery for advanced stage or recurrent parotid tumors often involves VII nerve sacrifice. Facial reanimation techniques aim to restore corneal protection and both static and dynamic facial symmetry, without compromising resection. Surgical strategies were based on tumor histology and intraoperative frozen section analysis. Masseteric to facial nerve branch (for the ZMM) neurorrhaphy was done in patients without perineural invasion, while temporalis muscle tendon lengthening was used when that nerve was resected. Facial symmetry and function were objectively assessed using the eFACE system preoperatively and in follow-up. Postoperative eFACE analysis demonstrated good results in both static and dynamic facial symmetry. Masseteric to facial neurorrhaphy achieved satisfactory smile excursion (81±14), while static symmetry parameters, including nasolabial fold orientation (90±4), were high across both surgical groups. Gentle and full eye closure scored lower (79±3 and 85±4), reflecting the limited impact of reanimation techniques on voluntary eyelid closure. The multimodal facial reanimation protocol adopted effectively addressed recovery of facial symmetry and function. Masseteric to ZMM branch neurorrhaphy combined with cross face nerve graft offers excellent dynamic results with minimal morbidity, while additional static techniques ensure immediate ocular protection and aesthetic outcomes.

“Eagle syndrome with bilateral stylohyoid ossification: a surgical case report with anatomical correlation”

The latissimus dorsi (LD) muscle is considered one of the most reliable donor sites for autologous breast reconstruction, particularly in patients with prior oncologic treatment or comorbidities precluding microsurgical options. While its consistent anatomy typically permits straightforward surgical planning, rare anatomical anomalies can dramatically alter intraoperative decision-making. We report the case of a 69-year-old woman with a long oncologic history and multiple comorbidities who underwent delayed breast reconstruction using a pedicled LD flap, 1 year after radical mastectomy and axillary lymphadenectomy. Intraoperatively, the LD muscle was found to be completely absent on the left side, with no identifiable muscle belly and tendon. Immediate adaptation was required, and a serratus anterior muscle flap based on a thoracodorsal branch was used instead. Interestingly, retrospective review of a CT scan performed 2 years earlier for a pulmonary complaint revealed clear evidence of unilateral LD muscle absence, an oversight that underscores the importance of targeted imaging review. This case is one of only four reported in the literature, where unilateral absence of the LD muscle in a non-syndromic patient was encountered, and the only one intraoperative discovery during breast reconstruction. This highlights the critical need for anatomical vigilance and intraoperative adaptability in reconstructive surgery. When standard options fail, familiarity with alternative flaps and sequential planning are essential to achieving functional and aesthetic outcomes.

Background/Objectives: Neurological impairments in children with Cerebral Palsy (CP) often lead to altered muscle architecture and function, resulting in calf muscle contractures. Orthotic immobilization aims to promote muscle–tendon unit lengthening through sustained stretch but may also induce disuse atrophy. This study investigated whether combining immobilization with daily activity yields different effects on muscle strength and gait function compared with immobilization alone. Methods: Fourteen ambulant children with spastic CP and equinus deformity (8 unilateral, 6 bilateral; mean age 9.93 ± 3.0 years; GMFCS I: 10, GMFCS II: 4) participated in a 12-week randomized controlled trial. Participants were assigned to either continuous immobilization (23 h/day) using a dynamic ankle–foot orthosis or a combined protocol consisting of 14 h/day immobilization and 10 h/day of activity involving ankle mobility and calf muscle activation. Outcomes included isometric muscle strength, joint range of motion, gait parameters, and functional measures (Gait Outcomes Assessment List (GOAL) and the Paediatric Outcome Data Collection Instrument (PODCI)). Data were analyzed using linear mixed models with Bonferroni correction. Results: Significant time effects were observed for the knee angle at initial contact (IC), the ankle angle at IC, maximum dorsiflexion, and maximum dorsiflexion during swing. A significant group × time interaction was found only for hindfoot-tibia angle at IC. Within-group improvements were noted in activities of daily living, body image and self-esteem, and basic mobility. No significant changes were found for muscle strength or for most questionnaire subscales. Conclusions: The findings indicate time-related improvements in gait, with no consistent advantage of the combined intervention. Further studies with larger samples are needed to evaluate potential long-term effects.

Ankle-foot deformities, such as clubfoot, pose treatment challenges due to complex and patient-specific biomechanics. Accurate assessment of muscle force behavior is essential for tailoring interventions, yet conventional gait analysis is limited in isolating muscle-specific function. Intraoperative force measurements via the muscle's tendon offer a unique opportunity to directly quantify muscle mechanics. This study aimed to characterize the passive and active force-angle relationship of the tibialis anterior (TA) muscle, intraoperatively. Ten patients (ages 3-62) undergoing corrective foot surgery were enrolled, including five with idiopathic deformities and five with neurogenic conditions (hereditary motor and sensory neuropathy, n=3; cerebral palsy, n=2). Isometric TA forces were recorded at multiple ankle angles. Patients with neurogenic deformities exhibited greater ankle range of motion compared to those with idiopathic deformities (by 30.1%, p=0.006). Passive forces were near 0N in dorsiflexion and increased toward plantar flexion (PF), with a maximum of 50.3N at 55° PF; no significant group differences were observed (p=0.42). Active force-ankle angle profiles showed high inter-individual variability, with peak values ranging from 31.1N to 431.6N and no significant differences between groups (p=0.81). Substantial variability in curve shape remained after normalization, indicating distinct functional profiles across patients. This study demonstrates the feasibility of directly quantifying the patient-specific force-generating capacity of the TA muscle. From a forward-looking perspective, incorporating such patient-specific force data into musculoskeletal models may improve force estimations and support more personalized surgical strategies for ankle-foot deformities.

The myotendinous junction (MTJ) is a critical interface between muscle fibers and tendons, essential for force transmission between muscle and bone. Laminin-α2, a key extracellular matrix (ECM) component, is strongly enriched at this interface. Mutations in the LAMA2 gene cause LAMA2-related muscular dystrophy (LAMA2 MD), an early-onset severe congenital muscular dystrophy. Here, we examined the MTJ in dyW/dyW mice, a mouse model for LAMA2 MD. We find a strong disruption of MTJ morphology, including altered muscle fiber tips, collagen XXII mislocalization, and reduced muscle tendon interface. As MTJ loading is altered in dyW/dyW mice and MTJ maintenance requires loading and unloading, we also examined MTJ structures upon denervation-induced unloading. While muscle fiber tip morphology resembled that of dyW/dyW mice, collagen XXII distribution was not affected and the muscle-tendon interface was preserved. Finally, proteomic profiling via laser capture microdissection and mass spectrometry revealed significant regional and global shifts in MTJ protein composition in dyW/dyW and denervated mice. Across both models, we identified integrin-associated remodeling as a shared response linked to the perturbed muscle fiber tip morphology. These findings demonstrate that laminin-α2 is required for MTJ stability, and that mechanical unloading contributes to the observed phenotype. Importantly, our results suggest that disruptions in MTJ structure and protein composition may contribute to the pathology observed in LAMA2 MD.

Background: Spasticity significantly impairs functional recovery after severe acquired brain injury. Current management methods predominantly rely on pharmacological interventions, which can cause substantial side effects or require invasive medical procedures in refractory cases. Focal muscle vibration, a noninvasive technique that applies mechanical vibrations to muscle–tendon units and alters spinal and cortical excitability via proprioceptive pathways, has been effective in reducing spasticity in subjects with stroke. However, there is limited data to support focal muscle vibration as a viable option for improving functional recovery in patients with severe acquired brain injury. Objectives: To evaluate the clinical effects of adding focal muscle vibration to standard physiotherapy compared with standard physiotherapy alone in patients with severe acquired brain injury and spastic hypertonia. Methods: Twenty-four patients were randomly assigned to receive focal muscle vibration in addition to standard care (n = 12) or standard care alone (n = 12) for 3 weeks. Assessments were conducted at baseline, immediately after physiotherapy, and 3 weeks after physiotherapy. The outcomes assessed included the Modified Ashworth Scale, Disability Rating Scale, Modified Barthel Index, and three pain measures. Results: A significant reduction in spasticity was observed in the focal muscle vibration group, as indicated by the Modified Ashworth Scale scores (p = 0.014). Disability Rating Scale scores demonstrated a statistically significant decrease in disability ratings at the end of treatment (p = 0.002) and during the follow-up phase (p = 0.002). Between-group comparisons of change scores revealed a statistically significant improvement in disability ratings in the focal muscle vibration group during the treatment phase (p = 0.011). Significant functional gains were noted on the Disability Rating Scale, which persisted at the follow-up evaluation. Conclusions: Focal muscle vibration reduces muscle spasticity and improves functional status in patients with severe acquired brain injury during inpatient rehabilitation. Future studies with larger sample sizes, blinded assessments, and stratified randomization are needed to verify these findings and develop standardized treatment protocols for this underserved population.

Muscle–tendon function can be categorised into “energy conservation” or “power modulation” tasks. However, little is known about how female tendons adapt to these different loading demands. This study compared muscle–tendon unit morphological and mechanical properties in athletes who regularly undergo either energy conservation (14 runners) or power modulation (eight netballers) activities. Static ultrasound was used to measure Achilles’ and patellar tendon thickness, as well as the thickness, pennation angle, and fascicle length of the gastrocnemii and vastus lateralis muscles. Achilles’ tendon length and moment arm were also measured. Muscle–tendon mechanical measures included plantar flexion and knee extension isometric strength, and Achilles’ tendon elongation, strain, and stiffness. Netballers displayed significantly higher absolute tendon thickness (p = 0.004 for Achilles’, p = 0.021 for patellar), but not when normalised to body mass. Netballers also displayed significantly higher Achilles’ tendon stiffness (p = 0.046) and isometric plantar flexion and knee extension strength (both p < 0.001). No differences were detected in any other measure of muscle or tendon morphology. The results of this study provide evidence that power modulation activities promote different muscle–tendon unit properties to energy conservation activities in females, but that these adaptations may be body mass dependent.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-026-47580-w.

Abstract Volumetric muscle loss (VML) refers to the loss of skeletal muscle that exceeds intrinsic repair and heals with fibrosis, poor perfusion and denervation. Conventional treatments such as muscle grafts and decellularized matrices improve structure but rarely restore normal strength or limb use. Hydrogels have emerged as injectable scaffolds that fill irregular defects, deliver cells and cues and better match muscle-like mechanics. This review summarizes hydrogels for VML repair, including natural and semi-synthetic systems (gelatin, collagen, hyaluronan, fibrin, alginate, muscle-derived decellularized extracellular matrix (ECM)), synthetic networks and peptide-based hydrogels. Natural matrices provide tissue-derived signals but offer limited control over stiffness and degradation. Synthetic hydrogels allow precise tuning of mechanics and porosity but require additional ligands and growth factors to effectively support VML repair. Peptide hydrogels self-assemble into ECM-like nanofibres and can display multiple motifs for adhesion, immunomodulation, angiogenesis and neurotrophic support, although direct VML data remain sparse. Across these material classes, we highlight shared design principles: aligned architectures and hierarchical porosity, graded properties at muscle–tendon and muscle–nerve interfaces and degradation and cue delivery matched to overlapping healing phases, combined with appropriate cell strategies. Together, these concepts support a shift from passive defect filling towards reconstruction of a regenerative niche with hybrid hydrogel constructs for VML repair.

Musculo-Tendinous Changes in Spastic Plantar-Flexor Muscles After Spinal Cord Injury.

Artificial muscles have been in development for decades and play a crucial role in the field of wearable robotics. However, a universal device for both sensing and regulating forces in artificial muscles is still absent, rendering scenario-required force control unfeasible. Inspired by Golgi tendon organs, this work proposes bionic ExoTendon for force sensing and regulating in artificial muscles as a general solution. Leveraging the principles of triboelectrification and electrostatic induction, the ExoTendon offers high linearity, minimal hysteresis, and adjustable sensitivity and range, making it suitable as the tendon of artificial muscles. Specifically, the ExoTendon effectively enable adjustment to the pretension of the artificial muscles, yielding various assistive forces under the same input. With the optimized pretension level and closed-loop force control, the artificial muscle-based exosuit achieves self-force regulation, substantially improving walking balance and speed in stroke subjects under low input, demonstrating its promise in wearable robotics and rehabilitation medicine.

The median nerve (MN) is a main peripheral nerve that includes superficial motor and sensory fibers in the distal forearm. The proximity of the MN to the forearm muscle tendons and neurovascular structures enhances its clinical significance. The safety of invasive procedures in this area relies on a thorough understanding of the nerve morphometric characteristics. However, commonly used superficial anatomical landmarks may not provide the same reliability for every individual. This study aimed to precisely identify the morphometric features of the MN in the distal forearm by using fixed bony landmarks and to evaluate its positional relationships with nearby anatomical structures. Measurements of the length, width, surface area, and distances from the MN to the ulnar styloid process, radial styloid process, flexor carpi radialis tendon, and ulnar nerve were measured by dissecting the forearms of 31 formalin-fixed cadavers. Differences in gender and side were evaluated, along with the connections between wrist width and various morphometric parameters. There was no statistically significant difference between genders or sides. Without regard to sex or side, the mean distance from the MN to the radial styloid process was 20.97 ± 3.02 mm, to the ulnar styloid process was 19.44 ± 4.83 mm, and to the flexor carpi radialis tendon was 3.83 ± 0.96 mm. The mean surface area of the nerve was 1.49 ± 0.63 cm2. Median nerve-ulnar nerve distance was 12.09 ± 3.77 mm, and it remained within a narrow range. Furthermore, a positive correlation was observed between wrist width and both nerve length and surface area. The morphometric features of the MN in the distal forearm consistently align with bone landmarks, making these structures a more reliable guide than variable superficial tendon references. These data will contribute scientific knowledge to improve the safety of interventional methods, particularly in distal forearm and hand surgery. However, as these findings are based on cadaveric specimens, their direct clinical applicability should be interpreted with caution and warrants further validation in living subjects.

This study aimed to evaluate surgical management of superficial digital flexor tendon (SDFT) luxation by modifying the morphology of the calcaneal tuberosity to (1) reduce the risk of recurrent luxation and (2) challenge the need for tarsal joint immobilization postoperatively. Prospective observational study. A total of 11 surgeries in nine client-owned dogs. Dogs with SDFT luxation and no concurrent disease underwent modified block recession calcaneoplasty without joint immobilization. Follow-up at 6 weeks and 12 months included pressure-sensitive walkway analysis, ultrasonography, and computed tomography. A total of 11 limbs in nine dogs were treated using the described technique. All achieved full function at 12 months, with the symmetry index improving from 0.20 ± 0.13 preoperatively to 0.05 ± 0.03 at long-term follow-up (p = .03). Five complications occurred (45% overall): two major (18%) requiring revision surgery and three minor (27%) resolving without intervention. The modified block recession calcaneoplasty without subsequent tarsal joint immobilization led to a significantly improved symmetry index ratio and clinical function at the long-term follow-up compared with preoperative values. No recurrent luxation occurred except one case that suffered fracture of the medial wall of the calcaneal tuberosity. This was successfully revised and no further reluxation occurred. The modified block recession calcaneoplasty technique can be considered a complement to previously described surgical methods for treatment of SDFT luxation in dogs.

Os trigonum (OT) is an accessory bone at the posterior ankle that can lead to posterior ankle impingement. The flexor hallucis longus (FHL) muscle is a potential contributor to this pathology as it passes through the fibro-osseous tunnel behind the medial malleolus adjacent to the talus. To compare the morphology of the FHL muscle belly between patients with symptomatic and asymptomatic OT. Cross-sectional study; Level of evidence, 3. We performed a retrospective analysis of pediatric patients with an OT who underwent ankle magnetic resonance imaging at a single center from 2015 to 2023. We collected descriptive data, imaging indications, and the following radiographic measurements: distance from the distal end of the tibia to the FHL muscle musculotendinous junction (MTJ) (absolute FHL MTJ distance); ratio of absolute MTJ distance to the distance from the tibia to the tarsal tunnel (relative FHL MTJ distance); axial area of the FHL muscle belly or tendon at the midpoint of the OT/Stieda process; and axial and sagittal areas of the OT. A 1-tailed independent t test was used to compare continuous variables, guided by the Levene test for equality of variances. The FHL was positioned significantly lower in the symptomatic group (n = 14) than in the asymptomatic group (n = 21), when represented by both absolute (P = .044) and relative FHL MTJ distances (P = .037). The relationship between symptoms and sex was significant (P = .024). The relationships were also significant between symptoms FHL MTJ distance/patient height (P = .049) and FHL MTJ distance/patient body mass index (P = .041). There was no significant difference in age, FHL axial area, or OT length, area, and volume between groups (P > .05). These findings suggest that the FHL muscle may play a role in the pathogenesis and clinical presentation of OT syndrome. We propose that the evaluation and treatment of OT syndrome should include the assessment and management of the FHL muscle, and that future studies should explore the mechanisms underlying the association between the FHL muscle and OT syndrome.

Muscle-tendon vibration (MTV) has long been employed in both experimental and clinical settings, and its interest as a neurorehabilitation tool continues to grow. Yet, two primary physiological responses elicited by MTV, the tonic vibration reflex (TVR) and the kinaesthetic illusion (KI), remain inconsistently described across studies. This raises a fundamental limitation: how can vibration-induced adaptations be interpreted when the underlying reflexive or perceptual contributions are unclear? In this topical review, we examine the key mechanisms driving these responses and clarify the conditions that shape their expression. We outline how sensory, attentional and motor contexts can transform the same vibratory-induced afferent into strikingly different physiological and behavioural effects. We also address how the variability in these responses - including the antagonist vibratory responses - may contribute to heterogeneous findings and blur the distinction between responders and non-responders to MTV. We conclude that reflexive or perceptual expression should ideally be systematically monitored, or at minimum that experimental conditions be explicitly reported, as their emergence reflects a configuration in which proprioceptive drive and sensorimotor integration are strongly engaged. By reframing TVR, KI and antagonist vibratory responses as informative physiological markers rather than confounds, this review provides a conceptual and methodological framework to improve the design, interpretation and reproducibility of future studies. This perspective may also support the refinement of MTV as a cost-effective and non-invasive neuromodulatory approach for health and performance applications.

A rare anomaly of the cervicobrachial plexus: penetration of the anterior scalene muscle tendon by the T1 nerve root.

To summarize the current research progress of finger flexion deformity caused by forearm flexor muscle lesions, providing a reference for clinical diagnosis and treatment. The domestic and international literature about finger flexion deformity caused by forearm flexor muscle lesions was extensively reviewed. A summary analysis was conducted from the etiology and pathogenesis, diagnosis and differential diagnosis, and treatment methods. The three types of forearm flexor pathology leading to finger flexion deformity include Volkmann's contracture, pseudo-Volkmann's contracture, and congenital flexor muscle lesions with different pathogenesis. The diagnosis is mainly based on the patient's medical history, clinical features, and imaging examinations, with attention paid to differential diagnosis. Currently, conservative treatment for such deformities is not very effective, and surgical treatment is mainly adopted. According to the causes and severity, options such as resection of the contracture band, resection of contracture band, release of compressed muscle (tendon), and flexor origin muscle sliding surgery, could be performed to correct hand deformities and restore hand function, and thus resulting in favorable outcomes. Volkmann's contracture, pseudo-Volkmann's contracture, and congenital flexor muscle lesions causing finger flexion deformity have different causes and pathogenesis, which can be distinguished by carefully inquiring about the medical history, the clinical characteristics of the three, and imaging examinations, thereby selecting appropriate treatment methods.

ABSTRACTMuscle–tendon units (MTUs) tend to exploit their elastic elements to meet a range of energy-absorption and power input demands, but the extent of this may depend on how the muscle produces force. Muscle pre-activation is a habitual strategy observed in vivo during energy-absorbing demands, but it remains a question whether pre-activation alters the power input demands among elastic elements and muscle fascicles. To determine the effect of pre-activation on peak power input demands, we conducted in situ experiments using sonomicrometry and a linear actuator to simulate a pre-activation strategy in the lateral gastrocnemius MTU of wild turkeys (n=6). Onset timing of muscle activation was manipulated to start (1) simultaneously with or (2) before an active MTU stretch (i.e. no pre-activation versus with pre-activation). During MTU stretch, we quantified a peak power input decoupling ratio to determine the relative power input between muscle fascicles and elastic elements. We found that muscle pre-activation decreased the decoupling ratio (mean±s.d., 0.68±0.09 versus 0.56±0.11; P=0.015; Cohen's d=1.49), signifying that muscle fascicles absorbed a greater percentage of total MTU peak power input. We also found that the MTU generated greater force with pre-activation by relying more on active fascicle lengthening during the late phase of MTU stretch, which allowed for greater peak power input capacity of the MTU. These findings highlight how a simple shift in muscle activation timing can prime the MTU to deal with greater peak power input during energy-absorbing activities.