What is the identity of Gerota fascia? Histological study with cadavers.

OBJECTIVES: The advancement of laparoscopic surgery has allowed surgeons to see finer anatomical structures during surgery. As a result, several issues have arisen regarding Gerota fascia that cannot be explained by previous interpretations, such as its various forms observed during surgery. To address these issues, we histologically examined the structure of Gerota fascia. METHODS: Specimens for study were prepared from kidneys with Gerota fascia from four cadavers, and the structure was studied histologically. Its thickness and collagen fiber area ratios were measured using ImageJ and compared to those of the epimysium of the rectus abdominis muscle. RESULTS: Connective tissue that appeared to be Gerota fascia was observed in 26 specimens. Histologically, the basic structure of Gerota fascia was a sandwich-like structure with a thin layer of thick, long collagen fibers in the central layer, and small granular collagen fibers scattered at the edges. However, not all areas observed had a similar structure; eight specimens were composed only of small granular collagen fibers. The average thickness of the Gerota fascia was 466 µm, and the area ratio of collagen was 27.1%. In contrast, the epimysium was much thicker than Gerota fascia, and its collagen fibers were much thicker and denser. CONCLUSIONS: Gerota fascia, unlike the epimysium, was a very thin and fragile layer of collagen fibers, and its structure was diverse. This explains why Gerota fascia was observed in various states during surgery. It is important for surgeons to understand the properties of Gerota fascia and to treat it appropriately.

Determining Factors Which Limit Resectability in Advanced Hypopharyngeal Malignancy.

BACKGROUND: Preoperative radiological findings of hypopharyngeal cancers are used to determine suitability for surgical resection. We sought to examine preoperative imaging characteristics to determine how well imaging findings predicted surgical resectability. METHODS: A retrospective case-control study of patients undergoing a pharyngolaryngectomy in a tertiary referral center over a 2-year period was completed. Demographic details, previous treatment, subsite, TNM staging, imaging characteristics, and operative characteristics were collected. RESULTS: A total of 78 patients met initial inclusion criteria, of which 71 patients ultimately underwent successful surgical resection (91.1%). Preoperative images identified suspicion of prevertebral fascia invasion in 24 (30.7%) cases and carotid artery involvement in 14 (17.9%) cases. In cases of suspicion of prevertebral fascia invasion (24), 19 cases (79.2%) were resectable, and in those with carotid artery involvement (14), 11 (78.6%) were resectable. Concern for prevertebral fascia invasion on radiology led to a higher likelihood of a close margin (42% vs. 17%) in those without concerning features (p = 0.088). CONCLUSIONS: The present study demonstrated a high rate of resectability of hypopharyngeal and upper esophageal cancers despite imaging findings suspicious for factors that could limit resectability. In patients with advanced hypopharyngeal, especially in the salvage setting, surgery should be considered.

Functional and Structural Long-Term Effects of Repetitive Instrument-Assisted Manual Therapy (IAMT) of the Lumbar Back on the Dorsal Myofascial Chain Among Female Soccer Players: A Randomized, Placebo-Controlled Pilot Trial.

INTRODUCTION: Instrument-assisted manual therapy (IAMT) is suitable for optimizing movement prerequisites, such as range of motion, flexibility, microcirculation, and pain inhibition along myofascial chains, potentially leading to a reduction in hamstring injuries. To date, however, IAMT's modes of action remain largely unclear. This study aimed to examine the functional and structural effects of repetitive IAMT after 2.5 and five weeks. METHODS: Sixteen healthy female soccer players (age: 21.4 (±5.1) years) were randomly grouped into an intervention group and a placebo control group. The intervention group received nine IAMT sessions twice weekly at the right lumbar region. The placebo group received a single pressureless "therapy" at baseline. In addition to structural ultrasound analyses (absolute motion and shear motion), functional mobility tests (passive straight leg raise (PSLR) test and lumbar and thoracic double inclinometry) were performed 4.0 (±2.0) days after the fourth IAMT and 3.4 (±1.1) days after the ninth IAMT in both groups. RESULTS: Hamstring flexibility in the PSLR test improved significantly after the ninth IAMT compared with the placebo group (p < 0.05, effect size: 0.913). No systematic differences were seen at the structural level. CONCLUSION: Repetitive IAMT can improve hamstring flexibility. Further studies in larger groups and diverse collectives are necessary to additionally test the postulated preventive effect also on hamstring injuries. Whether ultrasound is the right method for detecting structural changes in this context needs to be verified in the future.

Ultrasound-guided fascial plane blocks in chronic pain: a narrative review.

BACKGROUND: Recent studies have unveiled the intricate and distinctive nature of fascia, no longer regarding it solely as a muscle container. Recent research highlights its complex innervation and structure, signifying its significance in chronic pain pathways. METHODS: We conducted a systematic literature search (updated on February 2024) to evaluate the role of fascial plane blocks in chronic pain treatment. All article types (randomized clinical trials, prospective and retrospective observational studies along with case reports and case series) were deemed eligible for inclusion if they referenced "fascial plane blocks" for the control of chronic pain conditions (persistent post-surgical, neuropathic, musculoskeletal-myofascial and cancer-related) and were published between 2010 and February 2024. RESULTS: The search revealed an increasing evidence in the literature for the implementation of fascial blocks in chronic pain management, although still heavily limited to case reports or series. CONCLUSION: With the integration of ultrasound technology and a deeper understanding of their mechanisms of action, the fascial plane blocks continue to broaden their application also in chronic pain management, as a part of a multimodal strategy or as an alternative to conventional drugs or opioids.

Design, implementation and effectiveness of human fascia lata biomechanics for tissue engineering.

The fascia lata (FL) is a multi-layered connective tissue with anisotropic mechanical behavior due to its fiber organization. It plays a key role in musculoskeletal functionality, making it important in tissue engineering. Understanding its mechanical response to stimuli like movement or applied pressure is crucial, as the elastic and viscoelastic behavior can vary significantly based on morphological characteristics, harvesting site, and load direction. Thus, the aim of this review is to summarise through a gap analysis the scientific literature on the biomechanical properties of the human FL, identifying all those features (from the experimental set up to its inherent structural variability) that could affect its biomechanical behaviour, and thus unveiling these emerging correlations. Our research reported key mechanical properties of the FL, such as Young's modulus, Ultimate Tensile Strength, failure strain, and anisotropic response, which are crucial for designing and applying obtained allografts and autografts in soft tissue repair. These insights can help surgeons optimize graft applications-selecting the proper harvesting location, technique, graft type, and suture size-and guide clinicians in rehabilitation for personalized medicine.

Parotid Gland Suspension Combined with Rhytidectomy to Recontour the Lower Face and Neck Enlargement Caused by Benign Parotid Hypertrophy.

BACKGROUND: Lower face and neck aging and facial shape changes are usually caused by soft tissue descent. During lower face and neck enlargement, parotid hypertrophy is an important influence factor of morphologic changes in the periauricular regions. Most plastic surgery techniques greatly improve the shape of the lower face and neck, but ignore the manipulation of the parotid gland. We aimed to resolve the lower face and neck enlargement caused by parotid hypertrophy. Thus, we performed parotid gland suspension combined with rhytidectomy to improve the lower face and neck contour. METHODS: This retrospective study recruited 22 patients who underwent parotid gland suspension combined with rhytidectomy from 2012 to 2020. The evaluation of patient outcomes was performed by selecting items from the FACE-Q scale. Surgical procedures involved parotid gland exposure and parotid fascia suspension. RESULTS: Patient-perceived age appraisal indicated a younger appearance with follow-ups for approximately 3-10 year after the surgery (mean ± standard deviation - 5.53 ± 3.67). Patients had a high satisfaction level for facial appearance (67.15 ± 16.84), lower face (74.69 ± 21.22), and contour of the parotid gland areas of the neck (65.76 ± 23.62). The lower face and neck contours were narrowed and tightened. The parotid gland area showed a remarkable improvement after surgery. CONCLUSIONS: Parotid gland suspension combined with rhytidectomy obtained an outstanding improvement. This method can achieve a better lower face and neck contour, especially in patients with benign parotid hypertrophy or lower face and neck enlargement in periauricular regions. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Comparative effectiveness of endoscopic plantar fasciotomy, needle knife therapy, and conventional painkillers in the treatment of plantar fasciitis: a real-world evidence study.

Plantar fascia (PF) is the commonest causes of foot pain in the adult population. Several surgical treatments are available to treat PF. This study was aimed to investigate the clinical efficacy of three different treatments for plantar fasciitis. It was conducted among 60 patients, divided equally into three treatment groups named Needle Knife Therapy, Endoscopic Plantar Fasciotomy, and Conventional Painkillers. Descriptive and analytical analysis were done by using SPSS 25 software. VAS and AOFAS scores were analyzed. The maximum (n = 31) participants were in 41-60 year age range group with normal BMI. These differences of mean VAS and AOFAS pain scores between different treatment groups were statistically significant (One-way ANOVA, p < 0.01). Both scores found lower in the Endoscopic Plantar Fasciotomy group. This study opens a new window of knowledge to achieve sustained pain relief and functional improvement. Moreover, the superiority of Endoscopic Plantar Fasciotomy in treating plantar fasciitis compared to Needle Knife Therapy and Conventional Painkillers was explored.

Anatomical landmarks and procedure technique of Levator Scapulae Plane Block (LeSP block): Case report: Ultrasound-guided block of the superficial, deep and distal planes of the levator scapulae muscle for treatment of shoulder girdle myofascial pain.

Neck pain is a prevalent issue associated with musculoskeletal disorders. This study describes the interfascial Levator Scapulae Plane Block (LeSP Block) technique, using ultrasound guidance for local anesthetic administration to treat chronic neck pain. Two patients, 1 77-year-old female and 1 50-year-old female, underwent the LeSP Block. Immediate postprocedure pain relief was achieved in both, with 1 patient experiencing complete pain remission (VAS = 0) and the other showing significant improvement (VAS = 2) after 30 days. The LeSP Block demonstrated effectiveness and ease of use, suggesting its inclusion in pain management strategies for shoulder girdle and scapular pain. Further anatomical studies aimed at improving the anatomical description of the accessory spinal nerve are recommended to refine the technique.

Allogeneic abdominal non-vascularized rectus fascia transplantation without immunosuppression equals syngeneic transplantation in a rabbit model at short-term follow-up.

Complex abdominal wall repair remains a major surgical challenge. In transplant patients, non-vascularized rectus fascia (NVRF) is successfully used to bridge the defect. To extrapolate this to non-transplant patients, we developed a rabbit model of NVRF-transplantation without immunosuppression comparing syngeneic versus allogeneic transplants. Short-term outcome (4 weeks) was evaluated macroscopically (ingrowth, seroma/hematoma, herniation, and infection), histologically at the graft interface and center (inflammation, neovascularization, and collagen deposition) and by mechanical testing. In both groups a similar macroscopic ingrowth of the NVRF was observed. In the syn-group, one seroma and one hematoma was seen. Two small herniations were detected at the suture line in the allo-group. No surgical site infections were observed. Histologically, graft neovascularization was observed in all animals. Infiltration of T-lymphocytes was seen at the graft interface in both groups, but more in the allo-group (p < 0.0001). Deposition of collagen was not different between groups. Macrophages were present in both groups around sutures and in the center more abundantly in the allo-group (p = 0.0001). Graft stiffness and strength were similar for both groups. With this model, we showed that allogeneic transplantation without immunosuppression results in favorable short-term inflammatory and mechanical outcomes. Long-term experiments are needed to further evaluate the effect on graft integration and hernia development.

Effects of lower back foam rolling on the pressure pain threshold and the range of motion of the lumbar spine in healthy individuals.

Introduction: The aim of this study was to determine the short- and long-term effects of foam rolling (FR) on the pressure pain threshold and the range of motion of the lumbar spine in healthy subjects. Methods: 43 healthy subjects without back problems were randomly assigned to an experimental group (EG) or a control group (CG). The subjects in the EG underwent a 4-week FR program (12 sessions). The subjects in the CG received no intervention. Range of motion was measured using the modified-modified Schober test for flexion and fingertip-to-floor distance for lateral flexion. The pressure pain threshold was measured with a hand-held pressure algometer. The measurements were taken before and after the first FR, after the 4-week program and at the 1-, 3- and 6-month follow-up. The significance level was set at p ≤ 0.05 and the desired power of the test was 92%. Results: We found an improvement in flexion (p = 0.03) and lateral flexion (p < 0.001) in the EG after the first FR and recorded a significant improvement in all measured variables (flexion, lateral flexion and algometry: p < 0.001) at the end of the entire 4-week program. The effects were noticeable up to 6 months after the end of the program (p ≤ 0.03) and were statistically significantly better than in the CG (p ≤ 0.04). The calculated Cohen's d value was 1.15 for flexion, 1.06 for lateral flexion and 0.98 for algometry, which represents a large effect size. Discussion: FR improves the pressure pain threshold and mobility of the lumbar spine in healthy subjects. The effects are noticeable at least 6 months after the end of an FR program.

Secondary rhinoplasty for unilateral cleft lip nasal deformity using the complex of autologous costal cartilage and fascia grafts.

BACKGROUND: Secondary unilateral cleft lip nasal deformity is a prevalent condition in the world, and surgical repair remains a formidable challenge. The objective of the study is to investigate functionally and aesthetically outcomes of a new technique using a complex of autologous costal cartilage and fascia grafts to repair the secondary unilateral cleft lip nasal deformity. METHODS: First, the autologous costal cartilage and fascia were harvested from a total of 34 patients with secondary unilateral cleft lip nasal deformity, who were undergoing treatments at the First Affiliated Hospital of Xi'an Jiaotong University from April 2020 to June 2023. Then, the cartilage was sub-divided into 6 pieces and placed on the depressed alar base, nasal columella, lower lateral cartilage, and nasal tip. At the same time, the fascia was trimmed to cover the nasal tip cap graft and augment the dorsum of the nose. Patient outcomes were assessed through subjective evaluation and objective anthropometric measurements. In addition, associated complications were also examined. RESULTS: All were primary healing incisions, and no patients were encountered with any clinical complications. We found that the overall mean score of the Independent Rhinoplasty Outcome Score (IROS) was very good during the subjective assessment. Also, the objective measurements indicated an excellent nasal symmetry. Furthermore, both functionally and aesthetically satisfactory outcomes were obtained in all the patients during long-time follow-up. CONCLUSIONS: Secondary rhinoplasty using the complex of autologous costal cartilage and fascia grafts is a safe and effective approach for unilateral cleft lip nasal deformity repair.

Fascial Manual Medicine: A Continuous Evolution.

From the perspective of fascial manual medicine (FMM), the body should not be considered as a set of compartments, but as a functional continuum, where most of the tissues (considering embryology) are fascia. The cells that make up the fascia can use multiple strategies to communicate, with neighboring cells, with the tissue to which they belong, and with the entire body, thanks to biochemical (microscopy) and electromagnetic (nanoscopy) possibilities. These multiple capacities to send and receive information make the border or layer of the different tissues seem absent. All the manual techniques that profess to be the only ones that work on the patient's symptoms, dictating a standardized manual procedure that all patients should undergo, represent a clinical deviation. Likewise, thinking that the manual approach can provide biomechanical stimuli only to a single specific structure or layer is a conceptual error. This narrative review briefly reviews the history of fascial-related nomenclature and how the fascial system is currently considered, posing new reflections on how the fascial continuum could be conceived by practitioners who apply FMM in the clinic, such as osteopaths, chiropractors, and physiotherapists.

Sacrocolpopexy: Alternatives to Mesh Grafts.

INTRODUCTION AND HYPOTHESIS: The ongoing pelvic mesh controversy, coupled with a regulatory pause in using pelvic mesh in some countries, has created a need for mesh-free alternatives for sacrocolpopexy (SCP). This article provides an overview of mesh-free alternatives for SCP. METHODS: MEDLINE and PubMed searches were conducted to identify studies reporting on autologous and non-autologous biologic grafts for SCP. Identified studies were reviewed by two of the authors (CY and MR). RESULTS: Emerging evidence on autologous fascia lata (AFL) and rectus sheath (ARS) for SCP is promising, with low donor site morbidity. Non-autologous biologic grafts for SCP are mostly reported to be inferior to mesh. CONCLUSIONS: Emerging evidence suggests that AFL and ARS might be safe and effective alternative options to mesh SCP. The main advantages of AFL for SCP over ARS are laparoscopy or robot-assisted laparoscopy approaches, and that a larger graft can be safely harvested. The benefits of utilising allografts and xenografts are limited by their reduced durability compared with mesh and patient acceptability.

Social issues and medico-surgical complications of improving the gluteal silhouette in African women: Case report and review of the literature.

INTRODUCTION: Voluntary gluteal augmentation is an ideal defined by society, region and period. The low income status of African women does not allow access to recommended medical and surgical methods for this. They use poorly understood and cheaper methods. These cheaper procedures present with serious complications that could be life-threatening. CASE PRESENTATION: We present the case of a 35-year-old woman who was received in a state of septic shock after injection of an unknown substance to improve her gluteal curve. This injection resulted to tissue necrosis and healing was impaired. It required repair using a fascio-cutaneous tensor fasciae latae flap given the aesthetic role the gluteal region accounts for. DISCUSSION: Known gluteal augmentation techniques used in Africa are either natural or artificial. These methods have not been the subject of scientific study. The complications are not known before hand; those encountered in our presentation are severe soft tissue infection with tissue necrosis, neurapraxia and impaired healing. Soft tissue defects caused by necrosis may require the use of a flap, choice of which would give the most satisfactory functional and aesthetic results. CONCLUSION: The complications of these methods cannot be anticipated. Management of these complications is multidisciplinary and must be done in a hospital setting.

Effects of Changing Hip Position on Scapular Kinematics.

The effects of hip position and posture on scapular kinematics have yet to be explored. The purpose of this study was to measure differences in scapular kinematics with changing hip position. Scapular kinematics were measured during scapular plane humeral elevation. Twenty-four subjects were required to elevate the dominant arm up to 120° in the following randomized conditions: standing, seated, seated ipsilateral hip flexion, and seated contralateral hip flexion. Two-way analyses of variance were used to evaluate effects of shoulder elevation and hip position on scapular upward rotation, posterior tilt (PT), and external rotation. For external rotation, there was no significant interaction (P = .714) and no main effect of elevation (P = .618) or condition (P = .390). For PT, there was no significant interaction (P = .693) but significant main effects of elevation (P < .001) and condition (P < .001), with the greatest PT in standing. For upward rotation, there was no significant interaction (P = .698), a significant main effect of elevation (P < .001), and no significant effect of condition (P = .726). The effect on PT may not be clinically significant. These results may serve as a baseline measurement of healthy scapular kinematics across hip positions.

Regional morphological adaptations of vastus lateralis muscle in response to different progressive resistance training programs: A randomised controlled trial.

Background: Resistance training often increases muscle size, a phenomenon known as muscle hypertrophy. These morphological adaptations were typically documented to occur in a non-uniform pattern. Investigating the specific morphological adaptations to different training programs was of interest. Objectives: This study aimed to investigate two resistance training programs, a high-intensity program (HI) and a combined high-intensity with low-intensity blood flow restriction program (MIX), on morphological adaptations of vastus lateralis muscle in healthy young men. Methods: Eighteen active participants were recruited and randomly assigned to the HI (n = 10) or MIX (n = 8) groups, undergoing different 6-week resistance training programs. The training volume set was equated and progressively increased from three sets in weeks 1 and 2 to six sets, and eight sets in weeks 3-4 and 5-6, respectively. Three specific regions of vastus lateralis were assessed by magnetic resonance imaging (MRI) and ultrasound imaging (US) during pre-and post-intervention. Results: Statistical analysis revealed statistically significant increases in muscle area at the proximal (HI: Δ12%, MIX: Δ9.2%), middle (HI: Δ8.7%, MIX: Δ9.0%), and distal (HI: Δ14%, MIX: Δ13%) regions. Additionally, both HI and MIX groups showed statistically significant increases in the sum of muscle thickness post-intervention (HI: Δ12%, MIX: Δ19%) and in the sum of fascia thickness post-intervention (HI: Δ27%, MIX: Δ54%). Despite the MIX group training with higher volume load, no statistical differences were observed between groups for any week. Conclusion: These findings suggested that both HI and MIX programs effectively induced increases in muscle area and sums of muscle and fascia thickness in healthy young men, allowing practitioners to choose either program based on individual preferences and constraints.

The Role of Pretarsal Fascia in Upper Eyelid Crease Formation and its Implications in East Asians.

OBJECTIVE: This study aims to investigate the role of pretarsal fascia in the formation of upper eyelid crease in East Asians. METHODS: Through intraoperative fascia retraction observation, fascia-stretching test, histological examination, and anatomical analysis of pretarsal fascia and surrounding tissues, we explored the mechanical consequences and their impact on upper eyelid crease formation. RESULTS: The levator aponeurosis extension comprises three parts to impact sub-orbicularis fat pad mechanically. The pretarsal fascia is anatomically distinct from the aponeurosis extension but is influenced by its mechanic forces. Differential distribution of collagen fiber bundles within the pretarsal fascia can buffer and transmit the forces of aponeurosis extension, leading to diverse upper eyelid crease patterns. CONCLUSION: The factors determining upper eyelid crease are multifaceted, and the buffering-conduction theory of pretarsal fascia can explain both physiological and postoperative crease in East Asians. It determines the presence, depth, and stability of crease, laying the foundation for the formation of upper eyelid crease in East Asians. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors   www.springer.com/00266.

Burst abdomen: a preventable risk of severe maternal morbidity in a developing country (a case-control study at a university teaching hospital in Tanzania).

Introduction: burst abdomen is a preventable complication of caesarean section that carries an increased risk of maternal death, especially in developing countries including Tanzania. The study aimed to identify the risk factors and high-risk patients for burst abdomen at Muhimbili National Hospital in Tanzania. Methods: a case-control study was performed at Muhimbili National Hospital in Dar es Salaam from 2nd April to 27th December 2019. Characteristics of interest of one case of burst abdomen were compared to three randomly selected controls that consisted of caesarean deliveries either 24 hours before or after the time of delivery of cases. The chi-square test, Fischer´s exact test, and multivariate analysis were used. The level of significance was p < 0.05. Results: a total of 524 women that met the inclusion criteria, comprising 131 cases and 393 controls, delivered by caesarean section in the most recent pregnancy at Muhimbili National Hospital. Cases were independently associated with perioperative illness, including cough (OR 3.8, 95%CI 1.9-7.6), chorioamnionitis (OR 4.5, 95% CI 1.3-14.7), and surgical site infection (OR 3.2, 95% CI 1.7-6.4), and a vertical midline incision wound (OR 1.9, 95% CI 1.2-3.1) compared to control group. Most cases (70%) had intact sutures and loose surgical knots. Conclusion: burst abdomen remains a cause of unnecessary severe maternal morbidity and is independently associated with perioperative illnesses such as cough, chorioamnionitis surgical site infection, and a vertical midline abdominal incision. Thus, there is a need for modifying abdominal fascia closure techniques for patients at risk.

Ultrasound-guided core needle biopsy of deep fascia: A cadaveric study evaluating feasibility, accuracy and reliability.

Over the past few decades, researchers and clinicians have dedicated significant attention to fascial tissues. Current interest focuses on their anatomical and pathophysiological features. Breakthroughs in ultrasound (US) and magnetic resonance imaging (MRI) have enhanced our ability to study the dynamics and alterations of the tissue structures. However, a microscopic perspective is also essential for a comprehensive understanding of some pathologies of the fasciae. The aim of this study was to investigate, using a cadaveric study: (1) the ease of visualization of the landmarks used for the US-guided fascial core needle biopsy (CNB); (2) the consistency and accuracy of needle placement inside fascial layers using US guidance and confirmed by histological examination; (3) inter-rater reliability. We assessed the feasibility of US-guided CNB in different topographical regions of human cadavers: the thoracolumbar fascia (TLF), fascia lata (FL), and crural fascia (CF). The results, confirmed by histological examination, revealed no significant difference in needle placements between the in-plane approaches in the long and short axes for all locations and fasciae studied (long axis: 91.88%; short axis: 96.22%); p > 0.05. US-guided core needle biopsy with the in-plane approach is feasible, consistent and reliable. It could provide most or all of high-quality fascial tissue samples required for pathological examination. It could also reveal changes in fascial pathologies, capturing the exact site of pathology thanks to US guidance, in particular in patchy diseases such as eosinophilic fasciitis.

Contribution of the plantar fascia and long plantar ligaments to the stability of the longitudinal arch of the foot.

The contribution of the Plantar Fascia (PF) and Long Plantar Ligament (LPL), two ligaments extending from the hindfoot to the forefoot, to arch stability has been studied in the past using in vivo, in vitro, and in silico methodologies. In silico studies were based on one single model obtained from one single subject and did not account for the known inter-subject morphological and biomechanical variations. In the present study, we developed computational dynamic models of nine different legs obtained from nine different individuals to evaluate the role of the LPL and PF in arch support, accounting for biological differences between subjects. These models were validated by comparing the simulation results against experimental results from the corresponding cadaver legs. After validation, we simulated body weight conditions for each model by applying a vertical load to the tibia, starting from zero and increasing linearly to 720 N. Kinematic and dynamic parameters, including the variation of the medial arch angle and of the navicular height, as well as the passive forces developed by the LPL and PF, were used to evaluate the contribution of these ligaments to arch support under body weight. The results indicate that a total collapse of the medial longitudinal arch occurred only when both the LPL and PF were absent, but a stable arch was maintained when either one of these two ligament structures were present. The results varied significantly among the specific models, highlighting the importance of using multiple models to account for inter-subject morphological differences.