Sonographic measurement of deep fascia parameters - Interrater reliability.

PURPOSE: The deep fascia has recently been a current topic in many medical fields, including rehabilitation. Some research has already focused on assessing deep fascia, however results of individual authors differ in certain aspects. This study focuses on the inter-rater reliability of ultrasound (US) measurement of the thickness of deep fascia and loose connective tissue (LCT). The aim was to define the causes of any discrepancies in measurement that could contribute to the unification of management of evaluating fascia. METHODS: An observational study was performed including 20 healthy individuals in whom fascia lata of the anterior thigh was examined by US imaging and then measured in Image J software. Three raters participated in this study: the first with 6 years of US imaging experience, other two were newly trained. The measurement of fascial parameters was conducted in two phases with special consultation between them resulting in an agreement of the research team on the more precise way of measurement. RESULTS: Results revealed the value of inter-rater reliability ICC3,1 = 0.454 for deep fascia thickness and ICC3,1 = 0.265 for LCT thickness in the first phase and any significant difference in the second phase. This poor inter-rater reliability led to a search for possible causes of discrepancies, which authors subsequently highlighted. CONCLUSION: The findings of the study show the main pitfalls of deep fascia measurement that should contribute to the unification of evaluation.

Change in gliding properties of the iliotibial tract in hypermobile Ehlers-Danlos Syndrome.

PURPOSE: Fascial changes in hypermobile Ehlers-Danlos syndrome (hEDS), a heritable connective tissue disorder, can be used visualized with sonoelastography. The purpose of this study was to explore the inter-fascial gliding characteristics in hEDS. METHODS: In 9 subjects, the right iliotibial tract was examined with ultrasonography. Tissue displacements of the iliotibial tract were estimated from ultrasound data using cross-correlation techniques. RESULTS: In hEDS subjects, shear strain was 46.2%, lower than those with lower limb pain without hEDS (89.5%) and in control subjects without hEDS and without pain (121.1%). CONCLUSION: Extracellular matrix changes in hEDS may manifest as reduced inter-fascial plane gliding.

Revascularization character of autologous fascia lata graft following shoulder superior capsule reconstruction by enhanced magnetic resonance imaging.

BACKGROUND: Fascia lata has been used for arthroscopic superior capsule reconstruction (ASCR) and verified to achieve a good clinical outcome. However, it is still not known about revascularization character of the fascia lata after ASCR. This study was performed to evaluate the revascularization of autologous fascia lata grafts after ASCR by enhanced magnetic resonance imaging (MRI). METHODS: A prospective study of 19 patients with irreparable rotator cuff tears underwent ASCR with autologous fascia lata grafts from September 2019 to April 2021. Radiography examinations and clinical evaluations were performed preoperatively and postoperatively at 6 weeks and 3, 6, and 12 months. The signal-to-noise quotient (SNQ) value and enhancement index (EI) of autologous fascia lata grafts in the great tubercle insertion (GTI), midpoint of the graft (MG), and glenoid insertion (GI) were compared for radiography examination. Clinical evaluation included the American Shoulder and Elbow Surgeons (ASES) score, University of California Los Angeles (UCLA) shoulder score, and Visual Analog Scale (VAS) score. RESULTS: The SNQ values in T1WI enhancement at GI and GTI were significantly higher than those at the plain MRI scan at all postoperative observation timepoints; however, the SNQ values in T1WI enhancement at MG did not show a significant difference until 3 months postoperation. EI values at GTI and GI were significantly higher than those at MG at 6 weeks and 3 months postoperation, while there was no significant difference in the EI value between GTI and GI. At 6 months postoperation, the EI value at GI was significantly higher than those at MG. At 12 months postoperation, the EI value at GI was significantly higher than those at MG and GTI; however, there was no significant difference between GTI and MG. The EI values at GTI and MG peaked at 3 months and 6 months postoperation, respectively, and then plateaued at 12 months postoperation. However, there was no significant difference in the EI value among the different postoperative timepoints at GI. The EI value did not correlate with the VAS and ASES, UCLA scores at any time point or any postoperative observation location. CONCLUSION: Revascularization of the fascia lata was dependent on the location of the fascia lata and plateaus at 12 months postoperation. The EI value did not correlate with the VAS and ASES, UCLA scores during12 months postoperation.

MRI of the Morel-Lavallée lesion - a case series.

INTRODUCTION: The aim of the study was to review the appearances of Morel-Lavallée (ML) lesions on magnetic resonance imaging (MRI). PATIENTS AND METHODS: 14 patients diagnosed with the ML lesion on MRI were analysed retrospectively (mean age = 35 years). Mechanism of injury, time frame from injury to MRI, location, shape, T1 and proton-density fat-suppression (PDFS) signal intensity (SI), presence of a (pseudo)capsule, septations or nodules within the collection, mass effect and fluid-fluid levels were analyzed. The Mellado and Bencardino classification was utilized to classify the lesions. RESULTS: In most cases, mechanism of injury was distortion. Mean time frame between the injury and MRI was 17 days. Lesions were located around the knee in 9 patients and in the peritrochanteric region in 5 patients. Collections were fusiform in 12 patients and oval in 2 patients. 9 collections were T1 hypointense and PDFS hyperintense. 4 collections had intermediate T1 and high PDFS SI. 1 collection had intermediate T1 and PDFS SI. (Pseudo)capsule was noted in 3 cases. Septations or nodules were found in 4 cases. According to the Mellado and Bencardino, collections were classified as seroma (type 1) in 9, subacute hematoma (type 2) in 1 and chronic organizing hematoma (type 3) in 4 cases. CONCLUSIONS: Characteristic features of ML lesion include a fusiform fluid collection between the subcutaneous fat and the underlying fascia after shearing injury. Six types can be differentiated on MRI, with the seroma, the subacute hematoma and the chronic organizing hematoma being the commonest.

Fascia lata packing and tension suturing for symptomatic pseudomeningocele after recurrent cervical intradural tumour resection.

In recurrent posterior cervical intradural tumour resections, serious complications can be developed. The dural can become affected by inflammatory factors or removed during tumor resection; if cerebrospinal fluid (CSF) leakage cannot be stopped by duraplasty, artificial meninges or fascia repair, large pseudomeningocele can develop posteriorly within the soft tissue of the neck. When the pressure of the CSF cannot be maintained steadily, persistent clinical symptoms can occur, such as postural headache or central fever. Moreover, the skin can also be penetrated in a few patients even after extension of the drainage duration, lumbar cistern drainage or skin suturing, leading to the induction of life-threatening intra-cranial infections. Is there a simple and effective surgical method to address this scenario? The aim of this study was, therefore, to investigate the effectiveness of fascia lata packing and tension suturing in the treatment of symptomatic pseudomeningocele after recurrent posterior cervical intradural tumour resection. In our study, nine consecutive spinal surgery patients were recruited from January 2008 to January 2018. All pseudomeningoceles were combined with postural headache, central neurological fever or wound non-union. There were 3 cases of melanocytoma, 3 cases of nasopharyngeal carcinoma metastasis, 2 cases of breast cancer metastasis, and 1 case of spinal canal lymphadenoma. Standard patient demographics, diagnosis, post-operative symptoms, wound healing time, and the largest pre- and last follow-up pseudomeningocele area on axial MRI sections were recorded. All cases were followed-up successfully, from 12 to 24 months, with an average of 15.3 months. Our observations indicate that all wounds healed successfully. The wound union time was 20.7 days on average. After wound union, these patients became symptom free. The largest cerebrospinal fluid area on axial MRI sections improved significantly from 42.9 ± 5.01 cm2 at p re-operation to 6.6 ± 1.89 cm2 at 1 year post-operation (P < 0.05); Our data indicate that .the proposed procedure is simple, safe and effective. And more importantly, it allows rapid closure of any cerebrospinal fluid leakage pools.

An anatomical comparison of the fasciae of the thigh: A macroscopic, microscopic and ultrasound imaging study.

Although the number of Ultrasound (US) imaging studies investigating the fascial layers are becoming more numerous, the majority tend to use different reference points and terminology to describe their findings. The current work set out to compare macroscopic and microscopic data of specimens of the fascial layers of the thigh with US imaging findings. Specimens of the different fascial layers of various regions of the thigh were collected for macroscopic and histological analyses from three fresh cadavers and compared with in vivo US images of the thighs of 20 healthy volunteers. The specimens showed that the subcutaneous tissue of the thigh is made up of three layers: a superficial adipose layer, a membranous layer/superficial fascia, and a deep adipose layer. The deep fascia is composed of an aponeurotic fascia, which envelops all the thigh muscles and is laterally reinforced by the iliotibial tract and an epimysial fascia, which is specific for each muscle. The morphometric measurements of the thickness of the superficial fascia were different (anterior: 153.2 ± 39.3 µm; medial: 128.4 ± 24.7 µm; lateral: 154 ± 28.9 µm; and posterior: 148.8 ± 33.2 µm) as were those of the deep fascia (anterior: 556.8 ± 176.2 µm; medial: 820.4 ± 201 µm; lateral: 1112 ± 237.9 µm; and posterior: 730.4 ± 186.5 µm). The US scans showed a clear picture of the superficial adipose tissue, the superficial fascia, and the deep adipose tissue, as well as the deep fasciae. The epimysial and aponeurotic fasciae of only some topographic areas could be independently identified. The US imaging findings confirmed that the superficial and deep fascia have different thicknesses, and they showed that the US measurements were always larger with respect to those produced by histological analysis (p < 0.001) probably due to shrinkage during the processing. The posterior region (level 1) of the superficial fascia had, for example, a mean thickness of 0.56 ± 0.12 mm at US, while the histological analysis showed that it was 148.8 ± 33.2 µm. Showing a similar pattern, the thickness of the deep fascia was as follows: 1.64 ± 0.85 mm versus 730.4 ± 186.5 µm. Study results have confirmed that US can be considered a valid, non-invasive instrument to evaluate the fascial layers. In any event, there is a clear need for a set of standardised protocols since the thickness of the fascial layers of different parts of the human body varies and the data obtained using inaccurate reference points are not reproducible or comparable. Given the inconsistent terminology used to describe the fascial system, it would also be important to standardise the terminology used to define its parts. The difficulty in distinguishing between the epimysial and aponeurotic/deep fascia can also impede data interpretation.

Massive Heterotopic Ossification of the Tensor Fascia Lata in a Bodybuilder Leading to Severe Hip Dysfunction: A Case Report.

CASE: A 42-year-old bodybuilder with no history of trauma presented to our clinic with persistent right hip pain and rapidly advancing joint stiffness. Imaging confirmed massive, mature heterotopic ossification predominantly involving the right tensor fascia lata. Six months after a tailored surgical removal, there were no signs of disability, pain, or clinical signs of recurrence, and the patient regained proper joint function. CONCLUSION: In massive heterotopic ossification, tailored surgical removal of the part of the lesion that is limiting function may result in a complete functional recovery.

Site dependent elastic property of human iliotibial band and the effect of hip and knee joint angle configuration.

The iliotibial band (ITB) is the lateral thickening of the fascia lata. The ITB has been extensively studied for its relevance to injury, but not much is known about its elastic properties. We aimed to investigate the site- and joint angle-dependence of ITB elasticity. We tested twelve healthy males (22-30 years; in vivo) and twelve male cadavers (69-93 years; cadaver). The Young's modulus of the ITB was measured in the longitudinal direction at five sites (over the proximal, middle, and distal bellies of the vastus lateralis (VL), superior border of the patella, and between femur and tibia) of the right limb, by ultrasound shear wave elastography (in vivo) and the tensile test (cadaver). Joint angle-dependence was also studied for nine different positions (knee angles at 0, 25, 90˚ x hip angles at 0, 40, 90˚) (in vivo). Over VL, the ITB was more compliant at the distal (17.6-190.1 kPa; in vivo, 219.4 ± 68.8 MPa; cadaver, mean ± SD) than other sites (24.2-221.4 kPa, 337.9-362.7 MPa). The ITB at the superior border of the patella and between femur and tibia was stiffer in vivo (31.8-271.8 and 50.9-208.8 kPa), while it was more compliant in cadavers (113.4 ± 63.7 and 130.4 ± 73.7 MPa), compared to other sites. The ITB became stiffer associated with increasing hip extension angle and knee flexion angle, and the hip remarkably affecting the values regardless of site (in vivo). Our findings have clinical significance with respect to the site- and joint angle-dependence of ITB-related overuse injury.

Ultrasound of iliotibial band syndrome.

Iliotibial band syndrome or friction syndrome is an overuse disorder of the lateral knee. It is commonly reported in athletes, such as runners and cyclists, and refers to pain related to physical activity. The diagnosis is based on clinical history and physical assessment. Imaging, including ultrasound, is mainly performed in recurrent or refractory cases. The purpose of this paper is to review the etiology, diagnosis, and therapy of iliotibial band syndrome with a focus on ultrasound imaging and ultrasound-guided treatment. Ultrasound findings include soft-tissue edematous swelling or discrete fluid collection, suggestive of bursitis, between the iliotibial band and the lateral femoral epicondyle. The thickening of the iliotibial band has been inconsistently reported. Treatment varies according to the disease phase and, in the acute phase, consists of rest, physical therapy, and anti-inflammatory medications. Ultrasound-guided local steroid injections are effective in relieving symptoms.

A fluoroscopic analysis of the length changes of the capsulo-osseous layer of the distal iliotibial band.

PURPOSE: Previous studies have implicated the iliotibial band and its deeper capsulo-osseous layer as key restraints against internal rotation. However, the kinematic properties of the capsulo-osseous layer, throughout knee range of motion, are not currently known. Therefore, the purpose of this research was to quantify the length changes of this structure through various degrees of knee flexion. METHODS: Ten cadaveric knee specimens were dissected to expose the capsulo-osseous layer of the iliotibial band. Radiopaque beads were embedded, at standardized increments, into the tissue and fluoroscopic images were taken from 0° to 105° of knee flexion in 15° increments. The positions of the beads were identified in each image and the length, width, and area changes of the capsulo-osseous layer were calculated. The data were analyzed as a percent change from 0° and compared across flexion angles using a repeated-measures analysis of variance (α = 0.05). RESULTS: There was a significant increase in the length of the capsulo-osseous layer at flexion angles greater than 30°, with changes occurring primarily at the level of the femoral insertion. Meanwhile, non-homogenous decreases in width and area were found with increasing flexion angle. The distance between the capsulo-osseous layer insertion on the distal femur and proximal tibia significantly increased from 60° to 105°; maximal changes occurred at 105° [9.64 (4.12) %, p = 0.003]. CONCLUSIONS: The capsulo-osseous layer of the iliotibial band behaves in a non-isometric fashion and this work suggests that tensioning and fixation should occur between 75° and 105° of flexion, if repair or reconstruction is indicated.

Muscle Size and Quality of the Gluteal Muscles and Tensor Fasciae Latae in Women with Greater Trochanteric Pain Syndrome.

Greater trochanteric pain syndrome (GTPS) is prevalent in women and severely impacts quality of life. A key muscle group demonstrating reduced strength are the hip abductors. An understanding of specific muscles affected will help guide targeted rehabilitation. Objectives of this case-control study were to compare gluteal and tensor fasciae latae (TFL) muscle size and quality (fatty infiltration) in women with symptomatic GTPS to asymptomatic age-matched female controls. Magnetic resonance imaging of 16 women with GTPS (mean age 55.75 years, range 23-69) and 15 asymptomatic controls (mean age 55.60 years, range 31-66) was undertaken. Muscle volumes of the gluteus maximus, gluteus medius, gluteus minimus, and TFL were calculated. Fatty infiltration was rated using the Goutallier classification system for all muscles in their entirety, as well as anterior and posterior segments of gluteus medius and minimus. Muscle volumes and fatty infiltration were compared between groups. Significantly smaller muscle volumes were identified in the symptomatic group for the upper (P = 0.01) and lower (P = 0.04) portions of gluteus maximus, gluteus medius (P = 0.03), and gluteus minimus (P = 0.02). There was no difference in TFL (P = 0.18). Symptomatic participants displayed significantly greater fatty infiltration in gluteus maximus upper (P = 0.021) and lower (P = 0.049) when adjusted for BMI, and gluteus minimus (P = 0.018), particularly in the posterior portion (P = 0.04). Anterior gluteus minimus demonstrated high amounts of fatty infiltration in both groups. Gluteal muscle atrophy and fatty infiltration in women with GTPS suggests gluteus maximus and minimus may be an important target for rehabilitation. Clin. Anat., 33:1082-1090, 2020. © 2019 Wiley Periodicals, Inc.

[Tensor fascia lata unilateral hypertrophy: A case report]. / Hipertrofia unilateral del músculo tensor de la fascia lata, a propósito de un caso.

Hypertrophy of the tensor fascia lata muscle is an uncommon clinical entity, which can simulate a soft tissue tumour. In most patients, it presents as a palpable proximal anterior thigh mass. The characteristic appearance on CT or MRI allows a confident diagnosis of muscle hypertrophy to be made, avoiding unnecessary diagnostic biopsy or surgical intervention. In cases with suspected radiculopathy, electromyography is also useful. We present an illustrative case of hypertrophy of the tensor fascia lata muscle and its outcome after rehabilitation treatment.

Assessment of Anterolateral Complex Injuries by Magnetic Resonance Imaging in Patients With Acute Rupture of the Anterior Cruciate Ligament.

PURPOSE: To assess anterolateral complex (ALC) injuries in patients with acute anterior cruciate ligament (ACL) rupture on magnetic resonance imaging (MRI). METHODS: Patients with acute ACL rupture who underwent ACL surgery between 2015 and 2017 and underwent MRI within 6 weeks of the initial trauma were included. Two radiologists assessed magnetic resonance images retrospectively for the status of the ALC, including the iliotibial band (ITB), Kaplan fibers, and anterolateral ligament (ALL), as follows: grade 0, normal; grade 1, periligamentous edema; grade 2, partial tear; and grade 3, complete tear. The findings were analyzed using the Friedman test and weighted κ values. RESULTS: Sixty-nine MRI scans were reviewed. Of the 69 patients, 51% had associated injuries to the ITB (grade 1, n = 31; grade 2, n = 4), 33% had associated injuries to the Kaplan fibers (grade 1, n = 21; grade 2, n = 2), and 57% had associated injuries to the ALL (grade 1, n = 12; grade 2, n = 22; grade 3, n = 5). We found a significant difference in the frequency and grading between ITB, Kaplan fiber, and ALL injuries (P ≤ .032). Inter-reader agreement for assessing the ALC on MRI was almost perfect (κ ≥ 0.922). CONCLUSIONS: On the basis of MRI analysis, ALL injuries were found with varying degrees of severity and intensity with noted injuries to associated surrounding fibers in patients with acute ACL rupture. LEVEL OF EVIDENCE: Level IV, case series.

MRI study of the ligamentization of ACL grafts in children with open growth plates.

INTRODUCTION: There is little published information on the ligamentization of pediatric anterior cruciate ligament (ACL) grafts. The aims of our study were to compare the MRI appearance of ACL grafts performed in a population with open growth plates to normal ACLs in adolescents and to determine whether the MRI signal in the grafts at 6 months could predict a retear. We hypothesized that ligamentization was a slow, gradual process. MATERIAL AND METHODS: This was a prospective multicenter study of 100 ACL grafts (quadriceps tendon, hamstring tendon, fascia lata) in children 7 to 16 years of age. Of these, 65 intact grafts underwent one or more MRI examinations between 6 months and 2 years postoperative. MRI images were also analyzed in 7 patients who suffered a retear and in the intact ACL of 20 adolescents (15 to 18 years of age). The other 28 patients did not undergo an MRI during the postoperative phase. For each MRI, the signal-to-noise quotient (SNQ) was calculated in three different areas in the ACL (proximal, middle, distal) along with the Howell intra-articular and intra-tibial grades from I to IV. The Mantel-Haenszel Chi-square, Wilcoxon signed-rank test and Student's t-test were used to compare groups. The Lin concordance correlation coefficients were calculated for inter-rater consistency. RESULTS: There was a difference in the SNQ between the three zones of a normal ACL. Most were Howell grade III (55% Howell III, 25% Howell II and 20% Howell I). For intact grafts, the SNQ improved significantly between 6 and 12 months and between 6 and 24 months. There was no difference in the SNQ between the three zones independent of the postoperative time point. The intra-articular Howell grade improved significantly between 6 and 24 months and between 12 and 24 months. The intra-tibial Howell grade improved significantly between 12 and 24 months. There were no significant differences between patients with intact grafts and those who suffered a retear. There were no differences between the various types of grafts used. CONCLUSION: Normal ACLs in adolescents have inhomogeneous SNQ and Howell grades. The SNQ and Howell grades in ACL grafts are more homogeneous and continue to improve out to 2 years, but do not reach that of a normal ACL. The signal and appearance of an ACL graft and normal ACL are very different, and the MRI signal at 6 months postoperative is not predictive of retear. LEVEL OF EVIDENCE: III, prospective study.

Morphometric and dynamic measurements of muscular fascia in healthy individuals using ultrasound imaging: a summary of the discrepancies and gaps in the current literature.

PURPOSE: The objectives of this work was to conduct a comprehensive state-of-the art review of the current literature to identify any gaps or discrepancies and summarize the main challenges for obtaining a homogeneous evaluation of muscular fascia in healthy individuals. METHODS: An electronic document search using key words and MeSH terms was performed with various databases. Two independent investigators were tasked with the screening of articles and data extraction. A critical appraisal of what is known was then conducted. RESULTS: The literature search identified 65 articles related to healthy facia in the various databases consulted and 20 articles were kept for the review. The thickest portion of the fascia lata (the iliotibial tract) and the plantar fascia are the most often studied muscular fasciae whereas there is paucity of studies on fascia related to other muscles in the body. CONCLUSION: US imaging is suitable to complement physical examination and for evaluating treatment outcomes. However, the small number of studies and the heterogeneity of the methods did not allow us to establish normal reference values for muscular fascia thickness and to provide strong recommendations about measurement protocols.

Friction Syndromes of the Knee: The Iliotibial Band and Anterior Fat Pads.

As participation in sporting activities increases among the general population, the incidence of overuse injuries continues to rise. Friction syndromes of the knee are common and are often clinically diagnosed without the need for imaging. However, clinical symptoms may overlap with other joint abnormalities, and physical examination may be limited in individuals with excessive pain. Magnetic resonance imaging has remained the modality of choice for the evaluation of internal derangements of the joints and is a useful aid in the diagnosis of friction syndrome of the knee. This case report provides clinicians with an understanding of the most common friction syndromes of the knee joint as well as their imaging findings. (Journal of Surgical Orthopaedic Advances 27(1):77-80, 2018).

[Pseudohypertrophy of musculus tensor fascia lata presenting as a soft tissue tumor: a case report]. / Muskulär pseudo­hypertrofi yttrade sig som mjukdels­tumör - Denervering av tensor fasciae latae visade sig vara orsaken.

Pseudohypertrophy of musculus tensor fascia lata presenting as a soft tissue tumor: a case report Conditions presenting as palpable soft tissue masses are a common clinical issue. This case report describes a patient with unilateral pseudohypertrophy of m. tensor fasciae latae, which is an uncommon differential diagnosis for a palpable soft tissue mass. The patient presented a palpable soft tissue mass located proximally and anteriorly on the right thigh. The primary concern was a sarcoma. The patient was examined with magnetic resonance imaging and electromyography and it could be concluded that the patient had pseudohypertrophy, i.e. accumulation of excess fat and connective tissue inside m. tensor fasciae lata which was caused by impaired function of the efferent nerve at the spinal level. If the diagnosis of soft tissue masses cannot be revealed with thorough clinical history and examination, magnetic resonance imaging is recommended for further investigation.

The iliotibial tract: imaging, anatomy, injuries, and other pathology.

The iliotibial tract, also known as Maissiat's band or the iliotibial band, and its associated muscles function to extend, abduct, and laterally rotate the hip, as well as aid in the stabilization of the knee. A select group of associated injuries and pathologies of the iliotibial tract are seen as sequela of repetitive stress and direct trauma. This article intends to educate the radiologist, orthopedist, and other clinicians about iliotibial tract anatomy and function and the clinical presentation, pathophysiology, and imaging findings of associated pathologies. Specifically, this article will review proximal iliotibial band syndrome, Morel-Lavallée lesions, external snapping hip syndrome, iliotibial band syndrome and bursitis, traumatic tears, iliotibial insertional tendinosis and peritendonitis, avulsion fractures at Gerdy's tubercle, and Segond fractures. The clinical management of these pathologies will also be discussed in brief.

Small femoral offset is a risk factor for lateral femoral cutaneous nerve injury during total hip arthroplasty using a direct anterior approach.

INTRODUCTION: Lateral femoral cutaneous nerve (LFCN) injury is a risk specific to the direct anterior approach (DAA) for total hip arthroplasty (THA). However, prevention strategies have not been established. This study aimed to identify the predisposing factors determining LFCN injury during THA via a DAA. HYPOTHESIS: Patients with LFCN injury after THA via DAA would demonstrate predisposing factors. MATERIAL AND METHODS: LFCN injury was identified using a patient questionnaire. Potential factors predisposing to LFCN injury were identified in four categories in patient records: patient factors (age, sex, BMI, diagnosis and range of hip motion), surgical factors (surgical time and surgeon's experience of the DAA), preoperative radiographic factors (neck-shaft angle, femoral offset, acetabular offset, total offset and length of muscle on computed tomography axial image) and radiographic changes (differences between each offset pre- and post-surgery). Multivariate analysis was performed to identify risk factors for LFCN injury during this surgery. RESULTS: After application of inclusion and exclusion criteria, 102 hips (28 with LFCN injury; 74 without) in 102 patients (17 males, 85 females; mean age 66.0 years [range, 26-88 years]) were included. Univariate analysis of patients with and without LFCN injury revealed that small preoperative femoral offset and short preoperative long axis of the tensor fascia lata were statistically significant risk factors for LFCN injury (P=0.004, and P=0.01, respectively). Multivariate analysis showed that small preoperative femoral offset was the only independent risk factor for LFCN injury (odds ratio, 0.895; 95% Confidence Interval, 0.817-0.981; P=0.0018). DISCUSSION: Smaller femoral offset was a significant risk factor for LFCN injury following THA via a DAA. Our recommendations are that careful attention should be paid to the skin-fascia incision and subcutaneous exposure, and that excessive retraction of the sartorius muscle and tensor fascia lata should be avoided, to reduce the risk of LFCN injury in patients with a small femoral offset. LEVEL OF EVIDENCE: IV, retrospective historical cohort study.

A semiautomatic method for in vivo three-dimensional quantitative analysis of fascial layers mobility based on 3D ultrasound scans.

PURPOSE: Recently, there has been an increasing interest in the role of deep fascia mobility in musculoskeletal dynamics and chronic pain mechanisms; however, no strategies have been presented so far to study in vivo fascial motion in 3D. This paper presents a semiautomatic method, based on ultrasound (US) imaging, enabling a 3D evaluation of fascia mobility. METHODS: The proposed approach relies on the acquisition of 3D US datasets at rest and during a voluntary muscular contraction and consists of two phases: 3D US dataset analysis and generation of a displacement vector field using a block matching technique (Phase 1) and validation and filtering of the resulting displacement vector field for outliers removal (Phase 2). The accuracy and effectiveness of the proposed method were preliminarily tested on different 3D US datasets, undergoing either simulated (procedural) or real (muscular contraction) deformations. RESULTS: As for the simulated deformation, estimated displacement vectors resulting from Phase 1 presented a mean magnitude percentage error of 8.05 % and a mean angular error of 4.78° which, after Phase 2, were reduced by 69.44 and by 83.05 %, respectively. Tests on real deformations further validated the effectiveness of Phase 2 in the removal of outliers from the displacement vector field. CONCLUSIONS: Obtained results preliminarily demonstrate the viability of the proposed algorithm for the analysis of fascia mobility. Such analysis can enable clinicians to better understand the fascia role in musculoskeletal dynamics and disorder. Further experiments are needed to optimize the method in consideration of the anatomical region to be studied.