High-resolution ultrasound in the evaluation of the adult hip.

This paper reviews ultrasound of the hip, which is a commonly requested examination for symptomatic hip issues. This includes both intra-articular and extra-articular causes of hip pain. Ultrasound is easily accessible, lacks radiation exposure, and allows for evaluation of the contralateral hip as well as assessment of dynamic maneuvers. Ultrasound can be used to guide interventional procedures. Ultrasound of the hip can be challenging due to the deep location of structures and complex anatomy. Typically, high-frequency transducers are used to examine the hip, however the choice of ultrasound transducer depends on the patient's body habitus, with lower frequency transducers required to penetrate deep structures in obese patients. It is important to have an approach to ultrasound of the hip which includes assessment of the anterior, lateral, posterior, and medial aspects of the hip. The technique and relevant anatomy of each of these compartments are discussed as well as the use of Doppler examination of the hip. Several dynamic maneuvers can be performed to help determine the cause of hip pathology in various locations, and these are described and illustrated. Ultrasound is useful for guided procedures about the hip, and these indications will be reviewed.

Analysis of factors affecting the time for implantation of a total hip arthroplasty in patients with symptomatic primary and secondary hip osteoarthritis.

BACKGROUND: Many studies have identified factors associated with an unfavourable clinical outcome or an early conversion to total hip arthroplasty (THA) after joint-preserving treatment. We analysed the effect and reliability of different factors on the age at which THA becomes necessary. METHODS: Hip joint radiographs of 2485 cases were evaluated using the lateral centre-edge angle (LCEA) and acetabulum angle (ACA) as well as the alpha angle to describe the femoral head shapes. Regressions were performed using patient's age at the time of THA and body mass index (BMI) as well as LCEA and ACA. Multiple linear regressions were used to create a formula comprising factors that significantly correlated with patient age at the time of joint replacement surgery. RESULTS: The BMI, LCEA, and ACA showed significant correlations with the age of THA implantation (p < 0.001). Multiple linear regressions produced the following formula: age (THA) = 72.40-0.40 × BMI + 0.20 × LCEA-0.18 × ACA. BMI showed a stronger impact on the age of end-stage osteoarthritis than the ACA. The formula explained 12.1% of the distributing data (r2). Surprisingly, the alpha angle did not show an impact on the age of THA surgery. CONCLUSIONS: BMI had the greatest impact on patient's age at the time of THA, followed by the characteristic radiological angles for hip dysplasia. The resulting formula could emphasise and visualise the significant impact of these factors. However, despite the calculation being based on 2485 cases, the calculated validity of 12.1% was limited.

The Insertion of Threaded Acetabulum Components: Indications According to Specific Acetabulum Anatomy and Methods to Avoid Pitfalls.

New-generation threaded acetabulum components have been used in total hip arthroplasty (THA) with good outcomes. We have extensively used the EcoFit® SC cup (Implantcast, Buxtehude, Germany) in our practice. In this report, we present some major complications related to the use of this implant, as well as insights regarding the surgical technique to avoid such adverse effects. Furthermore, we attempt to describe certain contraindications for using threaded cups in THA, taking into account specific patient anatomy and intraoperative acetabulum preparation. We have observed acetabulum roof and posterior wall fractures, as well as incomplete placement of the component. Ensuring the meticulous preparation of the peripheral rim of the acetabulum is crucial to prevent incomplete placement since threaded components have a larger diameter than that of the reamers used to prepare the acetabulum. Additionally, when dealing with the acetabula where the posterior or anterior walls have thinned, it is advisable to refrain from using a threaded cup to avoid the risk of intraoperative fractures caused by the torque forces exerted during implant insertion.

Morphological consistency of bilateral hip joints in adults based on the X-ray and CT data.

PURPOSE: The application of the anatomical parameters of the contralateral hip joint to guide the preoperative template of the affected side relies on the bilateral hip symmetry. We investigated the bilateral hip symmetry and range of anatomical variations by measurement and comparison of bilateral hip anatomical parameters. METHODS: This study included 224 patients (448 hips) who were diagnosed with osteoarthritis (OA) and avascular necrosis (AVN) of the femur head, and underwent bilateral primary total hip arthroplasty (THA) in our hospital from January 2012 to August 2020. Imaging data included 224 patients X-ray and 30 CT data at the end of the cohort. Anatomical parameters, including the acetabular abduction angle and trochanteric height, were measured using the Noble method. Postoperative measurements included stem size, difference of leg length and offset. RESULTS: Except for the isthmus width, there were no significant differences in the anatomical morphology of the hip joint. Among the demographic factors, there was a correlation between body weight and NSA. Among various anatomical parameters, a correlation was present between medullary cavity widths of T + 20, T, and T - 20. The difference in the use of stem size is not due to the morphological difference of bilateral medullary cavity, but due to the different of 1- or 2-stage surgery. CONCLUSION: Bilateral symmetry was present among the patients with normal morphology of the hip medullary cavity, theoretically confirming the feasibility of structural reconstruction of the hip joint using the hip joint on the uninjured side. Additionally, the difference in the morphology of the hip medullary cavity is not present in a single plane but is synergistically affected by multiple adjacent planes.

Correlation of hip capsule morphology with patient symptoms from femoroacetabular impingement.

The relationship between morphological characteristics of the hip capsule and patient symptoms in the setting of femoroacetabular impingement (FAI) is undefined. In this study, patients with symptomatic FAI prospectively underwent 3T magnetic resonance (MR) imaging of the affected hip and completed the hip disability and osteoarthritis outcome score (HOOS) to determine the correlation between hip capsule anatomy and patient symptoms. Anterior hip capsule volume, posterior capsule volume, anterior-posterior capsule volume ratio, and proximal-distal volume ratio in the anterior capsule were quantified and measured using axial-oblique intermediate-weighted 3D fast spin echo MR images. A total of 35 patients (35 hips) were included for analysis (mean age: 30.6 years; mean body mass index [BMI]: 24.9 kg/m2 ; 57% male). The mean alpha angle was 62.2° ± 4.7°, the mean anterior hip capsule volume was 1705.1 ± 450.3 mm3 , the mean posterior hip capsule volume was 1284.8 ± 268.5 mm3 , the mean anterior to posterior capsule volume ratio was 1.1 ± 0.39, and the mean proximal to distal volume ratio of the anterior capsule was 0.65 ± 0.28. There was no correlation between age, gender, or BMI, and any hip capsule characteristics. Worse scores on the HOOS pain scale were correlated with increased anterior to posterior volume ratio (r = -.38; 95% confidence interval: -0.06 to -0.63). In conclusion, hip capsule morphology correlates with patient symptoms in the setting of FAI as increased anterior capsular volume, relative to posterior capsular volume, is associated with greater patient pain.

Anatomía articular y parámetros radiográficos de la cadera como factor de riesgo de fractura: una mirada actualizada / Joint Anatomy and Radiographic Parameters of the Hip as Risk Factor for Fracture: An Updated Look

RESUMEN Introducción: Existe un aumento de la evidencia de que la estructura geométrica de la anatomía de la cadera juega un importante papel en la etiología de la fractura. Objetivo: Sistematizar los conocimientos más actuales referentes a las características anatómicas de los parámetros radiográficos de la articulación de la cadera, y su relación con la fractura. Métodos: Se realizó una investigación documental, con los artículos científicos publicados en las bases de datos médicas informáticas como PubMed, Ebsco y SciELo en los últimos 5 años. Resultados: La mayoría de las publicaciones analizan el ángulo cervicodiafisario y el eje de la cadera. Otras medidas analizadas son el eje femoral, la longitud y el ancho del cuello femoral, así como medidas acetabulares. No existe un consenso en la medida del largo del cuello femoral o del eje femoral, a pesar de ser un componente importante de la estructura. El conocimiento de las particularidades de la anatomía y de las características biomecánicas de la cadera permite establecer una base para la comprensión de los factores que afectan esta articulación. Conclusiones: Los estudios que se han realizado sobre las características de los componentes estructurales, demuestran que existe una asociación entre sus dimensiones y la ocurrencia de fractura de cadera, en algunos casos independientes de la densidad mineral ósea(AU)

ABSTRACT Introduction: There is increasing evidence that the geometric structure of the hip anatomy plays an important role in the etiology of the fracture. Objective: To systematize the most current knowledge regarding the anatomical characteristics of the radiographic parameters of the hip joint, and their relationship with the fracture. Methods: A documentary research was carried out, with the scientific articles published, in the last 5 years, in medical computer databases such as PubMed, Ebsco and SciELo. Results: Most of the publications analyze the cervicodiaphyseal angle and the axis of the hip. Other measurements analyzed are the femoral axis, the length and width of the femoral neck, as well as acetabular measurements. There is no consensus on the length of the femoral neck or the femoral shaft, despite being an important component of the structure. Knowledge of the particularities of the anatomy and biomechanical characteristics of the hip allows to establish basis for understanding the factors that affect this joint. Conclusions: The studies that have been carried out on the characteristics of the structural components show that there is association between their dimensions and the occurrence of hip fracture, in some cases independent of bone mineral density(AU)

The calcar femorale: A new perspective.

It is the role of the hip joint to support the superincumbent body weight while its complex range of movement, under a variety of stresses, allows the individual to undertake a wide range of physical activities. It is then perhaps not surprising that a recent anatomical study shows that the upper femur has a structure commensurate with the complexity of its movements. Mechanically, the upper femur consists of two separate bones: the combined femoral head and neck and the femoral shaft. Both bones consist of a mixture of two different types: cancellous bone and cortical bone, each with its own characteristics. Both bones are subjected to two different forces: those of weight bearing and movement and those of bone modelling. In the face of these complexities, this article tenders some theoretical considerations as to how this region functions and deals with these particular problems. From an anatomical viewpoint, the calcar femorale plays a central role in the mechanical structure of the femoral neck and is pivotal in the management of the stresses to which the region is subjected.

Bases anatomofuncionales de la articulación de la cadera y su relación con la fractura / Anatomic-functional bases of the hip joint and its relation with the fracture

Introducción: la sobrecarga en la epífisis proximal del fémur genera fuerzas deformantes sobre las características anatómicas, que junto a la pérdida de la masa mineral ósea resultan en la ocurrencia de fracturas. Existe un aumento de la evidencia de que la anatomía de la cadera juega un importante papel en la etiología de la fractura. Objetivo: sistematizar los conocimientos referentes a las características anatomofuncionales de la articulación de la cadera y su relación con la fractura desde el punto de vista radiológico. Materiales y métodos: se realizó una investigación documental, cuyo objeto de estudio fueron los textos clásicos de anatomía humana, ortopedia y traumatología, radiología, así como los artículos científicos publicados en las bases de datos informáticas. Desarrollo: desde hace más de 20 años se estudian las relaciones entre la anatomía imagenológica de la cadera y la ocurrencia de fracturas en esta región. Los estudios que se han realizado sobre las características de los componentes estructurales del hueso, tanto en su configuración interna como externa, demuestran que existe relación entre la anatomía de la articulación de la cadera y la fractura de la misma. Conclusiones: el conocimiento sobre la estructura anatómica, sus características funcionales y la relación de sus dimensiones con el riesgo de padecer de fractura provee de una base sólida para el entendimiento de los mecanismos de producción de las mismas y el diseño de futuras acciones de intervención para su prevención y tratamiento (AU).

Introduction: the overload of the femur proximal epiphysis generates deforming forces on the anatomic characteristics that together with the loss of bone mineral mass result in fractures´ occurrence. There is an increase of the evidence that hip anatomy plays an important role in the fracture etiology. Objective: to systematize current knowledge on the anatomic-functional characteristics of the hip joint and their relation with the fracture from the radiological point of view. Materials and methods: a documental research was carried; the objective of study were the classical handbooks of Human Anatomy, Orthopedics and Trauma, and Radiology, and also the scientific articles published in medical databases. Development: the relationship between the hip imaging anatomy and the occurrence of fractures in this anatomical region have been studied for more than 20 years. The studies carried out on the characteristics of the bone structural components, both in their internal configuration as in the external one, showed that there is a relationship between the hip join anatomy and its fracture. Conclusions: knowledge on the anatomic structure, its functional characteristics, and the relationship of its dimensions with the risk of suffering a fracture, provides a solid basis for understanding the mechanisms of their occurrence and for the design of future intervention actions to prevent and treat them (AU).

Bases anatomofuncionales de la articulación de la cadera y su relación con la fractura / Anatomic-functional bases of the hip joint and its relation with the fracture

Introducción: la sobrecarga en la epífisis proximal del fémur genera fuerzas deformantes sobre las características anatómicas, que junto a la pérdida de la masa mineral ósea resultan en la ocurrencia de fracturas. Existe un aumento de la evidencia de que la anatomía de la cadera juega un importante papel en la etiología de la fractura. Objetivo: sistematizar los conocimientos referentes a las características anatomofuncionales de la articulación de la cadera y su relación con la fractura desde el punto de vista radiológico. Materiales y métodos: se realizó una investigación documental, cuyo objeto de estudio fueron los textos clásicos de anatomía humana, ortopedia y traumatología, radiología, así como los artículos científicos publicados en las bases de datos informáticas. Desarrollo: desde hace más de 20 años se estudian las relaciones entre la anatomía imagenológica de la cadera y la ocurrencia de fracturas en esta región. Los estudios que se han realizado sobre las características de los componentes estructurales del hueso, tanto en su configuración interna como externa, demuestran que existe relación entre la anatomía de la articulación de la cadera y la fractura de la misma. Conclusiones: el conocimiento sobre la estructura anatómica, sus características funcionales y la relación de sus dimensiones con el riesgo de padecer de fractura provee de una base sólida para el entendimiento de los mecanismos de producción de las mismas y el diseño de futuras acciones de intervención para su prevención y tratamiento (AU).

Introduction: the overload of the femur proximal epiphysis generates deforming forces on the anatomic characteristics that together with the loss of bone mineral mass result in fractures´ occurrence. There is an increase of the evidence that hip anatomy plays an important role in the fracture etiology. Objective: to systematize current knowledge on the anatomic-functional characteristics of the hip joint and their relation with the fracture from the radiological point of view. Materials and methods: a documental research was carried; the objective of study were the classical handbooks of Human Anatomy, Orthopedics and Trauma, and Radiology, and also the scientific articles published in medical databases. Development: the relationship between the hip imaging anatomy and the occurrence of fractures in this anatomical region have been studied for more than 20 years. The studies carried out on the characteristics of the bone structural components, both in their internal configuration as in the external one, showed that there is a relationship between the hip join anatomy and its fracture. Conclusions: knowledge on the anatomic structure, its functional characteristics, and the relationship of its dimensions with the risk of suffering a fracture, provides a solid basis for understanding the mechanisms of their occurrence and for the design of future intervention actions to prevent and treat them (AU).

Wolff: straight not curved.

It was 140 years ago that George von Meyer presented his anatomical diagrams of human bones to a meeting in Zurich. There he was told by Prof. Karl Culmann that the trabecular lines shown within the diagram of the upper femur closely resembled those lines of force which Culmann had determined with Graphic Statics to be passing through a curved, loaded Fairbairn crane. This drew the attention of Julius Wolff, who used this as the basis for his 'Trajectorial theory' which was widely accepted and, to date, has been the underlying basis for all biomechanical investigations of this region. Following Wolff and Culmann, the upper femur is considered to be a curved structure and is investigated as such. Unfortunately, this concept is wrong. The upper femur is not curved but is angular. It is formed by the junction of two straight bones, the femoral neck and the femoral shaft, as may be simply seen as the neck/shaft angle constructed on the antero-posterior radiograph of any normal femur. The internal trabecular bone forms only part of the load bearing structure of the femoral neck. The configuration of this trabecular substance in this region suggests that it is related specifically to the force present during flexion and extension movements of the hip joint. This being so, combined with the delayed timing of the appearance of the trabecular columns, it must be questioned as to whether the remodelling of the upper femur is in response to one or to two distinct forces.

Calibration Marker Position in Digital Templating of Total Hip Arthroplasty.

BACKGROUND: We report a mathematical method to assess the vertical and horizontal positions of spherical radiopaque objects of known size in conventional radiographs. METHODS: The reliability and validity of the method were tested in an experimental setting and applied to 100 anteroposterior pelvic radiographs with external calibration markers and unilateral total hip arthroplasty (THA). RESULTS: We found excellent reliabilities; intraclass correlation coefficients for interobserver and intraobserver reliabilities were 0.999-1.000 (P = .000). The mean normal height of THA was 198 mm (range: 142-243 mm, standard deviation: 18 mm) above the detector. Vertical and horizontal external marker positions differed significantly from the true hip center (THA; P < .001 and P = .017). CONCLUSION: This method could enhance patient safety by enabling automated detection of malpositioned calibration markers by templating software.

The Influence of Hip Rotation on Femoral Offset Following Short Stem Total Hip Arthroplasty.

Short stem total hip arthroplasty (THA) is thought to be an advantageous surgical option for young patients. Femoral offset has been identified as an important factor for clinical outcome of THA. However, little is known on functional implications of femoral offset after short stem THA. Importantly, hip rotation influences the projected femoral offset and may lead to significant underestimation. Therefore, a novel method to identify and account for hip rotation was applied to a prospectively enrolled series of 37 patients (48 radiographs) undergoing short stem THA. Repeated measurements were performed and intraobserver and interobserver reliability was assessed and femoral offset was corrected for rotation. Based on this study, rotation-correction of femoral offset is of highest relevance for the correct interpretation in future studies.

The femoral neck-shaft angle on plain radiographs: a systematic review.

OBJECTIVE: The femoral neck-shaft angle (NSA) is an important measure for the assessment of the anatomy of the hip and planning of operations. Despite its common use, there remains disagreement concerning the method of measurement and the correction of hip rotation and femoral version of the projected NSA on conventional radiographs. We addressed the following questions: (1) What are the reported values for NSA in normal adult subjects and in osteoarthritis? (2) Is there a difference between non-corrected and rotation-corrected measurements? (3) Which methods are used for measuring the NSA on plain radiographs? (4) What could be learned from an analysis of the intra- and interobserver reliability? MATERIAL AND METHODS: A systematic literature search was performed including 26 publications reporting the measurement of the NSA on conventional radiographs. RESULTS: The mean NSA of healthy adults (5,089 hips) was 128.8° (98-180°) and 131.5° (115-155°) in patients with osteoarthritis (1230 hips). The mean NSA was 128.5° (127-130.5°) for the rotation-corrected and 129.5° (119.6-151°) for the non-corrected measurements. CONCLUSION: Our data showed a high variance of the reported neck-shaft angles. Notably, we identified the inconsistency of the published methods of measurement as a central issue. The reported effect of rotation-correction cannot be reliably verified.

Titanium-titanium modular neck for primary THA. Result of a prospective series of 170 cemented THA with a minimum follow-up of 5 years.

BACKGROUND: Although they have been in use since the end of the 1980s, modular titanium neck components are associated with a risk of wear or fracture, and their safety has recently become a subject of debate and has never been evaluated in a consecutive series of patients. The goal of this study was to evaluate: revision-free survival of these implants after a minimum follow-up of 5 years; clinical and radiographic results; and the potential complications associated with the use of modular titanium neck components. HYPOTHESIS: The use of titanium modular neck on cemented titanium THA is safe at a minimum follow-up of 5 years. PATIENTS AND METHODS: Between January 2006 and December 2008, we prospectively followed 170 patients (170 hips) who underwent primary anatomical THA with a modular cemented titanium stem design implant. The indications were unilateral THA for primary (n=160) or secondary (n=10) hip osteoarthritis (aseptic osteonecrosis of the femoral head or hip dysplasia). Mean age of patients was 75.4±5.8 years old (52-85), and mean BMI was 26.1±4.5 kg/m(2) (16.6-42.1). Patients were operated on by a modified Watson-Jones anterolateral approach based on preoperative 2D planning. All patients underwent annual clinical and radiological follow-up by an independent observer. RESULTS: At a mean follow-up of 71±8 months (60-84), 5 patients died and 7 were lost to follow-up. There was no revision of THA after a maximum follow-up of 84 months. The Harris score improved significantly from 50.4±11.3 (0-76) preoperatively to 84.5±15.2 (14-100) at the final follow-up. There was no difference in postoperative femoral offset or the position of the center of rotation compared to the opposite side. On the other hand, the neck-shaft angle (NSA) and limb length were corrected (2±5° [-11 to +14°] and 2.16±3.6 mm [-7.4 to +12.7 mm]) respectively. Fifteen patients (9%) had limb length discrepancies of more than 5 mm and 4 patients (2%) of more than 10 mm. There were no complications due to the modular implant design. DISCUSSION: Our study suggests that the use of cemented titanium implants with a modular titanium stem is safe at a follow-up of 5 years. The modular design does not prevent limb length discrepancies but restores femoral offset. LEVEL OF EVIDENCE: IV: prospective, non-comparative study.

Multi-pelvis characterisation of articular cartilage geometry.

The shape of the acetabular cartilage follows the contact stress distribution across the joint. Accurate characterisation of this geometry may be useful for the development of acetabular cup devices that are more biomechanically compliant. In this study, the geometry of the acetabular cartilage was characterised by taking plaster moulds of the acetabulum from 24 dry bone human pelvises and digitising the mould shapes using a three-dimensional laser scanner. The articular bone surface geometry was analysed, and the shape of the acetabulum was approximated by fitting a best-fit sphere. To test the hypothesis that the acetabulum is non-spherical, a best-fit ellipsoid was also fitted to the geometry. In each case, points around the acetabular notch edge that disclosed the articular surface geometry were identified, and vectors were drawn between these and the best-fit sphere or ellipsoid centre. The significantly larger z radii (into the pole) of the ellipsoids indicated that the acetabulum was non-spherical and could imply that the kinematics of the hip joint is more complex than purely rotational motion, and the traditional ball-and-socket replacement may need to be updated to reflect this motion. The acetabular notch edges were observed to be curved, with males exhibiting deeper, wider and shorter notches than females, although the difference was not statistically significant (mean: p = 0.30) and supports the use of non-gender-specific models in anatomical studies.

Femoral Offset (3D) in Patients without Osteoarthritis - Index Values from 200 Hip Joints.

INTRODUCTION: Femoral offset (FO) is a crucial parameter for hip joint biomechanics. Reference values for FO are particularly important when joint geometry has to be reconstructed during surgical interventions. Such reference values are scarce in literature and have mainly been obtained from osteoarthritis (OA) patients. The aim of this study was to conduct a patient-specific study of FO without osteoarthritis and to create a dataset of FO index values. MATERIALS AND METHODOLOGY: One hundred (49 female, 51 male; mean age: 59 (18 - 83) years) pelvic computed tomography (CT) scans were analyzed to determine FO in each patient. Bilateral symmetry and correlation between demographic data and FO were analyzed. RESULTS: The mean FO ± SD was different for male (4.36 ± 0.56 cm) and female patients (3.95 ± 0.35 cm) (p <.0001). No Side differences of FO were observed in male and female patients. Significant correlation between height and FO was only observed in male patients. CONCLUSION: The values obtained in this study can be used as index values for the restoration and evaluation of hip geometry. For men, FO can be approximated using the correlation between FO and height.

Hip: Anatomy and US technique.

Ultrasound (US) has always had a relatively limited role in the evaluation of the hip due to the deep location of this joint. However, many hip diseases are well detectable at US, but before approaching such a study it is necessary to be thoroughly familiar with the normal anatomy and related US images. The study technique is particularly important as optimization of various parameters is required, such as probe frequency, focalization, positioning of the probe, etc. Also the patient's position is important, as it varies according to the area requiring examination. For the study of the anterior structures, the patient should be in the supine position; for the medial structures, the leg should be abducted and rotated outward with the knee flexed; for the lateral structures, the patient should be in the controlateral decubitus position; for the posterior structures the patient must be in the prone position. US study of the hip includes assessment of the soft tissues, tendons, ligaments and muscles, and also of the bone structures, joint space and serous bursae. The purpose of this article is to review the normal anatomy of the hip as well as the US anatomy of this joint.