Muscle forces acting on the greater trochanter lead to a dorsal warping of the apophyseal growth plate.

The apophyseal growth plate of the greater trochanter, unlike most other growth plates of the human body, exhibits a curved morphology that results in a divergent pattern resembling an open crocodile mouth on plain antero-posterior radiographs. To quantify the angular alignment of the growth plate and to draw conclusions about the function of the muscles surrounding it, we analyzed 57 MRI images of 51 children and adolescents aged 3-17 years and of six adults aged 18-52 years. We measured the angulation of the plate relative to the horizontal plane (AY angle) and the trajectories of the muscles attaching to the greater trochanter of the proximal femur. From anterior to posterior, the AY angle shows a decrease of 33.44°. In the anterior third, the cartilage is angled at a mean of 51.64°, and in the posterior third, the mean angulation is 18.6°. This indicates that the cartilage in the anterior region of the greater trochanteric apophysis is subject to more vertically oriented force vectors compared to the posterior region, as the growth plates align perpendicular to the force vectors acting on them. Combining the measured muscle trajectories with the physiological cross-sectional areas (PCSA) available from the literature revealed that, in addition to the known internal and external lateral traction ligament systems, a third, dorsally located traction ligament system exists that may be responsible for the dorsal deformation of the AY angle.

Can pelvic tilt cause cam morphology? A computational model of proximal femur development mechanobiology.

Cam deformity of the proximal femur is a risk factor for early osteoarthritis. While cam morphology is related to mechanical force at a formative time in skeletal growth, the specific problematic forces contributing to the development of cam morphology remain unknown. Individuals with femoroacetabular impingement syndrome exhibit an increased anterior pelvic tilt during walking, which alters their hip joint forces. This study aims to investigate the influence of altered joint force caused by anterior pelvic tilt on proximal femur epiphyseal growth and the potential association between increased anterior pelvic tilt and the development of cam morphology. A computational model is utilized to simulate the endochondral ossification in the proximal femur and predict cam formation. Cartilage growth and ossification patterns for a gait cycle with and without anterior pelvic tilt were modeled. The simulated growth results indicated an increased alpha angle (53° for typically developing to 68° for anterior pelvic tilt) and aspherical femoral head in the model with anterior pelvic tilt. We conclude that anterior pelvic tilt may be sufficient to cause the formation of the cam morphology. Identifying the critical mechanical conditions that increase the risk of cam deformity could help prevent this condition by adjusting the physical activities before skeletal maturity.

Imaging of Anatomical Variants Around the Hip.

Considering the current widespread use of imaging as an integral part of managing hip pain, variable hip geometries and anatomical variants are increasingly being detected. These variants are commonly found in the acetabulum and proximal femur, as well as the surrounding capsule-labral tissues. The morphology of specific anatomical spaces confined by the proximal femur and the bony pelvis may also vary significantly among individuals. Familiarity with the spectrum of imaging appearances of the hip is necessary to identify variant hip morphologies with or without potential clinical relevance and reduce an unnecessary work-up and overdiagnosis. We describe anatomical variations and variable morphologies of the bony structures comprising the hip joint and the soft tissues, around the hip. The potential clinical significance of these findings is further analyzed in conjunction with the patient's profile.

Hip centre regression progression: Same equations, better numbers.

Accurate estimation of the hip joint centre (HJC) location is critical for modelling the kinematics and kinetics of the lower limb. Regression equations are commonly used to predict the HJC from anatomical landmarks on the pelvis, such as those published by Tylkowski et al., Andriacchi et al., Bell et al., and Seidel et al. Using a population of 159 CT-segmented pelvises, we assessed the accuracy of these methods as originally reported, and refined their parameters based on our larger cohort. We found the Tylkowski, Bell, and Seidel methods had mean Euclidean errors of 22.5, 26.4, and 17.9 mm, respectively. With new parameters for each method 'back-calculated' from our pelvic population, each method's error was reduced by an average of 69 %, with mean absolute errors of 7.9, 6.6, and 5.9 mm, respectively. For all methods, error has been reduced to below 1 cm, well below published levels for pelvic landmark estimation methods. These results highlight the need to validate and re-calibrate joint centre prediction methods on large, representative datasets to account for natural morphological variations.

Application of statistical shape modeling to the human hip joint: a scoping review.

OBJECTIVE: The objective of this scoping review was to identify all examples of the application of statistical shape models to the human hip joint, with a focus on applications, population, methodology, and validation. INTRODUCTION: Clinical radiographs are the most common imaging tool for management of hip conditions, but it is unclear whether radiographs can adequately diagnose or predict outcomes of 3D deformity. Statistical shape modeling, a method of describing the variation of a population of shapes using a small number of variables, has been identified as a useful tool to associate 2D images with 3D anatomy. This could allow clinicians and researchers to validate clinical radiographic measures of hip deformity, develop new ones, or predict 3D morphology directly from radiographs. In identifying all previous examples of statistical shape modeling applied to the human hip joint, this review determined the prevalence, strengths, and weaknesses, and identified gaps in the literature. INCLUSION CRITERIA: Participants included any human population. The concept included development or application of statistical shape models based on discrete landmarks and principal component analysis. The context included sources that exclusively modeled the hip joint. Only peer-reviewed original research journal articles were eligible for inclusion. METHODS: We searched MEDLINE, Embase, Cochrane CENTRAL, IEEE Xplore, Web of Science Core Collection, OCLC PapersFirst, OCLC Proceedings, Networked Digital Library of Theses and Dissertations, ProQuest Dissertations and Theses Global, and Google Scholar for sources published in English between 1992 and 2021. Two reviewers screened sources against the inclusion criteria independently and in duplicate. Data were extracted by 2 reviewers using a REDCap form designed to answer the review study questions, and are presented in narrative, tabular, and graphical form. RESULTS: A total of 104 sources were considered eligible based on the inclusion criteria. From these, 122 unique statistical shape models of the human hip were identified based on 86 unique training populations. Models were most often applied as one-off research tools to describe shape in certain populations or to predict outcomes. The demographics of training populations were skewed toward older patients in high-income countries. A mean age between 60 and 79 years was reported in 29 training populations (34%), more than reported in all other age groups combined, and 73 training populations (85%) were reported or inferred to be from Europe and the Americas. Only 4 studies created models in a pediatric population, although 15 articles considered shape variation over time in some way. There were approximately equal numbers of 2D and 3D models. A variety of methods for labeling the training set was observed. Most articles presented some form of validation such as reporting a model's compactness (n = 71), but in-depth validation was rare. CONCLUSIONS: Despite the high volume of literature concerning statistical shape models of the human hip, there remains a need for further research in key areas. We identified the lack of models in pediatric populations and low- and middle-income countries as a notable limitation to be addressed in future research.

Ultrasound-guided injection of the hip: Cadaveric description for the lateral approach.

BACKGROUND: Ultrasound (US)-guided intraarticular hip joint injections are commonly performed using an in-plane anterior approach, which has several limitations. OBJECTIVE: To describe and report a "lateral" (lateral to medial) approach for US-guided intraarticular hip injection. DESIGN: Cadaveric investigation. SETTING: Academic institution, department of anatomy. PARTICIPANTS: One cadaveric specimen. METHODS: Both hips of a single cadaver were injected using the US-guided lateral approach. In the left hip, the needle was inserted and kept in situ. The right hip was injected with white-colored water-diluted latex dye. Subsequently, a layer-by-layer anatomical dissection was performed. MAIN OUTCOME MEASURES: Presence and distribution of latex dye and location of needle tip within the joint capsule of the hip. RESULTS: Anatomical dissection of the left and right hips confirmed the correct intraarticular position of the needle tip and the placement of the latex dye, respectively. During layer-by-layer dissection of the left hip, positions of the lateral cutaneous nerve and the lateral circumflex femoral artery were observed anterior to the needle, 30 mm for the nerve and 8 mm for the artery. CONCLUSIONS: This preliminary study demonstrated that the US-guided lateral approach is a convenient technique to access the hip joint in a cadaveric specimen. Compared with the "classical" anterior technique, the lateral approach may provide several advantages, including improved needle visibility, theoretically decreased risk of vascular injury, and less risk of needle contamination. Because injury to the lateral epiphyseal arteries is possible when lateral approach is used, caution is required, especially in children. These preliminary conclusions will need to be validated in future/larger clinical studies.

Iliocapsularis: An exploration of the muscle and its omission in education.

Anterior hip joint musculature is classically characterized to include iliacus, psoas major, rectus femoris, and sartorius muscles. A lesser-known muscle, iliocapsularis muscle (ICm), has made infrequent appearances in the literature for the last ~70 years, but potentially has important functional and clinical value. The purpose of this study is to review the historical prevalence of the ICm in peer-reviewed literature (PRL), further explore the prevalence of the muscle in current anatomical textbooks (ATBs), characterize the muscle with a new series of dissections, assess the muscle's perceived importance to clinicians and educators, and comment on the possible functional significance of the muscle. The ICm was mentioned in 28 peer-reviewed articles and the muscle was present in 518 of 521 (99%) dissected hips in 13 publications which assessed prevalence. In an audit of 30 recently published ATBs, three texts mentioned the ICm. In 28 anterior hip dissections performed in the current study, the muscle was present in all hips. Anatomy educators were surveyed to determine if the ICm was presently taught in their curricula, and clinicians of various specialties were surveyed regarding their perceptions of the ICm and its clinical relevance. The ICm inclusivity within anatomical curricula from educators reported 8.5%, while 4% of clinicians reported trainees should have an educational background of the ICm. This study confirms that while the ICm is present within PRL, and is ubiquitous amongst human-donor dissection, the ICm is not mentioned in most ATBs and is absent in the vast majority of anatomical curricula. Lack of inclusion in curricula may lead to a perceived insignificance to currently practicing clinicians despite the potential functional importance at the hip. This discordance suggests that the ICm should be included in ATBs and anatomical curricula so that future clinicians can consider the ICm when evaluating and treating patients.

Developmental features of the canid proximocaudal femur.

We continued direct morphological studies of the canid coxofemoral joint, considering early-life spatial relationships around the locus of the proximocaudal joint capsule insertion. Our primary goal was to elucidate the postnatal developmental gross anatomy of the proximocaudal femur, among juveniles across Canidae. From an original database of 267 independent (museum) specimens from 11 canid taxa and 1 hybrid taxon, we identified 29 ancient or modern candidate juvenile specimens (nine taxa and one hybrid taxon). Based on optimal ability to recognize landmarks, the best photographic data were categorized into five groups of four each (n = 20). The data groups approximated early juvenile, early-mid juvenile, mid-juvenile, mid-late juvenile; and young adult stages. In this descriptive photographic essay, we demonstrate the developmental spatial proximity among (a) the dorsal meeting of the respective lateral and medial extensions from the growth centers of the femoral head and greater trochanter; (b) the caudodorsal aspect of the coxofemoral joint capsule attachment; (c) a segment of the proximocaudal femoral shaft physis; and (d) an eventual associated mineralized prominence. The latter occurs frequently but not universally, suggesting natural population variability across taxa. Across taxa and juvenile age categories, the morphology thus supports developmental conservation among ancient and modern Canidae. The biomechanical and biological cause-effect implications are not yet clear. For zoological purposes, we apply the term postdevelopmental mineralized prominence to the residual caudolateral surface feature. We extend the original anatomical work of Morgan in zoological and phylogenic arenas, using direct observation of cleared skeletal specimens.

Revision of hip flexor anatomy and function in modern humans, and implications for the evolution of hominin bipedalism.

Hip flexor musculature was instrumental in the evolution of hominin bipedal gait and in endurance running for hunting in the genus Homo. The iliacus and psoas major muscles were historically considered to have separate tendons with different insertions on the lesser trochanter. However, in the early 20th century, it became "common knowledge" that the two muscles insert together on the lesser trochanter as the "iliopsoas" tendon. We revisited the findings of early anatomists and tested the more recent paradigm of a common "iliopsoas" tendon based on dissections of hips and their associated musculature (n = 17). We rediscovered that the tendon of the psoas muscle inserts only into a crest running from the superior to anterior aspect of the lesser trochanter, separate from the iliacus. The iliacus inserts fleshly into the anterior portion of the lesser trochanter and into an inferior crest extending from it. We developed 3D multibody dynamics biomechanical models for: (a) the conjoint "iliopsoas" tendon hypothesis and (b) the separate insertion hypothesis. We show that the conjoint model underestimates the iliacus' capacity to generate hip flexion relative to the separate insertion model. Further work reevaluating the primate lower limb (including human) through dissection, needs to be performed to develop those datasets for reconstructing anatomy in fossil hominins using the extant phylogenetic bracket approach, which is frequently used for tetrapods clades outside of paleoanthropology.

Anatomic variations of the hip joint in soldiers of different ages / Variaciones anatómicas de la articulación coxal en soldados de diferentes edades

SUMMARY: Anatomic variations in hip joint are one of the risk factors for the occurrence of osteoarthritis of that part of locomotor system. Due to different age structure and a special way of conducting physical activity in the army, it is justified to presume the presence of even other risk factors which relate to the aging process, carrying of oversize weight and performing higher amplitudes of movement under load. The objective of the study related to determining the existence of eventual anatomic variations in the hip joint in soldiers of different age. This cross-sectional study covers 240 soldiers of Montenegro Army, divided into 8 age groups. Gathered data for morphological measures hip width and hip circumference were processed using the basic statistics, multivariate and univariate of variance and Tukey's Honestly Significant Difference test-HSD. The differences were considered statistically significant for p≤0.05. It was determined that for both morphological measures there are differences between soldiers of certain age. This is confirmed also by drastic deviations between certain age groups obtained for the defined level of statistical significance. The most pronounced is the detection of the annual increase of hip width of soldiers which is higher for 0.38 mm compared to general population. Based on the obtained results the existence of anatomic variations in soldiers' hip joints is stated. The confirmed anatomic changes in conjunction with other risk factors may lead to hip osteoarthritis, i.e to soldiers' health condition impairment. It is necessary to conduct longitudinal studies on the same examinees with precise diagnostics.

RESUMEN: Las variaciones anatómicas en la articulación coxal son uno de los factores de riesgo de la osteoartritis de esa zona del sistema locomotor. Debido a la diferente estructura respecto a la de edad y una forma especial de realizar la actividad física en el ejército, se justifica presumir la presencia de otros factores de riesgo que se relacionan con el proceso de envejecimiento, el transporte de peso sobredimensionado y la realización de mayores amplitudes de movimiento bajo carga. El objetivo del estudio fue determinar la existencia de eventuales variaciones anatómicas en la articulación coxal en soldados de diferentes edades. Este estudio transversal incluyó 240 soldados del Ejército de Montenegro, divididos en 8 grupos de edad. Los datos recopilados para las medidas morfológicas del ancho y la circunferencia de la articulación coxal se procesaron utilizando las estadísticas básicas, la varianza multivariada y univariada y la prueba HSD de diferencia significativa de Tukey. Las diferencias fueron consideradas estadísticamente significativas para p≤0,05. Se determinó que para ambas medidas morfológicas existen diferencias entre soldados de cierta edad. Esto fue confirmado también por las desviaciones drásticas entre ciertos grupos de edad obtenidos para el nivel definido de significación estadística. El más pronunciado es la detección del aumento anual del ancho de cadera de los soldados, que es superior en 0,38 mm en comparación con la población general. En base a los resultados obtenidos se afirma la existencia de variaciones anatómicas en las articulaciones coxales de los soldados. Los cambios anatómicos confirmados junto con otros factores de riesgo pueden conducir a la osteoartritis de cadera, es decir, al deterioro del estado de salud de los soldados. Es necesario realizar estudios longitudinales en los mismos examinados con diagnósticos precisos.

Spatial distribution of loose connective tissues on the anterior hip joint capsule: a combination of cadaveric and in-vivo study.

Recently, pathological changes in the fat pad on the anterior inferior iliac spine (AIIS), between the proximal rectus femoris and joint capsule, have been highlighted as a cause of anterior hip pain. However, precise fat pad features, such as the spatial distribution distal to the AIIS, histological features, and in vivo tissue elasticity, remain unclear. This study aimed to investigate the morphological characteristics of the fat pad on the AIIS. Four hips from four cadaveric donors were both macroscopically and histologically investigated, and eight hips from four volunteers were assessed using ultrasonography. The fat pad on the AIIS was also surrounded by the iliopsoas and gluteus minimus, extending distally to the superficial portion of the vastus lateralis, and the anterior portion of the gluteus maximus tendon. Histological analysis revealed that the fat pad was composed of loose connective tissue. Based on the ultrasonography, the shear wave velocity in the fat pad was significantly lower than that in the joint capsule. Conclusively, the pathological adhesion between the joint capsule and pericapsular muscles, if caused by fat pad fibrosis, may occur following the abovementioned fat pad spatial distribution.

Accurate and semi-automated reassociation of intermixed human skeletal remains recovered from bioarchaeological and forensic contexts.

Commingled remains describes the situation of intermixed skeletal elements, an extremely common occurrence in contemporary forensic cases, archaeological mass graves, as well as fossil hominin assemblages. Given that reliable identification is typically impossible for commingled contexts, a plethora of previous studies has focused on the development of refined methods for reassociating the bones of each individual skeleton. Here, a novel virtual approach for quantifying the degree of three-dimensional shape compatibility between two adjoining bone articular surfaces is put forth. Additionally, the integrability of this method with traditional osteometric techniques is evaluated. We focus on the paradigm of the hip joint, whose articulating bone elements (the femur and the innominate bone) are crucial for reconstructing the biological profile of unidentified human remains. The results demonstrate that this new semi-automated methodology is highly accurate both for large commingled assemblages (such as those resulting from mass disasters or burials) as well as smaller-scale contexts (such as those resulting from secondary burials).

Dynamic changes of the joint capsule in relation to the zona orbicularis: An anatomical study with possible implications for hip stability mechanism.

The zona orbicularis, which comprises the inner circular fibers of the joint capsule, is vital for hip stability in distraction. Despite the proximity of the whole joint capsule to the zona orbicularis, their anatomical relationship remains unclear. The aim of this study is to investigate the characteristics of the inner side of the joint capsule comprehensively. Twelve hips from nine bodies donated to science were examined. Six and three of the donated bodies, respectively, were embalmed using 8% formalin and Thiel's method. The joint capsules in three formalin-embalmed bodies were sturied by micro-computed tomography. During formalin fixation of six hips from these three bodies, one side was maintained at hip extension and the other at flexion. The remaining three formalin-embalmed bodies were examined histologically. Micro-computed tomography images revealed that the inward protrusion of the joint capsule narrowed the articular cavity, and the ratio of its narrowest area to that of the femoral neck was less at hip extension than at hip flexion. The Thiel's method specimens showed that the inner surface of the joint capsule protruded inward toward the femoral neck during hip extension. This inward protrusion was not histologically independent of the joint capsule. The zona orbicularis was interpreted as the inward protrusion caused by dynamic change of the joint capsule, rather than the local collar. In other words, the joint capsule could change its morphology dynamically depending on the hip position.

Is hip morphology a risk factor for developing hip osteoarthritis? A systematic review with meta-analysis.

OBJECTIVE: To appraise the highest evidence on hip morphology as a risk factor for developing hip osteoarthritis (OA). DESIGN: We searched for studies evaluating the association between radiological hip morphology parameters and the prevalence, incidence or progression of hip OA (based on different radiographic and clinical criteria) in the MEDLINE, EMBASE, Web of Science, Scopus, Cochrane Library and PEDro databases from inception until June 2020. Prospective and cross-sectional studies were separately evaluated. Data are presented as odds ratios (OR) with 95% confidence intervals (CI). RESULTS: We included 9 prospective and 21 cross-sectional studies in the meta-analysis, and evaluated 42,831 hips from 25,898 individuals (mean age: 59 years). Prospective studies showed that, compared with control hips, hips with cam morphology (alpha angle >60°; OR = 2.52, 95% CI: 1.83 to 3.46, P < 0.001) or hip dysplasia (lateral center-edge angle (LCEA) <25°; OR = 2.38, 95% CI: 1.84 to 3.07, P < 0.001), but not hips with pincer morphology (LCEA >39°; OR = 1.08, 95% CI: 0.57 to 2.07, P = 0.810), were more likely to develop hip OA than hips without these morphologies. Cross-sectional studies showed a greater prevalence of pincer morphology (LCEA >39°, OR = 3.71, 95% CI: 2.98 to 4.61, P < 0.001) and acetabular retroversion (crossover sign; OR = 2.65, 95% CI: 1.17 to 6.03, P = 0.020) in hips with OA than in control hips. CONCLUSION: Cam morphology and hip dysplasia were consistently associated with the development of hip OA. Pincer morphology was associated with hip OA in cross-sectional but not in prospective studies. The heterogeneous quantification of pincer morphology on radiographs limits a clear conclusion on its association with hip OA.

Hip geometry in hip fracture patients in Greenland occurring over a 7.7-year period.

BACKGROUND: Hip geometry influences hip fracture risk. Hip fractures are common, and they are associated with pain, disability, premature death and marked costs on society. Osteoporotic fractures are frequent in Arctic populations and increase with advancing age in this society with a steep rise in life expectancy. Greenland Inuit is a distinct ethnic group, and data on hip geometry is missing. We thus aimed to describe hip geometry in 7.7 years of consecutive hip fracture patients in Greenland. METHODS: We evaluated collodiaphysial angle, femoral neck length, the outer and inner diameter of the femur at 2 and 5 centimetres below the centre of the lesser trochanter and the cortical thickness from pelvic and hip radiographs in all patients operated in Greenland over 7.7 years. We included all 84 patients with one non-fractured hip visible for geometric analysis. Analyses were conducted in duplicate. RESULTS: We found a collodiaphysial angle of 134.8/132.6o in men/women (p = 0.06) and a femoral neck length of 38.0/33.9 mm in men/women (p = 0.001). Cortical thickness was affected by sex in the adjusted analysis (p < 0.001). Cortical thickness index at 5 cm below the centre of the lesser trochanter decreased with age (p = 0.026) and may be influenced by height (2 cm below the centre of the lesser trochanter, p = 0.053). CONCLUSION: Our findings differed from European data and suggest a delicate balance in hip geometry in Arctic populations. Ethnic peculiarities influence the structure of the hip and may influence fracture risk. A focus on hip geometry and risk factors for osteoporotic fractures in Arctic populations is warranted.

Trabecular organization of the proximal femur in Paranthropus robustus: Implications for the assessment of its hip joint loading conditions.

Reconstruction of the locomotor repertoire of the australopiths (Australopithecus and Paranthropus) has progressively integrated information from the mechanosensitive internal structure of the appendicular skeleton. Recent investigations showed that the arrangement of the trabecular network at the femoral head center is biomechanically compatible with the pattern of cortical bone distribution across the neck, both suggesting a full commitment to bipedalism in australopiths, but associated with a slightly altered gait kinematics compared to Homo involving more lateral deviation of the body center of mass over the stance limb. To provide a global picture in Paranthropus robustus of the trabecular architecture of the proximal femur across the head, neck and greater trochanter compartments, we applied techniques of virtual imaging to the variably preserved Early Pleistocene specimens SK 82, SK 97, SK 3121, SKW 19 and SWT1/LB-2 from the cave site of Swartkrans, South Africa. We also assessed the coherence between the structural signals from the center of the head and those from the trabecular network of the inferolateral portion of the head and the inferior margin of the neck, sampling the so-called vertical bundle, which in humans represents the principal compressive system of the joint. Our analyses show a functionally related trabecular organization in Pa. robustus that closely resembles the extant human condition, but which also includes some specificities in local textural arrangement. The network of the inferolateral portion of the head shows a humanlike degree of anisotropy and a bone volume fraction intermediate between the extant human and the African ape patterns. These results suggest slight differences in gait kinematics between Pa. robustus and extant humans. The neck portion of the vertical bundle revealed a less biomechanically sensitive signal. Future investigations on the australopith hip joint loading environment should more carefully investigate the trabecular structure of the trochanteric region and possible structural covariation between cortical bone distribution across the neck and site-specific trabecular properties of the arcuate bundle.

A systematic review and meta-analysis of the hip capsule innervation and its clinical implications.

Detailed understanding of the innervation of the hip capsule (HC) helps inform surgeons' and anaesthetists' clinical practice. Post-interventional pain following radiofrequency nerve ablation (RFA) and dislocation following total hip arthroplasty (THA) remain poorly understood, highlighting the need for more knowledge on the topic. This systematic review and meta-analysis focuses on gross anatomical studies investigating HC innervation. The main outcomes were defined as the prevalence, course, density and distribution of the nerves innervating the HC and changes according to demographic variables. HC innervation is highly variable; its primary nerve supply seems to be from the nerve to quadratus femoris and obturator nerve. Many articular branches originated from muscular branches of the lumbosacral plexus. It remains unclear whether demographic or anthropometric variables may help predict potential differences in HC innervation. Consequently, primary targets for RFA should be the anterior inferomedial aspect of the HC. For THA performed on non-risk patients, the posterior approach with capsular repair appears to be most appropriate with the lowest risk of articular nerve damage. Care should also be taken to avoid damaging vessels and muscles of the hip joint. Further investigation is required to form a coherent map of HC innervation, utilizing combined gross and histological investigation.

The Visible Korean: movable surface models of the hip joint.

PURPOSE: In this study, we presented movable surface models to help medical students understand the multiaxial movements of the hip joint. The secondary objective was to demonstrate a simple method to make movable surface models for other researchers. METHODS: We used 166 surface models of the virtual human, and the commercial software was used for all the processes described in this study. Virtual joints were created for the hip joint of the surface models to simulate realistic movements of the joints. Bone surface models were processed to maintain the original shape of the bones during movement. Muscle surface models were processed to express deformation of the muscle shapes during movement. Next, the muscle and bone surface models were moved over six movements of the hip joint (flexion, extension, abduction, adduction, lateral rotation, and medial rotation). The surface models of these six movements were saved and packaged in a PDF file. RESULTS: The PDF file enabled users to see the stereoscopic shapes of the bones and muscles of the hip joint and to scrutinize the six movements on the X, Y, and Z axes of the joint. CONCLUSION: The movable surface models of the hip joint of this study will be helpful for medical students to learn the multiaxial movements of the hip joint. We expect to develop simulations of other joints that can be used in the education of medical students using the materials and methods described in this study.

Morphological Changes of the Hip Commonly Associated With Femoroacetabular Impingement Are Not Correlated With Rotational Range of Hip Motion in Elite Soccer Athletes.

BACKGROUND: Morphological changes characteristic of femoroacetabular impingement (FAI) are common in soccer players. However, the clinical relevance of such anatomical variations is still not well-defined. HYPOTHESIS: We hypothesized that high alpha angle values and/or acetabular retroversion index (ARI) are correlated with rotational range of motion (ROM) of the hip and that there are clinical-radiological diferences between the dominant lower limb (DLL) and nondominant lower limb (NDLL) in professional soccer players. STUDY DESIGN: Cross-sectional. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 59 male professional soccer players (average age 25.5 years, range 18-38 years) were evaluated in the preseason. As main outcome measures, we evaluated the alpha angle and the ARI and hip IR and ER ROM with radiographic analysis. RESULTS: The measurements taken on DLL and NDLL were compared and a significant difference was found between the sides in the ER (P = 0.027), where the DLL measures were 1.54° (95% CI, 0.18-2.89) greater than the NDLL. There were no significant differences between the sides in the measures of IR (P > 0.99), total ROM (P = 0.07), alpha angle (P = 0.250), and ARI (P = 0.079). The correlations between the rotation measurements and the alpha angle in each limb were evaluated and the coefficient values showed no correlation; so also between the ARI and rotation measures. CONCLUSION: Morphological changes of the femur or acetabulum are not correlated with hip IR and ER ROM in male professional soccer players. ER on the dominant side was greater than on the nondominant side. There was no significant difference in the other measurements between sides. CLINICAL RELEVANCE: In clinical practice, it is common to attribute loss of hip rotational movement to the presence of FAI. This study shows that anatomical FAI may not have a very strong influence on available hip rotational movement in professional soccer athletes.

Unique hip and stifle extensor muscle patterns in the Eurasian lynx, Lynx lynx (Carnivora: Felidae).

The Eurasian lynx (Lynx lynx) is a medium-sized felid, with a tendency to hunt for prey larger than itself. We studied the lynx hindlimb musculoskeletal anatomy in order to determine possible anatomical adaptations to hunting large prey. In our previous work, we had found characters of both large and small felids in the lynx forelimb. The crouched limbs, typical of all felids, increase the energy demands for the antigravity muscles during locomotion. As a powerful pounce is required for the smaller felid to bring down large prey, strong hindquarters may be needed. We hypothesized that the muscle attachments are more mechanically advantageous and muscles heavier in the lynx as compared to other felids to compensate for the energy requirements. In support of this, we found unique patterns in the hindlimb musculature of the lynx. Insertion of the m. gluteus medius was large with a short moment arm around the hip joint, providing mechanical disadvantage, but rapid movement. The musculus vastus medialis was relatively heavier than in other felids emphasizing the role of the m. quadriceps femoris as a powerful stifle extensor. The extensor muscles support the crouched hind limbs, which is crucial when tackling large prey, and they are also responsible for the swift powerful pounce brought by extending the hindlimbs. However, we cannot rule out the possibility the characters are shared with other Lynx spp. or they are adaptations to other aspects of the locomotor strategy in the Eurasian lynx.