Acetabular Notch Research Articles

Profound Morphometric Analysis of Acetabulum in South Indian Population (Acetabular dimensions)

Aim- Acetabular dimensions plays a challenging role in various arthroplasties and reconstructions. Morphometric study of acetabulum of dry hip bones is a necessity to make proper prosthesis and to ensure good quality of life. Materials & methods - In this 71 dry human hip bones of 35 right and 36 left collected in department of anatomy of Chettinad Hospital and Research Institute, to analyze & measure the diameter, acetabular notch, acetabular circumference, depth and volume of acetabulum. Results – The transverse diameter on right- 49.33 ± 7.36 mm, left 48.57±6.79 mm, depth-right23.28±3.27 mm, left 22.50 ±3.18 mm, vertical diameter- right 48.05±4.40 mm, left 47.66±4.95 mm, acetabular notch- right 22.00±3.28 mm, left 20.56±2.61 mm, outer rim circumference -right 11.90±0.99 cm, left 12.43±0.87 cm, inner rim circumference- right 7.66±0.84 cm, left 8.06±0.72 cm, acetabular circumference- right 15.26±1.38 cm, left 14.60±1.35 cm, capacity- right 27.22±5.43 ml, left-27.22±5.77 ml. Conclusion - All the parameters were statistically analysed and the results suggest that the acetabular dimensions are mostly smaller in South Indian population and hip prosthesis should be made patient specific to increase the success rate of arthroplasties.

Hip Capsulolabral Complex: Anatomy, Disease, MRI Features, and Postoperative Appearance.

The hip is a uniquely constrained joint with critical static stability provided by the labrum, capsule and capsular ligaments, and ligamentum teres. The labrum is a fibrocartilaginous structure along the acetabular rim that encircles most of the femoral head. Labral tears are localized based on the clock-face method, which determines the extent of the tear while providing consistent terminology for reporting. Normal labral variants can mimic labral disease and can be differentiated by assessment of thickness or width, shape, borders, location, and associated abnormalities. The Lage and Czerny classification systems are currently the most well-known arthroscopic and imaging systems, respectively. Femoroacetabular impingement is a risk factor for development of labral tears and is classified according to bone dysmorphisms of the femur ("cam") or acetabulum ("pincer") or combinations of both (mixed). The capsule consists of longitudinal fibers reinforced by ligaments (iliofemoral, pubofemoral, ischiofemoral) and circular fibers. Capsular injuries occur secondary to hip dislocation or iatrogenically after capsulotomy. Capsular repair improves hip stability at the expense of capsular overtightening and inadvertent chondral injury. The ligamentum teres is situated between the acetabular notch and the fovea of the femoral head. Initially considered to be inconsequential, recent studies have recognized its role in hip rotational stability. Existing classification systems of ligamentum teres tears account for injury mechanism, arthroscopic findings, and treatment options. Injuries to the labrum, capsule, and ligamentum teres are implicated in symptoms of hip instability. The authors discuss the labrum, capsule, and ligamentum teres, highlighting their anatomy, pathologic conditions, MRI features, and postoperative appearance. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Morphologic and Morphometric Evaluation of the Acetabulum

Objective: The aim of this study is to reveal the morphological and morphometric features of the acetabulum and to compare them with the current literature. Materials and Methods: A total of 57 coxae (29 left, 28 right) were examined. The anterior ridge of the acetabulum was classified as curved, straight, angular, and irregular according to its morphological features and the transverse diameter of the acetabulum (TD), the vertical diameter of the acetabulum (VD), the anteroposterior diameter of the acetabulum (APD), acetabular depth (AD), acetabular notch width (ANW) and os coxae height (CH) were measured. Results: The types of the anterior ridge of the acetabulum were found as 19 (33.3%) straight, 18 (31.6%) curved, 14 (24.6%) angular, and 6 (10.5%) irregular in shape. The mean values of the TD, VD, APD, ANW, AD and CH were 50.67±3.12 mm, 52.21±3.52 mm, 52.66±3.73 mm, 22.64±2.67 mm, 29.75±2.28 mm and 206.33±11.70 mm respectively. No significant difference was found between the right and left coxae in terms of the measured parameters (p>0.05). There was only a difference between the shapes and the depth of the acetabulum (p<0.05). Conclusion: Knowing the normal anatomy of the acetabulum is important in preventing complications during surgical procedures of this area.

POSITIONING OF ACETABULAR AND FEMORAL COMPONENT IN PRIMARY TOTAL HIP ARTHROPLASTY USING CT EVALUATED PATIENT NATIVE ANATOMY

In total hip arthroplasty, component orientation is an important task for stability. Acetabular and femoral component orientation is the key factor for outcome of total hip arthroplasty. The aim of this study is to assess the clinical and radiological effectiveness of positioning of acetabulum and femoral components in primary total hip replacement using CT evaluated patient native anatomy. Subjects of this study were 36 patients with nonunion neck of femur fractures or arthritic hip based on inclusion and exclusion criteria and treated with cemented or uncemented total hip arthroplasty. Pre operative CT scan with 3D reconstruction was done for all patients and the acetabular inclination and version was measured in coronal and axial planes. Femoral anteversion was measured in mid axial image. Transverse acetabular notch (TAN) and anterior acetabular notch (AAN) were identied intra operatively to reproduce the pre operative angles. Post operatively CT scan was done and all angles were measured as before. All patients were followed up and analyzed using Harris Hip Score. The mean preoperative Harris Hip Score is 34.5. The mean postoperative Harris Hip Score is 88.19. Mean acetabular cup inclination is 39.80°, Mean cup anteversion is 15.1° and mean femoral anteversion is 14.75°. No Dislocation was noted during follow up. No hips show clinical and radiological evidence of femoral and acetabular component loosening. All Postoperative CT measurements of angles are within the safe zone by Lewinnek et al. Preoperative CT guided parameters, intra operative anatomical landmarks (TAN&AAN) and the digital protractor device can aid better positioning of the acetabular and femoral component of THA and is independent of the position of the patient. It also provides a precise planning for component placement resulting in less intra operative time thereby reducing the chances of infection and decreases the dislocation rate and wear and tear and improves the functional outcome

Quantification of Acetabular Coverage on 3-Dimensional Reconstructed Computed Tomography Scan Bone Models in Patients With Femoroacetabular Impingement Syndrome: A Descriptive Study.

Background:Accurate assessment of osseous morphology is imperative in the evaluation of patients with femoroacetabular impingement syndrome (FAIS) and hip dysplasia. Through use of computed tomography (CT), 3-dimensional (3D) reconstructed hip models may provide a more precise measurement for overcoverage and undercoverage and aid in the interpretation of 2-dimensional radiographs obtained in the clinical setting.Purpose:To describe new measures of acetabular coverage based on 3D-reconstructed CT scan bone models.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Preoperative CT scans were acquired on the bilateral hips and pelvises of 30 patients before arthroscopic surgical intervention for FAIS. Custom software was used for semiautomated segmentation to generate 3D osseous models of the femur and acetabulum that were aligned to a standard coordinate system. This software calculated percentage of total acetabular coverage, which was defined as the surface area projected onto the superior aspect of the femoral head. The percentage of coverage was also quantified regionally in the anteromedial, anterolateral, posteromedial, and posterolateral quadrants of the femoral head. The acetabular clockface was established by defining 6 o’clock as the inferior aspect of the acetabular notch. Radial coverage was then calculated along the clockface from the 9-o’clock to 5-o’clock positions.Results:The study included 20 female and 10 male patients with a mean age of 33.6 ± 11.7 years and mean body mass index of 27.8 ± 6.3. The average percentage of total acetabular coverage for the sample was 57% ± 6%. Acetabular coverages by region were as follows: anteromedial, 78% ± 7%; anterolateral, 18% ± 7%, posterolateral, 33% ± 13%, and posteromedial, 99% ± 1%. The acetabular coverage ranged from 23% to 69% along the radial clockface from 9 to 5 o’clock.Conclusion:This study demonstrated new 3D measurements to characterize acetabular coverage in patients with FAIS and elucidated the distribution of acetabular coverage according to these measurements.

Amélioration de la précision des mesures tomodensitométriques du débord antérieur des cupules de prothèse totale de hanche dans le conflit ilio-psoas cupule: evaluation d’un nouveau protocole basé sur des repères anatomiques

BackgroundAnterior hip pain after total hip replacement (THR) can be caused by iliopsoas impingement (IPI). Validation of CT measured cup version is well published; however quantification of the anterior cup prominence has not been validated. Therefore, we did an in vitro study aiming to: 1) assess the accuracy of the current method of measuring the prominence of the acetabular component using a dry bone model, 2) develop a CT protocol based on bony anatomical landmarks that improves the accuracy of these measurements. HypothesisWe hypothesise that utilising reproducible anatomical landmarks on the acetabulum will improve the accuracy of measurement of anterior prominence at the psoas valley. MethodsA dry bone pelvic model was implanted with bilateral acetabular cups. The cup was manipulated into ten different combinations of inclination and version, and anterior prominence directly measured in relation to the acetabular rim. A CT scan was performed for each position. Anterior prominence was then measured by two radiologists, first using standard methods (axial slice at level of center of femoral head) and then again using a novel protocol (based on the position of the psoas valley in relation to the inferior medial acetabular notch). ResultsMean errors between direct measurement of anterior prominence and radiologist reported measurements using standard protocol were 6.94mm±5.24 (SD) (95%Confidence Interval: 3.25–4.27) and 5.14mm±3.07 (95%CI: 1.9-2.5) with a tendency towards overestimation of prominence. Using an anatomical landmark based protocol, mean error was reduced to 3.0mm±1.9 (95%CI: 1.16–1.53) and 4.3mm±4.3 (95%CI: 2.67–351) on the first attempt, and to 1.7mm±1.9 (95%CI: 1.15–1.52) and 2.1mm±1.4 (95%CI: 0.87–1.15) on the second attempt. Concordance correlation improved from 0.43 (95% CI: 0.19–0.68) and 0.59 (95% CI: 0.44–0.79) using the standard protocol, to 0.88 (95%CI: 0.61–0.91) and 0.9 (95%CI: 0.56 - 0.92) using the novel protocol. ConclusionsThere is a difference in mean error and reliability between radiologically measured values for anterior prominence and values measured directly with present methods. The use of our novel protocol based on bony acetabular landmarks, significantly improves the accuracy of measurement. This protocol may improve reproducibility and the accuracy of this measurement and aid in the decision between tenotomy or revision of the acetabular component. Level of evidenceIII, in vitro study comparing diagnostic tools.

Improved accuracy of CT based measurements for anterior prominence of acetabular prosthesis using a novel protocol based on anatomical landmarks

BackgroundAnterior hip pain after total hip replacement (THR) can be caused by iliopsoas impingement (IPI). Validation of CT measured cup version is well published; however quantification of the anterior cup prominence has not been validated. Therefore, we did an in vitro study aiming to: (1) assess the accuracy of the current method of measuring the prominence of the acetabular component using a dry bone model; (2) develop a CT protocol based on bony anatomical landmarks that improves the accuracy of these measurements. HypothesisWe hypothesise that utilising reproducible anatomical landmarks on the acetabulum will improve the accuracy of measurement of anterior prominence at the psoas valley. MethodsA dry bone pelvic model was implanted with bilateral acetabular cups. The cup was manipulated into ten different combinations of inclination and version, and anterior prominence directly measured in relation to the acetabular rim. A CT scan was performed for each position. Anterior prominence was then measured by two radiologists, first using standard methods (axial slice at level of centre of femoral head) and then again using a novel protocol (based on the position of the psoas valley in relation to the inferior medial acetabular notch). ResultsMean errors between direct measurement of anterior prominence and radiologist reported measurements using standard protocol were 6.94mm±5.24 (SD) (95%Confidence Interval: 3.25–4.27) and 5.14mm±3.07 (95%CI: 1.9–2.5) with a tendency towards overestimation of prominence. Using an anatomical landmark based protocol; mean error was reduced to 3.0mm±1.9 (95%CI: 1.16–1.53) and 4.3mm±4.3 (95%CI: 2.67–351) on the first attempt, and to 1.7mm±1.9 (95%CI: 1.15-1.52) and 2.1mm±1.4 (95%CI: 0.87–1.15) on the second attempt. Concordance correlation improved from 0.43 (95% CI: 0.19–0.68) and 0.59 (95% CI: 0.44–0.79) using the standard protocol, to 0.88 (95%CI: 0.61–0.91) and 0.9 (95%CI: 0.56–0.92) using the novel protocol. ConclusionsThere is a difference in mean error and reliability between radiologically measured values for anterior prominence and values measured directly with present methods. The use of our novel protocol based on bony acetabular landmarks, significantly improves the accuracy of measurement. This protocol may improve reproducibility and the accuracy of this measurement and aid in the decision between tenotomy or revision of the acetabular component. Level of evidenceIII, in vitro study comparing diagnostic tools.

How to restore rotation center in total hip arthroplasty for developmental dysplasia of the hip by recognizing the pathomorphology of acetabulum and Harris fossa?

PurposeTo restore rotation center exactly in total hip arthroplasty (THA) is technically challenging for patients with end-stage osteoarthritis due to developmental dysplasia of the hip (DDH). The technical difficulty is attributable to the complex acetabular changes. In this study, we investigated the pathomorphology of acetabulum and Harris fossa of Crowe types I to IV and discussed the method of restoring rotation center of the hip.MethodsThis study retrospectively reviewed 56 patients (59 hips) who underwent cementless THA due to end-stage osteoarthritis of DDH. The pathomorphology of acetabulum and Harris fossa was observed during operations. Using the preoperative and postoperative pelvic radiographs, the vertical and the horizontal distances of hip rotation center were measured in order to evaluate the effects of restoring rotation center of the hip.ResultsAdult DDH acetabulum could be classified into four basic pathological types which include the shallow cup shape, the dish shape, the shell shape, and the triangular shape. Adult DDH Harris fossa could be classified into four pathological types, including the crack shape, the closed shape, the triangle shape, and the shallow shape, in accordance with the osteophyte coverage. The vertical and horizontal distances of hip rotation center on the pelvic radiographs before and after operations were as follows: the preoperative vertical distance of hip rotation center was (39.96 ± 5.65) mm, and the postoperative one was (13.83 ± 2.66) mm; the preoperative horizontal distance of hip rotation center was (42.15 ± 6.42) mm, and the postoperative one was (28.12 ± 4.56) mm.ConclusionsThe acetabulum and Harris fossa can display different pathological types on account of different degrees of dislocation and osteophyte hyperplasia in the end-stage osteoarthritis of adult DDH. The hip rotation center can be accurately restored by locating the acetabular center with Harris fossa and acetabular notch as the marks.

Sex Differences in Morphometry of North Indian Acetabula—Forensic and Orthopedic Consideration

Abstract Background Acetabulum is a cup-shaped cavity of the hipbone. It constitutes the acetabular part of the hip joint. Its shape and position related to the head of the femur are crucial for the biomechanics of this joint. The knowledge of various acetabular dimensions is essential to diagnose various diseases of hip joint, to monitor patient recovery, to determine stability of the hip joint, to assess acetabular dysplasia, and also to create patient-specific acetabular implants in case of hip arthroplasty. Various parameters of acetabulum differ with respect to age, sex, race, and region. Thus, a region-specific knowledge of the acetabular dimensions will be helpful for surgical reconstruction and sex determination. Materials and Methods The current study was conducted on 100 adult os coxae (male:female = 80:20, right:left = 50:50). The various acetabular dimensions measured were (1) breadth of acetabulum, (2) vertical diameter of acetabulum, (3) maximum depth of acetabulum, (4) linear length of acetabular notch, (5) length of acetabular rim, and (6) total length of acetabular rim with notch. The values were statistically evaluated to find out the sex and side-related differences. Results All the parameters measured were larger in male bones as compared with female bones. Nevertheless, the difference in values was significant only for breadth of acetabulum, vertical diameter of acetabulum, length of acetabular rim, and total length of acetabular rim with notch. Also, the values were more on left side although results were insignificant. Conclusions The results of the present study will provide reference acetabular values for North India region.

Clinical Anatomy of the Ligament of the Head of Femur.

The ligament of the head of femur (LHF) has gained clinical attention recently and is reported to contribute to hip stability. This study explores its morphology and morphometry, information that may help inform surgical decision making. Gross anatomical dissections were undertaken on 229 embalmed hips from European (n = 105) and Thai (n = 124) adult cadavers to examine LHF anatomy. Ligament morphometry was statistically compared at different sites, between sexes and sides. The origin of ligamental arteries and absence of the ligament were documented. The LHF was pyramidal or quadrangular in shape. Sub-synovial fibrous bands originated from the transverse acetabular ligament, edges of the acetabular notch, and acetabular floor; less frequently from the hip joint capsule. Distally, the ligament flattened and converged onto the fovea capitis. The ligament was 22.3 ± 4.4 mm long and was significantly wider (P = 0.001) and thicker (P = 0.0003) at the fovea, compared to its mid-zone. Branches of the obturator artery entered the acetabular foramen inferomedially and penetrated the middle third of the LHF. Blood vessels ran within the LHF and appeared to enter the fovea. The ligament was absent in 2.8% of Thai hips and there were no significant sex or side differences in ligament dimensions. The morphology of the LHF is complex. While individual variation was apparent, blood vessels were seen in the distal ligament. Precise information on LHF morphometry and attachment sites will help inform appropriate graft dimensions and choice of fixation sites necessary for ligament reconstruction. Clin. Anat., 2018. © 2018 Wiley Periodicals, Inc. Clin. Anat., 2018. © 2018 Wiley Periodicals, Inc.

Comparative morphological interpretations on the bones of the pelvic limb of New Zealand rabbit (Oryctolagus cuniculus) and domestic cat (Felis domestica).

Objective:Regarding the displaying of the main differences between the pelvic limb of rabbit and cat.Materials and methods:Our work was performed on 10 New Zealand rabbits (Oryctolagus cuniculus) and domestic cats (Felis domestica) with variable ages and of both sexes. After weighing of the animals, sedation, and anesthesia, the animals were examined radiographically. The bones of the pelvic limb were prepared, measured for its length/cm then described and compared.Results:The iliac tuberosity and the conversion of the acetabular notch into foramen were characteristics of Os coxae of the rabbit. The intertrochanteric crest was detected on the femur of the cat. In the rabbit, the leg interosseous space was located in the proximal third of this region while in the cat, it was extended along its length. The first metatarsal was undeveloped in the cat but was absent in the rabbit so metatarsal were four in the rabbit and five in the cat. The digits of the pelvic limbs in both animals were four in number. The distal sesamoid was single, transversely situated, and shuttle-shaped in rabbit but it was absent in cat.Conclusion:So, the chief points of variation between the pelvic limb bones of rabbit and cat enabled us to keep away the commercial fraud and facilitated their use as an animal model for education purposes.

Quantitative Anatomic Analysis of the Native Ligamentum Teres.

Background:While recent studies have addressed the biomechanical function of the ligamentum teres and provided descriptions of ligamentum teres reconstruction techniques, its detailed quantitative anatomy remains relatively undocumented. Moreover, there is a lack of consensus in the literature regarding the number and morphology of the acetabular attachments of the ligamentum teres.Purpose:To provide a clinically relevant quantitative anatomic description of the native human ligamentum teres.Study Design:Descriptive laboratory study.Methods:Ten human cadaveric hemipelvises, complete with femurs (mean age, 59.6 years; range, 47-65 years), were dissected free of all extra-articular soft tissues to isolate the ligamentum teres and its attachments. A coordinate measuring device was used to quantify the attachment areas and their relationships to pertinent open and arthroscopic landmarks on both the acetabulum and the femur. The clock face reference system was utilized to describe acetabular anatomy, and all anatomic relationships were described using the mean and 95% confidence intervals.Results:There were 6 distinct attachments to the acetabulum and 1 to the femur. The areas of the acetabular and femoral attachment footprints of the ligamentum teres were 434 mm2 (95% CI, 320-549 mm2) and 84 mm2 (95% CI, 65-104 mm2), respectively. The 6 acetabular clock face locations were as follows: anterior attachment, 4:53 o’clock (95% CI, 4:45-5:02); posterior attachment, 6:33 o’clock (95% CI, 6:23-6:43); ischial attachment, 8:07 o’clock (95% CI, 7:47-8:26); iliac attachment, 1:49 o’clock (95% CI, 1:04-2:34); and a smaller pubic attachment that was located at 3:50 o’clock (95% CI, 3:41-4:00). The ischial attachment possessed the largest cross-sectional attachment area (127.3 mm2; 95% CI, 103.0-151.7 mm2) of all the acetabular attachments of the ligamentum teres.Conclusion:The most important finding of this study was that the human ligamentum teres had 6 distinct points of attachment on the acetabulum (transverse, anterior, and posterior margins of the acetabular notch and cotyloid fossa attachments: ilium, ischium, and pubis) and 1 on the femur. On the acetabulum, the anterior attachment was substantially larger than the posterior attachment and was located at a mean clock face position of 4:53 o’clock.Clinical Relevance:These quantitative descriptions of the ligamentum teres can be used by clinicians to arthroscopically identify the attachments of the ligamentum teres, guiding arthroscopic surgical interventions designed to address ligamentum teres pathology.

Shape variability of the adult human acetabulum and acetabular fossa related to sex and age by geometric morphometrics. Implications for adult age estimation

This study aims to explore shape variability of the acetabulum during the human adult life span, in relation to sex and age. The human acetabular shape was analysed in 682 os coxae from three different documented skeletal collections from the Iberian Peninsula. Two landmarks and thirty-two sliding semi-landmarks were used for the geometric morphometric procedures and a clock-wise standard was used for orientation. The 180° meridian (6:00) line was positioned over the midpoint of the acetabular notch and 36 reference points in 10° increments along the rim were marked. Data showed that size, sex and age significantly influence acetabular shape variation. Sex differences were significant in individuals younger than 65 years old and were characterised by males exhibiting relatively extended acetabular rim profiles from 10:00 to 1:00, narrower acetabular notches, and reduced acetabular fossae. In addition, three main age-related changes occurred to the acetabular shape in both sexes: outer acetabular profile modification, with extension from 10:00 to 1:00 and reduction from 7:00 to 9:00, acetabular notch narrowing, and acetabular fossa reduction. The age-related changes that were observed are shared by both sexes and seem to be related to bone production associated with age. Specifically, age appears to affect the entire border of the lunate surface: the acetabular rim, both acetabular horns, and the outer edge of the acetabular fossa. Furthermore, shape data confirmed the clover-leaf shape of the acetabular fossa in both males and females. These results improve our understanding of acetabular shape, and assist in refining age-estimation methods and enhancing hip surgery and rehabilitation.

Acetabular rim length: an anatomical study to determine reasonable graft sizes for labral reconstruction.

The purpose of this article is to determine normative values for the length of the acetabular rim and detect differences between gender, age, ethnicity, height and leg length. Six measurements were taken on the acetabular rim of 143 cadaveric skeleton specimens (286 acetabula) using a coordinate-measuring device: circumferential (excluding acetabular notch), anterior inferior iliac spine (AIIS)-anterior, AIIS-posterior, 12–3 o’clock, 12–9 o’clock and 11–5 o’clock. Museum specimen height data and leg length data from a previous study were recorded for 109 of 143 specimens. Intraclass correlation coefficients were calculated. Student t-tests compared mean values. Multiple regression analysis was used to determine the relationship between acetabular rim length and gender, age, ethnicity, height and leg length. The average acetabular rim length in males for circumferential, AIIS-anterior, AIIS-posterior, 12–3, 12–9 and 11–5 o’clock were 15.8, 4.2, 11.7, 4.9, 4.7 and 9.5 cm, respectively; and for females: 13.7, 3.7, 10.0, 4.3, 4.1 and 8.3 cm, respectively. Intraclass correlation coefficients were 0.953, 0.930, 0.958, 0.857, 0.913 and 0.951, respectively, for each measurement. All six measurements were significantly larger for males (P < 0.001). Multiple regression analysis demonstrated a significant relationship between gender and rim length for all six measurements (P < 0.001) and between height and leg length and acetabular rim length for five of the six measurements exclusive of AIIS-anterior (P < 0.001). No significant trends between age or ethnicity and rim length were found. Average acetabular rim lengths were established. The acetabular rim is significantly longer in males and correlates with height and leg length. Age and ethnicity do not appear to be significant predictors of acetabular rim length. Normative values for acetabular rim lengths may assist in hip preservation surgery.

Developmental dysplasia of the hip: A computational biomechanical model of the path of least energy for closed reduction.

ABSTRACTThis study utilized a computational biomechanical model and applied the least energy path principle to investigate two pathways for closed reduction of high grade infantile hip dislocation. The principle of least energy when applied to moving the femoral head from an initial to a final position considers all possible paths that connect them and identifies the path of least resistance. Clinical reports of severe hip dysplasia have concluded that reduction of the femoral head into the acetabulum may occur by a direct pathway over the posterior rim of the acetabulum when using the Pavlik harness, or by an indirect pathway with reduction through the acetabular notch when using the modified Hoffman–Daimler method. This computational study also compared the energy requirements for both pathways. The anatomical and muscular aspects of the model were derived using a combination of MRI and OpenSim data. Results of this study indicate that the path of least energy closely approximates the indirect pathway of the modified Hoffman–Daimler method. The direct pathway over the posterior rim of the acetabulum required more energy for reduction. This biomechanical analysis confirms the clinical observations of the two pathways for closed reduction of severe hip dysplasia. The path of least energy closely approximated the modified Hoffman–Daimler method. Further study of the modified Hoffman–Daimler method for reduction of severe hip dysplasia may be warranted based on this computational biomechanical analysis. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:1799–1805, 2017.

Experimental study on treatment of acetabular anterior column fractures: applyment of a minimally invasive percutaneous lag screw guide apparatus.

BackgroundThe aim of this study was to design a new minimally invasive percutaneous lag screw guide apparatus and to verify its adjuvant treatment of acetabular anterior column fracture on pelvis specimens.MethodsThis guide apparatus was self-developed based on the principles of “two points form a line” and “Rectangle”. Using C-arm fluoroscopy, this guide apparatus was used to conduct minimally invasive percutaneous lag screw internal fixation of acetabular anterior column fractures. Ten hollow lag screws were placed into 5 pelvis specimens.ResultResult showed no sign of any screws puncturing the cortex or entering into the hip joint on radiological assessment. The cross-section reconstructed vertical distance to the screw, on the cross-section acetabular notch and the cross-section of the screw where the distance of between the screw and the iliopectineal line’s arc roof was at its shortest, indicate that at all points (T, R-r) under the line with an inclination of 1 (namely T = R-r) the screw is within the cortex and does not puncture the acetabula anterior column or enter into the hip joint.ConclusionsWe may conclude that this self-developed guide apparatus solves the screw precision problem during the treatment of acetabular anterior column fractures through a minimally invasive percutaneous lag screw.

Is transverse acetabular ligament a reliable guide for aligning cup anteversion in total hip arthroplasty?: A measurement by CT arthrography in 90 hips.

Transverse acetabular ligament (TAL) has been used as a landmark for aligning cup anteversion. The use of TAL as a guide is based on the assumption that TAL version is distributed within the safe zone of acetabular cup. However, there was rarely reported to compare anteversion between TAL and acetabulum using direct measurement methods. The purpose of this study was to measure the anteversion of TAL in computed tomography arthrography (CTA) and compare it with Lewinnek's safe zone and anteversion of bony acetabulum. 81 patients (90 hips) were selected among 204 patients (228 hips) who received CTA for hip pathology evaluation between March 2010 and June 2013. The anteversion of TAL measured at the lowest level of the acetabular notch and the anteversion of the acetabulum was measured at the level of femoral head center. The mean TAL anteversion was 11.8° (SD 4.5, range 0-22.2). In eight hips (8.8%), TAL anteversion was outside the safe zone (15°±10°) as defined by Lewinnek. The mean acetabular anteversion was 13.3° ± 4.4° (range-1.0° to 22.6°). There was a strong correlation between TAL anteversion and acetabular anteversion (Pearson's correlation coefficient; 0.908, p<0.001). TAL anteversion has a large individual variation, and considerable portion of hips have TAL anteversion outside the safety zone of cup anteversion. TAL anteversion is influenced by acetabular anteversion. In hips with retroverted or pauci-anteverted acetabulum, TAL should be used cautiously because there is a risk of cup malposition.

Ligament of the head of femur: A comprehensive review of its anatomy, embryology, and potential function.

The functional significance of the ligament of the head of femur (LHF), or ligamentum teres has often been debated. Having gained recent attention in clinical practice, it is suggested to partly provide some mechanical stability to the hip joint. However, the anatomy of this ligament is not well studied. This paper systematically reviews the anatomy of the LHF with the aim of exploring our current understanding of this structure and identifying any gaps in knowledge regarding its morphology and function. A systematic search of Medline, Embase, ProQuest, Web of Science, and Scopus databases was undertaken and relevant data extracted, analyzed. A total of 69 references were obtained, that included 53 full text articles, three published abstracts, and 13 textbooks. Many publications related to clinical studies (n = 11) rather than gross anatomy (n = 7), with one report on variation of the LHF. Considerable inconsistency in the naming and description of the LHF morphology was observed. Variable attachment sites were reported except for the acetabular notch, transverse acetabular ligament, and the femoral fovea. Presence and patency of the ligamental arteries supplying the head of the femur and their exact location were variably described and were often incomplete. The LHF is believed to be taught in extreme hip adduction, but there is little evidence to support this. In conclusions, further investigation of the anatomy of the LHF is recommended, particularly to clarify its mechanical role, innervation, and vascular contribution to the developing and adult femur, so to better inform clinical practice.

First remingtonocetid archaeocete (Mammalia, Cetacea) from the middle Eocene of Egypt with implications for biogeography and locomotion in early cetacean evolution

AbstractRemingtonocetidae are Eocene archaeocetes that represent a unique experiment in cetacean evolution. They possess long narrow skulls, long necks, fused sacra, and robust hind limbs. Previously described remingtonocetids are known from middle Eocene Lutetian strata in Pakistan and India. Here we describe a new remingtonocetid,Rayanistes afer, n. gen. n. sp., recovered from a middle to late Lutetian interval of the Midawara Formation in Egypt. The holotype preserves a sacrum with four vertebral centra; several lumbar and caudal vertebrae; an innominate with a complete ilium, ischium, and acetabulum; and a nearly complete femur. The ilium and ischium ofRayanistesare bladelike, rising sharply from the body of the innominate anterior and posterior to the acetabulum, and the acetabular notch is narrow. These features are diagnostic of Remingtonocetidae, but their development also shows thatRayanisteshad a specialized mode of locomotion. The expanded ischium is larger than that of any other archaeocete, supporting musculature for powerful retraction of the hind limbs during swimming. Posteriorly angled neural spines on lumbar vertebrae and other features indicate increased passive flexibility of the lumbus.Rayanistesprobably used its enhanced lumbar flexibility to increase the length of the power stroke during pelvic paddling. Recovery of a remingtonocetid in Egypt broadens the distribution of Remingtonocetidae and shows that protocetids were not the only semiaquatic archaeocetes capable of dispersal across the southern Tethys Sea.

The ligaments of the canine hip joint revisited.

Numerous conventional anatomical textbooks describe the canine hip joint, but many contradictions, in particular regarding the ligament of the femoral head, are present. This paper presents a brief overview of the different literature descriptions. These are compared with own observations that have resulted in a revised description of the anatomy of the ligament of the femoral head in the dog. To this purpose, the hip joints of 41 dogs, euthanized for reasons not related to this study and devoid of lesions related to hip joint pathology, were examined. It was observed that the ligament of the femoral head is not a single structure that attaches only to the acetabular fossa, as generally accepted, but it also connects to the transverse acetabular ligament and is complemented by a strong accessory ligament that courses in caudal direction to attach in the elongation of the acetabular notch that extends on the cranioventral surface of the body of the ischium. The description of this accessory ligament in conventional anatomical handbooks is incomplete. This description of the accessory ligament of the femoral head could support the research unravelling the etiopathogenesis of hip instability.