RESEARCH ON ACETABULAR PARAMETERS, FEMORAL AND COMBINED ANTEVERSION ANGLES ON COMPUTED-TOMOGRAPHY SCAN

54 computed-tomography scans of 54 Vietnamese adults with at least 1 non-pathological hip at Hanoi Medical University Hospital are used on our research. The results are: Acetabular inclination angle: 37.48 ± 4.95o; Acetabular anteversion angle: 17.2 ± 5.81o; Femoral anteversion angle: 12.03 ± 7.32o; Combined anteversion: 29.23 ± 9.07o.

Retroversion of the hemipelvis rather than hypoplastic posterior wall decreases acetabular anteversion in hips affected by Perthes disease

The acetabular retroversion has a moderate incidence of 31–60% in all patients of the Perthes disease. It might be caused by posterior wall dysplasia based on recent animal researches. However, some studies support that hemipelvic retroversion is the main factor for the acetabular retroversion. The primary pathological factor of increasing retroversion angle is still controversial anatomically. This study aimed to identify whether there is acetabular retroversion in children with Perthes disease,and to find a method to distinguish version types. Forty children with unilateral Perthes disease who were admitted to our hospital from January 1, 2012 to December 31, 2018 were enrolled, and 40 controls were matched based on sex and age. The acetabular anteversion angle (AAA), internal wall anteversion angle (IWAA), anterior wall height of the acetabulum (A), acetabular posterior wall height (P), and acetabular width (W) were assessed on computed tomography (CT) at the level of the femoral head center. The acetabular wall difference index (AWDI; AWDI = P-A)/W*100) was calculated. The mean AAA was significantly lower in Perthes disease hips (10.59 (8.05–12.46)) than in contralateral hips (12.04 (9.02–13.33)) (p = 0.002) but did not differ from control hips (9.68 ± 3.76) (p = 0.465). The mean IWAA was significantly lower in Perthes hips (9.16 ± 3.89) than in contralateral hips (11.31 ± 4.04) (p = 0.000) but did not differ from control hips (9.43 ± 3.82) (p = 0.753). The mean AWDI did not differ between Perthes hips (0.41 ± 4.94) and contralateral hips (− 1.12 (− 4.50, 2.17)) (p = 0.06) or control hips (− 0.49 ± 5.46) (p = 0.437). The mean W was significantly higher in Perthes hips (44.61 ± 5.06) than in contralateral hips (43.36 ± 4.38) (p = 0.000) but did not differ from control hips (45.02 ± 5.01) (p = 0.719). The mean A and P did not differ between Perthes hips and contralateral hips or control hips. Correlation analysis of all hip joints revealed a significant correlation between AAAs and IWAAs (r = 0.772; r = 0.643; r = 0.608; and r = 0.540). Linear regression analysis revealed that AAAs increased with IWAAs. Multiple linear regression showed that IWAAs and AWDIs have good predictive value for AAAs in both Perthes and control hips (R2 = 0.842, R2 = 0.869). In patients with unilateral Perthes disease, the affected acetabulum is more retroverted than that on the contralateral side, which may be caused by hemipelvic retroversion. The measurements in this study could distinguish the form of acetabular retroversion. IWAAs and AWDIs can be used as new observations in future studies of acetabular version.

Designing Composite External Fixator For Intertrochanteric Fracture Treatment Based On Vietnamese Femur Morphological Parameters

Aim — 60 Vietnamese dry femurs were studied to design a carbon composite external fixator for intertrochanteric fracture. Its mechanical strength was evaluated. Material and Methods — The femurs were measured by standard goniometers. The fixator injection mold was created by a CNC machine. The fixator material included carbon fiber (30 – 40% content), BT4, and PA12 plastic. The fixator strength was calculated based on the Finite Element Method. Results — The average femoral neck-shaft angle, anteversion angle, bowing angle, head diameter, and neck width were respectively 124.850 (±7.12), 20.240 (±4.49), 14.900 (±3.27), 4.12cm (±0.30), and 3.05cm (±0.34). A mold and its resulting fixator were designed accordingly. The fixator elasticity modulus, tensile strength, Poisson ratio, and safety factor (K) were 1.32x1010 Pa, 2.21x108 Pa, 0.25, and 1.5, respectively, and max load, stress and transposition were 50-150 N, 1.21-1.38 x 108 Pa, and 0.4-1.27 mm, respectively. The composite fixator was more resistant against pressure across the x-axis but less against the y-axis than the chrome and Inox304 devices. Transposition was the smallest due to its tiny size. Load against z-axis pressure was safe for the patients. Conclusion — This study succeeded to design a prototype carbon composite external fixator with favorable mechanical traits compared with available metal fixators. Further clinical studies are needed to achieve an accurate evaluation of its effectiveness.

Unilateral premature osteoarthritis of the hip with excessive anteversion of the femoral neck developing in the early second decade: two surgical cases

Background Osteoarthritis (OA) of the hip rarely develops in the early second decade. As the incidence of this disease is low, no treatment method has been established. We report two patients with unilateral OA in their early teens in whom the anteversion angle of the femoral neck on the affected side was greater than that on the unaffected side. Case presentation Case 1 was an 11-year-old girl with left coxalgia and limited range of motion. There was no history of femoroacetabular impingement (FAI) or developmental dysplasia of the hip (DDH). Plain X-rays revealed the disappearance of the Y cartilage, joint space narrowing of the left hip, and acetabular/femoral head osteosclerosis. In CT images, the anteversion angle of the femoral neck (lt/rt) was 45/35 degrees. As osteoarthritis was severe, proximal femoral flexional derotational varus osteotomy (PFFDVO) and triple pelvic osteotomy (TPO) were performed. Case 2 was a 13-year-old girl with left coxalgia and limited range of motion. There was no history of FAI or DDH. Plain X-ray revealed irregularity of the left anterolateral femoral head, and a subcartilaginous cyst. In CT images, the anteversion angle of the femoral neck (lt/rt) was 30/20 degrees. As osteoarthritis was severe, PFFDVO was performed. In addition, we resected bone spurs on the femoral head because flexion was limited owing to the presence of osteophytes. In both patients, coxalgia and claudication/gait disorder resolved postoperatively, and joint space narrowing and osteosclerosis improved. However, in Case 1, there was a 3-cm difference in the leg length, and in Case 2, range-of-motion limits remained. Conclusions We present the findings in two patients with unilateral OA in their early second decade in whom the femoral anteversion angle on the affected side was greater than that on the unaffected side. PFFDVO + TPO was performed in Case 1, and PFFDVO + bone spur resection on the femoral head was performed in Case 2. Coxalgia resolved, and plain X-ray demonstrated improvements in OA; however, a difference in the leg length and range-of-motion limits remained.

Measurement of the Femoral Anteversion Angle in Medium and Large Dog Breeds Using Computed Tomography

To promote the development of an optimally functional total hip prosthesis for medium and large dog breeds, accurate measurements of the normal anatomy of the proximal femur and acetabular retroversion are essential. The aim of the current study was to obtain precise normal values of the femoral anteversion angle using computed tomography on cadavers of mature dogs with normal hip joints of both medium and large breeds. Based on the length of their femora 58 dogs were allocated either to group I: ≤195 mm or group II: >195 mm. In the study the femoral anteversion angle (FAA) was measured on each femur using multi-slice spiral computed tomography (CT). The data were processed as multi-planar and three-dimensional reconstructions using Advantage Workstation software. The CT measurements showed that the mean ± standard deviation (SD) FAA of group I was 31.34 ± 5.47° and in group II it was 31.02 ± 4.95°. There were no significant mean difference associations between the length of the femur and the femoral neck angle in either group (P > 0.05). The data suggest that a prosthesis FAA of 31 degrees would be suitable for a wide range of dog sizes.

Dependency of Lower Limb Joint Reaction Forces on Femoral Anteversion

BackgroundMusculoskeletal (MSK) models based on literature data are meant to represent a generic anatomy and are a popular tool employed by biomechanists to estimate the internal loads occurring in the lower limb joints, such as joint reaction forces (JRFs). However, since these models are normally just linearly scaled to an individual’s anthropometry, it is unclear how their estimations would be affected by the personalization of key features of the MSK anatomy, one of which is the femoral anteversion angle.Research QuestionHow are the lower limb JRF magnitudes computed through a generic MSK model affected by changes in the femoral anteversion?MethodsWe developed a bone-deformation tool in MATLAB (https://simtk.org/projects/bone_deformity) and used it to create a set of seven OpenSim models spanning from 2° femoral retroversion to 40° anteversion. We used these models to simulate the gait of an elderly individual with an instrumented prosthesis implanted at their knee joint (5th Grand Challenge dataset) and quantified both the changes in JRFs magnitude due to varying the skeletal anatomy and their accuracy against the correspondent in vivo measurements at the knee joint.ResultsHip and knee JRF magnitudes were affected by the femoral anteversion with variations from the unmodified generic model up to 11.7±5.5% at the hip and 42.6±31.0% at the knee joint. The ankle joint was unaffected by the femoral geometry. The MSK models providing the most accurate knee JRFs (root mean squared error: 0.370±0.069 body weight, coefficient of determination: 0.764±0.104, largest peak error: 0.36±0.16 body weight) were those with the femoral anteversion angle closer to that measured on the segmented bone of the individual.SignificanceFemoral anteversion substantially affects hip and knee JRFs estimated with generic MSK models, suggesting that personalizing key MSK anatomical features might be necessary for accurate estimation of JRFs with these models.

Direct anterior approach versus posterolateral approach in total hip arthroplasty: a meta-analysis of results on early post-operative period

Background This study was performed to compare the advantage and disadvantage of posterolateral approach (PLA) and direct anterior approach (DAA) in total hip arthroplasty (THA). Methods Relevant trials were identified via a search of the Cochrane Central Register of Controlled Trials and PubMed from inception to 1 June 2019. A meta-analysis was performed to compare postoperative perioperative and radiographic outcomes between DAA and PLA in THA with respect to the hospital stay, blood loss, incision length, operative time, complications, and femoral and cup component position. The Harris Hip Score (HHS) was also assessed before and after 6 months postoperatively. Results Nine eligible studies involving 22698 adult patients (DAA group, n = 2947; PLA group, n = 19751) were identified for analysis. Compared with the PLA group, the DAA group had shorter hospital stay and achieved better HHS within 6 months after operation (P < 0.05), but the HHS was no significant differences between the two groups over 6 months (P > 0.05). The DAA group had significantly longer operative time, more blood loss, and complications than the PLA group (P < 0.05). In addition, the femoral component positioned in neutral and cup component inclination angle was comparable between both groups (P > 0.05); however, cup component anteversion angle was significantly larger in the PLA group (P < 0.05). Conclusion Patients in the DAA group had higher HHS within 6 months and shorter hospital stay. The DAA could offer rapid early functional recovery after THA compared with the PLA. However, the DAA group often required longer operative time and had more blood loss. Furthermore, there was a higher early complication rate. Therefore, we believe that the direct anterior approach was a more difficult technique. The surgeon should be a well-trained joint surgeon with extensive prior hip replacement experience before performing THA through a DAA, and DAA was not suitable for beginners performing THA. In addition, we did not observe the difference with regard to the femoral component position and cup component inclination angle except for the smaller cup component anteversion angle in DAA group.

A Systematic Review and Meta-analysis of Direct Anterior Approach Versus Posterolateral Approach in Total Hip Arthroplasty

Background: To evaluate the difference of clinical results between DAA and PLA in primary THA.Methods: The PubMed , Embase and the Cochrane Library were searched by computer to collect and compare clinical randomized controlled trials of primary THA through DAA and PLA. The clinical outcome measures include operation time, total blood loss, acetabular abduction angle, acetabular anteversion angle, Harris hip score and postoperative dislocation rate. The Revman 5.3 software provided by the Cochrane Collaborat Network was used for Meta analysis of the data.Results: A total of 654 patients were included in 8 studies, including 328 patients in DAA group and 326 patients in PLA group. Meta-combined results, The number of acetabular abduction angle in DAA group is smaller than that in PLA group [MD =-0.87, 95%CI(-1.69 ~-0.04), p = 0.04], and the number of acetabular anteversion angle in DAA group is also smaller than that in PLA group [MD =-4.25, 95%CI(-4.96 ~-3.54), p < 0.00001], the differences are statistically significant. 6 weeks after operation, the Harris hip score of DAA was higher than that of PLA [MD = 5.35, 95%CI(2.38 ~ 8.32), P = 0.0004], and the difference was statistically significant. For the total Harris hip score , DAA is higher than PLA, and the difference is statistically significant [MD = 2.3, 95%CI (0.19 ~ 4.41), P = 0.03]; However, other results were not statistically significant.Conclusion: Compared with PLA, DAA can accelerate postoperative rehabilitation of patients, and at the same time can obtain better acetabular prosthesis location.

Lumbar shape factors extraction influencing the ratio of waist-darts’ volumes for young female

To improve the fitness of bottoms of individuals, this study is proposed to extract lumbar shape factors influencing the ratio of waist dart’s volumes of young females. A total of 27 measurement items including lumbar shapes and waist dart’s volumes were collected through overlapped graphics of lumbar feature sections obtained from 30 female college students aged 18 and 24via 3D body scanning method. Results of correlation analysis showed that the total waist dart’s volume was significantly correlated with the lateral lumbar bending level (ytc), and the ratio of each waist dart’s volume was significantly correlated with lumbar anteversion angle (β), lumbar anteverted amount (ytq) and buttock projected volume (ab) respectively with a correlation coefficient above r=0.7. Furthermore, a total of 2 factors with a characteristic value that was larger than 1 were extracted through principle component analysis, whose cumulative contribution rate reached 80.241%. Principle Component 1 represented factors of lumbar anteversion, which was related to the ratio of anterior/posterior waist dart’s volume; and Principle Component 2 represented the lateral lumbar shape characteristics affecting the total waist dart’s volume.