RÉSUMÉ
ObjectiveTo develop a deep learning system for early ultrasound screening of developmental dysplasia of the hip （DDH）， a new smart-hip ultrasound technique （S-hip）， and to validate its clinical application. MethodsWe selected 11，100 annotated and reviewed coronal ultrasound images of infant hips between November 2021 and August 2022， 8，100 of which were used for the training set and 3，000 for the test set， to build a S-hip deep learning system. To verify the consistency between the automated measurement by S-hip and the manual measurements by sonographers， 174 standard coronal ultrasound images of 87 infants' bilateral hips were acquired， then α angle， β angle and femoral head coverage （FHC） were measured by S-hip， an ultrasound expert and a resident. The measurement data and the time required for the measurements were recorded and statistically analyzed. Another 100 standard coronal ultrasound images of the hips were randomly selected and measured twice respectively by the ultrasound expert and resident to assess the intra-sonographer repeatability. ResultsThe intraclass correlation coefficient （ICC） （95% CI） values of α angle， β angle and FHC results measured by S-hip and ultrasound expert were 0.799 （0.738， 0.847）， 0.798 （0.737， 0.846） and 0.934 （0.954， 0.975）， respectively. Those values measured by the ultrasound expert and resident were 0.725 （0.645， 0.789）， 0.674 （0.583， 0.748） and 0.931 （0.908， 0.949）， respectively. The mean absolute errors （MAE） of α angle， β angle and FHC results between measurements by S-hip and ultrasound expert were 2.69 °， 4.43 ° and 2.47%， respectively. The time required for measurements by S-hip， ultrasound expert and resident was （1.59±0.36） s， （18.76±2.23） s and （19.45±2.76） s， respectively. The automated measurement by S-hip cost much shorter time than the manual measurements by sonographers and the difference was statistically significant （P<0.001）. The ICC （95% CI） values of α angle， β angle and FHC results between two measurements by the ultrasound expert were 0.943 （0.916， 0.961）， 0.959 （0.940， 0.972）， and 0.981 （0.971， 0.987）， respectively. Those values by the ultrasound resident were 0.884 （0.833， 0.921）， 0.921 （0.884， 0.946）， and 0.962 （0.944， 0.974）. ConclusionThe S-hip based on a deep learning system is a highly reliable automated technique to accurately measure α angle， β angle and FHC. Compared with ultrasound residents， S-hip allows for a more simplified and significantly quicker measurement， which may enhance the widespread use of hip ultrasound screening in infants.
RÉSUMÉ
Objective In order to simulate different angles of acetabular blocks that need to be adjusted during operation, the optimal angle was determined through analyzing the contact stress and contact area of cartilage around the hip joint, so as to provide an individual scheme for acetabular osteotomy. Methods The finite element models for development dysplasia of hip (DDH) and normal pelvis were established to investigate morphological characteristics of the acetabulum and the causes of stress concentration. To simulate osteotomy for the DDH model, a total of 20 postoperative osteotomy models were obtained through the combination of different angles for anterior rotation and lateral rotation of acetabular blocks, and the differences in optimal results of the models during simulated one legged-standing were compared and analyzed. Results The maximum contact pressure of acetabular cartilage in normal model was 7.85 MPa. The maximum contact pressure of acetabular cartilage in DDH model was 13.42 MPa. The optimal contact pressure after simulated osteotomy decreased to 8.49 MPa, and the contact distribution was improved more significantly. Conclusions Changing the anterior rotation angle can significantly improve the contact pressure distribution and size, as well as stay away from the preoperative lesion area, which has a positive impact on postoperative outcomes. Personalized osteotomy plan based on actual situation of each patient before the operation is crucial for the surgical effect.
RÉSUMÉ
Objective Based on the principle of uncemented stem design, the femoral anteversion in different CT planes before total hip arthroplasty (THA) and stem anteversion after THA was compared, so as to find out the preoperative measurement to estimate stem anteversion in patients with developmental dysplasia of the hip(DDH) after THA. Methods Twenty-one primary THA patients (28 hips) who were diagnosed with DDH between September 2007 and May 2013 in Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine were selected. Preoperative and postoperative CT scans were performed on all patients. The femoral anteversion angle was defined as the angle between the midcortical line between the anterior and posterior cortical line in five CT slices and the posterior condylar axis. The slice levels for the 4 femoral sites were selected，including the area just distal to the femoral head, the center of the lesser trochanter，1 cm height above center of the lesser trochanter, 2 cm height above center of the lesser trochanter (marked as femoral anteversion 1-4). Femoral anteversion 5 was defined as the midcortical line of the anterior cortical line in the slice of 2 cm height above center of the lesser trochanter and the posterior cortical line in the slice of 50% of the distance from the top of greater trochanter to the center of the lesser trochanter above the center of the lesser trochanter. The stem anteversion angle was defined as the angle formed by the stem neck major axis and the posterior aspect of the femoral condylar line. The cup version and stem alignment were also calculated. The difference value and correlation coefficients of femoral anteversion 1-5 and stem anteversion were compared. Results Femoral anteversion 1-5 was 17.70°±10.54°, 35.59°±7.21°, 31.09°±7.98°, 24.71°±9.11°, 21.94°±10.10°, respectively。Stem anteversion was 20.52°±10.90°. The difference value between stem anteversion and femoral anteversion 1-5 was 2.82°±6.27°, -15.08°±7.99°, -13.80°±15.68°, -4.19°±5.69°, -1.42°±4.07°, respectively. Cup anteversion was 25.60°±11.65°, and combined antevertion was 46.11°±13.28°，sagittal stem tilt was 1.13°±1.53°. There were statistically significant differences between femoral anteversion 1-4 and stem anteversion (P＜0.05), and no statistical difference was found between femoral anteversion 5 and stem anteversion. The correlation coefficients of femoral anteversion 1-5 and stem anteversion were 0.829, 0.681, 0.689, 0.853, 0.928, respectively. Conclusions Femoral anteversion 5 had a highly positive correlation with stem anteversion, which was an effective a substitute of stem anteversion before THA.
RÉSUMÉ
Objective To measure and investigate the anatomical characteristics of the proximal femur canal curves in patients with developmental dysplasia of the hip (DDH), and to provide references for the design of femoral stem of DDH patients. Methods Three-dimensional reconstructions of the proximal femur were conducted from the CT data, and the anatomical morphology characteristics were obtained from 64 patients with DDH (74 hips, 12 males, 52 females, average age of 45.3 years) and 30 healthy controls (30 hips, 21 males, 9 females, average age of 29.4 years). Multiple anteroposterior diameter and mediolateral diameter around the lesser trochanter at different heights and the fitting curves of different groups were obtained. Results The femoral neck anteversion angle, neck-shaft angle, height of the isthmus, canal flare index (CFI), femoral head diameter and femoral offset of DDH patients and healthy controls were 26.39°±14.74° and 15.68°±7.95°, 125.65°±5.73° and 129.19°±5.80°, (99.14±14.62) mm and (110.13±11.73) mm, 3.63±0.77 and 4.45±0.79, (44.01±5.75) mm and (47.26±3.94) mm, (31.80±3.82) mm and (36.42±4.84) mm, respectively. DDH group had the significantly greater femoral neck anteversion angle, and other anatomical morphology characteristics were significantly smaller than the control group. The obtained anteroposterior diameter, mediolateral diameter and the fitting curves showed that DDH group had narrow medullary cavity and forward shifting anteroposterior diameter. In addition, there was a statistical significance between the Crowe Ⅳ DDH and other types of DDH, and deformation degree of the femur increased with the increase of DDH type. Conclusions The proximal femur of DDH patients was significantly different from the healthy controls. Moreover, there were significantly morphological differences between different types of DDH. The research findings can be used as quantitative references for understanding the morphological feature of DDH patients and the corresponding design of femoral stem for DDH patients.
RÉSUMÉ
Objective To investigate the biomechanical effects of femoral offset (FO) on total hip arthroplasty (THA) patients with developmental dysplasia of the hip (DDH). Methods Based on the musculoskeletal dynamic software AnyBody and the related data from a female patient with Crowe Ⅳ DDH, the corresponding patient-specific lower extremity musculoskeletal multi-body dynamic model was constructed to analyze both hip joint forces and abductor forces within ±20 mm variation of FOs. The dynamic finite element (FE) model of S-ROM stem with varying offsets was also established. The dynamic load during a whole walking gait cycle calculated by the multi-body musculoskeletal model was applied to this FE models, and the Von Mises stress, contact stress, and stem-sleeve micromotion were then analyzed. Results A variation of ±20 mm offset had small influences on peak forces of hip joints. However, the decrease in FO could lead to an obvious increase in peak abductor force, while the increase in FO could lead to an obvious increase in the maximum Von Mises stress, contact stress, and micromotion of S-ROM prosthesis stem. Conclusions The change in FO had an obvious influence on the abductor forces, the maximum Von Mises stress, the contact pressure and the consequent fretting wear of THA patients with DDH, which should be carefully considered by surgeons.
RÉSUMÉ
Objective Based on the principle of uncemented stem design, the femoral anteversion in different CT planes before total hip arthroplasty (THA) and stem anteversion after THA was compared, so as to find out the preoperative measurement to estimate stem anteversion in patients with developmental dysplasia of the hip(DDH) after THA. Methods Twenty-one primary THA patients (28 hips) who were diagnosed with DDH between September 2007 and May 2013 in Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine were selected. Preoperative and postoperative CT scans were performed on all patients. The femoral anteversion angle was defined as the angle between the midcortical line between the anterior and posterior cortical line in five CT slices and the posterior condylar axis. The slice levels for the 4 femoral sites were selected，including the area just distal to the femoral head, the center of the lesser trochanter，1 cm height above center of the lesser trochanter, 2 cm height above center of the lesser trochanter (marked as femoral anteversion 1-4). Femoral anteversion 5 was defined as the midcortical line of the anterior cortical line in the slice of 2 cm height above center of the lesser trochanter and the posterior cortical line in the slice of 50% of the distance from the top of greater trochanter to the center of the lesser trochanter above the center of the lesser trochanter. The stem anteversion angle was defined as the angle formed by the stem neck major axis and the posterior aspect of the femoral condylar line. The cup version and stem alignment were also calculated. The difference value and correlation coefficients of femoral anteversion 1-5 and stem anteversion were compared. Results Femoral anteversion 1-5 was 17.70°±10.54°, 35.59°±7.21°, 31.09°±7.98°, 24.71°±9.11°, 21.94°±10.10°, respectively。Stem anteversion was 20.52°±10.90°. The difference value between stem anteversion and femoral anteversion 1-5 was 2.82°±6.27°, -15.08°±7.99°, -13.80°±15.68°, -4.19°±5.69°, -1.42°±4.07°, respectively. Cup anteversion was 25.60°±11.65°, and combined antevertion was 46.11°±13.28°，sagittal stem tilt was 1.13°±1.53°. There were statistically significant differences between femoral anteversion 1-4 and stem anteversion (P＜0.05), and no statistical difference was found between femoral anteversion 5 and stem anteversion. The correlation coefficients of femoral anteversion 1-5 and stem anteversion were 0.829, 0.681, 0.689, 0.853, 0.928, respectively. Conclusions Femoral anteversion 5 had a highly positive correlation with stem anteversion, which was an effective a substitute of stem anteversion before THA.
RÉSUMÉ
Objective To measure and investigate the anatomical characteristics of the proximal femur canal curves in patients with developmental dysplasia of the hip (DDH), and to provide references for the design of femoral stem of DDH patients. Methods Three-dimensional reconstructions of the proximal femur were conducted from the CT data, and the anatomical morphology characteristics were obtained from 64 patients with DDH (74 hips, 12 males, 52 females, average age of 45.3 years) and 30 healthy controls (30 hips, 21 males, 9 females, average age of 29.4 years). Multiple anteroposterior diameter and mediolateral diameter around the lesser trochanter at different heights and the fitting curves of different groups were obtained. Results The femoral neck anteversion angle, neck-shaft angle, height of the isthmus, canal flare index (CFI), femoral head diameter and femoral offset of DDH patients and healthy controls were 26.39°±14.74° and 15.68°±7.95°, 125.65°±5.73° and 129.19°±5.80°, (99.14±14.62) mm and (110.13±11.73) mm, 3.63±0.77 and 4.45±0.79, (44.01±5.75) mm and (47.26±3.94) mm, (31.80±3.82) mm and (36.42±4.84) mm, respectively. DDH group had the significantly greater femoral neck anteversion angle, and other anatomical morphology characteristics were significantly smaller than the control group. The obtained anteroposterior diameter, mediolateral diameter and the fitting curves showed that DDH group had narrow medullary cavity and forward shifting anteroposterior diameter. In addition, there was a statistical significance between the Crowe Ⅳ DDH and other types of DDH, and deformation degree of the femur increased with the increase of DDH type. Conclusions The proximal femur of DDH patients was significantly different from the healthy controls. Moreover, there were significantly morphological differences between different types of DDH. The research findings can be used as quantitative references for understanding the morphological feature of DDH patients and the corresponding design of femoral stem for DDH patients.
RÉSUMÉ
Objective To investigate the changes of plantar pressure distributions in children with the unilateral developmental dysplasia of the hip (DDH) who underwent the Pemberton’s pericapsular osteotomy (PPO) at early age, so as to provide valuable references for clinical therapy and rehabilitation of such patients. Methods Eighteen child patients who underwent PPO before 4 year old were selected as the PPO group, while 18 healthy children at the same age with normal feet were selected as the control group. Footscan system was used to measure the plantar pressure of these subjects during walking. The parameters, i.e. contact area percentage of the total foot contact area (CA%), pressure-time integral (PTI) and contact time percentage of the stance time (CT%) in both PPO group and control group were compared to evaluate changes of the plantar pressures during walking. Results Compared with the sound limb in control group and the unaffected limb in PPO group, the affected limb in PPO group showed higher PTI in the 2nd to 5th toe zone and lower PTI in the medial heel zone. The affected limb in PPO group had a higher CA% in the 4th and 5th metatarsals than the unaffected limb in PPO group and the sound limb in control group, and a lower CA% in the 1st and 2nd metatarsals than the unaffected limb. Compared with the unaffected limb in PPO group and the sound limb in control group, CT% of the affected limb in PPO group increased in the forefoot push-off phase and decreased in the initial contact phase, and the total contact time of the affected limb was shorter than that of the unaffected limb in PPO group and the sound limb in control group. Conclusions There exist residual plantar pressure deviations during walking in DDH patients following PPO at early age, thus a longer period of intensive rehabilitation may be required to change the residual abnormality.
RÉSUMÉ
Introducción: La Displasia del desarrollo de la cadera (DDC) es un espectro de enfermedades que abarca desde la luxación franca de la cadera hasta la displasia acetabular leve. El screening de detección de DDC se realiza de rutina en nuestro país, mediante una radiografía de pelvis a los 3 meses. El índice acetabular medido en estas radiografías se utiliza para evaluar la cadera displásica, tanto en la presentación inicial como durante el seguimiento posterior. Objetivo: Evaluar la variabilidad tanto intra como inter observador en la medición del índice acetabular, entre profesionales médicos. Material y Métodos: Cuatro evaluadores (un cirujano-ortopédico infantil, un médico general, un pediatra y un radiólogo) realizaron la medición del índice acetabular en 100 radiografías de screening (200 caderas), en tres ocasiones, separadas por un mes cada una (600 mediciones totales). Un observador independiente evaluó la reproductibilidad en la medición. Se utilizó el coeficiente de correlación intraclase para determinar diferencias significativas. Resultados: La variabilidad intra observador fue menor que la interobservador. La variabilidad intra observador fue similar para los diferentes evaluadores, +/- 1,5°. La variabilidad inter observador fue de +/- 3,4°. Conclusiones: Demostramos una alta concordancia entre las mediciones, determinando una alta reproductibilidad del índice acetabular. El índice acetabular es un método seguro para el diagnóstico y seguimiento de displasia acetabular.
Developmental dysplasia of the hip (DDH) is a spectrum of diseases ranging from frank dislocation of the hip to mild acetabular dysplasia. DDH screening for detection is performed routinely in our country using pelvic x-ray at 3 months of age. The radiographic measured acetabular index is used to evaluate the dysplastic hip, at initial presentation and during follow-up. Objective: Evaluation of the intra- and inter-observer variability, among medical professionals, when measuring acetabular index. Methods: Four reviewers (a children orthopedic surgeon, a general practitioner, a pediatrician and a radiologist) performed acetabular index measurement in 100 radiographs (200 hips), on three occasions, separated each by one month (600 total measurements). An independent observer evaluated the measurement reproducibility. The intra-class correlation coefficient to determine significant differences was used. Results: The intra-observer variability was less than the inter-observer variability. The intra-observer variability was similar among the different assessors, +/- 1.5 degrees. The inter-observer variability was +/- 3.4 degrees. Conclusions: A high concordance among measurements was reported, evidencing a high reproducibility of the acetabular index; this index is a reliable method for the diagnosis and follow-up of acetabular dysplasia.