Особенности ревизионного эндопротезирования тазобедренного сустава при изначально высоком расположении вертлужного компонента

Relevance. Total hip arthroplasty with a severe dysplasia refers to complex cases of joint replacement. One of the options for fixation of the acetabular component in this situation is to place the cup in the false acetabulum. Revisions in case of the acetabular component initial placement into the false acetabulum are highly complex. The purpose — to study the features of revision hip arthroplasty in the patients with dysplastic arthritis and loosening of the acetabular component initially placed in the false acetabulum. Materials and Methods. The clinical and functional results and complications were evaluated after 44 revisions performed by one surgical team from 2001 to 2019. How the position of vertical and horizontal centers of rotation of acetabular component after primary arthroplasty influenced the long-term survival of implants was analyzed. The degree of impact of the preoperative cranial displacement from the anatomical position of the femoral component center of rotation impact on surgical tactics was also investigated. Results. A combination of a highly porous cup with augment was used most frequently for acetabular component replacement (24 cases; 54.5%). Complications after the revision were detected in 6 (13.6%) patients. The values of the Oxford Hip Score, EQ-5D, VAS general health, and VAS pain depended on the postoperative position of the hip prosthesis center of rotation within 10 mm from the anatomical center. The odds ratio for the revision performed less than 10 years after the primary arthroplasty in the patients with a horizontal position of the center of rotation of 40 mm or more was equal to 14.571 (95% CI from 1.682 to 126.249; p = 0.011). The average value of the distal displacement of the center of rotation after the surgery was 32.0 mm (min-max 4.7 to 90.3 mm; Me 23.9 mm), the average residual displacement of the center of rotation after the surgery was 6.2 mm (min-max 10.8 to 32.1 mm; Me 4.75 mm). The standard approach was characterized by a lesser distal displacement of the center of rotation than various osteotomy options: 26.1 mm (min-max 4.7 to 77.2; Me 19.1 mm) vs 41.2 mm (min-max 10.8 to 90.3 mm; Me 36 mm), respectively (p = 0.021). A well-fixed stem preservation resulted in the mean distal displacement of the femur of 23.8 mm, the stem removed — of 35.0 mm. Conclusion. A horizontal center of rotation displacement of 40 mm or more affects the long-term survival of the implant. When the significant lowering of the femur is required (more than 30 mm) and a well-fixed femoral component is preserved, it is advisable to use the approach with extended trochanteric osteotomy or shortening femoral osteotomy. The acetabular component placement into the true acetabulum with weakened bone requires extended screw fixation. In this situation the use of individual 3D-printed implants has potential benefits.Тотальная замена тазобедренного сустава при выраженной степени дисплазии относится к сложным случаям эндопротезирования. Одним из вариантов фиксации вертлужного компонента при выраженной дисплазии является установка чашки в ложную вертлужную впадину. Наряду с этим ревизионные операции при изначальной установке ацетабулярного компонента в ложную вертлужную впадину отличаются высокой сложностью. Цель исследования — изучить особенности ревизионного эндопротезирования тазобедренного сустава у пациентов с расшатыванием вертлужного компонента, которым изначально по поводу диспластического артроза чашка была установлена в ложную вертлужную впадину. Материал и методы. Выполнена оценка клинико-функциональных результатов и осложнений после 44 ревизионных операций, проведенных одной хирургической бригадой c 2001 по 2019 г. Кроме того, был выполнен анализ влияния расположения вертикального и горизонтального центров ротации вертлужного компонента после первичной операции на долгосрочную выживаемость имплантатов и величины предоперационного краниального смещения центра ротации бедренного компонента от анатомического на тактику оперативного лечения. Результаты. Наиболее часто при замене вертлужного компонента использовалась комбинация высокопористой чашки с аугментом (24 случая; 54,5%). Осложнения после ревизии были выявлены у 6 (13,6%) больных. Значения шкал Oxford Hip Score, EQ-5D, ВАШ общего здоровья и ВАШ боли демонстрировали зависимость от позиционирования центра ротации эндопротеза тазобедренного сустава (ТБС) в послеоперационном периоде в пределах до 10 мм от анатомического центра ротации. Отношение шансов для ревизии в сроки менее 10 лет при горизонтальной позиции центра ротации 40 мм и более после первичной операции было равно 14,571 (95% ДИ от 1,682 до 126,249; р = 0,011). Средняя величина дистального смещения центра ротации после операции составила 32,0 мм (min-max -4,7–90,3 мм; Ме 23,9 мм), среднее остаточное смещение центра ротации после операции составило 6,2 мм (min-max -10,8—32,1 мм; Ме 4,75 мм) При стандартном доступе отмечалось меньшее дистальное перемещение центра ротации, чем при использовании различных вариантов остеотомии — 26,1 мм (min-max -4,7–77,2; Ме 19,1 мм) и 41,2 мм (min-max 10,8—90,3 мм; Ме 36 мм) соответственно, р = 0,021. При сохранении хорошо фиксированной ножки протеза средняя величина дистального смещения бедра составила 23,8 мм, а при удалении ножки — 35,0 мм. Заключение. Значение горизонтального центра ротации 40 мм и более влияет на долгосрочную выживаемость имплантата. При необходимости значительного низведения бедра (более 30 мм) с наличием хорошо фиксированного бедренного компонента целесообразно использовать доступ с расширенной вертельной остеотомией или укорачивающей остеотомией бедра. Установка вертлужного компонента в область истинной вертлужной впадины на фоне ослабленной кости требует расширенной фиксации винтами, поэтому использование кастомизированных имплантатов, изготовленных методом 3D-печати, имеет потенциальные преимущества.

Do exotic alpha-cluster states in 12 C show signatures of alpha-condensate structure? Analysis of recent data on the a -particle inelastic scattering

The diffraction model, DWBA and the Coupled Reaction Channels analysis of the novel data of α + 12C elastic and inelastic (to the states 4.44, 7.65 and 9.64 MeV) scattering in full angular range at an incident energy of 110 MeV is presented. The diffraction radii for the ground and the first excited (4.44 MeV) states are found to be equal. The diffraction radii for the 7.65 and 9.64 MeV states are enhanced by 0.5–0.8 fm. This result shows that the radius of the Hoyle’s 0+ 2 , 7.65 MeV state in 12C is larger by a factor of ∼ 1.2 - 1.3 than that of the ground state. It is demonstrated that the direct transfer of 8Be dominates at large angles in all four reactions reported here and that the relative angular momentum L=0 corresponding to the transfer of 8Be in its ground state 0+ has predominant probability for the 0 + 2 state in comparison with the ground state of 12C. Evidence of existence of some features of alpha-condensed structure of the Hoyle’s 0+ 2 state in 12C was obtained, particularly, its enhanced radius and large contribution of alpha-particle configuration with L =

Do exotic alpha-cluster states in 12 C show signatures of alpha-condensate structure? Analysis of recent data on the a -particle inelastic scattering

The diffraction model, DWBA and the Coupled Reaction Channels analysis of the novel data of α + 12C elastic and inelastic (to the states 4.44, 7.65 and 9.64 MeV) scattering in full angular range at an incident energy of 110 MeV is presented. The diffraction radii for the ground and the first excited (4.44 MeV) states are found to be equal. The diffraction radii for the 7.65 and 9.64 MeV states are enhanced by 0.5–0.8 fm. This result shows that the radius of the Hoyle’s 0+ 2 , 7.65 MeV state in 12C is larger by a factor of ∼ 1.2 - 1.3 than that of the ground state. It is demonstrated that the direct transfer of 8Be dominates at large angles in all four reactions reported here and that the relative angular momentum L=0 corresponding to the transfer of 8Be in its ground state 0+ has predominant probability for the 0 + 2 state in comparison with the ground state of 12C. Evidence of existence of some features of alpha-condensed structure of the Hoyle’s 0+ 2 state in 12C was obtained, particularly, its enhanced radius and large contribution of alpha-particle configuration with L =

Cluster rotational bands in 11B

Differential cross-sections of 11B+α inelastic scattering at E(α) = 65 MeV leading to most of the known 11B states at excitation energies up to 14 MeV were measured [1]. The data analysis was done using Modified diffraction model (MDM) [2] allowing determining radii of excited states. Radii of the states with excitation energies less than ∼ 7 MeV coincide with the radius of the ground state with an accuracy not less than 0.1 - 0.15 fm. This result is consistent with traditional view on shell structure of low-lying states in 11B. Most of the observed high-energy excited states are distributed among four rotational bands. Moments of inertia of band states are close to the moment of inertia of the Hoyle state of 12C. The calculated radii, related to these bands, are 0.7 - 1.0 fm larger than the radius of the ground state, and are close to the Hoyle state radius. These results are in agreement with existing predictions about various cluster structure of 11B at high excitation energies.peerReviewe

The cluster states in light nuclei

The differential cross-sections of the elastic and inelastic α +11B scattering was measured at E(α) = 29 MeV. The analysis of the data by Modified Diffraction Model (MDM) showed that the root-mean- square (RMS) radius of the 11B state 3/2-, E* = 8.56 MeV is ~ 0.5 fm larger than that of the ground state. It is found that the radius of 3/2- (8.56 MeV) state in the 11B nucleus is close to the radii of the Hoyle state in 12C

The cluster states in light nuclei

The differential cross-sections of the elastic and inelastic α +11B scattering was measured at E(α) = 29 MeV. The analysis of the data by Modified Diffraction Model (MDM) showed that the root-mean- square (RMS) radius of the 11B state 3/2-, E* = 8.56 MeV is ~ 0.5 fm larger than that of the ground state. It is found that the radius of 3/2- (8.56 MeV) state in the 11B nucleus is close to the radii of the Hoyle state in 12C

Study of the structure of the Hoyle state by refractive α-scattering

α + 12C elastic and inelastic to the Hoyle state (0+ 2, 7.65 MeV) differential cross-sections were measured at the energies 60 and 65 MeV with the aim of testing the microscopic wave function [1] widely used in modern structure calculations of 12C. Deep rainbow (Airy) minima were observed in all four curves. The minima in the inelastic angular distributions are shifted to the larger angles relatively those in the elastic ones, which testify the radius enhancement of the Hoyle state. In general, the DWBA calculations failed to reproduce the details of the cross sections in the region of the rainbow minima in the inelastic scattering data. However, by using the phenomenological density with rms radius equal 2.9 fm, we can reproduce the Airy minimum positions.peerReviewe