The main questions of the study: 1) is there any difference in anatomical features between subtypes C1 and C2 of high hip dislocation by Hartofolakidis classification; 2) are the conditions for performing the THA different and what are the surgical decisions; 3) what are the THA results in different groups? Materials and Methods. In a single center study the authors retrospectively evaluated the outcomes of 561 THAs performed in 349 patients with a high hip dislocation including 32 men (9.2%) and 317 women (90.8%) with the follow up from 12 to 188 months (average 69,4 months). In 326 cases (58.1%) the dislocation was assessed as type C1, and in 235 cases (41.9%) — as type C2. The average age of the patients at the time of surgery was 47.6 (19 to 74) years, for men — 39.1 years and 48.1 years for women. Results. Paavilainen shortening osteotomy was performed in 100% of patients with type C2 and only in 50.6% of patients with type C1, p<0.001. The cup was implanted into the true acetabulum cavity in 99.1% of cases with type C2, and for type C1 only in 69.0% of cases, p<0.001. Lateral under-coverage of the cup in patients with type C2 required supplementing by femoral head autograft only in three cases, and for type C1 — in 18 patients, p = 0.009. In the group of C2, the mean length of the osteotomized fragment of the proximal femur was 78.6 mm compared to 62.5 mm in patients with type C1. This provided a better contact area between the greater trochanter and the femur and in 92.8% of cases fixation was done by cerclage wires and two screws. In the group of patients with type C1, this option was feasible only in 60.0% of cases. Odds ratio (OR) for fixation of the greater trochanter by a special plate for primary indications in patients with type C1 were 10 367, p = 0.008. Harris Hip score improved averaged from 39.5 points to 83.6, without statistically significant differences between groups of C1 and C2. Early complications included 9 dislocations (1.6%), 8 cases of femoral nerve neuropathy (1.4%) and 3 early infections (0.5%). No cases of sciatic nerve paresis were observed. Non-union of the greater trochanter was observed with almost equal frequency in patients with C1 and C2 types, and revision fixation was needed in 27 patients (6.8%). Revision arthroplasty was performed in 22 cases (3.9%) due to 4 infections, 2 aseptic loosening of the stem, 11 aseptic loosening of the acetabular component and 5 recurrent dislocations. Conclusion. The group of patients with high hip dislocation is very heterogenic in terms of severity of anatomical changes and demands different surgical tactics. Hartofolakidis classification helps the surgeon to select the best type of the surgical procedure, minimize the mistakes and predict treatment outcomes.

Цель исследования-определить темпы износа полиэтиленового вкладыша в зависимости от разных факторов и оценить связь скорости износа со степенью двигательной активности. Материал и методы. В исследование было включено 467 больных коксартрозом. женщин было 322 (35,8%), мужчин-145 (31,0%). средний возраст пациентов составил 55,0 лет, без статистически значимых различий у мужчин и женщин (р = 0,743). у 167 (35,8%) пациентов с помощью шагомера оценивалась ежедневная двигательная активность. у них оценивалась степень смещения головки эндопротеза относительно центра вертлужной впадины, и соответственно расчет степени линейного износа полиэтиленового вкладыша в программе Medicad. у всех пациентов оценивались показатели, полученные с использованием модифицированной шкалы активности Харриса и VaS. Все данные анализировались и подвергались статистической обработке. Результаты. средняя степень двигательной активности составила более 1,9 млн шагов в год. общая величина износа полиэтиленового вкладыша зависела от срока наблюдения, коэффициент корреляции пирсона составил r = 0,297 (р<0,001). средняя скорость износа составила 0,16 мм/год (95% ДИ от 0,15 до 0,17), при этом темпы износа статистически значимо различалась в группах стандартного и поперечносвязанного полиэтилена и составила 0,18 мм/год (95% ДИ от 0,17 до 0,19) и 0,11 мм/год (95% ДИ от 0,1 до 0,11) (р<0,001). В данной группе наблюдений дополнительными факторами, влияющими на темпы износа узла трения, являлись угол наклона вертлужного компонента, r = 0,241 (р = 0,002) и уровень двигательной активности, r = 0,574 (р<0,001). не выявлено очевидной связи темпов износа с возрастом, r = 0,14 (p = 0,859) и с индексом массы тела, r =-0,094 (р = 0,226), что, вероятно, объясняется сильным воздействием смешивающих факторов. удовлетворенность пациентов результатами операции, измеряемая по VaS, составила в среднем 91,1 баллов (95% ДИ от 90,3 до 91,9). показатели по Harris Hip Score улучшились в среднем с 36,5 (95% ДИ от 35,1 до 37,9) до 91,6 баллов (95% ДИ от 91,1 до 92,0) Заключение. Из многочисленных факторов, которые ассоциированы с уровнем износа узла трения, только наклон вертлужного компонента и более высокий уровень двигательной оказались статистически значимыми. Ключевые слова: эндопротезирование тазобедренного сустава, пары трения, износ полиэтилена, двигательная активность пациента, молодые пациенты.

Background. Total hip arthroplasty is an effective type of surgery with excellent survival rates of modern implants. From the very beginning of the widespread introduction of total hip arthroplasty, the cement technique of components fixing prevailed. However, many researchers associated the development of osteolysis and the following loosening with the reaction to cement. The subsequent studies clarified the situation regarding the nature of osteolysis, but there remained the problem of insufficient stability of the cemented stems to withstand the penetration of polyethylene wear particles into the distal part of the stem with the development of loosening. An ideal endoprosthesis should ensure the normal hip biomechanics, joint painless functioning and improve the quality of life of the patient without the need for revision. The optimal results of cementless femoral stems functioning depend on the achievement of initial stability, osseointegration and equable transmission of tension onto the femur. There are many factors that influence osseointegration processes and the subsequent behavior of the implant. Understanding these factors is the key to choosing the optimal implant for a particular patient, taking into account the anatomical features of the femur.The purpose of this article is to discuss upon the literature review the application of cementless femoral components, the possible causes of failure and its prevention from the point of view of the evidence-based practice.Materials. The search was conducted in the PubMed, eLIBRARY databases and through the Web of Knowledge. Survival rates and prevalence of various implants in the structure of primary arthroplasty were estimated on the basis of annual reports of a number of national registries, as well as the hip arthroplasty registry of the Vreden National Medical Research Center of Traumatology and Orthopedics. Among the factors discussed are the properties of the components material, the form of the implants, surface properties, and the influence of the anatomical features of the femur. Additionally, the most used types of cementless femoral components were assessed.Conclusion. Cementless femoral components demonstrated the excellent long-term survival and functional results. The currently prevailing type of the prosthesis intimate attachment to the bone is the biological fixation, especially in groups of young patients. Future studies of cementless implants should necessarily take into account the patient’s age, level of activity, type of bone canal, the presence of deformities, and the friction pair used. This will make it possible to draw clearer conclusions in what clinical situation it is advisable to use the femoral components of a particular design.