Background. A retrospective cohort study analyzed the functional state of patients with acetabular fractures after arthroplasty at different times after injury. Materials and methods. The functional state of 4 groups of patients was assessed using the Merle d’Aubign Hip Score: group I (n = 28) underwent arthroplasty in the first 2 years after the injury due to complications of osteosynthesis of the fracture zone, group II (n = 18) had arthroplasty in the period from 2 to 10 years due to complications after osteosynthesis, mainly in the form of degenerative changes in the hip joint, group III (n = 8) underwent hip arthroplasty after 10 or more years, with the main reason being age-related degenerative diseases; group IV (n = 8) included patients who underwent arthroplasty immediately after the injury. Comparisons between groups were performed using the median test for k-samples. Comparisons of states before and after arthroplasty were performed using the Wilcoxon rank criterion (W, p). Results. Combined hip arthroplasty in the immediate post-traumatic period (group IV) gives excellent results, the patients have practically no pain, joint mobility and walking ability improve. Patients who had complications of osteosynthesis in the form of recurrent dislocation, ankylosis or significant limitation of movements, non-union of the fracture (group I) required combined hip arthroplasty. Since the condition of the joint in these patients was assessed as poor, the results of the arthroplasty were also not the best. Patients in groups II and III required hip arthroplasty mainly due to the development of secondary degenerative changes, i.e. their condition before arthroplasty can be compared to the condition of ordinary patients with coxarthrosis and aseptic arthrosis. The result of arthroplasty in group II mainly depended on the condition of the acetabulum, i.e. its ability to hold the load, some patients underwent combined arthroplasty with the installation of a cup. In group III, the outcome of fracture treatment can be considered good, therefore, hip arthroplasty 10 or more years after the injury did not require special approaches. Conclusions. According to the data of the conducted study, it was proven that hip arthroplasty shortly after the injury in patients with acetabular fracture contributes to the rapid recovery without the development of complications. Arthroplasty caused by a complication of osteosynthesis leads to a decrease in the joint functionality compared to early arthroplasty.

Background. Combat injuries of the suprahumeral region with clavicle fractures differ significantly from peacetime injuries. The most common approach to the treatment of clavicle nonunion is open reduction with fixation with a plate located on the upper surface of the bone, in combination with bone grafting. However, according to long-term studies, the frequency of nonunion remains at the level of 3.1–10.5 %. Objective: to study the stabilizing possibilities of the options for osteosynthesis of clavicle fragments in case of a fracture at the border of the diaphysis and the suprahumeral end with a bone tissue defect. Materials and ­methods. The stabilizing possibilities of osteosynthesis of the clavicle with bone plates were studied in case of a fracture at the border of the diaphysis and the suprahumeral end of the clavicle with a 2 cm defect, which was filled with a graft of the appropriate size and fixed with screws. Two options for osteosynthesis of the clavicle were considered: with one plate and two plates, 5 samples in each group. There was determined the value of fragment movement under the influence of bending load in two planes — vertical and horizontal. The load was increased from 0 to 50 N in steps of 10 N. Results. Osteosynthesis of the clavicle with one plate provides stable fixation of fragments only in the vertical plane, when the load acts on its suprahumeral end perpendicular to the plane of the bone plate. In this case, in order to displace the suprahumeral end, the clavicle is forced to deform a metal bone plate, which has significant strength properties. Under the influence of a load in the horizontal plane, the highest rates of movement of the suprahumeral end of the clavicle were observed. This is due to the fact that the load acts parallel to the bone plate and the resistance to the load is provided only by its fixing screws, which turns out to be insufficient. Therefore, the disadvantage of osteosynthesis with one bone plate is that it effectively counteracts loads only in one plane. Osteosynthesis of the clavicle with two bone plates located in mutually perpendicular planes ensures stability of its suprahumeral end under the influence of both vertical and horizontal loads. A small difference in the rates of movement of the suprahumeral end of the clavicle between the groups tested under the influence of vertical and horizontal loads was caused only by the factor of the geometric parameters of the plates. Conclusions. Osteosynthesis of the clavicle with one plate provides stability of its suprahumeral end only in the vertical plane. Under the influence of large loads acting in the horizontal plane, the displacement of the suprahumeral end of the clavicle can be equal to its diameter in cross section. Osteosynthesis of the clavicle with two plates located in mutually perpendicular planes provides stability of its suprahumeral end regardless of the direction of the load.

In the work, attention is paid to the role of artificial intelligence (AI) in scientific medical research: from the planning stage to generalization of results and the construction of visualizations. AI can significantly expand the researcher’s capabilities in the process of conducting a study, creating a dissertation, an analytical article, or a scientific report when it is necessary to perform a large amount of technical and analytical work. The purpose: to systematize the possibility of using artificial intelligence at diffe­rent stages of preparation of medical scientific research — from the analysis of sources to summarizing the results. The authors seek to show how AI can facilitate the analytical work of the researcher, leaving the main thing for humans — scientific thinking, logic, interpretation and responsibility for the conclusions obtained. Results. The tools based on AI to plan scientific research such as E-PICOS, MedLine and Cochrane Semantic Scholar, Scite are considered, as well as systems for conducting systematic reviews and meta-analyses: Elicit and ResearchRabbit. The work pays attention to the peculiarities of cooperation with general purpose programs like ChatGPT, Grok, Claude and others when writing programs on R, Python, assistance with Excel formulas for the preparation of graphic materials and statistical calculations. The preparation of scientific publication by means of AI is considered, starting with the verification of grammar and style of texts to the formation of reference lists according to the appropriate standard. This block of the article deals with tools such as Grammarly, QuillBot, SciSpace and others. Particular attention is paid to the opportunities and restriction of AI in scientific work, namely because the effective use of AI requires the researcher to have analytical thinking, a critical approach and a responsible attitude to the results. AI is not an alternative to the researcher, but an intellectual partner, which greatly facilitates the path but does not determine its direction. AI does not replace the researcher’s analytical thinking, but greatly expands their tools, allowing to focus on the essence of the study, and not on routine technical details. Conclusions. Artificial intelligence opens new opportunities in medical research, enables to automate information search, improve analytical processes and visualization of results. Its use helps researchers save time, increase the accuracy of analysis and present data in a convenient and understandable form. However, the key factors in the successful use of AI remain the competence and analytical thinking of the researcher. AI does not replace the scientist — it significantly enhances their capabilities. In the future, a combination of classical scientific approaches and artificial intelligence technologies will be the norm of quality medical research.

Background. Acetabular fractures were and still are a complex, not fully solved problem. Despite the entire modern arsenal of therapeutic measures, these injuries lead to disability in 73–88 % of cases. Objective: to evaluate the time of the hip joint “survival” and to analyze the risks of complications after metal osteosynthesis for acetabular fractures. Materials and methods. A retrospective analysis was performed of the development of complications after metal osteosynthesis in 65 patients with acetabular fractures. The analysis was conducted using the Kaplan-Meier survival function. Comparison of the results of arthroplasty was performed by the xi-square (Cramr’s V). Statistical calculations were done in IBM SPSS Statistics 26.0. Results. There were 3 main stages of complications development. Stage I (n = 46) — rapid development of complications that required hip arthroplasty in the first 2 years after injury. Stage II (n = 12) — complications appeared in the period from 24 months to 10–12 years, which led to joint replacement during this time. Stage III — late manifestations of joint disease with arthroplasty later than in 10 years. Among 54 patients who suffered acetabular fracture, 52 % (28 patients) required hip arthroplasty in the first 2 years after the injury, mainly due to osteosynthesis complications. According to the results of total hip replacement, only 9 (32.1 %) of them had a good treatment outcome, and 6 (21.4 %) reported a poor outcome. Arthroplasty within 10 years after the injury was performed in 18 (33.3 %) patients with early development of hip dege­nerative diseases such as coxarthrosis and/or aseptic necrosis. Only in 8 (14.8 %) patients who underwent arthroplasty in 10 years or later, the results of fracture treatment without replacement can be considered good, and joint arthroplasty can be considered necessary due to age-related changes. Conclusions. The analysis determined that most complications after treatment of acetabular fractures with osteosynthesis occurred in the first 2 years and patients required arthroplasty due to poor joint condition and recurrent dislocation. Only a small proportion of patients, mostly of young age, underwent this treatment with a positive outcome and developed degenerative complications in the long term. The low overall outcome of fracture treatment with osteosynthesis calls for a reassessment of treatment approaches in such injuries, which may include combined hip arthroplasty immediately after injury.

Immobilization of the joint leads to the formation of immobilization contracture, which is accompanied by a decrease in the elasticity of tendons and muscles, i.e. loss of full contraction and stretching. The torque in human joints is one of the key indicators in assessing rehabilitation. Objective. To study the effect of changes in the strength, length of muscles and tendons of the elbow joint on the torque in flexion. Methods. The basic OpenSim model arm26 was used for modeling. To determine the change in the length of the components of the muscle-tendon element (MTE), their length was determined at a 90° angle of elbow flexion. The decrease in muscle strength was considered a loss per day for elbow flexors — 1.2 %, extensors — 1.1 %. The decrease in strength was calculated for a period of immobilization of 45 days. Three models were created: Normal — a model without changes in muscle parameters; Contracture — a change in the length of muscles and tendons; Contracture + muscle (CM) — an additional decrease in muscle strength. Results. The obtained data of torques when changing the length of the MTE components showed their increase in conditions of unchanged isometric muscle strength. But this option is not possible after immobilization of the limb. Therefore, it is closer to the real model of СM, in which the torque is significantly reduced by the amount of decrease in muscle strength. These models show a tendency that the change in the components of the MTE due to immobilization increases the joint torque and, when trying to apply excessive force during joint development, can lead to traumatic consequences. During immobilization, the flexor muscles shorten, which prevents the patient from fully extending the elbow joint. Conclusions. This work on predicting the elbow joint torque generated by the muscles can be useful in studying specific clinical situations with elbow joint contractures, but cannot be fully transferred to practice due to the significant conventionality of the model parameters. However, the modeling method can show trends in changes in muscle function parameters when their geometry changes.

Hip arthroplasty is a reliable and quick way to relieve the patient of pain, restore movement in the hip joint and improve the function of the affected limb, but the question of how effective this intervention is in dysplastic or idiopathic coxarthrosis requires further study. The objective of the study was to evaluatethe effectiveness of treatment of patients with idiopathic and dysplastic coxarthrosis, and the effect of endoprosthetics on the work of the pelvic muscles. Methods. A comparative analysis of the treatment of 121 patients was conducted, which were divided into two groups — with dysplastic coxarthrosis(63 patients) and with idiopathic coxarthrosis (58 patients). The functional results of the treatment were studied according to the Harris scale, the data of stabilographic studies and the evaluation of the work of the muscles of the pelvic girdle, which are responsible for maintaining the horizontal balanceof the pelvis. Results. In general, the results of endopros thesis were evaluated as good in both groups. At the same time, the average results in the group of patients with idiopathic coxarthrosis are significantly better (t = 2.08; p = 0.001) than in the group of patients with dysplastic coxarthrosis. However, the indicators of the muscles that ensure the horizontal balance of the pelvis, in most cases, remain reduced within 6–8 months after the endoprosthesisoperation. This is evidenced by clinical data and statistical research data. Conclusions. Endoprosthesis of the hip joint is an effective method of coxarthrosis and allows to significantly improve both the patientʼs support and kinematic function and his quality of life. The results of treatment of patients withidiopathic coxarthrosis according to the Harris scoring scale are significantly better than the results of treatment of patients with dysplastic coxarthrosis. But the performance indicators of the muscles of the pelvic girdle, in most cases remain reduced within 6–8 months after endoprosthesis surgery in patientsof both groups.

Background. Bone fractures are a public health concern. In recent years, there has been an upward trend in body weight of people of all age groups. Obesity has long been thought to help protect against fractures, but recent studies have shown that for every 5 cm increase in waist circumference, the risk of any fracture is 3 % higher. The purpose: according to the meta-analysis of modern medical literature, to determine the main directions of surgical treatment for long bone fractures, their advantages, and disadvantages, including in overweight patients, the features of diaphyseal fracture fixation in overweight patients. Materials and methods. A meta-analysis of special literature from scientific databases was conducted: Cochrane Library, Scopus, National Library of Medicine — National Institutes of Health, ReLAB-HS Rehabilitation Resources Repository. One hundred and thirty articles were analyzed, from them 31 were selected, which, in our opinion, reflect the purpose of the study. Results. All methods of surgical fixation of fractures have their advantages and disadvantages. The frequency of nonunions caused by intramedullary fixation of the femoral shaft can reach 10 %, and varus/valgus and rotational deformities and shortening can also be observed. But the use of locking screws prevents the occurrence of most complications. When fixing the fractures with plates, the main complications are related to superficial and deep infections, which were more often observed in overweight patients. The analysis demonstrated that in overweight and obese patients, the main complicating factor is not the method for fixing the fracture zone, but factors related to the health of the patient himself. So, despite the fact that the results of treatment of fractures in patients with normal weight and obesity did not have a statistically significant difference, an increase in cardiovascular complications, exacerbation of chronic respiratory diseases was observed. Moreover, it is the presence of concomitant diseases that often makes surgical intervention impossible. Conclusions. There is a large amount of research on surgical methods of fixing tibial diaphyseal fractures, but data on the choice of fixation method in overweight and obese patients as a separate approach were not found. There are data on complicating factors of excess weight in the treatment of fractures and surgical interventions. Systematic studies related specifically to the algorithm for choosing the method of fracture fixation and complications have also not been found.

A geometric model with muscles functionally related to the hip joint was created. We studied the effect of muscles on the vector of the net effect when changing the position of the limb: passive lifting and adduction. During passive hip flexion, stretching occurred in gracilis, adductor magnus, gluteus maximus, biceps femoris, semitendinosus, semimembranosus. The net force vector initially decreases, and at maximum bending it increases. When increasing the effort of muscles m. gluteus maximus - the angle of co-action is reduced, and m. gracilis, adductor magnus, biceps femoris, semitendinosus, semimembranosus -is increased. Adduction of the lower limb leads to passive stretching of the muscles: mm. rectus femoris, gluteus medius, gluteus minimus, tensor fascia latae, biceps femoris, semitendinosus, semimembranosus. The greatest elongation is determined in m. tensor fasciae latae, and the greatest efforts were found in m. gluteus medius. With simultaneous bending and adduction of the lower were subjected to passive stretching, which causes an even greater deviation of the resultant force vector from the normal than when the limb is flexed or adducted.

Background. Dislocations of the acromial end of the clavicle are quite common traumatic injuries of the locomotor apparatus and, according to various authors, account for 3 to 26.1 % of dislocations of other locations and about 10 % in the structure of acute injuries of the shoulder girdle, ranking third after dislocated shoulders and forearms. They occur mainly in young men of the most working age, which determines the social significance of this injury. Stabilization of the acromial end of the clavicle, as a rule, was ensured by fixation according to Weber and the use of a hook plate. The purpose of the study: to determine the shortcomings and strength characteristics of the fastening elements in the fixation of the acromial end of the clavicle according to Weber. Materials and methods. From 2015 to 2020, a retrospective analysis was performed of treatment outcomes in 57 patients who underwent surgery for dislocation of the acromial end of the clavicle and Weber fixation. Calculations of the strength of fixation of the acromial end of the clavicle with a cerclage wire and spikes in case of its dislocation were carried out in the biomechanics laboratory of the State Institution “Sytenko Institute of Spine and Joint Pathology of the National Academy of Medical Sciences of Ukraine”. Results. According to the results of clinical studies, a violation of the integrity of the wire and spikes was observed in 10.5 % of cases, destruction of the acromion process and acromial end of the clavicle — in 19.3 %, migration of the spikes — in 12.3 %. Results of the experimental study show that these shortcomings are clearly correlated with the mechanical properties of the wire and spikes. Conclusions. The factors for unsatisfactory results of surgical treatment for dislocations of the acromial end of the clavicle when using Weber’s method are the violation of the integrity of the wire and spikes, the destruction of the acromion process and the acromial end of the clavicle, the migration of the spikes, which are caused by the mechanical properties of these structures.

Muscles that can be damaged during endoprosthesis are indicated. Objective. To study the features of muscle work to ensure walking function after hip arthroplasty depending on the surgical approach. Methods. The basis of the simulation is the basic OpenSim Gate2392 model. Six models were created that predicted the condition of the muscles of the lower limb in normal conditions, during coxarthrosis and after 6 and 12 months. after surgery with lateral and anterior approaches. The results. For lateral access in 6 months. after the operation, the adductor muscles responsible for stabilizing the pelvis in the single-support phase of the step and during the transfer of the foot do not work enough, while the hip flexor muscles (in the model, the rectus femoris muscle) take over the responsibility for the step, but with overvoltage. On the contrary, with the front approach, we observe a weakening of the flexor muscles, which leads to overstrain of the gluteal muscles and hip stabilizer muscles. After 12 months, the muscle strength normalizes for most of them to 90–95 % of the norm, a 2–3 times increase in the torque of the hip flexor muscles and hip stabilizer muscles is observed. Taking a normal step causes muscle strain. During the anterior approach, the foot is transferred during the phase, that is, when most of the muscles are involved. The rectus femoris muscle, which is the strongest of the muscles discussed in the paper, does the main work of moving the foot. In the case of possible damage to the rectus muscle during anterior access, even after a year there is a violation of its work — excessive overexertion and involvement of the reserves of other muscles. Conclusions. Mathematical modeling of the work of muscles that may be damaged during hip arthroplasty surgery, conditional muscle strength for 6 months. after the operation, they are not able to develop the necessary torque to take a normal step. For muscle strength, which in the model corresponded to 12 months,the muscles are able to perform a normal function regardless of surgical access, but their overstrain is observed.

Funnel-shaped chest deformity is the most common anomaly of the chest wall development, occurring in 8 out of every 1 000 children. The defect is noticeable at birth in approximately 86 % of patients with chest deformity. Objective. To conduct a systematic review comparing the treatment of funnel-shaped chest deformity in children and young people under 20 years of age by surgical methods according to Ravitch and Nuss by the number of complications that occur in the short (up to 30 days) and long-term periods (2–3 years). Methods. A search of scientometric databases revealed 1 734 sources, of which 8 papers were selected for further analysis. Results. We evaluated systematic reviews and meta-analyses comparing methods of treatment of lumbar deformity in children and adolescents. It was determined that there are currently no randomized trials comparing these procedures in children and adolescents. A comparative analysis of the risk of complications in the surgical treatment of the funnel-shaped sternum in children and young adults using the Ravitch and Nuss methods determined that there is no difference in the overall incidence of complications between the Nuss and Ravitch procedures when considering the pediatric population in terms of overall, early, and late complications. With the development of the Nuss technology, complications associated with plate mixing are practically non-existent, and the development of new methods of controlling operations, anesthesia and further patient management has reduced the development of both postoperative and long-term complications. Conclusions. According to the results of the meta-analysis of the risk of early and late complications, it is impossible to definitively determine the advantage of any surgical method for the correction of lumbar deformity of the chest. The number of Nuss surgeries has been increasing over the years, which means that the minimally invasive approach is the method of choice for patients and surgeons, although questions remain about achieving structural stability and the method of Nuss correction in severe deformities. The lack of definitive conclusions is more related to the methodological problems of the analyzed data, including a limited number of observations and a large age difference in the observation groups, the lack of a standard for presenting data to describe the patient's condition (magnitude and type of deformity, primary complications of the cardiac and respiratory systems, the presence of complicating factors).

Background. In orthopedics and traumatology, polymer materials that are resorbed and dissolve in biological fluids occupy a significant place as screws and fixation pins, plates and anchors, cages. Most often, implants from L-polylactic acid (PLA) are used. It is possible to increase their quality by including ceramic materials into their composition, in particular tricalcium phosphate (TCF) and hydroxylapatite (HA). However, implants with different percentages and compositions of ceramic material differ in strength and behavior in bone. The purpose was to check the bending strength of plates made of a composite material based on polylactide, tricalcium phosphate and hydroxylapatite for compliance with the calculated indicators under experimental conditions. Materials and methods. Plate samples were made from a material containing 70 % PLA, 20 % TCF and 10 % HA. Using the 3D printing method, plates with a thickness of 8.5, 9.5, and 10.7 mm were produced which, according to the calculated data, correspond to the patient’s weight of 50, 70, and 100 kg, respectively. A total of 3 plates of each size were made. All samples were tested for bending. The load magnitude increased gradually from 100 to 1000 N with a step of 100 N. At each step, the deflection of the sample was recorded. Results. As a result of the research, the deflection was evaluated for samples of plates with different thicknesses made of composite material based on PLA, TCF and HA, depending on the load magnitude. The deflection of the plate samples was checked under loads corresponding to the patient’s weight for which they were calculated — 50, 70 and 100 kg, and the permissible limit of deflection, for which the calculated deflection of the standard titanium plate was chosen. The results showed that the deflection indicators of all samples do not have statistically significant deviations from the permissible limit. For all groups of samples, the p criterion significantly exceeds the critical value of 0.05. Conclusions. Experimental studies on the bending strength of plates made of composite material containing 70 % PLA, 20 % TCF and 10 % HA proved that the deflection of all tested samples correspond to the calculated values, the deviations of the indicators do not exceed the permissible level of 5 %.

Уроджений псевдоартроз кісток гомілки - рідкісне захворювання, яке характеризується наявністю незрощення (псевдоартрозу) кісток гомілки, що не зростається самостійно. Більшість хірургічних методик передбачає видалення патологічних м’яких тканин у зоні псевдоартрозу з наступною кістковою аутопластикою та фіксацією фрагментів великогомілкової кістки в апаратах зовнішньої фіксації чи за допомогою інтрамедулярних фіксаторів. Мета - дослідити напружено-деформований стан моделей гомілки за наявності псевдоартрозу в середній третині під впливом згинаючого навантаження та їх остеосинтезу з використанням інтрамедулярних стрижнів різних конструкцій у дітей із незавершеним ростом. Матеріали та методи. Виконано математичне моделювання трьох варіантів остеосинтезу кісток гомілки за їх уродженого псевдоартрозу в середній третині: 1 - стрижень без ротаційної стабільності; 2 - стрижень із ротаційною стабільністю; 3 - стрижень із ротаційною стабільністю та блокованим рухом при стисканні. Вивчено напружено-деформований стан моделей під впливом згинаючого навантаження величиною 300 Н. Результати. За використання ротаційно нестабільного стрижня, що «зростає», максимальний рівень напружень 18,5 МПа і 23,1 МПа визначається на проксимальному та дистальному кінцях великогомілкової кістки, відповідно. У зоні перелому рівень напружень мінімальний і не перевищує позначки 0,2 МПа. У діафізарній частині напруження визначаються на рівні 0,3 МПа і 0,4 МПа вище і нижче зони перелому, відповідно. У зоні перелому малогомілкової кістки рівень напруження також незначний - 0,7 МПа і 0,8 МПа в проксимальному та дистальному фрагментах. Використання стрижня з ротаційною стабільністю не приводить до будь-яких значних змін напружено-деформованого стану моделі порівняно з остеосинтезом великогомілкової кістки ротаційно нестабільним стрижнем. Використання інтрамедулярного стрижня з блокованим рухом при стисканні дає змогу знизити величини напружень на проксимальному та дистальному кінцях великогомілкової кістки - до 16,9 МПа і 21,2 МПа, відповідно. В усіх контрольних точках діафізарної частини великогомілкової кістки напруження мінімальні і дорівнюють 0,2 МПа. Слід звернути увагу, що в даному випадку практично зникають напруження в зоні перелому малогомілкової кістки, де вони не перевищують позначки 0,1 МПа. Висновки. У разі навантажень на згин усі типи інтрамедулярних стрижнів забезпечують мінімальний рівень напружень у зоні перелому великогомілкової кістки. Додаткові ротаційна та повздовжня стабільність стрижнів дають змогу незначно знизити рівень напружень у проксимальному та дистальному кінцях великогомілкової кістки. Дослідження виконано відповідно до принципів Гельсінської декларації. Протокол дослідження ухвалено Локальним етичним комітетом зазначеної в роботі установи. На проведення досліджень отримано інформовану згоду батьків дітей. Автори заявляють про відсутність конфлікту інтересів.

Актуальність. Контрактура суглобів є найбільш поширеною клінічною проблемою, яка негативно впливає на щоденне життя пацієнтів, знижуючи його якість. Одним з маловивчених реабілітаційних методів відновлення рухливості суглобів з іммобілізаційними контрактурами є низькочастотна малоамплітудна вібрація. Мета роботи: розробити алгоритм проведення реабілітаційної програми низькочастотної вібраційної терапії пацієнтів з іммобілізаційними контрактурами суглобів верхніх та нижніх кінцівок. Матеріали та методи. В основу програми покладені результати лікування пацієнтів з контрактурами суглобів кінцівок та результати експериментальних досліджень формування іммобілізаційних контрактур та подальшого відновлення обсягу рухливості колінного суглоба у лабораторних щурів. Результати. Вібротерапію починають проводити за відсутності гострих больових відчуттів, виражених пошкоджень шкіри, конструктивних елементів фіксації відламків, які можуть бути пошкоджені при вібрації. Курс становить 14–15 сеансів. За рекомендаціями лікаря курс може бути продовжений. На всіх етапах вібраційної розробки контрактури суглобів проводиться контроль стану пацієнта. За результатами проведених експериментальних досліджень на лабораторних тваринах було доведено, що низькочастотний вібраційний вплив на тварин у процесі іммобілізації не дає сформуватися стійкій контрактурі, а відновлення повного обсягу рухів у колінному суглобі відбулося на 2 тижні раніше, ніж у інших щурів. З огляду на це можна пропонувати проведення локальної низькочастотної розробки пацієнтам з неускладненими переломами довгих кісток кінцівок та необширними оперативними втручаннями після первинного натяжіння рани (на 3-тю — 5-ту добу). При вібраційному впливі на пошкоджену кінцівку, коли ще не сформувалися контрактури, головне — не дати зупинитися процесам живлення тканин суглоба, скорочення м’язів і, відповідно, кровозабезпечення. Зважаючи на те, що вібрація діє як знеболювальна процедура, слід передбачити, що пацієнт зможе через короткий проміжок часу після зникнення болю відновити рухливість суглоба в повному обсязі. Висновки. Низькочастотна локальна вібраційна розробка рухів у суглобах та вправи на розтягування з елементами постізометричної релаксації є ефективним методом розробки іммобілізаційних контрактур, у тому числі застарілих. Ці процедури у пацієнтів з термінами іммобілізації до 2 місяців приводять до відновлення розгинання у суглобах. У пацієнтів з більш тривалою іммобілізацію обсяг рухів повністю не відновлюється за стандартний курс у 14 процедур, тому такі хворі потребують додаткових реабілітаційних заходів. Низькочастотна вібрація є тим механізмом, який запускає процеси відновлення та сприяє початку функціонального відновлення колінного суглоба. Можливість проведення вібраційних процедур пацієнтам у процесі іммобілізації потребує подальшого вивчення для розробки умов та алгоритму її проведення.

Congenital pseudoarthrosis of the bones of the lower leg is a rare disease characterized by the presence of non-union (pseudoarthrosis) of the bones of the lower leg, which does not grow independently. The majority of surgical techniques involve the removal of pathological soft tissues in the zone of pseudarthrosis followed by bone autoplasty and fixation of tibial bone fragments in external fixation devices or with the help of intramedullary fixators. Purpose - to investigate the stress-deformed state of models of the leg in the presence of pseudarthrosis in the middle third under the influence of bending load and their osteosynthesis using intramedullary rods of various designs in children with incomplete growth. Materials and methods. Mathematical modeling of 3 variants of osteosynthesis of lower leg bones with congenital pseudarthrosis in the middle third was performed: 1 - rod without rotational stability; 2 - rod with rotational stability; 3 - rod with rotational stability and blocked movement during compression. The stress-strain state of the models under the influence of a bending load of 300 N was studied. Results. When using a rotationally unstable «growing» rod, maximum stress levels of 18.5 MPa and 23.1 MPa are determined at the proximal and distal ends of the tibia, respectively. In the fracture zone, the stress level is minimal and does not exceed 0.2 MPa. In the diaphyseal part, stresses are determined at the level of 0.3 MPa and 0.4 MPa above and below the fracture zone, respectively. In the zone of the fracture of the fibula, the stress level is also not significant - 0.7 MPa and 0.8 MPa in the proximal and distal fragments. The use of a rod with rotational stability does not lead to any significant changes in the stress-strain state of the model compared to tibial osteosynthesis with a rotationally unstable rod. The use of an intramedullary rod with blocked movement during compression allows to reduce the values of stresses at the proximal and distal ends of the tibia - up to 16.9 MPa and 21.2 MPa, respectively. In all control points of the diaphyseal part of the tibia, the stresses are minimal and equal to 0.2 MPa. It should be noted that in this case the stresses in the area of the fracture of the fibula, where they do not exceed the mark of 0.1 MPa, are almost negligible. Conclusions. Under bending loads, all types of intramedullary rods provide a minimum level of stress in the tibial fracture zone. Additional rotational and longitudinal stability of the rods allow to slightly reduce the level of stress in the proximal and distal ends of the tibia. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Актуальність. На сьогодні в ортопедії та травматології для заміщення кісткових дефектів все частіше використовуються полімерні матеріали, які резорбуються та розчиняються у біологічних рідинах. Як матеріали для заповнення кісткових дефектів використовують кісткові чипси, кераміку на основі трикальційфосфату (ТКФ) та гідроксилапатиту (ГА), а також імплантати з L-полімолочної кислоти (ПЛА). Мета. Визначити межу міцності композитного матеріалу на основі ПЛА та ТКФ, виготовленого методом 3D-друку, з різними варіантами поруватості. Матеріали та методи. Проведено експериментальні дослідження міцності зразків із матеріалу на основі ПЛА з домішками ТКФ, виготовлених методом 3D-друку по 5 зразків із поруватістю 70, 50, 30 та 10 %. Зразки були кубічної форми, зі стороною ребра 10 мм. Усі зразки випробовували на стискання. Результати. Міцність зразків композитного матеріалу на основі ПЛА і ТКФ з поруватістю в 70 % за середнім значенням 6,7 ± 0,4 МПа нижча за мінімальну міцність губчастої кістки (7,0 МПа), це статистично значимо не відрізняється від мінімальної міцності губчастої кістки. Межа міцності зразків з 50% поруватістю визначається лише на рівні 18,2 ± 2,9 МПа, що статистично значимо перевищує середнє значення (14,5 МПа) межі міцності губчастої кістки. Однак також статистично значимо нижче верхньої межі міцності (22,0 МПа) губчастої кістки, в середньому на 3,8 МПа. Межа міцності зразків з 30% поруватістю (37,4 ± 1,7) МПа і тим більше з 10% поруватістю (5,9 ± 2,2 МПа) повністю перекриває міцність губчастої кісткової тканини і статистично значимо перевищує її верхню межу міцності (22,0 МПа). Висновки. Межа міцності композитного матеріалу на основі ПЛА та ТКФ, виготовленого за допомогою 3D-друку, з поруватістю 70 % (6,7 ± 0,4 МПа) та 50 % (18,2 ± 2,9 МПа) відповідає діапазону (від 7,0 до 22,0 МПа) межі міцності губчастої кісткової тканини (від 7,0 до 22,0 МПа), і він може бути використаний для її заміщення.

Monocondylar knee arthroplasty allows to restore normal kinematics and function of the knee joint in the case of osteoarthritis limited to the medial or lateral part of the joint. Objective. To identify the patterns and features of secondary anatomical and functional changes in the knee joint after monocandylar arthroplasty depending on the patientʼs gender, weight, etiology of gonarthrosis, the magnitude of the primary joint deformity and bone tissue condition. Methods. The results of the examination of 71 patients (age 37–83 years, follow-up period 3–10 years) were analyzed. In 20 (28.2 %) patients, problems with the arthroplasty joint occurred. joint: increased frontal deformity angle — 8 (40 %), decreased joint mobility — 12 (60 %), pain in the implantation area — 10 (50 %). Results. Preoperative factors that may affect the outcome of monocandylar knee arthroplasty were identified. The main one is reduced bone density, especially localized osteoporosis. In the presence of osteoporotic areas in the area of arthroplasty, the risk of endoprosthesisinstability can reach 100 %. The second important factor is frontal deformities of the knee joint of more than 10°. Other factors, such as obesity, meniscal and crossed ligament injuries, fractures of the femoral and tibial condyles, also affect the development of complications, especially with a simultaneousdecrease in bone mineral density and/or significant frontal deformity of the knee joint. Conclusions. Monocondylar knee arthroplasty is a reliable, costeffective, low-traumatic method of treating gonarthrosis, but subject to clear indications for its implementation. In the long term, patients with osteoporosis, meniscal and ligamentous injuries, fractures of the condyles, and frontal deformities of more than 10° may develop signs of endoprosthesis instability.

One of the leading methods of reconstruction of the funnel-shaped deformity of the chest is nonresection thoracoplasty, or Nuss surgery. For its implementation, implanted systems consisting of one or two corrective plates are used. The technique is minimally invasive, does not require large incisions and resection of ribs. But there are complications related to the insufficient strength of bone tissue, which according to the literature is defined in a very wide range. Purpose - to determine the dependence of the amount of deflection of single and double plates for the correction of sternum deformity on the amount of bending load; to develop a method of determining the corrective load that the plate exerts on bone structures during correction. Materials and methods. Experimental studies of plates for correction of sternum deformities were performed. We used 6 plates. In the first part of the experiment, each plate was tested separately. In the second part, the plates were connected in pairs, and each pair was tested for bending. In total, 3 pairs of plates were tested. The bending force was gradually increased from 0 N in increments of 50 N. At each step, the deflection of the plate was recorded. Results. The results of experimental studies of single plates showed that the deviation of deflection values did not differ statistically significantly (p>0.05) from the calculated values over the entire range of bending loads. The studies of the twin plates for the correction of sternum deformities also did not reveal statistically significant (p>0.05) differences in the deflection values of the samples obtained in the experiment from the calculated values. The results of the study made it possible to develop a methodology for calculating the force with which the plate acts on the sternum when correcting its deformation. Conclusions. A methodology has been developed for determining the force with which the plate acts on the sternum when correcting a deformation of a certain magnitude. It is confirmed that the calculated data on the deflection of the plate under the influence of bending load and the data obtained in the experiment do not differ statistically significantly. The data obtained can be useful for selecting the size of the corrective plate, the method of its attachment to the ribs, as well as for modeling the options for applying plates to correct various sternum deformities. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the institution mentioned in the paper. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Contractures — limitation of passive movements in the joint — are a fairly frequent complication after immobilization or limitation of mobility and loading of the limb due to injuries, but the exact cause of their formation has not been clarified. Objective. Based on the meta-analysis of the results of experimental modeling and clinical studies of immobilization contractures, create a conceptual model of their formation. Methods. Literature sources from scientific bases were analyzed: Cochrane Library, Scopus, National Library of Medicine, ReLAB-HS Rehabilitation Resources Repository, Mendeley Reference Manager, The Physiological Society library, Google Scholar. Results. A conceptual model of the development of contractures was created. It is shown that immobilization of the joint of the injured limb blocks the execution of the signal of motor impulses. The lack of movement in the joint leads to a decrease in muscle strength and a slowdown in blood circulation. These processes are interrelated: hypotonia of the muscle is due to the restriction of nutrition through the blood supply, and the lack of contractile activity of the muscles leads to the rearrangement of the blood vessels. Articular cartilage is nourished through the subchondral bone and due to osmosis from the synovial fluid during movements. The lack of movement limits nutrition, protein synthesis is disrupted, the surface of the cartilage, synovial membrane and fluid begins to be rebuilt, the joint capsule, ligaments, and tendons thicken. At the same time, the structure of the muscles changes, they shorten and become denser. With long-term immobilization, degenerative processes in the tissues of the joint worsen its general condition, which can eventually lead to complete immobilization. Conclusions. The created conceptual model of the formation of immobilization contractures of joints takes into account the morphological changes of tissues as a result of immobilization. Immobilization affects all components of the joint and adjacent tissues from the first days, the changes progress over time. The use of the model will allow the development of a system of treatment measures to prevent the development of contractures.

Minimally invasive correction of funnel-shaped chest deformity by the Nuss is an effective and cosmetic method of surgical correction of this deformity. Some authors have proposed the use of two plates with a crossed technique for correction. Purpose - to study the changes that occur in the stressed-deformed state of the chest model in comparison of the parallel crossed arrangement of the fixators during the minimally invasive correction of funnel-shaped chest deformity according to Nuss. Materials and methods. 2 schemes for the correction of the funnel-shaped deformation of the sternum were modeled: with a parallel arrangement of plates (parallel method), with a cross-shaped arrangement of plates (crossed method). The models were loaded with a distributed force of 100 N applied to the sternum. They studied the stress values in the bone elements, the relative deformations of costal cartilage, as the softest and, as a result, the most favorable to deformation element of the models. The magnitudes of the maximum movements of the sternum and corrective plates were also studied as an indicator of the preservation of the achieved correction. Results. The crossed method of positioning the corrective plates ensures a slightly lower level of stress in almost all bone elements. An exception can be considered the seventh ribs, where the stress, in this case, reaches 9.0 MPa, which is close to the lower limit of the indicators of the strength limit of the ribs. From the point of view of preserving deformation correction, the crossed method of arranging the correcting plates has a slight advantage of 1.0 mm. But the parallel scheme provides a smaller relative deformation of the costal cartilages. Taking into account all of the above, it can be concluded that none of the studied schemes has an unequivocal advantage over the other according to the criteria of mechanical indicators. Therefore, when choosing one or another scheme for the correction of a funnel-shaped sternum deformity, additional information should be taken into account, such as the shape of the sternum deformity and the rib, the convenience of carrying out the plates, the age of the patient, etc. Conclusions. None of the studied schemes has an unequivocal advantage over the other according to the criteria of mechanical indicators. From the point of view of preserving deformation correction, the crossed method of arranging the correcting plates has a slight advantage of 1.0 mm. The parallel scheme ensures a smaller relative deformation of the costal cartilages. According to the criterion of stress distribution in the bone elements of the model, the crossed method of arranging the corrective plates provides a slightly lower level in almost all bone elements, but the maximum stress value of 9.0 MPa on the seventh rib with the cross-shaped arrangement of the corrective plates approaches the lower limit of the index of the strength limit of the ribs which, in some cases, can cause its fracture. Additional information should be taken into account when choosing one or another scheme for the correction of the funnel-shaped deformity of the sternum. No conflict of interests was declared by the authors.