Endoprosthesis Components Research Articles

POSSIBILITIES FOR MEDICAL REHABILITATION IN PATIENTS AFTER HIP ENDOPROSTHETICS

Hip replacement surgery is currently the only effective surgical treatment option for patients with severe forms of degenerative-dystrophic diseases of the hip joint, so the problem of medical rehabilitation of such patients remains very relevant. One of the problems that arise after hip replacement surgery is a violation of the biomechanics of the artificial joint. The leading role in this process is played by the functional state of muscle tissue, which determines the problem of adaptation of the endoprosthesis components and can subsequently cause complications. The solution to this problem lies in timely comprehensive medical rehabilitation, individually selected for each patient, taking into account the characteristics of the postoperative period. Traditional methods of medical rehabilitation, including various methods of therapeutic exercise, natural and preformed physical factors, are undoubtedly effective, as indicated by an extensive scientific evidence base, but despite the proven effectiveness, these methods are time-consuming and require the presence of specialists. Along with traditional methods of medical rehabilitation, new technologies are currently used, including telerehabilitation, digital products based on virtual reality and artificial intelligence, robotic mechanotherapy, the effectiveness of which has been proven by scientific works of domestic and foreign colleagues and is in no way inferior to classical methods of rehabilitation treatment.

Complications of revision knee arthroplasty

Due to the growing scale of arthroplasty and the widening of indications for knee joint replacement, the durability of joint functioning has become a critical issue. Untimely diagnosis and inadequate treatment of patients with endoprosthesis component loosening leads to major bone defects. This problem arises from repeated joint interventions, large bone defects and duration of revision surgeries, that is fraught with catastrophic consequences for patients – revision prosthesis removal or even limb amputation. The project aims to improve the treatment for patients with instability of components after knee joint arthroplasty. The aim of the study is to analyze the results of revision knee arthroplasty and identify the causes of mistakes and complications of revision arthroplasty with the intention of prevention. Materials and methods. A retrospective analysis of 50 revision knee arthroplasties performed at the Centre for Arthroplasty of the State Institution “Institute of Traumatology and Orthopedics of the National Academy of Medical Sciences of Ukraine” was conducted. Clinical and radiological findings were evaluated for all patients. All revision prostheses used in this study were of the semi-constrained type. Cementation technique was used for all implants. In the revision of the septic complication group, a full cementation technique with antibiotics according to a sensitivity profile were used, while in the aseptic complication group, a surface cementation technique with antibiotics according to sensitivities were used. Results. The authors of the project have analyzed the results of treatment of 50 revision arthroplasty procedures performed between 2013 and 2022 for instability of the endoprosthesis components. The structure of complications has been examined and the causes of failure in revision knee arthroplasty have been identified. This study has shown promise in preventing complications and developing personalized approaches to revision arthroplasty. Conclusions. The analysis of revision knee arthroplasty failure has shown the prevalence of septic complications (56.0 %). In the case of septic complications after revision arthroplasty, Staphylococcus aureus prevailed (57.1 %), gram (-) microorganisms were causative agents in other cases. Factors resulting in aseptic complications included those associated with the surgical intervention (81.8 %), the patient (45.4 %) and the combination thereof (72.7 %). Significant causes of the femoral revision component loosening were residual valgus deformity, medial instability in the frontal plane; significant causes of the tibial component loosening were residual varus deformity and lateral instability in the frontal plane.

Special aspects of total hip arthroplasty in patients with proximal femur pseudarthrosis

IntroductionThe rate of proximal femur fractures (PFF) in the structure of musculoskeletal system injuries among all fractures of long bones ranges from 3.9 to 18%. According to Russian Ministry of Health 2020 data, the incidence of femoral fractures in Russia was up to 61 cases per 100,000 population (90,000 per year); and femoral neck fractures incidence was 4 times higher among people over 75 years of age. The choice of surgical technique and the fixator used depend on many factors, such as fracture location and its nature, the age of the patient, comorbidities, and the quality of bone tissue. Internal osteosynthesis, is the current treatment method of choice for extra-articular proximal femur fracture, but every treatment method has its limitations. a significant number of complications caused by technical errors, vicious union or nonunion with the subsequent development of false joints, the development of femoral head aseptic necrosis, which leads to coxarthrosis and persistent pain syndrome. To solve the above-described problems, it is necessary to use a conversion surgery - total hip replacement. Objectiveslong-term analysis of the results of total hip replacement in patients with proximal femur pseudarthrosis. MethodsThe study was based on clinical and laboratory data analysis and on the results of total hip arthroplasty (THA) in 45 patients aged 56–84 years (mean age 68.3), including 32 (71.1%) women and 13 (26.1%) men. 12 patients initially received conservative treatment, and 33 patients received initial surgical treatment using various metal osteosynthesis procedures. The time from osteosynthesis or from the moment of injury to admission to the hospital for hip arthroplasty ranged from 12 to 30 months. All patients, before conversion arthroplasty and after discharge, were repeatedly invited to the clinical diagnostic department for a clinical examination and for assessment using rating scales. 3, 6 and 12 months after the surgery, pain syndrome and patient quality of life were assessed using the following questionnaire scales: Harris Hip Score, MOS SF-36, VAS. The maximum follow-up period ranged from 12 to 60 months. ResultsBased on the results obtained, patients of all 4 groups after conversion arthroplasty noted a significant quality of life improvement, a decrease in pain severity and functional results improvement. This was probably due to the presence of a severe limitation of range of movements in the joint, intense pain, absence of support ability of the extremity, as well as low operative efficacy expectations.In 1 (2%) patient, acute PJI was diagnosed in the early postoperative period, followed by sepsis and death.In 4 patients (9%) the result was considered unsatisfactory. At 1 year of follow-up after surgery, they complained of pain and claudication in the operated joint.3 (6%) patients underwent reduction of dislocation. ConclusionsStrict adherence to the recommended treatment algorithm for patients with proximal femur pseudarthrosis made it possible to achieve good treatment results in 90% of surgically treated patients. An important step in the treatment of this patients is a careful preoperative planning with thorough assessment of bone tissue quality and muscles condition in the proximal femur area, allowing to choose the optimal endoprosthesis components.

Towards the First Generation of Biomimetic Fixation for Resurfacing Arthroplasty Endoprostheses.

This paper presents advances in designs of resurfacing arthroplasty endoprostheses that occurred through their historical generations. The critical characteristics of contemporary generation hip resurfacing arthroplasty endoprostheses are given and the failures resulting from the specific generation cemented and short stem fixation of the femoral component are reviewed. On the background of these failures, the critical need arises for an alternative approach to the fixation of components of resurfacing arthroplasty leading towards the first generation of biomimetic fixation for resurfacing arthroplasty endoprostheses. The state of the art of the completed bioengineering research on the first biomimetic fixation for resurfacing arthroplasty endoprostheses is presented. This new design type of completely cementless and stemless resurfacing arthroplasty endoprostheses of the hip joint (and other joints), where endoprosthesis components are embedded in the surrounding bone via the prototype biomimetic multi-spiked connecting scaffold (MSC-Scaffold), initiates the first at all generations of biomimetic endoprostheses of diarthrodial joints.

Materials for the friction pair of the hip joint endoprosthesis (review)

Objective: to determine the effectiveness of hip endoprosthesis friction pair materials in addressing aseptic instability. Review writing methodology. Literature data analysis was performed in the national database e-Library RSCI and the international database PubMed, with the search keywords being "materials of endoprosthesis friction pairs", "reasons for revision hip arthroplasty", "osteolysis". A total of 443 sources were analyzed, further using the filters of a systematic review and the knowledge of the authors on the topic (50 were selected for review). The duration of the retrospective analysis is 15 years (2009-2023). Conclusion. The materials used in modern endoprosthesis replacement can't solve the problem of aseptic loosening of endoprosthesis components. The main way to combat the complications associated with aseptic loosening is to use new bioinert materials whose wear products do not cause osteolysis.

Robot-assisted knee arthroplasty: first experience (a prospective randomized study)

Introduction Primary total knee arthroplasty has long been proven effective in the treatment of stage 3–4 knee osteoarthritis. It is well known that this intervention not only improves the quality of life, but also helps to restore the function of the joint and eliminate axial deformities.Purpose To compare early results of total knee arthroplasty using robot-assisted technology with conventional manual technique.Materials and Methods 20 patients diagnosed with stage 3 osteoarthritis of the knee joint and varus deformity of the knee joint axis were included in a prospective randomized study. Patients were divided into 2 representative groups, 10 subjects underwent robot-assisted knee arthroplasty, and the conventional manual technique was used in the other 10 patients. For clinical assessment, functional scales KSS, WOMAC, Lysholm Score were used, postoperative radiographs were evaluated.Results According to clinical functional scales, 10 days after surgery, there was an improvement in performance in the patients of both groups (p < 0.05); the duration of the operation in the patients of both groups did not differ in general; intra-operative blood loss in the group with robot‑assisted arthroplasty was lower; and assessment of postoperative results by radiological imaging showed a better component positioning according to preoperative planning in the robotic group.Discussion When the operation is performed by experienced surgeons, one can expect the correct position of the components and the balance of the ligamentous apparatus in standard arthroplasty. However, the use of robot-assisted technology provides a secure intervention performance even at a hospital where a small number of such operations is performed.Conclusion Despite the high cost and the need for additional consumables, robot-assisted arthroplasty has a number of advantages over classical manual techniques. These advantages include: accurate restoration of the limb axis even in extra-articular deformities, correct position of the endoprosthesis components, reduction of intraoperative blood loss due to closed medullary canals, and safety for patients. However, the role of the surgeon in such operations remains paramount, as it is the surgeon who is responsible for planning the operation, performing it, and achieving soft tissue balance.

ASSESSMENT OF THE USE OF AN INDIVIDUAL TOOL FOR KNEE ARTHROPLASTY

Objective. On the basis of comparative radiometric analysis, before and after surgery, to assess the accuracy of the knee arthroplasty with an individual instrument. Methods. The analysis of knee arthroplasty of 26 patients operated with a special instrument was performed. Age: 50–59 years — 6, 0–69 — 12, 70–79 — 5, 80 and older — 3 patients. Men — 3, women — 18. Before the operation performed a computed tomography of the lower extremities, and after operation radiography of the lower extremities completely with the vertical positions of the feet. Patient specific instrument made according to the original method. The results of the analysis were performed by comparing X-ray parameters before and after operations: 1) position of the mechanical axis in the frontal plane on the plateau of the tibia in percent; 2) medial tibial resection angle to the mechanical axis; 3) the size of the components of the endoprosthesis (femoral, tibial and liner height). Results. Deviations in the values of the medial tibial and of the lateral femoral angles between the planned and actually obtained value was an average of 0.7 %, which can be considered a high indicator of the accuracy of the implant position. The position of the mechanical axis of the limb after the operation differed from the planned by a little more than 0.9 %. The dimensions of the endoprosthesis components and the height of the tibial insert fitted to the patients matched the planning results in 100 % of the cases, with the tibial insert height being 9 mm in all cases. The use of an individual tool made it possible to reduce the time of the operation, not to open the bone marrow canal of the thigh Conclusions. The use of the original individual tool for knee arthroplasty provided a high precision to install the components of the arthroplasty.

PHYSICAL AND MATHEMATICAL MODELING OF THE DISTRIBUTION OF LOAD FORCES ON THE FEMINAL COMPONENT OF AN ENDOPROSTHESIS OF THE HIP JOINT UNDER REAL CONDITIONS

Determination of the factors causing the development of aseptic instability of endoprosthesis components is one of the main tasks of modern traumatology and orthopedics. It is important from a scientific and medical point of view to carry out physical and mathematical modeling of the distribution of load forces and their moments on the femoral component of a hip endoprosthesis. The purpose of the study: to conduct a physical and mathematical modeling of the distribution of load forces on the femoral component of a hip endoprosthesis under real conditions of incomplete axially symmetrical contact of the femoral component of the endoprosthesis and the femur, when the surface of the lower end of the endoprosthesis is not in contact with the surface of the bone. In the work, mathematical modeling of the distribution of point load forces and their moments on the contact surface between the femoral endoprosthesis stem and the bone marrow canal of the femur in real conditions is carried out. For qualitative estimates of point distributions of the load force, based on the analysis of previous results, an estimated empirical formula was obtained for these distributions: g(λ,λ1)=Р(λ,λ1) / 140λ7/2, in which the pressure Р(λ,λ1) is taken in kilograms per square centimeter (kg/cm2), and the point force g(λ,λ1) is in kilograms (kg). It was determined that the best, from the point of view of minimizing the harmful mechanical impact of the prosthesis on the femur, is the situation when the length of the prosthesis stem is not less than half the length of the femur (λ≥0.5). In this case, the values of the point load forces do not exceed 0.1 kg, at least for the length of the area of real contact, which is not less than half the length of the prosthesis stem (λ1≥0.5λ). It has been proven that the use of a prosthesis stem that is less than a third of the length of the femur is not advisable. Since already at the length of the prosthesis stem, which is 30 % of the length of the femur (λ=0.3), point loads increase rapidly and can reach from 0.55 to 1.5 kg depending on the length of the contact area. Such point loads are undesirable for the femur in the area of contact with the prosthesis in terms of the integrity of the femur.

USE OF AN INDIVIDUAL TOOL FOR KINEMATIC ALIGNMENT OF THE LIMB AXIS DURING KNEE ARTHROPLASTY (CLINICAL CASE)

Objective. To give a clinical example where, under the conditions of gonarthrosis, the patient underwent preoperative planning using modern technologies of three-dimensional modulation; outline the stages of individual instrument preparation and for kinematic alignment of the axis of the lower extremity and installation of knee joint endoprosthesis components. Methods. A 69-year-old patient was diagnosed with stage IV right-sided gonarthrosis. For preoperative planning, a computer tomography of the lower extremities was performed in the position of full extension in the knee joints and neutral rotation of the feet (slice thickness 1 mm). A 3D model of the lower extremities was built in the "STL" format in the RadiAnt DICOM Viewer Version2021.2 program and imported into the FreeformPlus program. Preoperative planning was performed according to the principle of kinematic alignment to restore the constitutional axis of the limb and the inclination of the knee joint plane. The main stages of preparation of an individual instrument and carrying out operative intervention are given. Functional evaluation was performed before and after the operation at different stages according to the EuroQol-5D, KSS, HSS scales and a six-step functional test. Results. Individual navigation made it possible to precisely carry out resections of the articular ends and perform the planned kinematic alignment of the limb. According to the EuroQol-5D scale, the improvement of the patient's quality of life was determined, starting from the 3rd day after the operation. According to the KSS scale, an excellent result (85 points) was obtained 6 weeks after the surgical intervention, which remained after 3 months. The evaluation of the result of endoprosthesis according to the HSS scale after 6 weeks was 36 points, after 3 months — 38 points. Conclusions. A clinical example of the use of an original individual instrument for knee endoprosthesis showed the main advantages of the method — accurate installation of endoprosthesis components according to the preoperative design, which ensured high patient satisfaction and a good functional result.

Mathematical modeling of the acetabulum fracture (type 62-B1.3 by AO/ASIF) deformities and hip endoprosthetics in combination with osteosynthesis

Secondary degenerative disabling changes in the hip joint often develop in the long term after surgical treatment of hip fractures. A well-founded differential approach to the selection of endoprosthesis components and additional means of stabilizing bone fragments is necessary. Objective. To investigate changes in relative deformation values in a hip joint model with a acetabulum fractures 62–B1.3 type by AO/ASIF classification under the conditions of its endoprosthesis using various osteosynthesis options. Methods. A basic finite-element model of the pelvic girdle of a person with a fracture of the bottom of the cruciate ligament type 62-B1.3 (АО/ASIF) was developed, on which 7 variants of endoprosthesis of the left hip joint were modeled: without fracture (1); without osteosynthesis of fragments (2); fixation of a fragment of the acetabulum back wall with two screws (3), two screws and a bone plate (4), two screws and a bone plate with a Jumbo cup implantation (5); 5 case, long screw in the front column (6); option 5, long screws in the front and rear columns (7). Results. When using a large-sized Jumbo cup, the relative deformations of the bone regenerate in the center of the bottom of the KZ were reduced to 1.0 %, regardless of the osteosynthesis option. Around the free fragment of the short circuit, the largest relative deformations (3.0 %) were found in version 5 of the model. The use of long rods in the columns led to decrease in the relative deformations of the bone regenerate around the free fragment of the KZ to 2.0 %. Conclusions. Mathematical models proved that an increase in the number of osteosynthesis tools under the conditions of the total hip endoprosthesis replacement, 62-B1.3 (АО/ASIF) type KZ fracture leads to a decrease in the relative deformations of the bone regenerate along the entire fracture line. The use of a large-sized Jumbo cup makes it possible to reduce the level of relative deformations of the bone regenerate in the cent­ral part of the KZ.

Some clinical factors of aseptic instability of the knee joint endoprosthesis

Background. Conducting clinical studies to determine the factors determining the aseptic instability of knee joint endoprosthesis components is an urgent issue in modern orthopedics. The aim of the study was to determine some clinical factors of aseptic instability of knee joint endoprosthesis components. Materials and methods. Comprehensive research was conducted on 285 patients who underwent primary knee arthroplasty between 2010 and 2021, including 85 patients with clinical and radiological signs of aseptic instability of knee arthroplasty components (AIKAC). Also, 200 patients made up a control group with no signs of AIKAC instability observed. Clinical research methods included general, and special orthopedic methods of studying local changes in the knee joint. They included measurement of body mass index (BMI), overloading of the knee joint due to work, previous surgical interventions and early postoperative complications of primary arthroplasty, and presence of angular deformities in the knee joint. For the clinical assessment of the knee joint of patients after knee arthroplasty, we used our own point assessment of the state of the knee joint. Results. It was determined that significant factors for the development of instability of components of the knee joint endoprosthesis are both directly related to the patient (increase in BMI, difficult working conditions, the presence of operative interventions on the knee joint), and factors related to errors during the primary total arthroplasty (residual deformities of the knee joint and early postoperative complications). Conclusions. We determined important factors of aseptic instability of the knee joint in the patients after arthroplasty. Taking into account the results of this study will improve the diagnosis and treatment of aseptic instability of the knee joint.

Total hip arthroplasty in the treatment of severe stages of osteonecrosis of the femoral head and osteoarthritis: results and complications

BACKGROUND: Nowadays total hip arthroplasty (THA) is the method of choice for the treatment of late stages osteonecrosis of the femoral head (OFH) and osteoarthritis (OA) of the hip joint.
 OBJECTIVE: To evaluate the efficacy and complication pattern of THA in late stages of OFH and OA.
 MATERIALS AND METHODS: The study included 74 patients who underwent primary THA for OA stages IIIIV (Kellgren and Lawrence classification) and for OFH stages IIIIV (ARCO classification). Group 1 included 34 patients with OFH stages IIIIV, and group 2 40 patients with OA stages IIIIV. The groups were comparable by gender and age. All patients underwent implantation of endoprosthesis components using press-fit fixation with a metalpolyethylene articulation. Treatment results were assessed with regard to the incidence of complications and functional results at 3, 6 months, 1 and 3 years after THA.
 RESULTS: In our study, the survival rate of components after THA within 3 years after implantation was 100%. No cases of periprosthetic fracture, periprosthetic infection, and aseptic instability of endoprosthesis components were observed in both groups. The surface inflammation of the postoperative wound was detected in 1 (2.9%) patient in the OFH group and in 1 (2.5%) patient in OA group. Dislocation of the endoprosthesis occurred in 1 patient with OFH; there were no such findings in the OA group. The frequency of peri-implant osteolysis was twice lower (2.5%) in patients with OA compared to OFH group (5.8%). There were no statistically significant differences in the functional results dynamics before and after surgery between the groups (Harris score). The average Harris scale score in patients with OFH was 63 and reached 94 after 3 years; in OA group 58 and 94, respectively.
 CONCLUSION: THA is an alternative method in the treatment of severe hip arthroplasty. Endoprosthetics using a cementless endoprosthesis with a metalpolyethylene articulation demonstrated high efficacy as well as a low number of complications among patients with OFH and OA. We found no significant difference in THA results in terms of survival, postoperative complications, and functional outcome in patients with OFH and OA. Longer postoperative follow-up is advisable, which may allow us to establish some differences in treatment outcomes.

ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ ФРЕЗЕРУВАННЯ ПОВЕРХОНЬ ЕНДОПРОТЕЗІВ

Purpose to work: is to increase the efficiency of milling endoprosthesis components, taking into account their kinematic characteristics. Methodology: theoretical research was carried out on the basis of mathematical analysis, computer modeling using modern software and computing equipment. The PowerMILL CAM system was used for statistical processing of milling trajectories. Results: when manufacturing endoprosthesis components, the best processing strategies were "Selection of 3D model by model shift" and "Selection of 3D model by shift". These two strategies give the lowest idle time for the lowest core processing time. Machine processing time when using the strategies "3D model selection" by model shift and "3D model selection" by shift is reduced by 2 times compared to the "3D model selection" raster strategy, and by 3 times compared to the "3D model selection" strategy Vortex. However, it should be noted that all 4 studies were conducted at the same cutting modes, which are not typical for high-speed milling. Vortex's "3D Model Selection" is ineffective in these cutting modes due to the fact that it is designed exclusively for high-speed milling. "Sampling a 3D model" with a raster also turned out to be ineffective due to the fact that it is intended for work on open planes. Scientific novelty: the most effective milling strategy for the manufacture of endoprosthesis components is proposed. Practical significance: recommendations for the use of milling strategies are given. Key words: milling, strategy, endoprosthesis, idle movements, model, technological process, operation, machine time.

Анализ эффективности локального протокола диагностики перипротезной инфекции

The diagnosis of periprosthetic joint infection is a difficult task because there is no absolute test to confirm or rule out infection. We have developed a local protocol for diagnosing periprosthetic joint infection to use a combination of diagnostic studies with the highest level of sensitivity and specificity.The purpose of the study: To evaluate the effectiveness of a local protocol for diagnosing periprosthetic joint infection to determine surgical treatment tactics.Methods. We analyzed 283 audits that took place during 2020-2022 at the Federal Center for Traumatology, Orthopedics and Endoprosthetics (Smolensk, Russian Federation). Patients with a preliminary diagnosis of aseptic loosening of knee or hip joint endoprosthesis components and periprosthetic joint infection were monitored. All patients were examined in accordance with the local protocol for the diagnosis of periprosthetic joint infection, which includes clinical and radiological data, CRP and ESR, analysis of the cellular composition of synovial fluid, microbiological examination of biopsies, endoprosthesis components, planned and frozen sections. The final diagnosis was made taking into account clinical and laboratory data. The effectiveness was assessed by delayed treatment results. Results. Positive microbiological cultures were isolated in 165 patients (58%), 150 patients had increased cytosis of synovial fluid (53%), leukocyte esterase was increased in 147 cases, according to the results of an urgent histological examination, 159 conclusions of «infectious type membrane» (56%) were obtained, a combination of increased ESR and CRP was observed in 93 cases.Conclusions. Analysis of the local periprosthetic joint infection diagnostic protocol showed that each stage of diagnosis allows to identify additional cases of infection, therefore, all patients admitted for revision endoprosthetics should be examined throughout hospitalization. The inclusion of urgent histological diagnostics at the intraoperative stage makes it possible to change the tactics of surgical treatment in a timely manner. In general, the local protocol of step-by-step diagnosis of periprosthetic joint infection with the inclusion of urgent histological examination helps to increase the chances of a successful outcome of revision endoprosthesis surgery, regardless of the nature of loosening.

Замещение дефектов бедренной и большеберцовой костей при ревизионном эндопротезировании коленного сустава с применением не биодеградируемых материалов: обзор литературы.

In order to restore the function of the knee joint in the terminal stages of arthrosis, primary total knee arthroplasty is used. Primary total knee arthroplasty consists in replacing the femoral and tibial (in some cases, patellar) components of the knee joint with metal and polyethylene (ceramics are used in some types of endoprostheses). This operation has established itself as a method that improves the function of the knee joint in the later stages of gonarthrosis. But in cases of development of aseptic instability of the endoprosthesis components or septic instability of the endoprosthesis components due to periprosthetic infection, it is necessary to resort to revision arthroplasty. During revision arthroplasty, there are frequent cases of the formation of defects in the femur and tibia, which can become an obstacle to stabilization and return of knee joint function. To replace such defects at the present stage, the following methods are used, which relate to non-biodegradable materials: cementing, cementing with screw reinforcement, factory cement spacers with augments, modular metal augments, metaphyseal bushings with pressed porous titanium coating and structural cones made of porous tantalum, megaendoprostheses or individual endoprostheses. This review article analyzes sources describing methods for replacing defects in the bones forming the knee joint during revision knee arthroplasty and consisting of non-biodegradable materials from the PubMed, Google Scholar, SCOPUS, Web of Science databases. The analyzed methods of bone defect replacement are widely used in everyday practice, but also have a number of disadvantages. The use of thick layers of bone cement increases the risk of thermal necrosis and worsens the pressure of bone cement. Factory cement spacers with augment allow only the full defect of the plateau to be replaced. Modular metal augments are associated with corrosion and the development of instability. Metaphyseal bushings and structural cones can cause bone fracture upon insertion and are difficult to remove during revision. Mega endoprostheses or individual endoprostheses are associated with a high risk of infection. Modular metal augments, metaphyseal sleeves, structural cones, mega endoprostheses or individual endoprostheses also have a high cost. At this time, there is a need to develop new methods of defect replacement that will improve the function of the knee joint, improve the quality of life of patients, will be widely available and cost-effective.

Замещение дефектов бедренной и большеберцовой костей при ревизионном эндопротезировании коленного сустава с применением не биодеградируемых материалов

In order to restore the function of the knee joint in the terminal stages of arthrosis, primary total knee arthroplasty is used. Primary total knee arthroplasty consists in replacing the femoral and tibial (in some cases, patellar) components of the knee joint with metal and polyethylene (ceramics are used in some types of endoprostheses). This operation has established itself as a method that improves the function of the knee joint in the later stages of gonarthrosis. But in cases of development of aseptic instability of the endoprosthesis components or septic instability of the endoprosthesis components due to periprosthetic infection, it is necessary to resort to revision arthroplasty. During revision arthroplasty, there are frequent cases of the formation of defects in the femur and tibia, which can become an obstacle to stabilization and return of knee joint function. To replace such defects at the present stage, the following methods are used, which relate to non-biodegradable materials: cementing, cementing with screw reinforcement, factory cement spacers with augments, modular metal augments, metaphyseal bushings with pressed porous titanium coating and structural cones made of porous tantalum, megaendoprostheses or individual endoprostheses. This review article analyzes sources describing methods for replacing defects in the bones forming the knee joint during revision knee arthroplasty and consisting of non-biodegradable materials from the PubMed, Google Scholar, SCOPUS, Web of Science databases. The analyzed methods of bone defect replacement are widely used in everyday practice, but also have a number of disadvantages. The use of thick layers of bone cement increases the risk of thermal necrosis and worsens the pressure of bone cement. Factory cement spacers with augment allow only the full defect of the plateau to be replaced. Modular metal augments are associated with corrosion and the development of instability. Metaphyseal bushings and structural cones can cause bone fracture upon insertion and are difficult to remove during revision. Mega endoprostheses or individual endoprostheses are associated with a high risk of infection. Modular metal augments, metaphyseal sleeves, structural cones, mega endoprostheses or individual endoprostheses also have a high cost. At this time, there is a need to develop new methods of defect replacement that will improve the function of the knee joint, improve the quality of life of patients, will be widely available and cost-effective

Mycoplasma as a possible trigger for the development of idiopathic avascular necrosis of the femoral head

BACKGROUND: The death of bone tissue cells with impaired blood supply, followed by the development of secondary arthrosis/arthritis of the adjacent joint, is most characteristic of osteonecrosis of the femoral head. This condition is common in young patients mainly in men of working age. Hip arthroplasty at a young age has a high risk of loosening of the endoprosthesis components, which can lead to many repeated surgical interventions. In recent years, hypotheses about the possible role of infectious agents in articular pathology have been discussed, as evidenced by the detection of specific antibodies and antigens of pathogens in the joint fluid and periarticular tissues. Mycoplasmas can trigger the development of osteonecrosis because the bone marrow is the main depot and source of endogenous reinfection (when immunity is weakened).
 АIM: This study aimed to identify signs of the presence of mycoplasmas in the soft tissues of the hip joint and bone marrow of the femur during hip arthroplasty in patients with idiopathic avascular necrosis of the femoral head.
 MATERIALS AND METHODS: Clinical and laboratory data of 36 patients with idiopathic aseptic necrosis of the femoral head who underwent total hip arthroplasty were analyzed, and 11.1% of the patients had a history of sexually transmitted diseases. The tissues of the synovium and bone marrow were examined by polymerase chain reaction for the presence of DNA to sexually transmitted infections.
 RESULTS: The average age of the patients was 42.7 years, and the average period from disease onset to the time of surgery was 46.2 months. Bilateral joint damage was found in 78% of cases, and 91.7% of the patients had stage 4 femoral head disease (ARCO). The preoperative Harris score was 33.7 points on average. In history, 4 (11.1%) patients had sexually transmitted diseases. During the study, when analyzing tissue samples of the synovial membrane and bone marrow, DNA fragments of Chlamydia trachomatis, Mycoplasma genitalium, Ureaplasma spp., and M. hominis were not isolated in any case, including in patients with previous mycoplasma and chlamydial infection.
 CONCLUSION: The absence of mycoplasma suggests that a history of sexually transmitted diseases does not significantly affect the outcomes of hip arthroplasty in aseptic necrosis of the femoral head.

Results of Revision Knee Arthroplasty With Individual Implants

Background. The presence of extensive bone defects significantly complicates the possibility of stable fixation and correct spatial positioning of the revision endoprosthesis components. The primary task of revision surgery is to restore the lost bone. The use of modern implants makes it possible to replace large metaphyseal defects of the tibia and femur, including AORI type 2B и 3 bone defects.
 The aim of the study was to evaluate the long-term results of surgical treatment of patients with extensive bone defects (2B and 3 according to AORI) of the proximal tibia and/or distal femur using custom-made implants for revision knee arthroplasty.
 Methods. A retrospective clinical study was performed in 24 patients who underwent revision arthroplasty using individual implants (9 femoral and 18 tibial) made on a 3D printer in the period from 2017 to 2021. T3 defect according to AORI classification was diagnosed in 12 patients (50%), F3 defect in 1 (4.17%), F2B in 8 (33.3%), T2B in 6 (25%). All patients before surgery and 3, 6, 12 months after surgery were surveyed according to the international scales VAS, KSS, WOMAC and SF-36.
 Results. At the follow-up examination 12 months after the surgery, 9 out of 24 patients (37.510%) walked without additional means of support, 10 out of 24 (41.710%) with a cane, 4 out of 24 (16,78%), walkers 1 out of 24 (4.210%). There were no periprosthetic fractures during surgery and in the postoperative period. When evaluating the functional state of the knee joint, an excellent result was registered in 45.810% and 33.310%; good in 37.510% and 54.210%; satisfactory in 16.678% and 12.57% according to the KSS and WOMAC scales, respectively. When assessed on the VAS scale, there was a positive trend in the form of statistically significant decrease in pain in all patients (p0.01).
 Conclusion. The use of individual implants made using additive 3D printing technologies in revision knee arthroplasty in the presence of extensive bone defects (2B and 3 according to AORI) allows to perform an organ-preserving surgery without loss of the statodynamic function of the lower limb. This study has limitations due to the small sample size. We believe that it is promising to study the long-term results of surgical treatment of patients with extensive bone defects (2B and 3 AORI) of the proximal tibia and /or distal femur using individually manufactured implants for revision knee replacement and a comparative analysis of these results with those using conventional implants.

Results of the Articular Spacer Application in Treatment of Knee Periprosthetic Infection

Background. Currently, on the general background the number of primary totak knee arthroplasties (TKA) increasing, so does the revisions. Among all the causes of revisions, periprosthetic joint infection occupies one of the leading positions. The generally accepted tactics of two-stage revisions, along with the infection suppression, implements other tasks: reducing pain, preserving and/or restoring joint function. Articular antibacterial spacers allow you to complete all the tasks and preserve/restore the quality of patients` life on staged treatment. However, studies demonstrating the results of periprosthetic joint infection treatment and the use of various articular spacers still do not clear it`s optimal design.
 The aim of the study was to improve the intermediate treatment results of periprosthetic knee joint infection using articular spacer implantation.
 Methods. A single-center retrospective cohort study was performed. At the first stage of the study, the results of surgical treatment of 420 patients with periprosthetic knee joint infection treated at the clinic in 20112019 were analyzed. At the second stage, after applying the inclusion and exclusion criteria, 182 patients were included in the analysis. Two representative groups are identified among them. In the comparison group, hand-made cement liner with articulating surface was used, in the main group conventional one.
 Results. The implantation of the endoprosthesis components with the restoration of anatomical relationships in the joint and the ligamentous balance, the replacement of the cement liner with conventional one made of ultra-high molecular weight polyethylene led to reduction in the surgery duration, intraoperative blood loss and period of hospitalization, an increase in the range of motions in the joint, greater stability of the components and suppression of infection in 94.6% of patients.
 Conclusion. The use of various spacers did not significantly affect the probability of infection suppression; however, the number of infection relapses was lower in the group where the liner made of ultra-high molecular weight polyethylene was used. Optimization of surgical treatment techniques and the use of articular spacer based on a three-component conventional endoprosthesis has significantly improved the treatment results of patients with periprosthetic infection of the knee joint.

A case of treatment of a fungal periprosthetic infection with a carbon-coated implant

Background. Arthroplasty is the most common surgical treatment for patients with end-stage knee arthrosis. From 2 to 7% of those operated on are patients with rheumatoid arthritis. The inflammatory process in the joint, low rehabilitation potential, long-term therapy with hormonal and genetically engineered biological agents, poor bone quality form a high risk of periprosthetic infection. In this group of patients, the saprophytic microorganism Candida albicans more often forms biofilms on endoprosthesis components, which presents difficulties in the treatment of periprosthetic infection.Aims: demonstration of a clinical case and rationale for the treatment of periprosthetic knee infection caused by Candida albicans using a revision implant with an anti-biofilm coating.Materials and methods. A clinical case presents the results of examination and treatment of a 46-year-old patient with secondary gonarthrosis on the background of rheumatoid arthritis with developed periprosthetic infection are evaluated. Surgical treatment was carried out by two-stage sanitation, using as part of the spacer an implant coated with silver-doped two-dimensionally ordered linear-chain carbon, against the background of etiotropic intravenous treatment with fluconazole.Results. The likely cause of the development of a fungal periprosthetic infection is a decrease in the activity of the immune system against the background of taking cytostatics and hormonal drugs in combination with the frequent uncontrolled use of antibacterial drugs. The choice of surgical tactics in favor of a two-stage revision is justified by the isolation of a «difficult to treat» Candida albicans. Timely diagnosis and the chosen method of treatment in combination allowed to no recurrence during the observation period of 12 months after the 2nd stage of revision.Conclusions. The results demonstrate the effectiveness of a spacer coated with silver-doped two-dimensionally ordered linear-chain carbon at the stage of sanitation for the treatment of periprosthetic infection caused by the «difficult to treat» Candida albicans.