Introduction. Metastatic bone lesions are the 3rd most common metastases after lung and liver metastases. In many cases, lesions in the long bones are accompanied by lesions in the femur; their incidence is 71 %. In 25 % of cases of metastases in the bone diaphysis, pathological fracture of the femur occurs. Primary bone sarcomas usually develop in the metaepiphysial areas which requires resection of both the affected bone and the intact joint located in the immediate vicinity of the tumor. According to various authors, the main problems of evaluation of the results of endoprosthesis of diaphyseal defects are long duration of data accumulation (retrospective study design) due to small number of tumors in this area requiring surgical correction, differences in follow-up duration, and heterogenous histological structure of the tumor.

Aim. To analyze the results of postresection defect reconstruction in tumors of the diaphyseal parts of the bones using different endoprostheses models.

Materials and methods. The study included 50 patients with primary tumors of the bones and soft tissues who underwent 59 primary and revision surgeries consisting of reconstruction of the diaphyseal and metadiaphyseal defects of the tibia, humerus and femur between 1995 and July of 2025. The primary endoprosthesis group (n = 50) included 29 men and 21 women. Mean patient age was 50.8 years (16–77 years). The group of repeat endoprosthesis (n = 9) included 6 men and 3 women. Mean patient age was 46.2 years (27–68 years). Primary tumors were observed in 30 (61.2 %) patients, metastases in 20 (38.8 %). In 22 (73.3 %) patients with primary tumors, bone sarcomas were diagnosed; in 8 (26.7 %) – soft tissue sarcomas with long bone lesions. In the 29-year period, results of 50 (84.7 %) primary endoprosthesis surgeries and 9 (15.3 %) repeat oncological endoprosthesis surgeries of the diaphyseal part of the long bones were analyzed. Surgical interventions for lesions in the femoral diaphysis were the most common: 49 % (29/59) cases. For lesions of the humeral diaphysis, surgeries were performed in 27 % (16/59) cases; for lesions of the tibial diaphysis, in 24 % (14/59).

Results. During the 29-year observation period, overall rate of type I–IV complications (per the International Society of Limb Salvage classification 2013, ISOLS 2013) was 40.7 %, mean time to diagnosis of oncological and nononcological complications was 14.3 (1–58) months. Type IA complications (construction instability) were observed in 3 (4.8 %) cases, type IIА (early aseptic instability) in 9 (14.3 %), type IIВ (late aseptic instability) in 2 (3.2 %), type IIIA (destruction of endoprosthesis elements) in 5 (8 %), type IIIВ (periprosthetic bone fraction) in 1 (1.6 %), type IVA (early endoprosthesis infection) in 1 (1.6 %), type VА (soft tissue recurrence) in 6 (12 %), type VВ (bone recurrence) in 1 (2 %). Total percentage of oncological complications was 32 %. Among oncological complications, only local recurrence was diagnosed in 10 % of cases, only metastasis in 18 %, progression in the form of local recurrence and metastasis in 4 %. Total percentage of non-oncological complications (types I–IV per ISOLS 2013) was 35.6 %. In the current study, the most common adverse events after endoprosthesis of the tibial, humeral and femoral diaphyses were aseptic instability (17.5 % of cases) and tumor recurrence (14 % of cases).

Conclusion. According to the study results and literature data, the most optimal are modular implants and models manufactured using 3D printing. Resection of the diaphyseal part of the bone with its reconstruction with an endoprosthesis is the method of choice for patients with primary and metastatic lesions of this part of the bone. Complication rate per the ISOLS 2013 classification corresponds to the average results after oncologic endoprosthesis presented in literature. Moreover, the patients’ functional results and quality of life were better than after surgeries with endoprosthesis of the neighboring joints.

Osteoid osteoma is the 3rd most common benign osteogenic tumor characterized by the presence of an osteoid in the central nidus and an area of reactive osteosclerosis in the adjacent bone tissue. Disease pathogenesis is based on the production of prostaglandin E2 and prostacyclin in the nidus causing local inflammation, vasodilation and osteosclerosis stimulation which leads to pain syndrome which can be managed with nonsteroidal anti-inflammatory drugs. The main diagnosis methods for osteoid osteoma are X-rays and computed tomography allowing to identify the type of tumor: dense bone tissue lesion with distinct scalloped borders including the central zone (nidus) surrounded by sclerosis. The article presents a rare clinical case of diagnosis and treatment of osteoid osteoma of the middle third of the radius. Long diagnostic search due to atypical tumor location negatively affects the patient’s quality of life, requires long-term administration of nonsteroidal anti-inflammatory drugs.

Introduction. Modern treatment of osteosarcoma requires multicomponent therapy including pre-surgery chemotherapy. The benefits of such therapy are in vivo evaluation of chemotherapy drug activity and creation of conditions for more effective surgical intervention.

Aim. To analyze the effectiveness of three-component chemotherapy based on a combination of doxorubicin, cisplatin and methotrexate in young adults with osteosarcoma.

Materials and methods. Between 2022 and 2024, 22 patients between the ages of 18 and 42 years (mean age 30 years) with malignant tumors of the bones received treatment at the N.N. Blokhin National Medical Research Center of Oncology. Before the start of chemotherapy, all patients underwent morphological and clinical imaging examinations. The patients received 2 courses of neoadjuvant chemotherapy (doxorubicin + cisplatin + methotrexate) with subsequent surgical treatment stage.

Results. Sixteen patients fully completed neoadjuvant polychemotherapy and local control stage, 12 of them received 2 courses of MAP (doxorubicin + cisplatin + methotrexate) chemotherapy. Complete response was not observed. Stable disease was registered in 1 (8.3 %) patient, partial response in 8 (66.6 %) patients. Tumor control was achieved in 74.9 % of patients. In 3 cases, disease progression was observed. Surgical treatment was performed in 10 (83.3 %) cases, among them 9 (75 %) interventions were organ-sparing. One patient refused surgical treatment and received radical external beam radiotherapy. In 1 (8.3 %) case grade IV therapeutic pathomorphosis was observed, in 3 (25 %) – grade III, in 3 (25 %) – grade II, in 3 (25 %) – grade I, in 2 (16.7 %) cases it was not registerable (disease progression was observed).

Conclusion. During our study we achieved high level of tumor control (74.9 % of cases) but grade III–IV therapeutic pathomorphosis was achieved only in 33.3 % cases. According to our data, peak methotrexate concentration does not affect therapy effectiveness. In the future, it is necessary to include more patients in the study group, analyze recurrence-free and overall survival and compare MAP chemotherapy with standard regimen chemotherapy (cisplatin+ doxorubicin).

Introduction. With the increase in the number of primary oncological knee joint replacement, the frequency of postoperative complications has also increased, among which infection has become one of the most serious, occurring in 10–25 % of patients. Two-stage revision, including removal of an infected prosthesis and installation of a spacer followed by antibiotic therapy, is considered the gold standard for treating infection. However, removing an infected prosthesis can lead to a number of problems, such as loss of bone mass, cortical defects, muscle atrophy, and impaired joint function, which reduces the effectiveness of the second stage of treatment. These circumstances highlight the need to evaluate the actual effectiveness of two-stage revision interventions, which was the reason for this study.

Aim. To study the results of treatment of patients who underwent two-stage cancer revision arthroplasty of the knee joint.

Materials and methods. In our study, 56 patients were enrolled, who underwent the first stage of revision arthroplasty of the knee joint in our clinic. The inclusion criterion was a follow-up period of at least 36 months after the second stage of surgical treatment. At the first stage, arthrodesis cement spacers were used, installed using titanium lockable intramedullary rods. After a course of antibiotic therapy, further tactics of treatment were chosen, which could include various types of final surgical interventions, such as endoprosthesis, amputation, arthrodesis using an external fixation apparatus or modular oncological structures. The average age of the patients was 52 years, the majority of whom were women (58.9 %). To achieve the goal, the following parameters were analyzed: the presence of infection recurrence, the nature of the final treatment, the duration of use of the spacer, the presence of bone and extensor apparatus defects, functional results, and endoprosthesis survival. Functional results were evaluated 12 months after surgery using the Musculoskeletal Tumor Society Score (MSTS) scale.

Results. In the study, 56 patients participated, with no signs of infection recurrence detected in 43 (76.8 %) of them after installing the spacer. Of these 43 patients, three performed a buried arthrodesis with an oncological modular system, 8 – arthrodesis using AFV, 5 – installation of a spacer with blocking. Endoprosthesis was performed in 27 (48.2 %) patients, of whom 19 had resection of the distal femur, and eight – proximal tibia. After implantation of the endoprosthesis, infection recurred in three patients after 39, 46, and 56 months, respectively. Five-year survival without infection recurrence was 87.5 %. The median time to event-free survival of the structure was 88 months. In the presence of extensive intraosseous defects, the risk of revision surgical intervention increases significantly (p = 0,041). Of the 13 patients diagnosed with infection recurrence after installing the spacer, only eight managed to perform resetting of the spacer, while the remaining five underwent lower limb amputation. Using the MSTS scale, an analysis of the function of the knee joint was performed in patients who underwent knee endoprosthesis. The median was 76.7 %, and in patients with resection of the distal femur, the knee joint function was statistically significantly better (p <0.001).

Conclusion. Our results confirm that two-stage revision oncological arthroplasty of the knee joint is effective in treating infectious complications in patients with oncological lesions of the knee joint. This approach provides control over infection and allows for the reinstallation of the endoprosthesis. To reduce the likelihood of failures and improve the functional outcomes of treatment, it is necessary to take into account the risks associated with extensive intraosseous defects, insufficiency of the extensor apparatus, and the timing between stages of the operation.

Introduction. Aggressive benign spinal tumors in children frequently require extensive surgical resection necessitating complex reconstructive interventions. Currently, vertebrologists have at their disposal a large number of prostheses for replacement of the anterior supporting column. Both static implants and extendable spacer are used. However, these implants have limitations which can affect long-term results especially in children when growth should be taken into account and long-term stability of the prosthesis should be assured. Design of personalized titanium prostheses adapted to anatomical features of the vertebrae allows to solve these problems.

Aim. To evaluate the effectiveness of using personalized titanium vertebral corpectomy prostheses for reconstruction of postresection defects in children with aggressive benign spinal tumors (stage III per the Enneking classification).

Materials and methods. The study included 5 patients of pediatric age who underwent two-stage surgical intervention including dorsal stabilization, tumor resection and installation of a personalized titanium vertebral corpectomy prosthesis manufactured using direct metal laser sintering (DMLS) 3D printing.

Results. No significant complications were observed in the postoperative period. In the first 3 months, neurological status was completely restored in all patients. Computed tomography showed stable implant integration; minimal signs of prosthesis subsidence (1 mm without signs of resorption around screw implants) were observed only in 1 case.

Conclusion. The use of personalized titanium vertebral corpectomy prostheses improves the results of surgical treatment of spinal tumors in children. The proposed innovative technique of postresection defect replacement with personalized implants manufactured by 3D printing increases spinal fixation stability after extensive tumor resection and decreases the risk of complications associated with implant instability. The use of additive methods of prosthesis manufacturing allows to solve complex reconstruction problems in spinal surgical interventions in children.

Primary malignant tumors of the bones are a rare oncological pathology. The risk of bone sarcoma development is higher in young people which underlies the social significance of treatment of this disease. The structure of the radiocarpal joint and deficit of soft tissues near this joint complicates achieving good functional results after surgery and causes high risk of postoperative complications.

In this article, the results of studies demonstrating different techniques of surgical treatment of patients with tumors of the radiocarpal joint are analyzed, their advantages and disadvantages described.

Introduction. Melanoma is the main cause of death in patients with malignant tumors of the skin. While at early stages disease prognosis is relatively favorable, biological characteristics of the tumor can negatively affect patients with this pathology. Cancer stem cells and anaplastic lymphoma kinase (ALK) expression in the presence of translocation of its gene are potential prognostic factors in stage I–II cutaneous melanoma are.

Aim. To evaluate prognostic significance of cancer stem cells (CD133+ and ABCB5+ ) and ALK protein expression in patients with primary stage I–II cutaneous melanoma after surgical and combination treatment.

Materials and methods. The study included 48 patients with stage I–II cutaneous melanoma (30 with superficial spreading type, 18 with nodular type). In all patients, expression of cancer stem cell markers (ABCB5 and CD133) and ALK was immunohistochemically determined. Statistical data analysis was performed using Jamovi (version 2.2.5) software. Follow-up duration was 5 years.

Results. During the 5-year observation period, progression of stage I–II cutaneous melanoma was observed in 12 (25 %) patients. Intensity of ABCB5 and CD133 expression in patients with tumor progression was similar. In patients with melanoma progression, ALK expression was observed in 33.3 % of cases, was absent in 8.3 % (р = 0.034) of cases. Five-year recurrence-free survival in patients with ALK expression was 43 %, without ALK expression – 79 % (р = 0.015). ALK protein expression in the presence of its gene translocation increases progression risk 4.3-fold irrespective of histological type of the tumor (р = 0.025). During the 5-year observation period, death due to stage I–II disease progression was observed in 27.1 % of cases. Intensity of CD133 and ALK expression in cases with fatal outcome and without it was the same. ABCB5+ cancer stem cells were more common in cases of fatal outcome (61.5 % of cases) than in cases without it (34.3 % of cases) (р = 0.085). Five-year overall survival of patients with ABCB5 expression was 56 %, without it – 82 %. The presence of ABCB5 increased the risk of death in patients with localized stages of cutaneous melanoma 3.7-fold irrespective of the presence of CD133 (р = 0.041).

Conclusion. ALK protein expression and presence of ABCB5 cancer stem cells can serve as additional unfavorable prognostic factors in stage I–II cutaneous melanoma.

According to the concept of quality of life in patients with bone tumors, quality of life is integral characteristic of person’s well–being in conditions of severe musculoskeletal disease with vital threat, reflecting person’s ability to live an active life, be involved in professional activities, take part in family and social affairs, i.e. personality adaptation during and after treatment. Quality of life in patients with this pathology is significantly reduced due to disease and therapy, which is often severe and prolonged, which requires the use interdisciplinary approach to therapy and comprehensive psychosocial rehabilitation. Rehabilitation of patients with bone tumors of extremities after organpreserving surgery, which is currently considered as priority surgical procedure providing local tumor control, involves two types of measures: restorative (aimed at returning to independence from outside help in everyday life) and supportive (aimed at restoring partial independence from outside help in everyday activities and improving the quality of life). One of the key components of early postoperative rehabilitation is formation of patient’s confidence in the possibility of independent activity and understanding of its necessity. Comprehensive rehabilitation of patients after lower limb amputation plays a major role in restoring functions, makes it possible to return to self-care, work, and activity. It is important that independence from outsiders in everyday life, achieved during rehabilitation, significantly correlates with higher level of 6-month survival. The article considers various approaches to psychosocial rehabilitation of patients with bone tumors of the extremities after organ-preserving surgery and patients who have undergone amputations, emphasizing the importance of timely rehabilitation measures.

Introduction. Surgical intervention remains the most significant treatment approach for the majority of malignant tumors of the thoracic cage. In the presence of massive defects, the use of muscle and musculocutaneous flaps does not provide the necessary rigidity and structure of the thoracic wall. The optimal method in this case is personalized endoprosthesis of the thoracic wall defects developed based on anthropometric data of each individual patient.

The choice of implant fixation technique to the bone structures is an important question in orthopedic oncology because reliable fixation decreases the risk of postoperative complications and allows to achieve rigid structure of the thoracic wall. Currently, there is no consensus on the most optimal technique for implant attachment.

Aim. To determine the most reliable technique of implant fixation to the ribs in reconstruction of the rib and muscle frame of the thoracic cage after surgical intervention for tumors of the thoracic wall to decrease the risk of instability of the metal construction in the postoperative period and hospitalization time and to increase the quality of life and esthetic results of the patients.

Materials and methods. An experiment using 9 porcine ribs was performed. The accuracy of 3 different techniques of implant fixation to the ribs was determined: using screws oriented at the 90° angle, at the 45° angle relative to the bone, and using multidirectional fixation.

Results. The highest strength of the construction was observed in fixation of the implant using screws oriented at the 90° angle relative to the bone (maximal separation force – 131 kg, mean – 86 kg). Attachment to the ribs using screws oriented at the 45° angle relative to the bone and multidirectional fixation showed lower strength: maximal separation force was 34 and 39 kg, respectively, mean – 27 and 32 kg, respectively.

Conclusion. Fixation of the implant using screws oriented at the 90° angle relative to the bone is the most optimal method. This technique can be used in patients with tumor lesions in the thoracic wall who underwent extensive resection. The use of this method decreases the risk of metal construction instability in the postoperative period, decreases hospitalization time, and improves the quality of life and esthetic results in patients after surgical intervention.

Bone sarcomas are one the rarest types of malignant tumors comprising only 0.2–1 % of oncological diseases. Chondrosarcoma is the 3^rd most common bone sarcoma. This tumor is characterized by low sensitivity to drug and radiological treatment. According to literature data, the current golden standard of bone chondrosarcoma treatment is en bloc radical surgical resection with preservation of clean resection margins. However, common for this tumor location in the pelvic bones can pose difficulties at the stage of surgical planning.

The article presents a clinical case of surgical treatment of sacrum G₂ chondrosarcoma in the volume of total sacrectomy with defect replacement using a personalized implant manufactured using a 3D printer and with lumbosacral stabilization.