Effectiveness of titanium mesh in performing oncological endoprosthesis in patients with tumor lesion of the proximal tibia

Abstract

Introduction. Oncologic endoprosthesis of the knee joint in patients with tumors of the proximal calf requires reconstruction of the joint and surrounding structures including the extensor mechanism. This study is based on our experience of using titanium meshes as additional fixation aids for attachment of the patellar ligament to the endoprosthesis. We have developed a technique of extensor mechanism reconstruction and performed comprehensive assessment of the results of its clinical use.Aim. To evaluate the effectiveness of using titanium meshes for reconstruction of the knee extensor mechanism during primary and revision oncologic endoprosthesis of the knee joint.Materials and methods. The study included 2 stages: 1) retrospective analysis of the effectiveness of using titanium mesh implants in primary endoprosthesis of the knee joint; 2) prospective study to evaluate the results of using polymer and titanium meshes during revision oncologic endoprosthesis of the knee joint.The retrospective study included 78 patients divided into 3 groups: the 1st group included 25 patients in whom the extensor mechanism was attached directly to the endoprosthesis; the 2nd group included 30 patients who underwent surgery involving use of a polymer mesh; the 3rd group included 23 patients who underwent surgery involving use of a titanium mesh.In the prospective study, analysis of the results of treatment of 40 patients who underwent surgery between 2019 and 2023 was performed. Depending on the type of treatment, 2 groups were formed: control and treatment. The control group included 20 patients who underwent surgery with a polymer mesh, the treatment group included 20 patients who underwent surgery with a titanium mesh per the technique proposed by the authors (patient No. 2791407). The groups were matched per sex, age, and follow-up duration. The risks of type I and IV complications per the International Society of Limb Salvage 2014 (ISOLS 2014) classification and functional results per the Musculoskeletal Tumor Society Score (MSTS) scale were evaluated. Additionally, the angle of deficit of active knee joint extension was measured.Results. In the retrospective part of the study, significant differences (p = 0.004) were found in probability of type I complications: the use of polymer and titanium meshes as additional fixation aids for attachment of the extensor mechanism to the endoprosthesis significantly decreased the probability of this type of complications. Functional evaluation per the MSTS scale showed that the use of additional fixation aids for attachment of the extensor mechanism to the endoprosthesis (both titanium and polymer meshes) significantly improved functioning of the limb (p <0.001). In the prospective part of the study, significant differences were found in the probability of extensor mechanism failure (p = 0.020): the use of titanium meshes decreased the probability of failure. In the patient group involving titanium meshes, functional results 12 months after surgery were significantly better than in the group with polymer meshes (p <0.001). Evaluation of the deficit of active knee extension did not show significant differences between the groups (p = 0.160).Conclusion. The use of titanium mesh as an additional fixation aid for the preserved elements of the extensor mechanism showed good results both in primary and revision oncologic endoprosthesis of the knee joint. Titanium meshes can be recommended for use in clinical practice, but formulation of the final conclusions requires more clinical material and longer follow-up duration.