Background:Careful preoperative planning in revision cases with complex acetabular defects is crucial for optimal surgery outcome. However, in many cases, computed tomography (CT) scans cannot give a clear understanding of the pelvic destruction. Three-dimensional (3D) models-based on CT data can help surgeon in planning of complex acetabular reconstruction.Materials and Methods:We used 3D plaster pelvic models in 17 revision cases. There were 5 patients with Paprosky II C acetabular defects, 2 patients with Paprosky IIIA defects, and 10 patients with Paprosky IIIB defects (3 patients among them with pelvic discontinuity). We used 3D printer and digital 3D models based on CT scan data for 3D models printing. In 3 cases with Paprosky IIIB defects, we implanted custom-made acetabular components with the porous coating, also printed on the 3D printer.Results:In 14 cases, we used trabecular metal (TM) augments with TM cups. In 100% of cases, number and type of planned and used augments were same. In 9 (64.3%) cases, size of planned and used cups was same. In other cases, the difference was not >2 mm.Conclusions:Use of 3D plaster models for the revision hip arthroplasty planning with complex acetabular defects has shown high accuracy in the clear understanding of acetabular bone deficiency.

BACKGROUND: Osteoarthritis of the knee joint leads to a decrease in the volume of movements, a violation of the sliding of articular surfaces, and a change in the axis of the limb under load, which affects the biomechanics of walking. AIM: This study aims to compare the results of robot-assisted total knee arthroplasty (TKA) and manual techniques, their influence on the biomechanical and podometric parameters of the patient’s walk. METHODS: A prospective randomized study of 68 patients was carried out in the period from 2020 to 2021. Our follow-up period was 1 year. All patients were performed arthroplasty of one knee joint. The main Group “A” included 33 patients TKA with the use of an active robotic setting “TSolution-One” (“THINK Surgical, Inc.” [Fremont, California, USA]); the comparison Group “B” consisted of 35 patients with manual technic of TKA. We studied pain syndrome on the visual analog scale, functional state on the Oxford Knee Score (OKS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC), the volume of ROM movements, and the deviation of the mechanical axis by teleroentgenography of the lower limb. Objective analysis of limb function was performed on the «Alter-G» and the «C-mill». RESULTS: Post-operative pain syndrome on the 1st day after surgery in Group A is stronger by 7.9%, but by the 5th day after surgery in Group A, the pain syndrome is lower by 14.3%. ROM in Group A is better by 16% by 3 months after surgery, after 1 year by 10%. The positioning accuracy of the implant in Group A is 30% better. There are no statistically significant differences in the OKS and WOMAC scales between the groups. The results of restoring normal step in Group A are 13.5% better than in Group B. CONCLUSIONS: Robot-assisted TKA gives more accurate alignment of the mechanical axis, which improves the biomechanics of walking.

Introduction: Durability and better function are the challenging issue of any tribological pair. Ceramic on Ceramic (CoC) friction pairs should provide long-term wear and functional results.Objectives: To evaluate the mid-term results of using the monoblock acetabular system Maxera Cup (Zimmer Biomet) in cementless total hip arthroplasty.Materials and Methods: We evaluated the THA with Monoblock Maxera Cup (Zimmer Biomet) acetabular system in 93 patients. The mean follow-up was 4 years (49.5 ± 11.7 months). All 103 total hip arthroplasty cases in 93 patients were divided into 3 groups according to the diameters of CoC friction pairs (40, 44, 48 mm) used. The achieved functional results were evaluated using the Harris Hip Score (HHS) scale. Results: When assessing long-term results, the average score on the HHS scale significantly increased. During the first year after surgery, there was a 2.2-fold improvement in functional results. There was inconsistent creaking in the implanted joint in only 2.6% of cases with a CoC friction pair with a diameter of 44 mm. Conclusions:The CoC monoblock provides good joint function as perceived by the patient. Acoustic effects, in the form of a minor creaking, did not affect the functional results.

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