Total Talar Replacement with Ceramic Implant in Combination with Tibial Component of Ankle Endoprosthesis: A Case Report

Background. Surgical treatment of patients with talus posttraumatic aseptic necrosis and its consequences usually includes tibiotalocalcaneal arthrodesis with various foot joints according to additional indications. This type of surgical treatment has number of significant disadvantages: traumatic surgical technique, permanent loss of movement in functionally significant joints, high risk of non-union, high frequency of residual deformities, the need for long periods of limb immobilization. The question arises: how to overcome the existing disadvantages and improve the results of talus posttraumatic aseptic necrosis treatment? A potential solution to this problem is the total talus endoprosthetics. Clinical case. A 64-year-old patient came to the clinic complaining of pain and deformity of the right foot and ankle area. After the examination, talus posttraumatic aseptic necrosis was diagnosed. The patient underwent ankle joint arthroplasty using total talus ceramic endoprosthesis in combination with the tibial component of the ankle joint endoprosthesis, a course of rehabilitation treatment was performed. Results. The VAS and AOFAS scales indicators showed a significant improvement both in the pain decrease (from 75 mm before surgery to 10 mm after), and in the functional state according to AOFAS by 2.2 times (from 36 to 80 points 20 months after surgery). By the last follow-up the patient could take more than 8000 steps a day. Conclusion. Considering the good clinical result achieved, the ankle joint arthroplasty using total talus ceramic endoprosthesis in combination with the tibial component of the ankle joint endoprosthesis can be considered a promising method of treatment of this severe pathology.

Morphometric measurement of the proximal tibia to design the tibial component of total knee arthroplasty for the Thai population

Purpose This study evaluates the morphology of the Thai proximal tibia based on three-dimensional (3D) models to design the tibial component. Methods The 3D models of 480 tibias were created using reverse engineering techniques from computed tomography imaging data obtained from 240 volunteers (120 males, 120 females; range 20–50 years). Based on 3D measurements, a digital ruler was used to measure the distance between the triangular points of the models. The morphometric parameters consisted of mediolateral length (ML), anteroposterior width (AP), medial anteroposterior width (MAP), lateral anteroposterior width (LAP), central to a medial length (CM), central to a lateral length (CL), medial anterior radius (MAR), lateral anterior radius (LAR), and tibial aspect ratio (AR). An independent t-test was performed for gender differences, and K-means clustering was used to find the optimum sizes of the tibial component with a correlation between ML length and AP width in Thai people. Results The average morphometric parameters of Thai proximal tibia, namely ML, AP, MAP, LAP, CM, and CL, were as follows: 72.52 ± 5.94 mm, 46.36 ± 3.84 mm, 49.22 ± 3.62 mm, 43.59 ± 4.05 mm, 14.29 ± 2.72 mm, and 15.28 ± 2.99 mm, respectively. The average of MAR, LAR, and AR was 24.43 ± 2.11 mm, 21.52 ± 2.00 mm, and 1.57 ± 0.08, respectively. All morphometric parameters in males were significantly higher than those of females. There was a difference between the Thai proximal tibia and other nationalities and a mismatch between the size of the commercial tibial component and the Thai knee. Using K-means clustering analysis, the recommended number of ML and AP is seven sizes for the practical design of tibial components to cover the Thai anatomy. Conclusion The design of the tibial component should be recommended to cover the anatomy of the Thai population. These data provide essential information for the specific design of Thai knee prostheses.

The personalized Berger method is usable to solve the problem of tibial rotation

Purpose The revision of any total knee replacement is carried out in a significant number of cases, due to the excessive internal rotation of the tibial component. The goal was to develop a personalized method, using only the geometric parameters of the tibia, without the femoral guidelines, to calculate the postoperative rotational position of tibial component malrotation within a tolerable error threshold in every case. Methods Preoperative CT scans of eighty-five osteoarthritic knees were examined by three independent medical doctors twice over 7 weeks. The geometric centre of the tibia was produced by the ellipse annotation drawn 8 mm below the tibial plateau, the sagittal and frontal axes of the ellipse were transposed to the slice of the tibial tuberosity. With the usage of several guide lines, a right triangle was drawn within which the personalized Berger angle was calculated. Results A very good intra-observer (0.89-0.925) and inter-observer (0.874) intra-class correlation coefficient (ICC) was achieved. Even if the average of the personalized Berger values were similar to the original 18° (18.32° in our case), only 70.6% of the patients are between the clinically tolerable thresholds (12.2° and 23.8°). Conclusion The method, measured on the preoperative CT scans, is capable of calculating the required correction during the planning of revision arthroplasties which are necessary due to the tibial component malrotation. The personalized Berger angle isn’t altered during arthroplasty, this way it determines which one of the anterior reference points of the tibia (medial 1/3 or the tip of the tibial tuberosity, medial border or 1/6 or 1/3 or the centre of the patellar tendon) can be used during the positioning of the tibial component. Level of evidence Level II, Diagnostic Study (Methodological Study).

New option of tibial plateau plasty in total knee arthroplasty

Introduction There are several options of fixation and plasty for tibial defects. Screw and cement augmentation of the tibia is an alternative to conventional bone autograft and allograft. Although use of metal and cement augments provides reliable support for the tibial plateau and facilitates early weight-bearing on the operated limb the technique fails to maintain enough bone stock for future revisions. The purpose was to present an option of cement and metal augmentation of the tibial component in total knee arthroplasty (TKA). Material and methods The technique consists of cement and screw augmentation using three screws placed vertically as a regular triangle and being perpendicular to the tibial plateau. We describe the technique and a clinical instance of type 2A defect of the proximal tibia using the author's method. Outcome measures were goniometry and radiography. Results Goniometry examination showed positive dynamics in the first week after surgery with flexion of 110.0 degrees, extension 175.0 degrees; at 12 months with flexion of 90.0 degrees and extension of 180.0 degrees. Radiographic examination demonstrated no instability and micromobility of the cement mantle. Discussion The author's technique of screw and cement augmentation of the tibial component was practical for type 2A defects of the proximal tibia with a shortage of materials of bone autografts. This is a pilot study that requires further investigations.

Outcomes of total knee replacement with the use of a NexGen MIS Tibial Component (Mini-keel) : a systematic review

NexGen MIS Tibial Component (Mini-keel) is a tibial component specially developed for minimally invasive surgery in total knee replacement (TKR), and the size limitations of its design and the modular system could affect tibial fixation strength, however, this has not been precisely evaluated thus far. This study aimed to systematically review the literature describing the outcome following TKR with the use of a Mini-keel. Electronic searches of databases were undertaken in July 2019 by two experienced orthopaedic surgeons according to the PRISMA guidelines for literature describing the outcomes of TKR with the use of a Mini-keel. Quality of studies was assessed using the Joanna Briggs Institute Critical Appraisal Checklist. The initial search found a total of 623 studies from all the databases. Seven studies met all the inclusion criteria and were eligible for critical appraisal and quality assessment. In total, 2,198 cases were included in the systematic review. Thirty-five revision cases due to aseptic loosening were found from the systematic review. Two studies were negative about using a Mini-keel and three studies were positive about it, while the other two studies did not judge the quality of a Mini-keel. There have been conflicting conclusions among studies for the use of a Mini-keel. There remains a paucity of prospective cohort studies between TKRs with the use of a Mini-keel and those with the use of a conventional implant, which makes it difficult to determine the usefulness and reliability of this implant.

Finite element analysis of the tibial component alignment in frontal and sagittal plane in total knee arthroplasty

Background. This study aims to analyze the tibial component using the finite element method by cutting the tibial in frontal and sagittal planes at an angle between 1.5° (valgus and anterior tilt) and -1.5° (varus and posterior tilt). Methods. This experimental study used the finite element method as an useful tool for simulating the positioning of the tibial component in order to create a personal pre-operative planning. For the finite element method analysis, a geometrical model of a tibia from a cadaver was three – dimensionally scanned and the tibial component, polyethylene and cement, were three-dimensionally shaped in Computer-Aided Design program using material data such as Young modulus (gigapascal – GPa) and the Poisson coefficient. The analysis determined the equivalent von Mises stress, the maximum displacement of the components and the equivalent von Mises deformation. The results showed that equivalent tension and deformation have higher values in the tibia and the polyethylene, which deform faster than cement and the tibial component. In our study, we chose to simulate the tibial resection at a cutting angle ± 1.5° from neutral positioning (which is represented in frontal plane by the perpendicular on the mechanical axis and in sagittal plane by the posterior slope of 7 degree) in frontal and sagittal plane in order to find the minimum threshold from which the tibial component malalignment may begin to determine unfavorable effects. Results. Our results have shown detrimental effects begin to appear for the polyethene component at -1.5° in frontal plane, and the rest of the components at 1.5° in sagittal plane. Conclusion. This finding leads us to propose preoperative planning based on personal calculus of predefined angles, which may show the surgeon the optimal implantation position of the tibial component.