Application of Anthropometric Data of Chinese Knees for the Development of Personalised Total Knee Replacement Prosthesis

• Main Author: Chui, Chun Sing
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01.01.2018
• Subjects: Aging; Osteopathic Medicine; Surgery
• ISBN: 0438850440; 9780438850446

Background: Total knee replacement is a common orthopaedic surgery for the patients with severely damaged knees due to arthritis or injury. Currently, most TKR prostheses in the market are designed according to the sizes of Caucasians. However, extensive studies have indicated that anatomies of human are different across different ethnicities. Due to the lack of available prostheses to fit Chinese anthropometric characteristics, some Chinese TKR patients do not match with available prostheses. Undersize of the prosthesis will lead to prosthesis subsidence, while overhang of the component will result in soft tissue abrasion and ultimately operation failure. In this study, three dimensional anthropometric data of Chinese knees was analyzed and the integrated shape of Chinese knees was resulted. Incorporating the integrated shapes of Chinese knees, biomechanical analysis, kinematic requirements and manufacturing considerations, personalized TKR prosthesis for Chinese knees was developed. More precise implantation and bone preservation for patients was expected. Aim of Study: This study aims to develop a knee prosthesis basing on Chinese population data. The developed prosthesis could fit better on the Chinese knees, facilitate better bone preservation of patients and provide better biomechanical performance. Objectives: (1) To develop a standard method for collecting the comprehensive anthropometric data, including the index data and geometric data from Chinese knees; (2) To identify the pattern and correlation of anthropometric parameters of Chinese knees; (3) To develop a method to integrate the anthropometric data from various CT data and (4) To analyze the biomechanical effect of the Chinese population based TKR prosthesis. Hypothesis: Incorporating the index and geometric anthropometric data, a population based Chinese knee model can be generated. Supplementing biomechanical analysis and manufacturing considerations, knee prosthesis can be designed according to the population average to archive better surgical outcome. Materials and Methods: CT images of 52 knees were included in this study for anthropometric measurements in a standard and repeatable protocol. There were two types of measurements, index measurements and geometric measurements. Index measurements included the length, depth and width of anatomy. Correlation analysis was performed to identify some key parameters and ratios from the measurement results. Detailed geometries of knees were measured to record the shapes of knees in curvatures and coordinates. Geometries of individual knees were integrated and analyzed for knee prosthesis design. Measurement parameters were selected according to literature review and industrial standards. Prosthesis was then designed according to the analyzed results. Biomechanical analysis was conducted to validate the proposed prosthesis design. A trial TKR surgery was operated in laboratory by replacing the condyles of cadaveric knees with the newly designed prosthesis. The compatibility of the prostheses and knees and the feasibility of surgery were verified. Results and Discussion: Comparing with other Asian knees, Chinese femoral medial-lateral dimension was found to be larger than those of the other Asian studies, while the femoral anteroposterior results were smaller than those of other Asian studies. Both the tibial anteroposterior and the tibial medial-lateral values of Chinese proximal tibias were comparable with those of other Asian studies. However, with an average proximal tibial aspect ratio of 1.47, Chinese proximal tibias were narrower than Caucasian ones. The reconstructed femoral condylar surface was compared with the femoral condylar surface in the original CT scanning data. The average root-mean-square point-to-surface distances of the reconstructed femoral condylar surface among all data was 1.1±0.18 mm which was comparable to other femur statistical shape modeling methods. Femoral component designed by this study was resulted with the highest accuracy among the three products as compared to Weigao Alpha Motion femoral component and Weigao Posterior stabilizing model. The bone resection volume of the current study was also less than that of the commercial group. The smallest amount of average resected bone volume was recorded from the current study which was smaller than the Alpha Motion series and the Weigao Posterior Stabilizing series. Comparing with literature, the stress distribution areas in the tibial plateau of our designed prosthesis was similar. The peak stress values in the tibial plateau of the current study was similar to those in the Zhi’s study but more than those in Zhang’s study. Comparing the static stress distribution of our design with normal knee, the stress distribution on the tibial insert was similar to that on the normal knee. The peak stress in the lateral and medial platform of the knee with our prosthesis model installed was about 10 MPa lower than those in the normal knee under all steps of compression force. That could be explained by the difference in the tibial plateau materials. (Abstract shortened by ProQuest.)