ABSTRACT
Objective To establish the three-dimensional (3D) finite element model of unicompartmental knee arthroplasty (UKA) with 3° and 7° posterior tibial slope at different knee flexion angles, and to study biomechanical properties and prosthetic wear of the knee joints with two types of posterior tibia slope and their effects on knee function. Methods Combining CT and MRI images of human knee joints with the 3rd-generation Oxford prosthesis, the finite element UKA model with 3° and 7° posterior tibia slope were established. The 1 kN load was applied to center point of the medial and lateral condyles of the femur to simulate the standing load of human body. The maximum stresses and distributions of the prosthesis and articular cartilage at different knee flexion angles were analyzed. ResultsThe maximum stress of the meniscus liner with 3° posterior tibia slope at 0°, 30°, 60°, 90°, 120° knee flexion angles increased by 28.06%, 68.99%, 19.45%, 21.06% and 53.38%, the distribution area was concentrated from the side of the meniscus liner to the central area, and the stress concentration was obvious at 120° knee flexion. The maximum stress of prosthesis with 3° posterior tibia slope was greater than that with 7 ° posterior tibia slope. The expansion of stress concentration area would cause wear and loosening of the prosthesis, contact stress and concentration area of the articular cartilage would subsequently increase with posterior tibia slope increasing, and stress concentration would be more obvious at high knee flexion angles. Conclusions Tibial prosthesis has the higher stress and greater wear under the condition of 3° posterior tibia slope than 7° posterior tibia slope. The research findings provide theoretical basis for the UKA design in clinic.
ABSTRACT
Objective: To summarize the methods of tibial prosthesis rotation alignment in total knee arthroplasty, and provide reference for clinicians to select and further study the methods of tibial prosthesis rotation alignment. Methods: The advantages and disadvantages of various tibial prosthesis rotation alignment methods were analyzed and summarized by referring to the relevant literature at home and abroad in recent years. Results: There are many methods for tibial prosthesis rotation alignment, including reference to relevant anatomical landmarks, range of motion (ROM) technique, computer-assisted navigation, and personalized osteotomy. The inner one-third of the tibial tuberosity is a more accurate reference anatomical landmark, but the obesity, severe knee deformity and dysplasia have impacts on the precise placement of the tibial prosthesis. ROM technique do not need to refer to the anatomical landmark of the tibia, and aren't affected by landmark variation. It can be used for severe knee valgus deformity and the landmarks that are difficult to identify. However, it may cause internal rotation of tibial prosthesis. Computer- assisted navigation and personalized osteotomy can achieve more accurate alignment in sagittal, coronal, and rotational alignment of femoral prosthesis. However, due to the lack of reliable anatomical landmarkers related to tibia fixation, it is still controversial whether it can help the alignment of tibial prosthesis rotation. Conclusion: The surgeon should master the methods of rotation and alignment of tibial prosthesis, make preoperative plans, select appropriate alignment methods for different patients, and achieve individualization. Meanwhile, several anatomical landmarkers should be referred to properly during the operation, which can be used to detect the correct placement of tibial prosthesis and avoid large rotation error.
ABSTRACT
PURPOSE: To provide the morphometric data about the Korean proximal tibia to design a total knee prosthesis for Korean population. MATERIALS AND METHODS: We measured morphologic data from the proximal part of the tibia from 60 knees of 30 male and 30 female cadavers. The 3D images were reconstructed from the data obtained by computed tomography scanning from femoral head to ankle joint. These image were processed as a ideal tibial resection surface which was made during a total knee arthroplasty operation. Then, antero-posterior lengths, medio-lateral lengths and aspect ratios of the cut surface were measured. Measurements were analyzed and compared with those of five popular total knee prosthesis models. RESULTS: The average medio-lateral length, lateral antero-posterior length, aspect ratio of male was 79.4 +/- 3.8 mm, 39.6 +/- 5.0 mm, 49.8 +/- 5.1% respectively. And that of female was 70.4 +/- 3.7 mm, 34.3 +/- 3.6 mm, 48.8 +/- 4.7% respectively. Component size of medio-lateral length of 65~85 mm and lateral antero-posterior length of 30~45 mm, would be required for the Korean population. Aspect ratios were correlated to antero-posterior lengths positively (p < 0.05). CONCLUSION: No prostheses had fulfilled all the requirements for Korean knees in this study. These data could be used for design the optimal components for Korean.
Subject(s)
Female , Humans , Male , Ankle Joint , Arthroplasty , Cadaver , Head , Knee Prosthesis , Knee , Korea , Prostheses and Implants , TibiaABSTRACT
PURPOSE: To provide the morphometric data about the Korean proximal tibia to design a total knee prosthesis for Korean population. MATERIALS AND METHODS: We measured morphologic data from the proximal part of the tibia from 60 knees of 30 male and 30 female cadavers. The 3D images were reconstructed from the data obtained by computed tomography scanning from femoral head to ankle joint. These image were processed as a ideal tibial resection surface which was made during a total knee arthroplasty operation. Then, antero-posterior lengths, medio-lateral lengths and aspect ratios of the cut surface were measured. Measurements were analyzed and compared with those of five popular total knee prosthesis models. RESULTS: The average medio-lateral length, lateral antero-posterior length, aspect ratio of male was 79.4 +/- 3.8 mm, 39.6 +/- 5.0 mm, 49.8 +/- 5.1% respectively. And that of female was 70.4 +/- 3.7 mm, 34.3 +/- 3.6 mm, 48.8 +/- 4.7% respectively. Component size of medio-lateral length of 65~85 mm and lateral antero-posterior length of 30~45 mm, would be required for the Korean population. Aspect ratios were correlated to antero-posterior lengths positively (p < 0.05). CONCLUSION: No prostheses had fulfilled all the requirements for Korean knees in this study. These data could be used for design the optimal components for Korean.
Subject(s)
Female , Humans , Male , Ankle Joint , Arthroplasty , Cadaver , Head , Knee Prosthesis , Knee , Korea , Prostheses and Implants , TibiaABSTRACT
OBJECTIVES: The purpose of this study is to provide the basic data for anatomy of proximal tibia by real measurement, to determine the morphologic fitness between the proximal tibia of Korean and the tibial prosthesis in total knee arthroplasty, and consequently to provide basic data for development of prosthesis that appropriate to Korean. MATERIALS AND METHODS: The anteroposterior length and mediolateral length of proximal tibia were measured for 173 knees of 117 patients who underwent total knee arthroplasty. Also, obtained data from intraoperative measure of proximal tibia were analysed according to patient's age, sex and disease. RESULTS: The results show that average mediolateral length of proximal tibia is 72.7 +/- 4.0mm, average anteroposterior length of medial plateau is 48.0 +/- 3.1mm, and average anteroposterior length of lateral plateau is 39.8 +/- 2.9mm. The mediolateral length of proximal tibia and the anteroposterior length of medial tibial plateau are significantly larger than tibial prosthesis designed by 5 different companies. The morphological differences according to disease entity are significantly larger in osteoarthritic patient group than in other disease entity. The significant difference according to patient's age is not found. CONCLUSION: The results of this study show the morphologic discrepancy between the proximal tibia of Korean and the tibial prostheses, and the development of design of tibial prosthesis for Korean should be considered.