Toshitaka Fujito1, Tetsuya Tomita1, Takaharu Yamazaki2, Kosaku Oda3, Hideki Yoshikawa4, Kazuomi Sugamoto1. 1. Department of Orthopaedic Biomaterial Science, Osaka University, Graduate School of Medicine, Suita, Osaka, Japan. 2. Department of Information Systems, Saitama Institute of Technology, Fukaya, Saitama, Japan. 3. Department of Orthopaedic Surgery, Takatsuki Red Cross Hospital, Takatsuki, Osaka, Japan. 4. Department of Orthopaedic Surgery, Osaka University, Graduate School of Medicine, Suita, Osaka, Japan.
Abstract
BACKGROUND: The purpose of this study was to investigate the influence of posterior tibial slope (PTS) on knee kinematics after cruciate-retaining total knee arthroplasty (CR-TKA). These influences were evaluated using a prosthesis designed with high geometric conformity to the medial articular surface under the weight-bearing condition of deep knee bending. METHODS: We evaluated 71 knees (52 patients) after CR-TKA using 2- to 3-dimensional registration techniques. All patients were categorized into 2 groups: group A (PTS ≤ 7°) and group B (PTS ≥ 8°). We compared in vivo knee kinematics during deep knee bending under weight-bearing conditions between the 2 groups. The anteroposterior position of the nearest points, flexion angles, and external rotation angles of the femoral components relative to the tibial components were evaluated. Additionally, the knee flexion angles of the femur relative to the tibia obtained from the installation angles of the components were evaluated. RESULTS: PTS did not affect the external rotation angles and anteroposterior position. The postoperative maximum flexion angle and range of motion between the femur and tibia in group B were significantly greater than those in group A. CONCLUSION: PTS of 8° or more in CR-TKA using prosthetics designed with high geometric conformity to the medial articular surface did not affect the anteroposterior position and external rotation, but increased the postoperative maximum flexion angle and range of motion.
BACKGROUND: The purpose of this study was to investigate the influence of posterior tibial slope (PTS) on knee kinematics after cruciate-retaining total knee arthroplasty (CR-TKA). These influences were evaluated using a prosthesis designed with high geometric conformity to the medial articular surface under the weight-bearing condition of deep knee bending. METHODS: We evaluated 71 knees (52 patients) after CR-TKA using 2- to 3-dimensional registration techniques. All patients were categorized into 2 groups: group A (PTS ≤ 7°) and group B (PTS ≥ 8°). We compared in vivo knee kinematics during deep knee bending under weight-bearing conditions between the 2 groups. The anteroposterior position of the nearest points, flexion angles, and external rotation angles of the femoral components relative to the tibial components were evaluated. Additionally, the knee flexion angles of the femur relative to the tibia obtained from the installation angles of the components were evaluated. RESULTS: PTS did not affect the external rotation angles and anteroposterior position. The postoperative maximum flexion angle and range of motion between the femur and tibia in group B were significantly greater than those in group A. CONCLUSION: PTS of 8° or more in CR-TKA using prosthetics designed with high geometric conformity to the medial articular surface did not affect the anteroposterior position and external rotation, but increased the postoperative maximum flexion angle and range of motion.
Authors: David Williams; Andrew Metcalfe; June Madete; Gemma Whatling; Peter Kempshall; Mark Forster; Kathleen Lyons; Cathy Holt Journal: J Biomech Date: 2020-09-11 Impact factor: 2.712