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Kinematics of three variations of the Freeman-Samuelson total knee prosthesis
Tuuli Saari1, Johan Uvehammer, Lars V Carlsson
1Department of Orthopaedics, Göteborg University, Sahlgrenska University Hospital, Göteborg, Sweden. tuuli.saari@swipnet.se
Clinical Orthopaedics and Related Research
|May 29, 2003
Summary
Different total knee replacement designs impact knee motion. A spherical medial condyle design improved anteroposterior stability but increased vertical motion, unlike the meniscal design which enhanced component congruency.
Area of Science:
- Orthopedic Surgery
- Biomechanical Engineering
- Medical Device Design
Background:
- Total knee replacement (TKR) aims to restore knee function.
- Articulating surface design significantly influences TKR kinematics.
- Understanding component interaction is crucial for optimizing TKR performance.
Purpose of the Study:
- To evaluate the effect of modified articulating surfaces on Freeman-Samuelson TKR kinematics.
- To compare the in-vivo motion of standard fixed-bearing, mobile-bearing, and spherical medial condyle fixed-bearing TKR designs.
- To assess the impact of design variations on component translation and rotation.
Main Methods:
- Radiostereometry and film-exchangers were used to track TKR component motion.
- Twenty-two patients (22 knees) were randomized into three TKR design groups.
- Kinematic data were collected during non-weightbearing and weightbearing knee extension.
Main Results:
- Mobile-bearing TKR showed a more anterior tibial tray position compared to fixed-bearing designs.
- The spherical medial condyle design stabilized anteroposterior motion.
- The spherical design exhibited greater medial proximodistal displacement during extension compared to standard and meniscal designs.
Conclusions:
- Component congruency, particularly in the meniscal design, reduced anteroposterior and proximodistal translations.
- The spherical medial condyle design offers anteroposterior stability but may introduce different motion patterns.
- Articulating surface geometry is a key determinant of TKR kinematics and stability.