preservation of the both cruciate ligaments.19 In 1973, Marmor designed a modular knee for unicompartment & bicompartment replacement .20
The Total Condylar Prosthesis (TCP) designed by Insall and others, its introduction in 1973 marked the beginning of the modern era of total knee arthroplasty. (Fig. 20) This prosthesis design allowed mechanical considerations to outweigh the desire to reproduce anatomically the kinematics of normal knee motion.
Influenced largely by the previous ICLH (Imperial College London Hospital) design, both cruciate ligaments were sacrificed, with sagittal plane stability maintained by the articular surface geometry. The original cemented total condylar prosthesis dramatically reset the standard for survivorship…show more content… Originally, the medial and lateral tibial plateau components were separate, but this was soon revised to a one-piece tibial component with a cutout for PCL retention. (Fig. 21)
The duopatellar prosthesis evolved into the kinematic prosthesis, which was widely used in the 1980’s. 22
In view of short comings of the Total Condylar Prosthesis (TCP) in terms of tendency to subluxate posteriorly and inability of the prosthesis for “rolling back” mechanism, the Install- Burstein posterior cruciate substituting or posterior stabilized design was developed in 1978 by adding a central cam mechanism to the articular surface geometry of the TCP.23 (Fig. 22)
Newer designs incorporate greater areas of patellofemoral contact through a larger range of motion and asymmetrical anterior flanges designed to resist patellar subluxation.
Laskin et al. Compared deep-dish components with posterior-stabilized devices using the same femoral components and concluded that there was no difference at follow-up in range of motion, pain scores and ability to climb or descend stairs. They concluded that posterior impingement in flexion was avoided by proper flexion-extension gap balancing, resulting similar knee flexion to the posterior- stabilized…show more content… (Fig. 27) Compared to TKA, unicompartmental arthroplasty results in better knee joint with quicker rehabilitation time and greater range of motion.
Revision of UKA to tricompartmental prostheses, requires special components, bone grafting or cement with screw augmentation to fill osseous defects, was necessary in 76% of patients reported by Padgett, Stern, and Insall.30 and in 45% reported by Scot RD and Cobb AG.31
They concluded that the revision of UKA to TKA were simpler than typical revision TKA because of lessen incidence of significant bony defects at the time of revision.31 HINGED IMPLANTS
In Kinematic Rotating Hinge prosthesis, two polyethylene and cobalt chrome bearings allow flexion-extension and axial rotation. (Fig. 28)
Rand, Chao, and Stauffer reported that there was no significant difference between Kinematic Rotating Hinge and the earlier GUEPAR prosthesis with respect to infection, loosening and patellar
