Geometric knee

The evolutionary step from the Polycentric knee to bicondyiar knee arthroplasty is perhaps best appreciated in the "Geometric" knee design, developed by a group of five surgeons at the Mayo Clinic and clinically introduced in April 1971 (Skolnick et al. 1976). The design was marketed imder the Geomedic... 

Although the two components of Geometric knee were somewhat easier to implant than the four components of the Polycentric knee, long-term fixation... 

Knee arthroplasty designs from the 1970s. (A) Modified geometric (B) Townley (C) Leeds (D) Total Condylar (E) Charnley load-angle inlay (F) Freeman-Swanson (G) Marmor modular. (Reprinted with permission from Walker RS. 1977. Human joints and their artificial replacements. Springfield, IL CC Thomas Publisher.)... 

Jones W.T., R.S. Bryan, L.F. Peterson, and D.M. Ilstrup. 1981. Unicompartmental knee arthroplasty using polycentric and geometric hemicomponents. / Bone Joint Surg 63 946-954. 

Rand J.A., and M.B. Coventry. 1988. Ten-year evaluation of geometric total knee arthroplasty. Clin Orthop 232 168-173. 

Rigid geometric registration between a surface model obtained from preoperative CT and intraoperative surface data on the same anatomy obtained by touching landmarks or collecting sample points with a tracker. This method is widely used in CIS orthopedic systems, such as pedicle screw fixation, total hip and knee replacement, and trauma. 

Torres-Morenos, R., Solomonidis, S.E. and Jones, D. (1992) Geometric and mechanical characteristics of the above-knee residual limb. Proc. 7th. World Cong. Int. Soc. Prosthetics Orthotics, pp. 149. 

Co-Cr-Mo + UHMWPE (Geometric) 0.3 mg/105 cycles NA Knee Joint simulator 700 lb peak load Velocity = 33 cycles/min Duration = 10 cycles Lub double spun bovine serum Creep and fatigue cracks evident. Rose et al (1984)... 

Jones WT, Bryan RS, Peterson LF, Ilstrup DM. Unicompartmental knee arthroplasty using polycentric and geometric hemicomponents. 

Wilson DR, O Connor JJ (1997) A three-dimensional geometric model of the knee for the study of joint forces in gait. Gait Posture, 5,pp. 108-115. 

For simple geometric shapes, one can obtain each dimension separately by fitting Eq. (6.15) to the I q) curve where each knee is observed. In these cases, one obtains a value of / g and must use the appropriate relationship to obtain the actual dimension of the inhomogeneity [1, 3]. Therefore, the Guinier approximation can be used to determine the volume parameters of a dilute scattering inhomogeneity. 

C. H. Cho, T. Murakami, Y. Sawae, N. Sakai, H. Miura, T. Kawano, and Y. Iwamoto. Elasto-plastic contact analysis of an ultra-high molecular weight polyethylene tibial component based on geometrical measurement from a retrieved knee prosthesis. Proceedings of the Institution of Mechanical Engineers, Part H Journal of Engineering in Medicine, 218 (4), 251-259 (2004). 

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