St. Georg knee endoprosthesis system (slide and hinge principle). Observations and results following 10 years' experience with over 3,700 operations

Some 2000 total knee endoprostheses were inserted from 1970-1978 and about 1700 of these have been followed two different types of knee replacement were used, a surface replacement of a non-constrained design and a total hinge prosthesis. Serious complications, such as infection, loosening and fracture of the components were regarded as significant determinants in the evaluation of the durability of total and partial knee replacement. The highest and lowest incidence of complication were recorded. The longevity of knee arthroplasty and the survival rates were estimated by constructing survivorship tables. Patients with knee replacement having no complications were designated "survivals" while patients with an established complication were treated as "deaths". The success rates of total hinge prosthesis were compared with those of the sledge prosthesis. Failure rates of aseptic complications were assessed and compared with failure rates due to septic complications. A differentiation was also made between the sledge prosthesis and the total hinge prosthesis. Furthermore, significant differences in the indication for the insertion of the sledge or the total hinge were determined by group assessment (log-rank-test). Unlike the general trend to use a semiconstrained knee replacement the evaluation of this clinical trial has induced us to improve our hitherto used total knee prosthesis model rather than to develop a new surface replacement.