Abstract
During 7.5 years from Jan. 1976 to Jun. 1983, 23 patients of medial fractures of the femoral neck and necrosis of the femoral head were operated by the femoral neck prosthetic replacement, 12 patients were fracture type and the others were necrosis type. Dual bearing type Bateman (Bateman type) and Bi-centric endoprosthesis system (Bi-centric type) were used and post-operative R. O. M. and cup varus degrees were studied.
An average mark of post operative score of coxarthrosis by Japanese Orthopaedic Association were determined. Cases using Bateman type showed cup varus 45.6° in the average, in Bi-centric type was larger than the Bateman type, 63.0° in the average. But R. O. M. of Bi-centric type was not so bad.
Difference of varus angle of cup between these two types might present some minor problems in future. From our experience, cases over 45 varus degree gained better R. O. M. of hip joint comparing with cases below 45°.
