Late results in 243 arthroplasties with an acrylic prosthesis for traumatic or osteoarthritic conditions are reported.

Early results (after one year) show the importance of the restoration of the normal mechanics of the hip joint by the preservation or the restoration of normal length of the femoral neck, the exact correction of anteversion, and the precise fit of the prosthetic head to the acetabulum. A good exposure of the joint through the posterolateral approach appears necessary in order to fulfill these conditions.

Late results (from two to five years) show deterioration of the functional results in 20 per cent. These deteriorations appear to be caused by bone absorption around the Judet prosthesis and the consequent loosening of the prosthesis.

A new type of cervico-capital prosthesis is proposed which makes possible:

1. Restoration of the normal length of the femoral neck when it is congenitally or pathologically short;

2. Correction of anteversion, even when very marked;

3. A weight-bearing surface on a more vascularised part of the femur;

4. The distribution of pressure on bone so as to lessen bone absorption, to prevent its ill effects, and, particularly, to decrease mobility of the prosthesis.