From 5.1989 to 12.1992, the Walter-Motorlet cementless hip endoprosthesis provided with "Arbond" hydroxyapatite coating was clinically tested. This femoral component was applied to 34 patients, among those 26 women and 8 men having the average age of 42 years (range 24-82 years). We compared the results with a control group of patients constituted of 20 men and 49 women on average 48.3 years of age, in which the same type of endoprosthesis was used, but without hydroxyapatite coating. Both groups were evaluated by the same surgeons according to the usual international standards (ALLOPRO CHART). The substantially higher quality of the osteointegration of the hydroxypatite implants especially where primary osseous fixation is not quite stable and thus not perfect is undoubtedly evident from this study.