In the First Department of Orthopaedics of St. Anna University Hospital in Brno, Czech Republic, a total number of 9,393 total hip replacements (THR) were performed from 1964 to 2000. Since 1986, the cementless technique has been used primarily for young patients suffering from late DDH. Within the last ten years we have implanted 5,574 THRs, including 440 cementless systems and 2,122 hybrid THRs.

We focused on cases of patients with late DDH where dysplastic acetabulum was found and where the smallest available cementless CLS acetabular cup was implanted through the anterolateral approach.

We present five to seven years follow-up of 41 hips with dysplastic acetabulum that was evaluated by coxometry and where the expansion acetabular cup of diameter 46 mm was implanted together with different types of femoral stems.

After five to seven years no significant aseptic loosening has been found. None of the Harris grafts of the superior acetabulum used in 10 (24.4%) implantations have failed. We have had good medium-term results with this type of cementless acetabular cup. A few case reports from our earlier history include acetabular components under 40 mm in diameter, or intercalar shortening osteotomy of the proximal femur due to the high post-dysplastic dislocation of the hip combined with implantation of a THR.