[Roentgenological follow-up of Lord-type cementless total hip arthroplasty].

The Lord-type cementless total hip arthroplasty has been employed for 240 hips involving 205 patients from 1979 to 1993. During this period, the following four types of prostheses were used incorporating the design changes suggested by Lord: Madréporique, Mark II, Polarisée and L. F. R. Postoperative roentgenological analysis was performed on 172 hips followed up for longer than one year. The Kaplan-Meier survivorship rating method was used for the assessment. With respect to the femoral component, intramedullary bone formation and cortical hypertrophy occurred mainly at zones 3, 4 and/or 5 (in 20%), while focal osteolysis occurred at zones 1 and 7 (2-6%). This was attributed to stress shielding in the long straight Lord stem. Radiolucent line around the femoral component (zone 1 through 7) was seen in 13 hips (7.6%), 8 of which showed definite subsidence and, consequently, 7 of these were revised. The five-and ten-year roentgenological survivorships of the Madréporique type stem were 100% and 92.8%, respectively. With respect to the acetabular component, a radiolucent line around the ring (zone I through III) was observed in 32 hips, 28 of which showed definite migration after two to nine-and-a-half years (average five years and nine months), for which 15 hips required revision. The five-and ten-year roentgenological survivorships of the acetabular component were 95.3% and 83.7%, respectively. The selection of a cemented rather than a cementless total hip arthroplasty has continued to be a subject of debate till the present. In our 14 year of experience using the Lord-type cementless prostheses, the Madréporique stem yielded satisfactory results, but the screw-in type ring acetabular component could be improved.