Surface replacement of the hip in chronic arthritis. A clinical, radiographic and roentgen stereophotogrammetric evaluation.

Surface replacement of the hip was performed on nine patients (11 hips) with chronic arthritis. The results were evaluated twice clinically, as well as by radiography and roentgen stereophotogrammetry, an average of 15 and 23 months postoperatively. The early clinical results were promising. One or both of the components were loose in five hips and the acetabular socket had migrated in one hip, as revealed by the radiograms. Roentgen stereophotogrammetry revealed loosening in one hip and migration of one or both of the components in eight hips altogether. The radiograms gave the information needed in the daily routine but roentgen stereophotogrammetry gave more accurate information about early migration. At the third clinical follow-up, an average of 35 months postoperatively, two hips had been reoperated on and two had developed pain.