UNIVERSAL PROXIMAL FEMORAL ENDOPROSTHESIS - SHORT-TERM COMPARISON WITH CONVENTIONAL HEMIARTHROPLASTY

The recognized problems of pain, acetabular wear, and protrusio acetabuli that may accompany conventional hemiarthroplasty of the hip have promoted the development of a family of new implants. These have in common the interposition of an inner prosthetic bearing intended to reduce the effects of frictional wear on acetabular cartilage. The authors compared 101 Bateman hemiarthroplasties of the hip with 160 cemented Thompson hemiarthroplasties with respect to complications and short-term results. No differences were found in operative time; blood requirements; length of hospitalization; rates of infection, dislocation, or mortality; or over-all morbidity. While dislocations occurred with no greater frequency in the Bateman group, five of nine dislocations could not be successfully treated by closed reduction, whereas all dislocations of Thompson hemiarthroplasties were reduced by closed means. Ten patients with a Bateman implant and ten with a Thompson device for fractures of the femoral neck were examined an average of 3.0 and 3.4 years postoperatively, respectively. The difference in the mean Harris hip-rating score for the two groups (77.5 versus 76.4) was not statistically significant and probably resulted from the differences in their mean ages (74.4 and 81.1 years, respectively). Thirteen Bateman arthroplasties in nine patients were performed for osteonecrosis of the femoral head following renal transplantation in patients with a mean age of 29.0 years. These were studied at yearly intervals postoperatively to determine the amount of and changes in sagittal-axis motion of the inner and outer bearing surfaces. Although some inner bearing motion did occur in most implants, it was less than predicted and in several cases it decreased even more between two and four years postoperatively and under conditions of weight-bearing. The mean Harris hip-rating score for this group of patients after 3.4 years was 93.0, however. The ultimate relationship between inner bearing motion and the development of pain and protrusio acetabuli is not yet known.