EARLY FAILURE OF ACETABULAR COMPONENTS INSERTED WITHOUT CEMENT AFTER PREVIOUS PELVIC IRRADIATION

The effect of previous irradiation of the pelvis on the survival of ac etabular components inserted without cement in primary total hip arthr oplasty was examined, We searched a database of 1319 patients who had been managed with a primary total hip arthroplasty with insertion of a hemispherical porous-coated acetabular component without cement, This revealed twelve hips in eleven patients who had been managed with pre vious irradiation of the pelvis, Three patients had died after less th an one year of follow-up, leaving eight patients with nine acetabular components available for study at an average of thirty-seven months (r ange, seventeen to seventy-eight months) after the operation, The type of radiation as well as the fractionation, dose, and portals were rev iewed to determine the exposure of the periacetabular region to radiat ion, Failure of the component was assessed radiographically and clinic ally. At the time of follow-up, three of the nine acetabular component s had migrated, as seen on radiographs, and had been associated with c linical symptoms; two had been revised. One additional component was a ssociated with progressive radiolucency without clinical symptoms, Thu s, four of the nine acetabular components failed, at an average of twe nty-five months (range, sixteen to thirty-eight months). The other fiv e components had not failed clinically and were stable radiographicall y at an average of thirty-six months (range, seventeen to sixty-three months). The insertion of acetabular components without cement in a pr eviously irradiated pelvis has a high rate of failure, However, a supe rior method of acetabular reconstruction in this difficult situation h as yet to emerge.