Failed Christiansen total hip arthroplasty. A radiographic and histologic study

Twenty-two consecutive cases of the Christiansen total hip arthroplasty revised because of aseptic loosening were analyzed with regard to radiographic changes and operative and histopathologic findings. This prosthesis was designed with a socket and a trunnion sleeve made of polyoxymethylene or Delrin. In 18 cases there was isolated socket loosening, in all cases there was obvious bone resorption beneath the collar of the stem, and in 20 cases the socket had migrated. The radiographic socket wear rate averaged 0.4 mm/year. In 18 cases a significant amount of debris material was found in the joint cavity. Light microscopy revealed a severe foreign body reaction with numerous plastic particles, most often engulfed by macrophages. Taken together, these findings indicate that socket wear leading to a foreign body reaction with bone resorption is the main cause of the poor results noted with this particular total hip prosthesis.