THE RICHARDS-SERIES-2 TOTAL HIP-PROSTHESIS - A 13-YEAR STUDY AND RADIOGRAPHIC EVALUATION

This retrospective long-term study analyzes the clinical function, fai lures, and radiographic status of 131 Richards Series 2 prostheses in total hip arthroplasties (THAs) performed during 1981 and 1982. After a minimum follow-up period of 11 years, the results were evaluated. Si xty two (54%) patients with 71 THAs were available for follow-up; 44 ( 38%) patients with 49 THAs had died. Three patients with three THAs we re lost to follow-up, and seven patients with eight THAs were unable t o participate in the examination due to causes not related to their pr esent hip status. Ten patients underwent revision THA during the obser vation period. The median hip functional index (HFI) was 8.6 preoperat ively and 15.8 at follow-up. Hip functional index correlated to radiog raphic signs of loosening. With revision as endpoint, the Kaplan-Meier survivorship for all 131 hips was 93% after 10 years and 91% after 12 years. The radiographic examination at follow-up revealed 5 (8%) defi nite loose cups and 12(19%) definite loose stems. Including the number of aseptic loosened cups and stems confirmed at revision, aseptic loo sening was found in 6% of all cups and 13% of all stems. This radiogra phic evaluation confirmed that lack of containment of the cup and varu s position of the stem were factors influencing the long-term stabilit y of the prostheses, whereas etiology, type of arthritis, and ectopic ossification did not. A fixation and stability score that was modified for cemented prostheses was developed and was of value in detecting t he prostheses at risk. The long-term results of the Richards Series 2 THA are acceptable and comparable with other longterm studies on conve ntional prosthestic designs. Ten percent to 20% revision THAs due to a septic loosening can be expected. In addition, patients younger than a ge 60 at surgery and especially men were found to belong to a high-ris k group with regard to revision THA. These patients must be evaluated carefully so that revision THA can be performed before the bone bed is destroyed.