Background Hip joints are important for daily like activities, which become limited when destruction occurs. Joint destruction caused by rheumatoid arthritis (RA) can be limited by administration of a biological drug, thus it is considered that the number of surgeries for affected patients will decrease in the future, with some recent reports noting that the number of total hip arthroplasty (THA) procedures for RA patients is decreasing. Bone destruction inhibition by use of methotrexate (MTX) and biological drugs has been suggested. However, few studies have investigated whether hip joint destruction in RA patients was altered by treatment with such new drugs.

Objectives The purpose of this study was to examine whether the number of RA cases in Japan has shown a decreasing trend. We investigated the records of all patients who underwent THA at our institution during the most recent 12-year period including preoperative X-rays to determine any difference in tendency for hip joint destruction.

Methods We investigated all patients with RA who underwent a THA procedure at our hospital from January 2000 through December 2011 and noted the number of THA cases each year, age at surgery, duration of RA, and medication administered. In addition, 2 investigators independently evaluated pre-operative X-ray findings using the Larsen classification (1) to determine whether the number of severe cases (Larsen grade 5) of hip joint destruction decreased during the study period.

Results The total number of primary THA procedures was 561, while RA was diagnosed in 54 patients (9.6%). That latter value showed a decreasing tendency, as 31 of the 54 cases occurred from 2000 to 2005 and 23 from 2006 to 2011, a decrease of approximately 30%. There were few changes in patient background in regard to age at surgery and duration of RA. The rate of steroid use decreased from 80.6% to 65.2%, whereas the rate of MTX rate use increased from 41.9% in the first 6 years of the study to 65.2% in the final 6 years. Furthermore, the rate of biological drug use increased from 0% to 30.4%. Cases classified as Larsen grade 5 by X-ray evaluation decreased to only a single case in the final half from 7 cases in the first half.

Conclusions The number of patients who underwent THA for RA was decreased and patient backgrounds were also changed. Preoperative X-ray evaluations showed that cases of severe joint destruction in particular were remarkably decreased.

1. Larsen A, et al. Radiographic evaluation of rheumatoid arthritis and related conditions by standard reference films. Acta Radiol Diagn 1977;18:481-91.

Disclosure of Interest None Declared