Background Some recent reports indicate that the number of total hip arthroplasty (THA) procedures for RA patients worldwide has been decreasing in recent years. Bone destruction inhibition by use of methotrexate (MTX) and biological drugs has been suggested as a possible reason. 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 requiring THA has shown a decreasing trend, and to identify any reason for a change.
Methods We investigated the records of all patients with RA who underwent a THA procedure at our hospital from January 2000 through December 2014. All cases were sorted by date into 3 groups: the first 5 years (from 2000 to 2004), the middle 5 years (from 2005 to 2009), and the final 5 years (from 2010 to 2015). We noted the number of THA cases each year, age at surgery, duration of RA, and medications administered. In addition, 2 investigators independently evaluated pre-operative X-ray findings using the Larsen classification1 to determine whether the number of severe cases (Larsen grade 5) of hip joint destruction changed during the study period.
Results In the 15 year period there were 786 primary THA cases in our hospital, of which 67 (8.5%) were RA cases. The number of THA showed a decreasing tendency, as 29 cases occurred from 2000 to 2005 and 19 from 2009 to 2014, a decrease of approximately 30%. There was little change in patient background in regard to age at surgery and duration of RA. The rate of steroid use decreased from 82.8% to 57.9%, whereas the rate of MTX use increased from 31.0% in the first 5 years to 73.7% in the final 5 years. Furthermore, the rate of biological drug use increased from 0% in the first 5 years to 31.6% in the final 5 years. Cases classified as Larsen grade 5 (Figure 1a) by X-ray evaluation decreased to only two cases in the middle 5 years and a single case in the final 5 years from 8 cases in the first 5 years (Figure 1b).
Conclusions The number of patients who underwent THA for RA was decreased and the patient medications administered were also changed. Preoperative X-ray evaluations showed that cases of severe joint destruction (Larsen grade 5) were remarkably decreased. We consider that bone destruction of hip joint can be inhibited by use of MTX and biological drugs.
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