抄録
In total hip arthroplasty (THA) in patients with rheumatoid arthritis (RA), major concerns includes low bone quality and the relatively young age of the patients. Taking into account the possibility of revision surgery in the future, preservation of bone stock is considered important. We have performed cementless THA using a bone preservation-type stem (BiCONTACT® stem) in patients with RA. The purpose of this study was to investigate the short-term clinical results of this procedure.
Eighteen hip joints in 14 RA patients, 2 males (3 joints) and 12 females (15 joints), with a follow-up of at least 2 years after surgery were retrospectively enrolled. The average age at surgery was 61.1 years old (range 35-76 years old), and the mean follow-up period was 4.1 years (range 2-5.3 years) . The hip rating score of the Japanese Orthopaedic Association (JOA score) and the existence of thigh pain were used for clinical evaluation. Radiographic evaluations included bone quality before surgery, classified using Engh's bone quality scale, subsidence of the femoral stem, existence of osteolysis around the stem, and the stability of the stem according to Engh's classification.
The mean JOA score before surgery was 32.1 points (range 18-54 points), improving to 74.3 points (62-100 points) at the time of follow-up. No patient complainted of thigh pain after surgery. Bone quality before surgery was good in 3 joints and poor in 15 joints.There was no case showing sinking or osteolysis postoperatively. As for the stability of the stem, bone ingrown fixation was obtained in all hip joints. Regarding postoperative complications, dislocation occurred in one hip joint six months after surgery. In that case no re-dislocation occurred after replacement of the inner head and polyeth-ylene. There was no case needing revision due to problems in the stem.
In spite of the short follow-up period (average: 4.1 years), the clinical results of the cementless THA using the bone preservation-type stem (BiCONTACT ®stem) were good.
