[Total hip replacement in psoriatic arthritis--raport of 4 cases].

Background: It is unusual for the hips to be affected by psoriatic arthritis. But in that rare cases, totalhip replacement (THR) is at present an accepted treatment in patients with severe and painfull deformity. The aim of this paper is to evaluate the results of THR in patients suffering from psoriatic arthritis of the hip, operated from 2000 to 2008 in the Orthopaedic and Traumatologic Department of Poznan University of Medical Sciences.

Material: Material included 4 patients, 2 females and 2 males, on whom 5 THRs were performed, lateral approach was used in all cases. At the time of operation, the age of patients ranged from 48 to 61 years (mean 53). Follow-up ranged from 2 to 10 years (mean 6 years). The operative treatment was a multistage process (during one operation only one joint was replaced). Cementeless total hip arthroplasty was used during all of the THRs.

Method: The patients were clinically and radiologically evaluated preoperatively, postoperatively, and at final examination. The clinical state was evaluated with Harris hip score and WOMAC scale. We based our radiological examination on Hip Society system.

Results: The average preoperative Harris score for the group of patients was 31, WOMAC score 77. After an average of 6 years follow-up all hips were considered excellent, with average Harris score of 90, WOMAC Score of 5. All patients had increased function and decreased pain. The radiograms of all patients revealed that the acetabular and femoral components were correctly positioned with no radiographic evidence of loosening in the last examination. The inclination angle of the acetabular component was 30-48 (mean: 39 degrees) and the acetabular opening angle was 3-20 degrees (mean: 4 degrees). The stem was neutral-oriented in all hips. No ectopic ossification concentrations were found.

Conclusion: The hip may be involved by the psoriatic arthritis. Clinical and radiological evaluation of our material showed that total hip replacement in the treatment of psoriatic arthritis allows regaining good lower limb function, which helps the patients staying less dependant on the surrounding environment. Ectopic ossification is not the clinical problem during THR in patients who suffer from psoriatic arthritis.