Purpose: The purpose of this study is to report 13 cases and review the literature for pyarthrosis occurring in the setting of rheumatoid arthritis (RA). Special emphasis is placed on evaluating both the changing, as well as the constant, features of this complication and on assessing diagnostic and therapeutic aspects that have a bearing upon outcome.
Patients and methods: A retrospective review of records from our institution revealed 13 cases of pyarthrosis in patients with RA over the past 14 years. Information obtained included patient demographics, RA history, concomitant illnesses and medications, length of symptoms prior to the diagnosis of pyarthrosis, peri-articular manifestations, probable source of infection, joint(s) involved, relevant laboratory data, and information on treatment and outcome based on initial surgical therapy versus closed needle drainage. In addition, 213 cases from 45 citations were reviewed for similar information.
Results: Our series was notable for a high percentage of associated serious medical illnesses and peri-articular manifestations of the pyarthrosis (i.e., sinus tract formation, concomitant septic bursitis, or infected synovial cyst). The erythrocyte sedimentation rate was a useful monitor of adequate therapy and was often a signal of recurrent infection. In all patients, the skin was the major source of infection. The mortality from pyarthrosis has declined over the past 40 years but is still unacceptably high, especially in patients with polyarticular involvement. Preliminary observations suggest that an initial surgical approach to joint drainage may be preferable to closed needle drainage in order to improve joint outcome in patients with RA and pyarthrosis.
Conclusion: Pyarthrosis occurring in patients with RA continues to produce unacceptable morbidity and mortality despite 40 years' experience. Earlier recognition (which may include peri-articular features) and perhaps an aggressive surgical approach to drainage may improve the prognosis.