Incidence and risk factors of prosthetic joint infection after total hip or knee replacement in patients with rheumatoid arthritis.

OBJECTIVE: Prosthetic joint infection is one of the most dreaded complications after total joint arthroplasty, a common procedure in patients with rheumatoid arthritis (RA). We conducted a study to evaluate potential risk factors of prosthetic joint infection and to clarify if RA is an independent predictor of this complication. METHODS: This study included all patients with RA who underwent total hip or knee replacement at the Mayo Clinic Rochester between January 1996 and June 2004. The association of potential risk factors with prosthetic joint infection was examined using Cox models. A matched cohort of patients with osteoarthritis (OA) was assembled to determine whether RA is an independent risk factor for prosthetic joint infection. RESULTS: We identified 462 patients with RA who underwent a total of 657 hip or knee replacements. Overall, 23 (3.7%) joint arthroplasties were complicated by an infection during a mean +/- SD followup of 4.3 +/- 2.4 years. Revision arthroplasty (hazard ratio [HR] 2.99, 95% confidence interval [95% CI] 1.02-8.75) and a previous prosthetic joint infection of the replaced joint (HR 5.49, 95% CI 1.87-16.14) were significant predictors of postoperative prosthetic joint infection. Comparison of RA patients with a matched cohort of OA patients identified an increased risk of prosthetic joint infections (HR 4.08, 95% CI 1.35-12.33) in patients with RA. CONCLUSION: Patients with RA who undergo total hip or knee replacement are at increased risk of prosthetic joint infection, which is further increased in the setting of revision arthroplasty and a previous prosthetic joint infection. These findings highlight the importance of perioperative prophylactic measures and vigilance during the postoperative period.

Hearing loss in rheumatoid arthritis.

OBJECTIVE: The objective of this study was to evaluate whether patients with rheumatoid arthritis (RA) are more likely to have subclinical hearing loss compared with persons without RA. METHODS: This is a case-control cross-sectional study of 29 patients with RA with disease duration greater than 5 years. Five males and five females were recruited into each decade category (age 40-49, 50-59, and 60-69). These cases were matched in a 1:1 ratio by sex and age to 30 control subjects. A comprehensive set of audiometric and disease severity assessments were performed. RESULTS: Seventeen (59%) of 29 patients with RA had abnormal hearing for at least one frequency (four in one ear, 13 in two ears) by audiometry as did 14 (47%) of 30 control subjects (five in one ear, nine in two ears). The percentage of patients with hearing loss (% RA vs. % control subjects) was: 45% versus 40% sensorineural, 10% versus 7% conductive, and 3% versus 0% mixed hearing loss. In RA versus control subjects, acoustic reflex threshold was abnormal in 17% versus 7%; speech reception threshold was abnormal in 10% versus 3%. Tympanometry and otoacoustic emission findings were similar in both groups. Word recognition did not differ between patients with RA and control subjects. In patients with RA/control subjects, hearing handicap, dizziness, and health assessment questionnaires were abnormal in 28%/7%, 14%/3%, and 72%/7%, respectively. CONCLUSION: There was no difference found in objective audiometric measurements in patients with RA compared with non-RA control subjects. Subjectively patients with RA were more likely to perceive themselves as having hearing disturbances, which may be related to overall disease related functional impairment.

Natural history of thromboembolism in AL amyloidosis.

To determine the natural history of thromboembolism in patients with biopsy-proven AL amyloidosis, medical records of 2,132 patients evaluated at Mayo Clinic between 1975 and 2000 were reviewed. Forty patients (21 male) were found to have objectively documented thromboembolism. The median age was 65 years. Four patients had a monoclonal gammopathy of undetermined significance, 20 had an unspecified plasma cell proliferative disorder, 11 had multiple myeloma, and 1 had Waldenström macroglobulinemia. Twelve patients had cardiac amyloid, and 20 had renal amyloid. Neither the extent of the amyloid nor the type of monoclonal protein was predictive of the development of thromboembolic events. Thromboembolism preceded the diagnosis of AL amyloidosis in 11 patients, occurred at the time of diagnosis or within 1 month after diagnosis in 11 patients, and occurred 1 month or more after diagnosis in 18 patients. Twenty-nine patients (73%) had venous thrombosis and 11 (28%) had arterial thrombosis. Eight patients (20%) died within 1 month after the thrombotic event, and 18 (45%) died within 1 year. The development of thrombosis in patients with AL amyloidosis appears to predict significant mortality within the first month and year after the event.