Study of 500 patients with limb joint osteoarthritis. I. Analysis by age, sex, and distribution of symptomatic joint sites.

Five hundred subjects with symptomatic limb joint osteoarthritis, who had been referred to a rheumatologist, were enrolled into a continuing study. They comprised 342 women (mean age 65.3) and 158 men (mean age 59.7), with a mean symptom duration of 15.4 years at entry. Only 31 patients (6%) had symptomatic osteoarthritis of one joint alone; however, in a further 205 (41%) the disease was limited to one site. One hundred and eighty two (36.4%) had two sites affected and 82 (16.4%) three or more sites of symptomatic osteoarthritis. Of 847 affected joints the most commonly involved were 349 (41.2%) knees, 254 (30%) hands, and 161 (19%) hips. Hip disease stood out as a separate entity, often occurring alone, and having a stronger male preponderance and different associations than osteoarthritis at other joint sites. Knee and hand disease were significantly associated in women. Obesity, hypertension, and Heberden's nodes were common. The number of sites affected, as well as the distribution, was strongly related to age as well as sex, suggesting that polyarticular osteoarthritis arises from slow acquisition of new joint sites in a non-random distribution. 'Generalised' osteoarthritis did not emerge as a distinct entity.