Destruction of the first carpometacarpal joint behaves differently from that of the entire carpus in rheumatoid arthritis. A 20-year follow-up study

The links between joint damage and disability in rheumatoid arthritis

OBJECTIVE

The characteristic joint damage and disability of rheumatoid arthritis (RA) increase slowly over 10-20 yr. Although it is generally believed that persisting inflammatory synovitis causes joint damage and subsequent disability, the strength of their relationship has not been systematically evaluated. This review describes their progression and interrelationship in treated RA.

METHODS

MEDLINE and Current Contents databases were searched for the combined terms of rheumatoid arthritis AND X-rays, Health Assessment Questionnaire, slow-acting anti-rheumatic drugs and all identifiable synonyms. This search identified 1303 articles and from these we evaluated in detail 23 reports on the progression of joint damage, 12 reports on the progression of disability and 25 reports dealing with their interrelationship. Additional information was obtained from four data sets comprising 725 RA patients studied cross-sectionally and 33-126 cases followed prospectively for 1-5 yr. X-ray damage was primarily assessed by Larsen and Sharp indices, and disability by the Health Assessment Questionnaire (HAQ).

RESULTS

Joint damage and disability both increase throughout the duration of RA. Although disability (HAQ score) is correlated with disease duration (correlation coefficients between 0.27 and 0.30), the link between X-ray damage and disability is stronger (correlation coefficients between 0.30 and 0.70). In the earliest phases of RA, X-ray damage and HAQ scores are not related. By 5-8 yr, there are significant correlations with correlation coefficients between 0.30 and 0.50. In late RA (>8 yr), most studies show highly significant correlations between 0.30 and 0.70.

CONCLUSIONS

Joint damage progresses constantly over the first 20 yr of RA. It accounts for approximately 25% of disability in established RA. The link between damage and disability is strongest in late (>8 yr) RA. However, avoiding or reducing joint damage in both early and established/late RA is likely to maintain function.

When does subluxation of the first carpometacarpal joint cause swan-neck deformity of the thumb in rheumatoid arthritis: a 20-year follow-up study

The aim of our study was to assess the incidence of subluxation of the first carpometacarpal joint (CMC I) and to evaluate which degree of subluxation produces swan-neck deformity of the thumb in rheumatoid arthritis (RA) occurring over 20 years. The hands of 83 rheumatoid factor (RF)-positive RA patients with recent (< or = 6 months) arthritis were evaluated radiographically at onset and at 1, 3, 8 and 15 years; 68 patients were evaluated at 20 years from entry. Subluxation was assessed in millimetres and compared with the MCP-I angle measurement to evaluate the thumb deformity. A statistical end-point analysis was performed between two different grades of subluxation. Subluxation of 2-3 mm was non-specific and only one third of these thumbs showed swan-neck deformity. At the end-point, subluxation of > or = 4mm was present in 17% of the thumbs, 81% of which had the swan-neck deformity; only five thumbs did not show this deformity, but presented deformed and unstable MCP I and interphalangeal joints. The frequency of swan-neck deformity was highly significantly (p < 0.0001) increased in the thumbs with severe CMC I subluxation (> or = 4 mm) compared with lesser subluxation (< 4 mm). When subluxation of the CMC I exceeds 4 mm, the swan-neck deformity of the thumb is a common consequence. This deformity is often progressive, and the hand function of such patients should be followed up carefully, both clinically and radiographically.