Prevalence of nail involvement in nodal osteoarthritis.

The presence of nail changes was investigated in 102 patients with nodal osteoarthritis of the hand. Nail lesions were seen in 14/102 patients (13.7%), a prevalence higher than that observed in 96 controls (4/96, 4.2%; chi square 4.37, p = 0.036). An increased risk of nail changes was associated with osteoarthritis of the hand (odds ratio = 3.7, 95% CI 1.13 to 11.8). Longitudinal lines were the most frequent nail alteration and accounted for 10/14 of the observed lesions. Nail involvement was associated with long-lasting symptoms related to osteoarthritis and high serum iron concentration. This complication of osteoarthritis is not as rare as might appear from the literature, and its pathogenesis remains to be investigated.