[Post-traumatic psoriatic arthritis. 2 cases].

Physical trauma is generally accepted as a possible factor in the pathogenesis of rheumatoid arthritis. In the last ten years, there have been a few rare case reports of physical trauma precipitating psoriasic arthritis. We observed two such cases following an occupational accident discovered one and a half year and two and a half year after onset of the first clinical manifestations. In the first case, a 43-year-old man had a fracture of the right calcaneus in March 1991. He was treated with nailing and also required emergency surgery of the posterior tibial artery. The tibiotarsal joint was normal radiologically. Pain persisted after treatment and in 1993 he presented with psoriasis of the scalp and several other localizations together with Hallopeau's acrodermatitis continua of the ankle, pathognomonic for psoriasic arthritis. Salazosufapyridin was given. The second case was a 50-year-old man who had major pain in both wrists immediately after falling on the palm of his hands in 1992. Bilateral carpal tunnel syndrome developed which did not respond well to surgery. In 1993, he developed inflammatory synovitis and also had psoriasis mainly located at the elbows. Immunological tests were negative. Cortisone and salazosulfapyridin were not particularly effective and the patient later developed arthritis of the hip and ankle joints. Physicians should be aware of physical trauma as a causative factor in psoriasic arthritis due to the potential legal implications. Criteria for imputability are: single major physical trauma, absence of clinical signs prior to the trauma, continuous clinical course, first signs occurring then predominating at the joint exposed to trauma. The pathophysiology of this type of arthritis is not well understood. Deep Koebner's phenomena could be involved. Activation of substance P has also been hypothesized.