Recurrent knee arthritis diagnosed as juvenile idiopathic arthritis with a 10-year asymptomatic period after arthroscopic synovectomy: a case report

INTRODUCTION Juvenile idiopathic arthritis is a chronic inflammatory disease associated with arthritis of unknown etiology that begins before the age of 16 and persists for longer than 6 weeks. The frequency of recurrence after arthroscopic synovectomy in patients with oligoarthritis juvenile idiopathic arthritis was reported to be lower than that in patients with polyarthritis. However, recurrence in cases of oligoarthritis after arthroscopic knee synovectomy was shown to be 67% in one recent study and, furthermore, a shorter period free from recurrence was also reported after synovectomy. Here we report a child who suffered recurrent knee arthritis with a 10-year asymptomatic period after arthroscopic synovectomy. CASE PRESENTATION A 12-year-old Japanese girl presented with normal birth and developmental history. At the age of 2 years she experienced joint swelling in both knees. Her symptoms continued and arthroscopic synovectomy was eventually performed. During the operation, rice bodies and thickening of the synovial membrane were observed; however, no definitive diagnosis was made. After a 10-year asymptomatic period, knee joint swelling recurred on one side without any cause. Arthroscopic synovectomy was beneficial in reducing the symptoms and in diagnosis. CONCLUSIONS Children who suffer prolonged joint swelling have a risk of juvenile idiopathic arthritis. Even if the symptoms heal and no definite diagnosis is made at the first treatment, informed consent is needed to make the patients understand the future risk of recurrent arthritis after even lengthy asymptomatic periods.