[Knee joint synovectomy in treatment of juvenile idiopathic arthritis]

The objective of this study was to assess short-term outcomes of knee joint synovectomy in a group of patients with juvenile rheumatoid arthritis and to present the authors' view on this approach.

Between 1990 and 1999, synovectomy of the knee joint was performed in a group of 46 children with juvenile rheumatoid arthritis. This group comprised 19 girls and 27 boys aged 4 to 16 years (mean 9.8 years) with all forms of the disease. A total of 85 synovectomy procedures, including repeat operations, were performed on 58 knee joints.

Arthroscopic synovectomy was used to treat 21 knee joints, open synovectomy from two approaches was indicated, as a primary procedure, in 37 knees. The assessment of subjective and functional conditions of patients was based on a modified rating systems of Lysholm and X-ray films were evaluated by the Larsen classification. The evaluation was carried out at 1 and 2 years after the primary operation.

Articular lesions corresponding to mere synovitis were found in 10 knee joints (17.2%), a developing pannus without erosion was seen in 16 (27.6%) and erosion of the articular surface in 32 (55.2%) knee joints. At 1 year, the value of Lysholm's score rose from 47.9 to 84.3 points and was followed by a decrease to 73.2 at 2 years. Within 2 years of the primary operation, the condition recurred in 9 out of 21 knees (42.8%) treated by arthroscopic synovectomy and in 12 cases (32.4%) operated on by open synovectomy. The relapse was observed mostly in patients with an overall high inflammatory activity and polyarticular and systemic progression of the disease.

We do not agree with the view of some authors that surgical intervention is not indicated until erosions are radiologically manifested. In children, erosions usually present at a late stage, as shown by 12 findings of articular surface destruction in our group that were not detected by radiography. For indication purposes, we distinguished between preventive and therapeutic synovectomy. We found a significant association between the overall activity and early recurrence of the disease. In 60.7% of the cases (28) with excellent outcomes, this activity was low at the time of surgery. On the other hand, in 75% of the cases (8) with poor outcomes, the activity of disease was very high and had a lasting tendency to recur. These findings are in agreement with the conclusions of several other authors who consider the presence of systemic disease to be a contraindication for synovectomy. Advantages of arthroscopic synovectomy reported in adult patients seem to be relative in children. A good view of and accessibility to individual articular components, which are made an advantage of in the adult knee, are rather exceptional in the "tight" child knee. The evaluation of our patients at a short-term follow-up did not give convincing results although the early effect of synovectomy was very good. The poor outcomes seen in our group, which corresponded with observations of other authors, allow us to learn more about the potentials of synovectomy and thus to promote our policy of a thorough consideration of indications for surgery.

Indications for surgical treatment in patients with juvenile rheumatoid arthritis are evaluated in cooperation with a rheumatologist after an appropriate conservative therapy administered for at least 6 months. Cases with clear signs of plastic synovitis and skeletal lesions shown by radiography as well as all recurrent conditions are treated by open synovectomy. The state of low disease activity is preferred for surgical intervention. It has to be borne in mind that, from whole range of curative procedures, conservative therapy supervised by a pediatric rheumatologist is the method of choice.