The efficacy and safety of intra-articular injections with the TNF-a antagonist infliximab in patients with chronic or recurrent arthritis of the knee.

Rheumatic disorders of the joint are characterised by inflammation and hyperplasia of the synovial tissue(1).
The inflammation can lead to loss of function of the affected joint and finally to (irreversible) joint damage. The use of Disease Modifying AntiRheumatic Drugs (DMARDs) suppresses disease-activity and slows down the potentially irreversible damage of the joint and bone.
Besides systemic therapy persistent inflammation of a (single) joint can also be treated with a local corticosteroid injection into the affected joint. Local therapy is preferred over systemic treatment because of the reduced chance of side effects. Although intra-articular corticosteroid injections are widespread and effective in reducing symptoms of the inflammation(2;3) some studies show less favourable results(4). Post-injection rest(3), removal of the synovial fluid before injection(4) and the choice of the injected steroid(5), all influence the duration of symptom relief.
The application of more than three injections into the same joint per year is advised against(6;8) because of the risk for procedure- and steroid associated side-effects like infection or local osteoporosis. In one study eight injections in two year were administered in patients with osteoarthritis(9).


In synovial biopsies of patients with rheumatoid arthritis (RA) an increased expression of inflammatory cytokines such as TNF-a is prominent(10;11). The pro-inflammatory cytokine TNF-a has a definite role in the induction and persistence of joint inflammation(12). Systemic treatment with anti-TNF-a has shown to be a very effective treatment for rheumatoid arthritis(13-16). In patients with a persistent monoarthritis an intra-articular injection with corticosteroids is the first choice of therapy. When the arthritis persists or relapses a reduction of inflammatory symptoms by intra-articular administration of anti-TNF-a seems a good option from a theoretical point of view. The outcome of intra-articular injections with anti-TNF-a (infliximab) was reported in a number of case reports with varying results. The results of 20 patients with an inflammatory arthritis are shown in Table 1(17;18)+ (22-24). In these case reports no (local) side effects were reported.


The volume of the synovium is directly correlated to the disease activity of the affected joint(19;20).When corticosteroids are administered into the joint the decrease of inflammatory symptoms is related to the volume of the synovial tissue as assessed by MRI-techniques(21). Magnetic Resonance Imaging is a safe and non-invasive way to image the joint with great sensitivity to detect a small change in synovial volume.

The systemic treatment of rheumatoid arthritis with anti-TNF-a is very successful. In a number of case reports varying success rates of intra-articular injections with the TNF-a blocking agent infliximab have been reported. In this study we want to assess the safety and efficacy of intra-articular injections with infliximab in patients with relapsing or persistent (mono-) arthritis of the knee.

Treatment with infliximab 100mg intra-articular or methylprednisolon 80mg intra-articular.