Patients with recurring or persisting inflammatory arthritis of the knee despite anti-rheumatic therapies are frequently treated with intra-articular steroid injections. Lavage of a rheumatic joint may also be beneficial by removing synovial debris and proinflammatory substances from the joint. Only uncontrolled studies have been performed so far and none of these has studied local synovial features.
To compare the therapeutic effect of three local interventions: arthroscopic lavage with steroid application (AL + st), arthroscopic lavage with placebo (AL + pl) and needle biopsie with steroids (NB + st, as a representative of joint injection). To study synovial tissue biopsies for predictive factors for the response to local therapy.
Arthroscopic lavage with 1 l saline was performed under local anaesthesia using 2 trocharts. At the end of the procedure 80 mg methylprednisolone or placebo was instilled. Needle biopsy was performed under local anaesthesia with 1 trochart and instillation of 80 mg methylprednisolone. In all patients synovial tissue specimens were obtained and histologically analyzed. Kaplan–Meier curves were constructed depicting the time until recurrence of arthritis. Cumulative incidences of recurrence were used to calculate relative risks (RRs) between treatment groups.
Seventy-eight patients were equally randomized over the three interventions. AL + st was the best therapy with a median time untill recurrence of 0.58 years, followed by NB + st (0.23 years) and AL + pl (0.08 years) (Fig. 1) The RR for recurrence compared with AL + st was 2.0 for NB + st (P = 0.03) and 4.7 for AL + pl (P < 0.001). Synovial tissue analysis showed a relation between infiltrating lymphocytes and outcome of AL + st; RR = 2.7 (P = 0.01) in patients with less infiltrating lymphocytes. The opposite was found for fibrosis; RR = 2.9 (P = 0.03) in patients with more fibrosis.
Figure 1. Kaplan–Meier curves for the time until recurrence of arthritis.
Joint lavage preceding steroid injection had a marked effect on time until recurrence when compared with joint lavage or steroid injection alone. The clinical effect was correlated with the presence of a lymphocytic infiltrate and the absence of fibrosis.