Effects of needle-arthroscopic lavage with different volumes of fluid on knee synovitis in rheumatoid arthritis.

To determine the appropriate volume of physiological fluid needed to effectively reduce synovitis and to determine the indications for intra-articular lavage of knee joints with rheumatoid arthritis (RA), intraarticular lavage with different volumes of physiological fluid via needle arthroscopy were performed on 102 rheumatoid knees in 98 patients (25 males, 77 females) with an average age of 46 years at the time of operation. Intra-articular lavage of a knee joint with 5 or 10 l of physiological fluid gave better clinical results than did intra-articular lavage with 0.5-1.5 l. There was no difference between the beneficial effects of intraarticular lavage using 5 1 or 10 l of fluid. The preoperative conditions (CRP, frequency of the susceptible factors of HLA-DRB1 alleles, radiological change in the knee joint) and the intraoperative chondroscopic assessments were correlated with clinical improvement. Our study demonstrated that intra-articular lavage with 5 l of physiological fluid performed using needle arthroscopy was beneficial. The following points at least should be checked before performing intra-articular lavage: (1) CRP is not elevated to a high level (> or =5 mg/dl), (2) the patient does not have susceptible factors in both HLA-DRB1 alleles, (3) the grade of rheumatoid knee is below Larsen II in preoperative X-ray findings, and (4) the degree of cartilage damage is not more than grade 3 in arthroscopic findings.