Effect on Pain and Symptoms of Aspiration Before Hyaluronan Injection for Knee Osteoarthritis: A Prospective, Randomized, Single-blind Study

Objective The main objective of this study was to observe whether synovial fluid aspiration of the knee joint compared to no aspiration, before and after 5 weekly injections of intra-articular hyaluronan, provides an improvement in knee pain and physical function. Design Patients were randomized to an arthrocentesis group (n = 92) or a nonarthrocentesis group (n = 88). In the arthrocentesis group, knee joints were maximally aspirated before each hyaluronan administration. In the nonarthrocentesis group, synovial fluid was not removed. Hyaluronan was injected into the knee joints once a week for 5 weeks. Patients were followed up for 25 weeks. Outcome measures included patient pain (using the 100-mm visual analog scale [VAS] during a 50-foot walking test), Western Ontario McMaster University Osteoarthritis Index (WOMAC) function scores, and overall effectiveness evaluated by patients and investigators on a scale of 1 to 6. Results The arthrocentesis group showed significantly greater improvement from baseline to week 25 in VAS pain (P < 0.001) and WOMAC function scores (P < 0.001) than the nonarthrocentesis group. However, the differences of patient and investigator assessment of effectiveness did not achieve significance. Conclusions Synovial fluid drainage before injection of intra-articular hyaluronan significantly improved VAS pain and WOMAC function scores in patients with knee osteoarthritis, however, the differences of patient and investigator assessment did not achieve significance.