ObjectiveTo compare the clinical efficacy of glucosamine hydrochloride and diacerein for patients with knee osteoarthritis and the MRI variation. MethodsBetween January and June 2014, 90 patients with knee osteoarthritis were randomized into three groups: group A (treated by glucosamine hydrochloride), group B (treated by diacerein) and group C (treated by both glucosamine hydrochloride and diacerein). The score of Western Ontario and McMaster Universities (WOMAC) index of osteoarthritis, MRI cartilage injury Recht grading and the curative effects for bone marrow edema, joint cavity effusion and meniscus injury were compared before and after the treatment. ResultsThe scores of WOMAC after treatment in all the groups were improved, while the therapeutic effect of group C lasted longer when medical treatment suspended. The number of articular surface with different degrees of cartilage injury showed no statistically significant change in all three groups (P ＞ 0.05) . The state of bone marrow edema and joint cavity effusion were improved with a statistically significant difference in all groups (P ＜ 0.05) . Patients with lateral meniscus degeneration in group A and patients with medial meniscal tear in group B both increased with statistically significant differences (P ＜ 0.05) . However, in group C, patients with lateral meniscus degeneration or meniscal tear decreased with statistically significant differences (P ＜ 0.05) . ConclusionsThe treatment for osteoarthritis by glucosamine hydrochloride is effective, and the curative effect lasts longer when treated by both glucosamine hydrochloride and diacerein. Glucosamine hydrochloride ameliorates the bone marrow edema and joint cavity effusion. Treatment together with diacerein leads to a better therapeutic effect for patients with meniscus degeneration, yet further studies are needed to prove its effects in ameliorating cartilage injury.