Osteoarthritis of the knee is more prevalent in the elderly population, and most patients with osteoarthritis are treated with medications that provide symptomatic relief, with only a small number of patients requiring surgical treatment. A recent meta-analysis published in Ann Intern Med, a leading international journal, analyzed the effectiveness of acetaminophen tablets for osteoarthritis of the knee and found that acetaminophen tablets were not as effective as most other treatments for osteoarthritis of the knee. The investigators examined the extant database, which included 33,243 patients and 137 studies. The studies compared the degree of pain relief, knee stiffness and functional recovery after 3 months in patients with knee osteoarthritis treated with medication for pain and in the oral placebo group. Medications included in the comparison were oral acetaminophen tablets, diclofenac, ibuprofen, naproxen; intra-articular injections, such as glucocorticoids, hyaluronic acid; and oral and intra-articular placebo. The investigators found that intra-articular injections of hyaluronic acid provided the best pain relief, while oral acetaminophen tablets provided the least pain relief, which is a departure from the previous notion that COX-2 inhibitors have better pain relief. Specifically, in terms of pain relief, the injectable class of drugs was better than the oral class; the injectable placebo group was also better than the oral NSAIDs class of drugs, a finding that is quite subversive, but the study is also particular in that the intra-articular placebo injection was better than the oral NSAIDs class of drugs, not because the placebo effect was greater than the oral drug pain relief effect, but because intra-articular injections of Any drug can provide pain relief. Naproxen, ibuprofen, and diclofenac were more effective than oral placebo and acetaminophen tablets for joint stiffness relief, and intra-articular injections of hyaluronic acid were more effective than the intra-articular placebo group. However, intra-articular cavity placebo injections did not provide as good a degree of stiffness relief as the oral placebo group. In terms of functional recovery, all measures, except for the glucocorticoid injection group, were better than the oral control group. Similarly, other oral analgesic drugs were better than acetaminophen tablets. And the joint cavity injection of hyaluronic acid group was better than the glucocorticoid and control groups. The researchers concluded that similar drugs in the treatment of osteoarthritis of the knee yielded different conclusions. In addition to the complex etiology of pain in osteoarthritis of the knee and the significant inter-individual heterogeneity, inflammation, peripheral pain reception, and central pain control all have an impact on pain in osteoarthritis, and an in-depth understanding of the pain-generating mechanisms can help in the rational management of pain in arthritis. The conclusion is not representative. The current selection of anti-inflammatory and analgesic drugs for osteoarthritis of the knee tends to be more individualized, and some individuals do very well with such drugs, and the rules of which have to be figured out. However, in general, ibuprofen, naproxen and diclofenac are more effective.