Patients typically experience pain relief 24 to 48 hours after corticosteroid injections in osteoarthritic knees, with relief lasting for an average of six to 12 weeks, states WebMD. Hyaluronic acid injections lubricate and cushion the knees on a short-term basis and relieve inflammation and pain for up to six months.
The first corticosteroid injection is usually the most effective, and patients can take the injections up to three times annually, explains WebMD. However, later injections tend to provide less relief, and taking the injections frequently can lead to damage of cartilage-manufacturing cells. Five versions of hyaluronic acid injections are offered in the United States. With some versions, a patient receives up to five injections in five weeks, and with others, one injection is enough. If necessary, a patient can receive another injection after six months.