A closed injection, which is a mixture of a certain concentration and volume of prednisolone injection (prednisolone used, and similar drugs: dexamethasone, betamethasone, etc.) and procaine hydrochloride (or their analogs), is injected into the lesion area. Closed injections can be given in muscles, joints, fascia, paratendons and even in the spinal canal. Prednisolone is a synthetic hormone that can improve capillary permeability, inhibit the inflammatory response, and reduce the damage caused by pathogenic factors to the body; procaine hydrochloride is a local anesthetic, which is used for tooth extraction and minor surgery to relieve pain and enhance the healing effect. Sometimes it is also used its analogue lidocaine, the effect is similar. The effect of local anesthetics is to temporarily block local nerve conduction, so that the corresponding areas innervated by these nerves produce anesthesia, thereby relieving pain. Local injection of hormonal drugs is the most common and effective method of treating chronic injuries to soft tissues, and this therapy has been used in China for more than 40 years. Most orthopedic patients need to play closed needle, such as frozen shoulder, arthritis, tenosynovitis, lumbar strain, lumbar disc herniation, etc., although their pathogenesis is not the same, but have a common feature: that is, soft tissue injury and sterile inflammation, for this reason, the hospital doctors often choose closed therapy, which is often referred to as playing “closed needle “.