In 2019, the American College of Rheumatology recommended against prolotherapy for knee osteoarthritis. Contraindications Contraindications for patients to receive prolotherapy injections may include: Local abscess Bleeding disorders Patient on anticoagulant medication Known allergy to prolotherapy agent Acute infections such as cellulitis Septic arthritis Relative contraindications include: Acute gouty arthritis Acute fracture Side effects Patients receiving prolotherapy injections have reported generally mild side effects, including mild pain and irritation at the injection site (often within 72 hours of the injection), numbness at the injection site, or mild bleeding. Pain from prolotherapy injections is temporary and is often treated with acetaminophen or, in rare cases, opioid medications. NSAIDs are not usually recommended due to their counter action to prolotherapy-induced inflammation, but are occasionally used in patients with pain refractory to other methods of pain control. Theoretical adverse events of prolotherapy injection include lightheadedness, allergic reactions to the agent used, bruising, infection, or nerve damage. Allergic reactions to sodium morrhuate are rare. Rare cases of back pain, neck pain, spinal cord irritation, pneumothorax, and disc injury have been reported at a rate comparable to that of other spinal injection procedures. Technique Prolotherapy involves the injection of an irritant solution into a joint space, weakened ligament, or tendon insertion to relieve pain. Most commonly, hyperosmolar dextrose (a sugar) is the solution used; glycerine, lidocaine (a commonly used local anesthetic), phenol, and sodium morrhuate (a derivative of cod liver oil extract) are other commonly used agents. The injection is administered at joints, ligaments, or tendons where they connect to bone. Prolotherapy treatment sessions are generally given every two to six weeks for several months in a series ranging from three to six or more treatments. Many patients receive treatment at less frequent intervals until treatments are rarely required, if at all. Terminology and mechanism The term originated with George S. Hackett, MD, in 1956 in a publication titled "The rehabilitation of an incompetent structure by the generation of new cellular tissue". He applied the term prolotherapy from the words "proli’" (Latin), meaning offspring, and "proliferate", meaning to produce new cells in rapid succession. Although the erroneous term "sclerotherapy" was utilized by some in the past to describe this treatment, it is now clear that prolotherapy does not cause scarring. The mechanism of prolotherapy requires further clarification. It is expected to involve a number of mechanisms. Criticism Some major medical insurance policies view prolotherapy as an