Prolotherapy, repeated injections of a sugar solution into joints affected by arthritis, is a controversial therapy that may not work, with disadvantages that include irritating cells and tissues, and changing the composition of the synovial fluid to cause more irritation instead of less according to the Arthritis Foundation. On the other hand, some research studies show that prolotherapy provides relief for arthritis symptoms beyond a placebo effect.
During prolotherapy, a medical professional injects a sugar solution or another irritant into the knee joint, and surrounding ligaments and tendons to reduce pain associated with knee arthritis and improve joint function, maintains the Arthritis Foundation. Although the practice has been shown effective in some studies, it is not known how it works. One theory is that it causes irritation that encourages healing and growth in damaged tissues.
One randomized, controlled study showed a 24-percent improvement in patients given prolotherapy compared to only 11- or 12-percent improvement in groups receiving harmless saline injections or exercise advice, states the Arthritis Foundation. A few other studies have shown similar improvements, but some studies did not replicate these results. In spite of some evidence that prolotherapy works, the medical community recommends against the treatment until it is better understood how, why or even if it works.