What Is Prolotherapy?

Invented in the 1950s by George Hackett, prolotherapy is based on the theory that chronic pain is often caused by laxness of the ligaments that are responsible for keeping a joint stable. When ligaments and associated tendons are loose, the body is said to compensate by using muscles to stabilize the joint. The net result, according to prolotherapy theory, is muscle spasms and pain.

Prolotherapy treatment involves injections of chemical irritant solutions into the area around such ligaments. These solutions are believed to cause tissue to proliferate (grow), increasing the strength and thickness of ligaments. In turn, this presumably serves to tighten up the joint and relieve the burden on associated muscles, stopping muscle spasms. In the case of arthritic joints, increased ligament strength would allow the joint to function more efficiently, thus reducing pain.

Prolotherapy has not been widely accepted in conventional medicine. The technique is used by prolotherapy practitioners to treat many conditions, including back pain, osteoarthritis, fibromyalgia, plantar fasciitis, sciatica, sports injuries, temporomandibular joint disorder (TMD), tendinitis, and tension headaches. Most studies have focused on its use in back pain and osteoarthritis, but this evidence does not clearly support its effectiveness.

How Is Prolotherapy Performed?

Prolotherapy is generally administered at intervals of 4 to 6 weeks, although studies have used a more frequent schedule. The treatment involves injection of a mixture containing an irritant and a local anesthetic. A total of 4 to 6 treatments is typical.

When treating back pain, prolotherapy practitioners frequently use a form of manipulation somewhat similar to chiropractic. However, it is applied after local anesthetic has been injected and is somewhat intense.

There are several irritant solutions used in prolotherapy. Concentrated dextrose or glucose has become increasingly popular because it is completely non-toxic. Phenol (a potentially toxic substance) and glycerin are also sometimes used. Other non-irritant substances may be added to the solution, such as vitamin B 12, corn extracts, cod liver oil extracts, zinc, and manganese; however, there is no evidence that these substances add any benefit.

What Is the Scientific Evidence for Prolotherapy?

Some animal and human studies have found that prolotherapy injections increase strength and thickness of ligaments.1-4

Six double-blind human trials of prolotherapy have been reported: four involving back pain (with mixed results), and the other two involving osteoarthritis (with positive results).

Although two studies have suggested prolotherapy may be effective for low back pain,5,6 two more recent studies found prolotherapy to be ineffective.10,13

In a review of five studies, three found prolotherapy to be no more effective than control treatments for low back pain. The other two studies suggested that prolotherapy was more effective than control treatments when used with therapies such as spinal manipulation and exercise.11 Another review suggested prolotherapy may be effective when used with other therapies, but not when used alone.12

What can one make of this contradictory evidence? When used alone prolotherapy is probably no more effective than a placebo injection for the treatment of low back pain. However, there is some evidence that the technique may be beneficial when combined with other therapies.

A double-blind, placebo-controlled study evaluated the effects of 3 prolotherapy injections (using a 10% dextrose solution) at 2-month intervals in 68 people with osteoarthritis of the knee.7 At the 6-month follow-up, participants who had received prolotherapy showed significant improvements in pain at rest and while walking, reduction in swelling, episodes of "buckling," and range of flexion, as compared to those who had received placebo treatment.

The same research group performed a similar double-blind trial of 27 people with osteoarthritis in the hands.8 The results at the 6-month follow-up showed that range of motion and pain with movement improved significantly in the treated group as compared to the placebo group.

Safety Issues

In studies, prolotherapy has not caused any serious, irreversible injury. There is usually discomfort after each injection that lasts for a few minutes to several days, but this discomfort is seldom severe.9 Of more concern, severe headaches have been reported in treatment of low back pain in a minority of patients. Because phenol is a potentially toxic substance, treatment with a dextrose solution alone is preferable.

Finding a Qualified Prolotherapy Practitioner

Prolotherapy is practiced by a medical doctor (MD) or doctor of osteopathy (DO). Generally, physicians specializing in orthopedics or physical medicine and rehabilitation are most likely to practice prolotherapy. To find a qualified practitioner, contact the following groups: