Prolotherapy in animals

Dr. Sagiv Ben-Yakir BSc, DVM, MRCVS
“ORSHINA” – The Israeli Institute for Modern Holistic Veterinary Medicine & Sciences,
Hod-Hasharon, Israel

Webster’s Third New International Dictionary defines prolotherapy as “the rehabilitation of incompetent structure, such as ligaments or tendons, by the induced proliferation of new cells”, that is done for the purpose of strengthening weakened connective tissue and alleviating musculoskeletal pain. The term derives from the word prolo - short for proliferation. The therapy aims to proliferate tissue growth in the damaged area.

Prolotherapy is also called "proliferation therapy" and "regenerative injection therapy” (RIT). It can be distinguished from sclerotherapy, the use of injections of caustics into the veins, in vascular surgery and dermatology, to remove varicose veins and other vascular irregularities.

In prolotherapy we inject solutions into the area where connective tissue has been weakened or damaged through injury or strain. Many solutions are used, including dextrose, lidocaine, combination of both, animal own blood, added growth factors, phenol, glycerine, sodium morrhuate etc.

The injection is given into joint capsules or where tendon connects to bone. Many points may require injection. The Injected solution causes the body to heal itself through the process of inflammation and repair. In the case of weakened or torn connective tissue, induced inflammation and release of growth factor at the site of injury may result in a 30-40% strengthening of the attachment points.

Prolotherapy treatment sessions are generally given every two to six weeks. Many patients receive treatment at less and less frequent intervals until treatments are required only every several years, if at all. Prolotherapy is often used as an alternative to an invasive and expensive surgery.

In our practice we are using 15% dextrose as our injection solution into ligaments. Added to the solution is a small amount of Lidocaine without epinephrine. We take 1 ml of Lidocaine 2%, 3 ml of 50% Dextrose and 6 ml of sterile water. We shave the area to be injected, scrub it with Septal Scrub (4% Chlorhexidine), wash it with alcohol 70%, and finish up the preparation by putting on the area P.V.P Iodine 10%. The injection is done with 27-30 g needle and it is important to inject small webs into the ligaments rather than one or two large amounts. In most of the animals that can be done without sedation, nor anaesthesia. In some active animals – sedation or short time anaesthesia is needed.

For a successful therapy one should know the anatomy of the region to be treated. We know that many acupuncture points are located at the junction of ligaments to bones, or in ligaments, therefore it is easier to a qualified animal acupuncturist to locate the proper sites for injections, and be able to manipulate the small needles.

Usually there is some local pain and swelling for a few weeks, and great improvement is achieved after this period of time. In the first few weeks one can give NSAIDS on-off as needed, but not as a routine protocol – after all – we are looking for the inflammatory response to boost in.

Limited physical activity is advised (viz no jumping), but at the same token – do manual therapy 2-3 times a day (by the instructed owner) for the first few months. In some animals “a tune-up” injection is needed after 6 months or 12 months.

Different solutions can be injected in prolotherapy:

  1. By their higher osmotic pressure, osmotic proliferants, viz dextrose (water-soluble and not stored in the body but is excreted), induce the process of inflammation and healing.
  2. Irritants are substances that alter the surface of the cells and induce the process – viz phenol.
  3. Particulates, like pumic flour or the animal’s own blood, attract macrophages and induce the process of prolotherapy
  4. Chemotactics directly attract immune system cells to the area as sodium morrhuate.

Growth factors:

The mechanism of action of prolotherapy is complex and multifaceted. Six identified components include:

  1. Mechanical transection of cells and the matrix induced by the needle cause cellular damage, stimulating an inflammatory cascade.
  2. Compression of cells by the extracellular volume of the injected solution stimulates intracellular growth factors.
  3. Chemomodulation of collagen through inflammatory proliferative, regenerative/reparative responses induced by the chemical properties of the proliferants and mediated by cytokines and multiple growth factors.
  4. Chemoneuromodulation of peripheral nociceptors and antidromic, orthodromic, sympathetic and axon reflex transmission.
  5. Modulation of local hemodynamic, with changes in intraosseous pressure, leading to the reduction of pain. Empirical observations suggest that a dextrose/lidocaine combination has a much more prolonged action than lidocaine alone.
  6. Temporary repetitive stabilization of the painful hypermobile joints, induced by the inflammatory response to the proliferants, provides a better environment for regeneration and repair of affected ligaments and tendons.

Injections of irritant solutions were used in the late 1800’s to repair hernias and in the early 1900’s for jaw pain due to temporomandibular joint laxity. Dr George S Hackett MD developed the technique of prolotherapy in the 1940s. He claimed in his book “Ligaments and tendons relaxation treated by prolotherapy” (1958) that he cured 90% of 656 patients. At the time he used as an injection solution fatty acids mixture to induce inflammatory reaction. Today, we use a simple dextrose solution diluted with local anaesthetic, like lidocaine, to achieve the same results without the possible risks (viz shock). Hackett found that the injected tendons increased in diameter by 40% after prolotherapy, and histological exams showed no destruction of nerves or blood vessels and no scarring, which is a chaotic matrix of collagen fibres. The ligaments and tendons produced after prolotherapy appear much the same as normal tissue, except that they are thicker, stronger, and contain fibres of varying thickness with normal histological organization. There is an increase in collagen producing fibroblasts, the ligaments orientation and internal organization is linear.

Gustav A Hemwall MD is one of Hackett’s most famous students. He began his studies and treatments in the 1950s and continued until the mid 1990s. In his study of almost 10,000 cases, he found from 75%-90% successful results, and some of them for longstanding problems that have been resistant to other treatments.

If wonders what might happen in years to come with complementary and alternative veterinary medicine, the following story has a point of is interest. Dr. Everett Koop MD USA Surgeon General had a severe pain followed by almost a complete paralysis of his right hand during 1980. Since no therapy solved his condition, he approached Dr Hemwall, who treated Dr Koop by prolotherapy injections into his neck. This successfully solved the medical issue in a short time. Dr Koop studied more about prolotherapy and endorsed it. Today, prolotherapy is considered as sub-speciality of the American Association of Orthopaedic Medicine.

Indications for Veterinary Prolotherapy:

  1. Chronic pain from ligaments or tendons secondary to sprains or strains.
  2. Pain from overuse or occupational conditions (viz dog/horse racing) known as "Repetitive Motion Disorders".
  3. Chronic postural pain of the cervical, thoracic, lumbar and lumbosacral regions.
  4. Painful recurrent somatic dysfunctions secondary to ligament laxity that improves temporarily with manipulation.
  5. Painful hypermobility and subluxation at given peripheral or spinal articulation(s) or mobile segment(s) accompanied by a restricted range of motion at reciprocal segment(s).
  6. Thoracolumbar vertebral compression fractures with a wedge deformity that exerts additional stress on the posterior ligamento-tendinous complex.
  7. Recurrent painful subluxation of ribs at the costotransverse, costovertebral and/or costosternal articulations.
  8. Osteoarthritis of axial and peripheral joints, spondylosis, spondylolysis and spondylolisthesis.
  9. Painful cervical, thoracic, lumbar, lumbosacral and sacroiliac instability secondary to ligament laxity.
  10. Intolerance to NSAIDs, steroids or opiates. Prolotherapy may be the treatment of choice if the patient fails to improve after physical therapy, chiropractic or osteopathic manipulations, steroid injections or radiofrequency denervation, or surgical interventions in the aforementioned conditions, or if such modalities are contraindicated.

Syndromes and diagnostic entities, caused by ligaments and tendon pathology that have been successfully treated with prolotherapy include:

  1. Cervicocranial Syndrome (cervicogenic pain, secondary to ligament sprain and laxity, atlanto-axial and atlanto-occipital joint sprains, mid cervical zygoapophyseal sprains).
  2. Temporomandibular Pain and Muscle Dysfunction Syndrome
  3. Torticollis
  4. Cervical segmental dysfunctions
  5. Cervicobrachial Syndrome (shoulder/neck pain)
  6. Hyperextension/Hyperflexion injury Syndromes
  7. Cervical, Thoracic and Lumbar Sprain/Strain Syndrome
  8. Costochondritis/chondrosis
  9. Recurrent shoulder dislocations
  10. Lumbar instability
  11. Lumbar Spondylolysis
  12. Sacroiliac joint pain
  13. Sacrococcygeal joint pain
  14. Myofascial Pain Syndromes
  15. Ankylosing Spondylitis
  16. Shoulder, stifle, foot and ankle chronic sprain, instability, laxity of ligaments

Specific veterinary examples include:


  1. Allergy to anaesthetic or proliferant solutions or their ingredients such as dextrose, sodium morrhuate or phenol.
  2. Acute non-reduced subluxations or dislocations.
  3. Acute arthritis (septic or post-traumatic with haemarthrosis).
  4. Acute bursitis or tendonitis.
  5. Capsular pattern shoulder and hip designating acute arthritis accompanied by tendinitis.
  6. Acute gout or rheumatoid arthritis.
  7. Recent onset of a progressive neurologic deficit including but not limited to (severe intractable cephalgia, unilaterally dilated pupil, bladder dysfunction, bowel incontinence, etc).
  8. Requests for a large quantity of sedation and/or narcotics before and after treatment.
  9. Paraspinal neoplastic lesions involving the musculature and osseous structures.
  10. Severe exacerbation of pain or lack of improvement after local anaesthetic blocks.
  11. Relative contraindications: central spinal canal, lateral recess and neural foraminal stenosis.

Prolotherapy is a safe and effective therapy, in which a mild irritant solution is injected into ligaments, tendons, or their insertions to bones or muscles. This causes a mild inflammatory response that stimulates healing. The result is a thicker, stronger, more organized tendon/ligament that is less sensitive and that decreases local and remote structure stresses. Of patients treated with prolotherapy, 75-90% improve significantly or are cured.