Osteoarthritis (OA) is the most common joint disorder in the animals and one of the most common sources of pain and disability in the elderly animals. Chronic wear and tear on the joints is the underlying mechanism for OA. It is inevitable that there will be some degenerative change in animals’ joints over their lifetime. The most common sites are the elbows, hips, spine, and any joint that has sustained traumatic injury. Joint pain is the principal symptom, but swelling, deformity, stiffness, and loss of function also occur. Chronic pain is undoubtedly the biggest threat to our pets’ quality of life as they age. Fortunately, it is also a great example of a health issue that will benefit markedly from integrative therapy.
The initial step when addressing the arthritic patient is a thorough assessment of range of motion (ROM), weightbearing status, girth measurements, palpation, overall function and owner perception of problems with home activities. A pain scale may be used to determine the level of pain. Weightbearing status may be determined through dynamic or static force-plates, or scales. The overall function and goals of the owner should be determined in the evaluation, and progress using the various assessment tools should be monitored. After the problem list and the goals have been determined, integrative therapies can be implemented as part of a multimodal treatment program for OA.
Multimodal Approach to Osteoarthritis
When managing pain in OA patients, a multimodal approach should be used as early as possible. This can include the use of anti-inflammatories, opioids, tricyclic antidepressants, anticonvulsants, NMDA receptor antagonists, nutraceuticals, herbal therapies, acupuncture, laser, electromagnetic field, shockwave, therapeutic exercises, and adjunctive physical modalities. With this approach, both pharmacologic and non-pharmacologic therapies complement one another to increase the effectiveness of any given analgesic drug by intervening at multiple places along the nociceptive pathway. Utilizing a multimodal approach may also allow efficacious use at lower drug doses.
A. Weight Control
- The most important element in the treatment of OA is weight control.
- Overweight or obesity may contribute to the development and progression of OA because of excess forces placed on joints and articular cartilage, which may lead to inactivity and further development of obesity.
- Adipose tissue is recognized as being metabolically active and proinflammatory; therefore, obesity may potentiate the systemic and local effects of inflammation.
- Maintaining optimal or slightly lean body condition may be associated with lower risk of developing OA, development of less severe OA if it occurs, and delay of onset of clinical signs of OA in dogs.
- Several commercially available diets formulated for management of dogs with OA. These diets contain higher levels of omega-3 fatty acids and may contain chondromodulators and antioxidants.
- Acupuncture is defined as the insertion of thin, sterile needles into specific points, based on anatomical structures, which leads to a physiologic response. These physiologic responses are due to stimulation of the nervous system and lead to a release of endogenous substances such as β-endorphins, dynorphins, enkephalins, serotonin, epinephrine, gamma-aminobutyric acid (GABA), cortisol, and various hormones. Acupuncture has therapeutic clinical applications in rehabilitation and sports medicine such as pain relief, performance and endurance enhancement, and nerve regeneration.
- Acupuncture is a useful modality to integrate into pain management due to its analgesic properties and nerve stimulation effects. It also has calming/sedating effects which are useful for patients that need to be cage-rested.
C. Low-Level Laser Therapy (LLLT)
- Laser is a light source treatment that generates light of a single wavelength that elicits photochemical reactions in cells to promote tissue regeneration, reduce inflammation, relieve pain, increase fibroblasts and lymphocytes, and stimulate cartilage growth.
- The effects of laser therapy in OA include: inhibition of cyclooxygenase-2 enzyme and prostaglandins, reduction of oxidative stress, endorphin release, and cartilage stimulation.
D. Transcutaneous Electrical Stimulation (TENS)
- TENS is an electronic stimulus generator that transmits electrical impulses of various configurations to electrodes on the skin for the purpose of pain management. TENS can be effective for pain relief, especially in cases of chronic musculoskeletal and postoperative pain.
- Acute pain: 50–200 Hz, lower pulse width: relief is short-lasting.
- Chronic pain: 2–4 Hz with higher pulse width produces longer-lasting pain relief (several hours).
- Mechanisms of TENS:
- Gate control theory: pain signals are transmitted by small cutaneous A-δ and C fibers. If a TENS current is applied, the large cutaneous (A-β) fibers are stimulated. The signals from the A-β fibers activate inhibitory neurons in the spinal cord dorsal horn and block the transmission of pain impulses from the periphery to the brain.
- Release of endogenous opiates. These endorphins are released from the pituitary in response to low frequency (<10 Hz), high pulse duration (>100 µsec) stimulation, and they produce analgesia when released.
E. Therapeutic Ultrasound (US)
- US is a method of stimulating the tissue beneath the skin’s surface using very high-frequency sound waves, between 800,000 Hz and 2,000,000 Hz, which cannot be heard by humans. The sound waves to stimulate fibroblast activity, improves blood flow, increases protein synthesis and aids in soft tissue and bone healing. It also provides heat to injured body parts that lie deep within your body that are not able to be heated with a standard hot pack alone.
- Therapeutic US is considered an effective treatment modality for rehabilitating musculoskeletal conditions such as restricted range of motion (ROM) resulting from joint contracture, pain and muscle spasm, and wound healing.
F. Extracorporeal Shockwave Therapy (ESWT)
- ESWT is a new technology using shockwaves to treat chronic, painful conditions of the musculoskeletal system. A shockwave is an intense, but very short energy wave traveling faster than the speed of sound. ESWT may be beneficial as an ancillary treatment for OA as part of the multimodal approach to therapy of this condition. Improved weightbearing and passive range of motion are similar to results expected with NSAID use. In patients that are unable to tolerate the administration of NSAIDs, extracorporeal shockwaves may serve as a useful, noninvasive alternative for treatment of osteoarthritic conditions. Anecdotally, treatment of conditions affecting the elbow, hip, or back may respond better than other joints.
- Gate control theory.
- Induction of cell damage from shockwave application prevents appropriate membrane potentials required for transmission of signals.
- Production of cytokines and growth factors, endothelial nitric oxide synthase (eNOS) and upregulation of bone morphogenetic protein (BMP) expression resulting in a decline in inflammation and swelling, with short-term analgesia.
G. Chondroprotective Supplements
Chondroprotectants are products proposed to protect the cartilage (against degradation).
- Results take 4–8 weeks to develop. These improvements often last for several weeks after glucosamine supplements are discontinued.
- Studies and clinical experience in people and pets show that glucosamine/chondroitin are equally effective for treating OA when compared to NSAIDs without the side effects.
- Glucosamine is rapidly taken up by cartilage cells and helps stimulate the synthesis of synovial fluid and cartilage.
- Chondroitin sulfate is the major glycosaminoglycan found in cartilage; it also helps inhibit enzymes that are destructive to the joint.
- Glucosamine: ≥25 mg/kg, SID
- Chondroitin: ≥15–20 mg/kg
- Polysulfated glycosaminoglycan (Adequan®)
- Only FDA-approved chondroprotectant in dogs.
- Inhibit serine proteinases, which play a role in the interleukin-1-mediated degradation of cartilage proteoglycans and collagen.
- Inhibit some catabolic enzymes that degrade collagen, proteoglycans, and hyaluronic acid.
- Inhibit prostaglandin E synthesis.
- Reduce cartilage degradation by suppression of inflammatory mediators and stimulation of GAG synthesis.
- 2 mg/kg, twice weekly for 4 weeks, then once a month.
- Omega-3 fatty acids
- Include: Alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA).
- When omega-3 FA replaces arachidonic acid (AA) in cell membranes, the inflammatory cascade is decreased.
- Diet high in omega-3 FA helps with rheumatoid arthritis as well as OA.
- Implementation of a high-EPA diet together with an NSAID can reduce the amount of NSAID required for the same effect by 25%.
- 70–250 mg/kg, SID.
- Green-lipped mussel
- Natural source of GAGS including chondroitin, as well as a number of other nutrients including complex proteins, amino acids, nucleic acids, naturally chelated minerals, fatty acids, and an inhibitor of prostaglandin synthesis, which makes it effective as an anti-inflammatory supplement, Glycoflex.
- Studies have confirmed improvement in human OA.
- Study found that some owners perceive huge improvements in OA.
- 30 mg/kg, SID–BID.
- S-adenosyl-methionine (SAM-e)
- Human clinical trials show SAMe effective in treating OA.
- Positive results can persist for at least 2 years after treatment in people.
- Rabbit studies show some chondroprotective effects, by increasing proteoglycan synthesis.
- 18 mg/kg/day.
H. Chinese Herbal Supplements
Traditional Chinese Veterinary Medicine (TCVM) is an effective treatment to help complement current medications and improve pain management. From the TCVM standpoint, pattern differentiation (diagnosis) is important for the treatment strategy for OA pain. One diagnosis entity has different kinds of patterns. Selections of herbal formulas are based on the pattern differentiation of the patient.
- Pain worse in heat/summer: Di Gu Pi San
- Pain worse in cold/winter: Loranthus Formula
- More stiffness than pain: Coix Formula
- Muscle soreness: Body Sore
The conventional medical approach to OA focuses upon the signs and symptoms of the disease. Integrative therapies with multimodal approach are becoming more utilized in veterinary patients and more popular with both clients and practitioners to address OA. When properly administered by adequately trained professionals, these modalities are incredibly effective and safe to patient. They also have less side effects when compared to medications. Often in our integrative practice, we find that adding in these modalities enables lower doses of conventional pain medications, more frequent patient monitoring and followup, and clients feel more proactive leading to greater client compliance and satisfaction.
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