Surgery STAT: Intra-articular therapies for the elbow in dogs

In this third part of a three-part series covering the treatment of elbow disease in dogs, I review intra-articular medical treatment options for dogs.

After arthroscopic treatment of the elbow, nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly prescribed to decrease inflammation and discomfort. Injectable polysulfated glycosaminoglycans and oral joint-modifying agents (glucosamine, chondroitin sulfate, and avocado/soybean unsaponifiables) are recommended to decrease inflammation and potentially slow progression of osteoarthritis.

Table 1: Intra-articular Therapies

Additional therapies used in equine and human medicine not often considered for our canine patients include intra-articular injections (Table 1). These therapies are beneficial for dogs with significant elbow osteoarthritis, intolerance or nonresponsiveness to NSAIDs, frequent episodes of acute exacerbation of underlying elbow disease or residual postoperative signs (effusion, discomfort on range of motion and lameness) despite medical management and rehabilitation therapy. The technique for intra-articular injections of the elbow joint is outlined in Table 2.

Table 2: Intra-articular Injection Technique for the Canine Elbow

Hyaluronic acid

Viscosupplementation for the treatment of elbow osteoarthritis is based on improving the rheologic properties within the joint. Intra-articular administration of hyaluronic acid is a form of viscosupplementation, which slows progression of osteoarthritis and decreases joint inflammation by increasing joint fluid viscosity, increasing glycosaminoglycan formation and decreasing degradative enzymes and cytokines. Intra-articular hyaluronic acid has been widely used to treat osteoarthritis in animals and people. Several experimental studies using intra-articular hyaluronic acid in dogs demonstrated decreases in pain, lameness, osteophytosis, synovial hyperemia and hypertrophy and glycosaminoglycan and cartilage degradation. The mechanism by which hyaluronic acid produces beneficial effects remains controversial.

Complications may include temporary increased pain and lameness and septic arthritis. Reportedly, more than 70 percent of dogs respond well to hyaluronic acid. My clinical impression is that hyaluronic acid used alone is useful for mild to moderate elbow osteoarthritis, but to treat severe elbow osteoarthritis, intra-articular corticosteroid or stem cell therapy is recommended.

Corticosteroids

Intra-articular corticosteroids prevent formation of both prostaglandins and leukotrienes by causing the release of lipocortin, which by inhibiting phospholipase A2 reduces arachidonic acid release. Use of intra-articular corticosteroids for osteoarthritis in dogs has not been well-described, but benefits and deleterious adverse effects of intra-articular corticosteroids in horses and people have been well-documented.

Reports in dogs using the cranial cruciate ligament-deficient stifle model showed a positive effect from both intra-articular methylprednisolone acetate and triamcinolone, with significantly reduced incidence and size of osteophytes, significantly reduced cartilage lesions and significantly suppressed stromelysin synthesis and interleukin-1.1,2 Side effects are minimal; however, some dogs show signs of discomfort for the first 12 hours after injection. Studies evaluating the safety and efficacy of long-term treatment in dogs are not well reported.

Regenerative stem cell therapy

Regenerative stem cell therapy can also be used for persistent clinical elbow osteoarthritis. Adult regenerative stem cells are multipotent cells from bone marrow, joint capsule and fat tissue capable of maturing into bone, cartilage, tendon or ligament cells and can be used to repair and regenerate damaged tissues such as the cartilage in osteoarthritis.

The therapy involves adipose-derived progenitor cells (APCs). The cells are harvested from fat behind the shoulder, between the back legs or falciform ligament. After the fat is collected, it is shipped to be processed (cultured and expansion of APCs) and then returned for intra-articular injection. The patient is sedated, and the cells are injected into the osteoarthritic joints. A recent report evaluating the effect of intra-articular stem cell therapy for the treatment of elbow osteoarthritis in dogs found significant improvement in lameness, range of motion and client evaluation (functional disability scores).3

Dr. Canapp is an ACVS board-certified surgeon who practices orthopedic surgery and sports medicine at the Veterinary Orthopedic & Sports Medicine Group in Annapolis Junction, Md.

REFERENCES

1. Pelletier JP, Mineau F, Raynauld JP, et al. Intraarticular injections with methylprednisolone acetate reduce osteoarthritic lesions in parallel with chondrocyte stromelysin synthesis in experimental osteoarthritis. Arthritis Rheum 1994;37(3):414-423.

2. Pelletier JP, Martel-Pelletier J. Protective effects of corticosteroids on cartilage lesions and osteophyte formation in the Pond-Nuki dog model of osteoarthritis. Arthritis Rheum 1989;32(2):181-193.

3. Black LL, Gaynor J, Adams C, et al. Effect of intraarticular injection of autologous adipose-derived mesenchymal stem and regenerative cells on clinical signs of chronic osteoarthritis of the elbow joint in dogs. Vet Ther 2008;9(3):192-200.