Canine OA: advanced diagnostics and alternative therapies

Lisa Svara/stock.adobe.comAccording to the American College of Veterinary Surgeons, osteoarthritis (OA) affects about a quarter of the canine population. If poorly managed, the condition can become debilitating, with a decidedly negative impact on quality of life. In a session at Fetch dvm360 conference in Baltimore, Sherman Canapp Jr., DVM, MS, DACVS, DACVSMR, CCRT, discussed advanced diagnostics and alternative therapies that can improve outcomes in dogs with OA.

Get in-depth with arthroscopy

When it was first introduced in veterinary medicine, arthroscopy was a daunting procedure that involved large and expensive equipment. As technology has evolved, arthroscopy equipment has become smaller (with a device the size of a needle), more compact and significantly less costly. Today, advanced diagnostics such as arthroscopy allow veterinarians to take an in-depth look at arthritic joints; the modality can also be used for treatment.

One such technological development, Dr. Canapp said, is a needle scope from Companion Animal Health called INsight. Touted as a practice-friendly alternative to magnetic resonance imaging, INsight is an in-office needle scope system that facilitates illumination and visualization of the joint space. This device was originally designed for human orthopedics but can also be used in veterinary medicine.

“INsight eliminates the need for a traditional trocar and cannula system,” Dr. Canapp explained. By providing illumination and visualization of an affected joint, the device gives direct insight into a patient's condition, minimizing the likelihood of false readings associated with indirect diagnostic modalities. Use of INsight may also reduce the time from injury to recovery.

Needle placement is the same, whether arthroscopy is diagnostic or therapeutic. When using arthroscopy to diagnose and treat elbow dysplasia, for example, place the animal in lateral recumbency with a small towel under the elbow to widen the joint space. With the veterinary technician applying a small amount of pressure to keep the joint space open, use aseptic technique to locate the epicondyle and insert a 22-gauge needle distal to it. After aspirating fluid to ensure needle placement in the joint space, aspirate out all of the joint fluid because it contains toxic inflammatory mediators. After removing fluid, inject lactated Ringer's solution to distend the joint. “This helps allow access to the needle scope,” Dr. Canapp explained. Following the scope, a therapeutic injection (e.g., hyaluronic acid or platelet-rich plasma) can be administered.

Despite its benefits, arthroscopy is not used as frequently in small animal medicine as in equine or human medicine, possibly due to small animal general practitioners' concerns about their ability to perform arthroscopy. Telemedicine, Dr. Canapp said, could address this issue, naming the Canadian company Reacts as a provider of telemedicine-type software that would allow veterinarians to use real-time, patient-side guidance during a scoping procedure.

For veterinarians who may not see the value of arthroscopy in cases of chronic OA, Dr. Canapp countered that using arthroscopy to stage the OA and to arthroscopically clean out and resurface the affected joint can help enhance the efficacy of conservative treatment approaches (nonsteroidal anti-inflammatory drugs [NSAIDs], acupuncture, etc.) and improve overall joint function.

Alternative treatment modalities

Transcutaneous electrical nerve stimulation, hydrotherapy/underwater treadmill therapy, shock therapy, manual therapy and laser therapy can all be used to treat canine OA.

Laser therapy. Also known as photobiomodulation (PBMT), laser therapy involves the absorption of infrared light by cytochrome C to initiate a complex physiologic cascade of reactions to reduce inflammation, among other benefits.

Dr. Canapp highlighted a 2018 study that evaluated the use of PBMT in canine elbow dysplasia. Compared with the placebo group, dogs receiving PBMT had lower Helsinki pain scores, more improvement in lameness scores and a greater reduction in NSAID dose. Study results suggest the overall therapeutic benefit of PBMT in canine OA.

Which treatment and what dose?

In the early days of using alternative therapeutic modalities in veterinary medicine, the dose used was often not powerful enough to reach deeper tissues, such as with hip arthritis. Thus, Dr. Canapp advises veterinarians to ask themselves these four questions when determining which of these modalities to use and in what dose:

Is the right amount of energy being used?

Is the scanning speed (e.g. laser therapy) too fast or too slow?

Is the chosen modality the most appropriate treatment technique?

What are the patient's physical characteristics (skin pigmentation, body condition, etc.)?

Biologics. Biologics include hyaluronic acid, platelet-rich plasma (PRP) and stem cells. There are many indications for treating with biologics:

Intolerance to oral medication

Alternative treatment for more severe OA

Reduction of inflammation postoperatively and during episodes of acute exacerbations of lameness

Restoration of a joint's physiochemical properties after surgery, given blood's and saline's toxicity to chondrocytes.

A significant benefit of biologics is their long-lasting effects, which can reduce the use of oral medications such as NSAIDs.

Despite their indications and benefits, intra-articular injections of biologics are less common in small animal medicine than in equine or human medicine, possibly because of small animal practitioners' uncertainty about which biologic to use and in what dose as well as fear of damaging the joint.

Dr. Canapp focused his biologics discussion on PRP and stem cells. Platelets, he explained, contain alpha granules that upregulate stem cells and modulate pain and inflammation; these granules also contain growth factors. For blood samples being processed to concentrate platelets, it helps to know which blood components are the “good guy” platelets (monocytes and lymphocytes that are healthy for the joint space) and which are the “bad guys” (red blood cells and neutrophils that are toxic to the joint space). He noted, though, that PRP that is overly concentrated with platelets can cause tissue damage; the ideal platelet concentration is about sixfold, he said.

When using a PRP machine, make sure it has been validated for dogs. Dr. Canapp advised veterinarians to inquire about the company's data on preparing PRP for dogs, because the process used to separate blood components varies between species.

The majority of PRP injections can be done by knowing the appropriate anatomic landmarks; ultrasound and needle scoping can also be used for guidance. Dr. Canapp advised against icing the area after the injection, because ice can adversely affect platelets. NSAIDs can also affect platelets negatively, so he suggested that patients taking them should stop one week before PRP therapy and up to two weeks after therapy.

For mild OA, the effect of a single PRP injection can last for several months. Patients with more severe OA will need a series of injections, spaced two to four weeks apart, for six months. Encouraging pet owners to take pre- and post-PRP therapy videos can help veterinarians assess treatment response and determine whether the patient needs to continue with PRP therapy.

Stem cells are present in many different parts of the body, can self-renew, and should be collected using minimally invasive techniques. Stem cell therapy is regulated heavily in human medicine. Regulations for stem cell therapy are not as heavy-handed for veterinary use, Dr. Canapp noted, but an abundance of caution is still advisable to practice safe methods for patients.

Tissue samples can be collected from the fat (e.g. falciform fat) or bone marrow; collecting from the femoral bone marrow is preferable. After sending the sample out for processing, it can take about two to three weeks to receive an injection-ready sample. When analyzing the sample, it is important to differentiate the actual stem cells-CD+ mesenchymal cells-from other cells such as fibroblasts.

Concluding thoughts

Dr. Canapp finished his presentation by emphasizing the importance of first correctly diagnosing and staging OA. From there, he said, veterinarians can devise an appropriate multimodal management strategy, including weight management, supplements, rehab therapy, exercise, medical management, intra-articular injections and others. He encouraged veterinarians not to be afraid of using these alternative therapies and to counsel pet owners on long-term OA management.

Dr. JoAnna Pendergrass received her DVM from the Virginia-Maryland College of Veterinary Medicine. Following veterinary school, she completed a postdoctoral fellowship at Emory University's Yerkes National Primate Research Center. Dr. Pendergrass is the founder and owner of JPen Communications, a medical communications company.