Overview:

Osteoarthritis (OA) is the most common form of arthritis in dogs affecting a quarter of the population. It is a chronic disease characterized by loss of articular cartilage that is covering and protecting the ends of bones in most joints of the body. In association, there are other abnormalities present that include new bone formation around the joint (osteophytosis) as a response to increased instability and inflammation in the joint leading to pain.

In contrast to humans, OA in dogs most commonly occurs secondarily due to developmental orthopedic disease (cranial cruciate ligament disease, hip dysplasia, elbow dysplasia). The joints most commonly affected are the hip, stifle, and elbow. The exception to this is idiopathic (unknown cause) OA of small joints of digits (manus and pes) that is seen in older dogs. Contributing factors to OA include genetics, age of dogs, bodyweight, obesity, gender, exercise and diet.

Signs and Symptoms:

Signs of OA are often times non-specific and include:

  • Activity impairment: reluctance to exercise, decrease in overall activity, stiffness, lameness, inability to jump, changes in gait such as ‘bunny-hoping’.
  • Pain on manipulation: behavioral changes such as aggression or signs of discomfort.

Diagnostics:

Diagnosis of OA is usually made by a combination of physical exam and imaging modalities such as X-rays.

  • Initially physical exam will orient towards the affected joint or joints. The veterinarian will palpate the limbs and joints to assess for painful response, thickening of joint capsule, accumulation of joint fluid (effusion) or sometimes osteophytes and muscle atrophy (wasting).
  • The most common imaging modality used is X-ray. These are of limited use though, because they only give information on bony changes (osteophytosis) and show only limited soft tissue changes therefore should be combined with physical exam findings.
  • Other diagnostic tools becoming more popular include magnetic resonance imaging (MRI) which can provide information regarding soft tissue structures (ligaments, menisci) and computed tomography (CT) that is good for assessing bony changes in joints with more complex anatomy such as elbows, carpi (wrists) or tarsi (ankles).

Treatment:

Treatment recommendations for OA are multimodal which means they include different approaches and can be either conservative or surgical or a combination of both. All treatment decisions are made based on individual patients and in discussion with the animal owner and surgeon.

Here are some of the most commonly used approaches:

  • Nonsteroidal anti-inflammatory drugs (carprofen, meloxicam, deracoxib, ketoprofen etc.).
  • Adjunctive pain medications (amantadine, gabapentin, tramadol, codein, corticosteroids, acetaminophen) although there is an overall lack of studies that is evaluating their efficacy.
  • Joint supplements (chondroitin sulfate, glucosamine sulfate, omega-3-fatty-acid supplementation).
  • Local intra-articular injections (in the joint) with different agents (corticosteroids, platelet-rich plasma, hyaluronic acid).
  • Weight control. An overweight dog places additional force on joints causing more pronounced OA changes and can ultimately be more painful with limited mobility.
  • Activity modification, which means that high-impact activities such as running or jumping should be limited as they can cause more inflammation and pain. These activities should be replaced with more controlled activity like leash walks. Low impact consistent activity is good to help build the muscles around the joints and will eventually promote joint stability.
  • Surgical management can be indicated and in some instances the best treatment choice (cranial cruciate ligament rupture) and includes arthrodesis (fusion of joints), total joint replacement surgery (most commonly in hips, elbows), surgical stabilization of instable joints (for stifle: suture-based or osteotomy-based techniques).

Aftercare and Outcome:

Unfortunately OA is a progressive disease and continues to worsen with time. The conservative approach can slow down the progression of disease and many dogs can live comfortably for years following diagnosis. If surgery is performed the recovery of those dogs is usually very good especially with total joint replacement surgery as the diseased joint is completely removed and replaced.