What is arthritis?
Arthritis is defined as inflammation of joint. It occurs as a primary disease or secondary to known conditions affecting the joint concerned. Primary arthritis (also known as primary degenerative joint disease) is degeneration of cartilage occurring in elderly dogs for no known reason other than wear and tear that come with ageing or in obese dogs. In most other dogs, arthritis usually occurs secondary to trauma, unstable joints, poor alignment, conformation defects, or congenital conditions such as osteochondritis dissecans or hip dysplasia.
There are three common changes in arthritis:
(i) Degeneration of joint cartilage.
(ii) Small bone growth occurs at the margin of the joint or ligament attachments to the joint margin, or within the joint capsule.
(iii) Scarring of bone in areas where cartilage has been eroded.
Common signs on dogs with arthritis
(i) Pain - It is quite difficult to determine if an arthritic dog experiences pain as dogs cannot tell us that they are in pain and they do not cry or yelp. The most obvious sign of limb pain with arthritis is lameness. Other signs of pain that may be noticed are loss of exercise tolerance and reluctance to play, jump or go up and down stairs. The dog may 'bunny hop', take short steps, or show irritability and behavioural change when his/her affected legs are involved. Further, the pain may be seen to worsen with cold, damp weather or change in physical activity as with humans.
(ii) Stiffness - An arthritic dog experiences stiffness upon rising from a resting state. The stiffness disappears initially as the dog warms out of it, but with time the stiffness may become continual as scarring and reduced joint movement occur.
(iii) Joint grating - A grating sensation can be felt on dogs with severe arthritis. It occurs when bone starts to rub against bone.
(iv) Obesity - Most arthritic dogs are overweight. Obviously increased weight puts extra stress on the joint which in turn contributes to quicker abrasion and degeneration of the joint cartilage. In some cases dogs with chronic pain from arthritis seem to improve with weight reduction alone.
(v) Age - Arthritis is rarely seen in immature dogs as comparing with adults, except in cases where they have cartilage diseases such as Legg-Perthes disease or osteochondritis dissecans.
How can arthritis be treated?
The best treatment for arthritis is prevention. When known conditions that can potentially to lead to arthritis, corrective measures or environmental changes that lessen the problem should be implemented (e.g. surgical repair for ruptured cruciate ligaments, diet reduction for overweight dogs with hip dysplasia).
The objectives of treatments, medical or surgical, are to relieve pain, maintain function and range of movement, and to maintain or regain normal activity.
(i) Rest - When cases of arthritis flare up inflammation exists as debris is being absorbed and removed by the lining of the joint capsule. During this time weight bearing activities tend to aggravate and prolong the inflammation. Ideally the dog should largely be rested, but not completely or else the muscles will wither and joints will stiffen. Hence light walking is ideal (or if it is not possible gentle passive movement of the affected joints should be performed), but running and jumping should be stopped.
(ii) Heat - Heat (in the form of warm towels or heat pocks) are beneficial in relieving muscle spasm and pain in chronic, long standing cases. However, cold is indicated to reduce pain, swelling and bleeding in acute injuries.
(iii) Exercise - Limited exercise is advisable but weight bearing activities must be minimal. Swimming is a viable option as it is non-weight bearing exercise and it assists in reducing joint capsule adhesions.
(iv) Medication - Most medications do nothing to reverse arthritis. They serve to relieve pain and discomfort, or lubricate the joint. The common anti-inflammatories prescribed are buffered Aspirin, Rimadyl and Metacam, whilst the common 'joint lubricant' is Cartrophen.
Surgical treatment for arthritis really should only be considered when pain or movement is not helped by the non-surgical treatments. Surgical operations include removal of abnormal bone growth (which then reduces the tugging on the joint capsule and hence prevents pain), soft tissues or muscle releases, fusion of joints (to relieve instability and pain), arthroplasty and amputation (e.g. of a chronically arthritic toe).