There is a wide range of treatment options available for treating arthritis (also known as osteoarthritis or degenerative joint disease).

Rest: Dogs with degenerative joint disease need adequate rest. Rest helps to decrease inflammation and strengthen joints. Too much exercise and over-use of the damaged joints will aggravate symptoms and may also accelerate joint destruction. Unfortunately, it is often difficult to determine how much rest and exercise a pet needs.

Overexertion: As a guideline, any activity that causes your pet to become acutely lame for a period of time afterward is excessive and the level of activity should be reduced accordingly. Avoid strenuous exercise and periods of overexertion, which can accelerate the destruction within the joints.

Exercise: Properly controlled exercise will help maintain muscle tone and joint flexibility. Failure to provide adequate exercise is just as bad as providing too much. Controlled exercise can consist of several short walks on a leash every day, interspersed with short periods of rest. Swimming, when possible, is another ideal form of exercise, providing exercise without stressing the joints. As the dog strengthens, and if there are no adverse side effects, such as lameness, soreness,  or stiffness, periods of exercise can be lengthened and more strenuous types of exercise added.
Your veterinarian can prove very helpful in providing advice.

Weight Reduction: Dogs that are obese should be started on a weight-reduction program. Obesity places excessive stress on joints and may hasten further joint degeneration.

Pain Relief: Currently, there are a number of treatments available to help dogs with arthritis become pain-free and mobile once again. Nutritional supplements such as Glucosamine alone or in combination, may be helpful. Recently, the introduction of new drugs such as Metacam7™ (meloxicam) and Rimadyl7™(carprofen) have dramatically changed the way veterinarians treat arthritis. Your veterinarian can advise you on which treatments are best suited for your dog.
There are also portable steps that can be used to help your dog and ease the climb up to a couch or bed or car.