Once osteoarthritis is present on a radiograph, dysplastic changes are irreversible and usually continue to progress over time. If a dysplastic dog has secondary arthritis and pain, most owners elect to first treat their dog with medical management. The key to medical management of arthritis is weight control and exercise management. Studies have shown that up to 76% of severely dysplastic dogs with arthritis secondary to HD are able to function and live comfortable quality lives with conservative management.
With weight control, the goal is to prevent the dog from becoming overweight to reduce mechanical stresses applied to the hip joints. In general terms, the ribs should be easily palpated and there should be an indentation in front of the pelvic wings (waist line).
Controlled exercise is indicated to prevent or relieve the inflammatory process that leads to the pain associated with arthritis. The amount and difficulty of the activity is determined on a trial and error basis. Exercise should start with short leash walks and be gradually increased until the dog reaches the desired level of activity. If clinical signs start to reappear, the amount of exercise is scaled back to a level that will not cause clinical signs. Overall, exercise should fit to an individual dog's maximum intensity level with the goal to maintain muscle tone and cardiovascular function without causing pain, stiffness, and inflammation to the joint. The right amount of exercise helps to maintain muscle tone and strength and stabilizes the unstable dysplastic joint. Exercise also improves joint range of motion which in turn, keeps the dog more comfortable. Swimming, because it is a non-weight bearing exercise, can be a very useful means of maintaining muscle tone and range of motion without placing concussive forces on the joint.
Keep the dog in a warm environment. Warmth tends to help control the pain of arthritis from hip dysplasia. As in people, arthritic pain in dogs tends to be worse in the damp and cold of winter. Providing a well-padded and warm bed will help alleviate some of the pain associated with osteoarthritis. An egg-crate foam bed for dogs is commercially available. Applying superficial heat in the form of heating pads may also relieve pain. Care must be taken not to burn the skin especially with an electric heating pad. Heat works best for chronically inflamed joints from arthritis while cold works better to treat acute (sudden) types of joint injury.
Numerous drugs are available to control the signs of osteoarthritis secondary to HD. Nonsteroidal anti-inflammatory pain relievers can be used during bouts of lameness. These drugs inhibit prostaglandin release which decreases the inflammatory process and therefore, less pain is produced. These medications can also be given an hour or so before known periods of exercise to decrease inflammation. Side effects may be seen in some dogs which include vomiting, diarrhea, and inappetence.
Various alternative drug therapies known as disease-modifying osteoarthritis agents can be used. According to the manufacturers, these drugs work by providing the raw materials to enhance the synthesis of glycosaminoglycan and hyaluronate that cannot be adequately produced in the diseased arthritic joint. These are the molecules that form proteoglycan, which is an important constituent of the hyaline cartilage that lines the joint. These drugs may also enhance the synthesis of other macromolecules by cartilage cells that inhibit degradative enzymes produced within the arthritic joint. Controlled studies have been reported about the positive effects in people for osteoarthritis. No controlled studies, to date, have been reported on the clinical response when treating arthritis in dogs but clinically most dogs seem to respond.
- Oral disease-modifying osteoarthritis agents known as nutraceuticals are now on the market. These drugs take approximately one month to reach therapeutic levels in the blood stream. Minimal to no side effects have been reported with their use.
- Injectable disease-modifying osteoarthritis agents can be injected into the joint, vein or muscle and have been shown to be a useful adjunctive treatment for osteoarthritis in dogs. Since these drugs are injected, more rapid therapeutic levels are obtained. They may be initially used with the oral nutraceuticals for a series of injections for one month since the oral agents take approximately one month to reach therapeutic levels. The literature indicates that the earlier these drugs are administered, the more likely it will decrease inflammation and protect against cartilage degradation in osteoarthritis.
The use of these drugs should be tailored for the individual dogs and any improvement noted. If side-effects occur like GI upset, the medication should be given with food or discontinued altogether. If there is persistence of obvious lameness/pain after approximately 6 months using one medication, change the therapy to a different medication from the above choices.
In younger dogs usually less than 10 months old with only subluxation caused by dysplasia, a triple pelvic osteotomy (TPO) can be performed to reestablish joint stability and encourage normal joint development and minimize abnormal biomechanical forces on the joint before osteoarthritis occurs. This procedure is not indicated if osteoarthitis is already present. Recovery time is about 6 weeks and a good success rate has been reported with return of normal hip function.
For older dogs (over 10 months) that already have established osteoarthritis and can no longer be medically managed, a total hip replacement is the treatment of choice for reestablishing normal, pain-free limb function and joint mechanics. A high degree of success has been reported with this surgery and like the TPO, post-op recovery is about 4-6 weeks. The main disadvantage to this surgery is the high cost.
An alternative surgery which is more of a salvage procedure when there is significant osteoarthritis and a total hip is cost prohibitive is a femoral head and neck excision. This eliminates hip pain by removing the femoral head and neck and initiating the development of a fibrous false joint that permits ambulation. The false joint is less stable with a reduced range of motion than the normal joint which in turn, causes an abnormal gait. Nevertheless, pain relief with adequate function can be achieved. The procedure can be performed in all dogs of all sizes, but there are usually better long-term success rates in smaller dogs less than 20 kg (about 44 pounds). Preoperative muscle mass and early postoperative physical therapy are two important factors in determining a successful outcome. This surgery is usually not as successful if there is severe disuse muscle wasting (atrophy) present and/or the animal is obese.
Heavier dogs usually require more extensive postoperative rehabilitation to help promote an ambulatory pain-free false joint. Rehabilitation is aimed at preserving and promoting the leg's muscle mass, strength and range of motion through early (3-5 days) postoperative weight bearing ambulation and passive range-of-motion exercises. Early ambulation can be achieved by assisting the dog in getting up and walking. A towel can be placed under the abdomen to make assistance easier to perform in heavy dogs. Leash walks and/or swimming beginning the day of discharge from the hospital should be performed until near normal use of the leg returns. Passive range of motion physical therapy is also necessary to increase muscle strength and flexibility. Dogs that are obese, inactive or have substantial muscle atrophy and have poor owner compliance with physical therapy recommendations are poor candidates for this surgery.