ORTHOPEDIC PROBLEMS IN DOGS
by T. J. Dunn, Jr. DVM
This article appeared in Dog World Magazine

Dogs are born to run. Well, most breeds, anyway. By looking at them, Bassets, for example, don’t seem to be built for speed and agility. But in their hearts they, like all dogs, have an innate drive to run, jump, play and seek out new and interesting vistas! And in the process of their quest to cover ground as fast as possible, dogs do sustain orthopedic injuries very similar to human athletic injuries. An orthopedic injury refers to damage to the skeletal system or associated muscles, joints and ligaments.

Most at risk for orthopedic injuries are the Greyhounds and Coursing dogs, sled dogs, hunting dogs, security dogs and Search and Rescue dogs. But every veterinarian sees non-athletic housedogs with orthopedic difficulties. Orthopedic injuries to active dogs are an inevitable outcome of the high stress demanded of the body structures. In housedogs, orthopedic problems seem most often to have two common predisposing factors… the dog being overweight and the “weekend warrior”. Any overweight dog will be excessively stressing bone, muscles, joints and ligaments while engaged in active physical exercise. Jumping over obstacles, playing Frisbee, or exuberant retrieving of far-flung tennis balls can test the limits of anatomical structures. When there is any question about a dog’s weight, opt for keeping the dog slightly thin rather than slightly heavy.

The “weekend warrior” runs a risk of orthopedic injury (even if not overweight) because of lack of conditioning in tendons, ligaments, muscles and joints. Especially in middle aged and older dogs, an infrequent 4-hour bout of vigorous exercise is less desirable than 8 thirty-minute play periods. Back pain, and even intervertebral disc prolapse that has an adverse impact on spinal cord function, can result in poorly conditioned dogs that are unaccustomed to long periods of physical activity. Try to keep your dog physically fit by frequent (not necessarily long) periods of activity and you will help keep excess weight from sneaking up on your canine athlete, too!

YOUNG DOG PROBLEMS
Some orthopedic problems have developmental manifestations in young dogs and are not a result of stress or trauma. Everyone has heard of Hip Dysplasia where a multiple of factors result in abnormal hip joint tightness and architecture. A major orthopedic problem for dogs, it isn’t the only disorder affecting a young dog’s orthopedic health. Elbow Dysplasia is less common but may require surgery to repair. It includes four specific disorders: 1) Osteochondritis dissecans (OCD) of the humeral condyle in the elbow, 2) Fragmented medial coronoid process of the ulna (FCP), 3) Ununited anconeal process of the ulna (UAP), and 4) Abnormal matching of the joint surfaces within the elbow joint. These developmental lesions often do not show up until the dog approaches a year of age and their presence is often noted after bouts of exercise. The elbow joint is remarkably stable, but when anything does go wrong the dog always displays signs of discomfort. Limping and disuse places even greater stresses on opposite limbs, too. Many elbow problems, aggravated by physical activity, really have their origins in developmental aberrations that occurred as a puppy.

Osteochondritis dissecans (OCD) more often occurs in the head of the humerus within the shoulder joint. The flap of cartilage that lifts away from the humeral head creates havoc within the shoulder joint and nearly always requires surgery for its removal and eventual healing of the joint.

Luxating patellas commonly have hereditary influences that result in improperly formed joint surfaces and muscle and tendon tension angles. Dislocating (luxating) a patella from the groove in the front of the knee always creates discomfort and predisposes the joint to repeat episodes of dislocation and arthritis. Looseness of the patella often can be demonstrated in young dogs, well before they show signs of trouble. A chronic luxating patella will need surgical intervention to keep the dog active and vigorous.

LIGAMENTS AND CARTILAGE
Ligaments are bands of fibrous and slightly elastic tissue. They connect the bones of a joint and assist in stabilizing directional movement of the joint members. Collateral ligaments on the medial and lateral sides of the knee joint, for example, are rather notorious since human athletes often sustain damage to these structures. Certainly the most common serious orthopedic injury occurring in dogs is a torn ACL (Anterior Cruciate Ligament). There are two stabilizing ligaments that cross (hence the term cruciate) inside the knee joint that allow the joint to move only in a hinge-like fashion; but when the ACL is torn, the femur actually slides across the tibial surface and creates pain, inflammation and eventually a profound arthritis. Most ACL trauma occurs when a shearing force is exerted at the knee joint, such as when the dog attempts to stop rapidly. If the shearing force overcomes the strength of the ACL, stretching or complete tearing of the ligament results. In addition, cartilage damage can result. If at the time of an injury there are abnormal forces rotating the joint, supporting cartilage called the meniscus can be torn or loosened from its attachments. Time for surgery! (A new procedure for ACL repair is currently getting quite a bit of attention from veterinary surgeons. Called the Tibial Plateau Leveling Osteotomy, the technique is actually patented! Special training is needed to perform this method of correcting a torn ACL.)

MUSCLE AND TENDONS
When muscle fibers tear, called a strained muscle, healing usually takes place within two weeks if the dog is rested. Tendons are remarkably resistant to mechanical stresses and generally an associated muscle or bony attachment will fail before a tendon will separate. But torn tendons do occur, more often due to trauma such as a laceration than to exercise overload. A torn Achilles tendon behind the hock, an injury more common in dogs that jump vigorously or pull heavy loads, can be a seriously debilitating injury. Depending upon the severity of the torn or stretched tendon either rest or surgery will be required. Tendonitis refers to inflammation and irritation of a tendon. It creates pain and commonly occurs in the shoulder joint of dogs that are raced vigorously. Tendonitis often has obscure identifying signs but with anti-inflammatory medications and rest, irritated tendons and tendon sheaths will heal well. If you expect your dog to be pulling a cart or sled, be sure to do gradual increments of resistance to insure against muscle or tendon injuries.

BACK TROUBLE
Spinal muscles, tendons, and joint structures accept an inordinate amount of physical stress. Twisting, flexing, extending, absorbing compressive forces and yet remaining flexible in spite of these stressors places a huge demand on the spinal column’s members. Muscles of the back can suffer from strains but fortunately do heal rapidly. When an intervertebral disc is compressed, however, encroachment and inflammation of nerve roots can result in persistent and debilitating pain and mobility restrictions. Trauma or degenerative forces affect the intervertebral disc and can allow disc material to protrude into the spinal canal. If the situation progresses, spinal cord function may be compromised and partial or even complete paralysis of the hind limbs occurs.

FRACTURES
Most cases of fractured bones happen because of direct trauma to the structure rather than from stresses induced by muscle contraction. Broken toes and limbs often occur due to impact injuries and spiral fractures of long bones can happen when a torsion stress impacts the bone. In some lucky (!) situations where the bone fragments are stable and are aligned well, simple splinting and confinement may be all that is required for the slow process of bone healing to occur. In other injuries, internal fixation with pins, wires, plates, screws and bands may be needed to realign and stabilize the fragments. In ideal situations, even severely fractured bones can heal well within six weeks.

PHYSICAL THERAPY
Unfortunately, this vital aspect of the comprehensive treatment of canine orthopedic problems has been often overlooked. In the textbook CANINE SPORTS MEDICINE AND SURGERY, by Bloomberg, Dee and Taylor, published by W. B. Saunders, 1998 edition, there is an entire chapter on physical therapy covering such modalities as heat/cold applications, electrical stimulation, ultrasound, electromagnetic therapy, cold laser, massage and exercise. Properly applied physical therapy will minimize musculoskeletal disability, shorten the healing time and assist in restoring normal function. Any patient, whether or not it is considered a canine athlete, should receive the benefits of physical therapy after an orthopedic injury.

Fortunately there are veterinary specialists in orthopedic surgery whose advanced training will come to the rescue when we general practitioners encounter a complicated and challenging orthopedic problem. They are experts in getting even Bassets back on the trail!