Traumatic Muscle Pathology
Classifications and definitions
|
We can use a classification system inspired by that used in human medicine to specify the diagnosis and prognosis.
|
A cramp is an involuntary permanent contraction of the muscle, which gradually regresses through stretching.
|
An ache is a type of myalgia that appears after inhabitual exertion and entails localized inflammation. It regresses when the muscle is warmed up and disappears when physical activity is resumed.
|
A contracture is an involuntary permanent contraction of muscle fibers that cannot be relieved by simply stretching the muscle.
|
A sprain is a simple lesion of certain muscle fibers that is caused by stretching the muscle too far or too quickly.
|
A pulled muscle is one in which the muscle fibers have torn, associated with desinsertion from the aponeurosis.
|
A rupture is a significant break in the entire muscle.
|
Muscle rupture on Racing Greyhound
|
Specialists in racing Greyhounds prefer to use a different classification system, which is more arbitrary and divides the muscular disorders into three groups:
|
Stage 1: Development of myositis from a simple contusion with localized inflammation.
Stage 2: The localized myositis is associated with a sprain and/or tear in the corresponding fascia.
Stage 3: Rupture of the muscle fibers with development of a hematoma.
|
Muscle rupture on Racing Greyhound
© UMES
|
Dogs can damage any of their muscles during sports or work, but the muscles of the forelegs are most often the ones affected. These limbs are indeed greatly solicited. During exertion, they support two-thirds of the animal's body weight and participate in the acceleration process (20% of muscular power). They also serve as shock absorbers (80% of power).
|
Stages 1 and 2 are generally encountered in powerful muscle groups like the triceps, femoral biceps, quadriceps, fascia lata, semi-tendon and semi-membrane groups. Dorsolumbar muscles may also be affected.
|
We make a distinction between muscular accidents caused by direct or exogenous trauma and muscular accidents caused by indirect or endogenous trauma.
|
Direct Trauma
The cause varies. It may be bumping into other dogs (during Greyhound races for example), from bumping into a hard object (ring, sled), or from falling. The seriousness of the lesions depends on how violent the trauma was and on the functional state of the muscle during impact (contraction or relaxation).
|
Indirect Trauma
Indirect traumas are specific to the sporting activity in question. The physiopathogenic mechanisms of these disorders is not completed understood, but we do know that they are caused by sudden neural-vascular-muscular dysfunction. This type of accident is always linked to activity that solicits a muscle for performance that is beyond its capacities for contraction, extension, and elasticity. The collection of intramuscular hematomas is encouraged by the elevated capillary density inside the muscle from training.
|
Factors that contribute to direct trauma are generally human in origin, such as poor preparation of the terrain or equipment or improper use of the lure in Greyhound racing. These factors are easily controllable.
|
On the other hand, the factors contributing to or predisposing an animal indirect trauma vary greatly and are quite numerous:
|
– the dog: The extremely muscular close-couple body type is the most often affected, especially if the animal suffers from articular asynchronism;
|
– the preparation of the muscle: poorly managed training (either excessive or lacking), insufficient or nonexistent warm-up of muscles, and general fatigue considerably increase the risk of accidents;
|
– the stress from the environment, insufficient rest and/or sleep, unbalanced diet, and neglected water supply are also contributing factors to accident;
|
– finally, use of anabolic drugs is an aggravating factor.
|
When a muscular accident happens, a simple and precise clinical exam is enough to establish a diagnosis. From least to most serious, we distinguish between: sprains and aches, tears and ruptures, ruptures from endogenous trauma, and contusions from exogenous trauma.
|
A muscular injury is diagnosed through a visual examination, careful palpation, and witnesses accounts of the accident. Indeed, Sporting dogs don't show pain very much and may not limp despite serious injury. For these reasons, it is extremely important to study accounts of the accident since the animal may not really begin to limp until 24 hours after the trauma, but may simply show a slight drop in performance a subtle change in its gait (stiffness in the first three or four minutes of walking).
|
Jumps may often cause muscular traumas.
© Royal Canin
|
The easiest time to pinpoint a muscular injury is, in fact, the day after it happens, once the dog has resumed training.
|
During Stage I of an injury, if the animal is examined before inflammation and swelling have developed, there will be localized pain and firm palpation of the muscle is painful. Nevertheless, we do not note a hot zone and there is virtually no loss of function.
|
During Stage II, clinical symptoms become more severe. There is noticeable loss of function and limping, and we note a weakness in resistance to force and an asymmetry. The injured area is swollen and hot. The pain is localized and sometimes we can palpate the rupture in the tissue.
|
In Stage III limping is extreme and there is complete asymmetry in the animal's limbs. There are clear localized signs: hematoma, swelling, sub-cutaneous hemorrhaging. The pain is severe and we can easily palpate the rupture in the tissue.
|
Several other examinations may be done to determine the diagnosis and prognosis for the muscular trauma.
|
Biological amounts (CPK, LDH, blood and urinary creatinine) are only useful in obtaining an overview of the lesion and determining the prognosis.
|
Echography is not used enough yet in the field of canine muscular-tendinous pathology, despite the fact that it allows us to quickly determine the extent of the muscular lesions (dissociation of fibers, ruptures, amount and location of hematomas) and sometimes to intervene by puncturing the hematomas. Echography does not, however, allow us to track fiber scarring that may prove incapacitating for the animal.
|
Infrared thermography allows us to objectively visualize the vascular reactions to the trauma (hyperthermia of hematomas), and/or reflex vascular reactions (hypothermia due to vasomotor problems). It also allows us to monitor the evolution of the lesions and helps the veterinarian make decisions regarding therapy. The high price of infrared thermography limits is use in current practice.
|
Finally, scanning can also be quite helpful by providing very precise diagnoses. Its use is generally reserved for extremely valuable dogs because it is a very expensive exam, unusable in current canine sports medicine.
|
Before determining local and general treatments, certain basic principles must be specified. First of all, rest is imperative and no weight whatsoever must be put on the limb in the case of serious ruptures or tears. Nevertheless, the limb must not be immobilized in a cast because it may cause serious vascular complications. Massages are contraindicated for serious injuries because they actually slow and hinder healing and can cause severe or recurring complications (extensive fiber scarring). Finally, to guard against infection, avoid puncturing or injecting into hematomas.
|
During a traumatic muscular accident, treatment depends on how serious and how old the injuries are.
|
Medicinal treatments must take into account the pharmacokinetic information of the molecules listed on the drug products for Sporting dogs, sled dogs, ski-pulka dogs, and racing Greyhounds.
|
If the injury is recent, we apply ice to the damaged muscle for a few hours at a time for two to three days. A compressive bandage should hold the limb at the place of injury. We apply anti-inflammatory and antalgic liniments. At first they should be applied without massage and held in place by the bandage. Then, once the injury has begun to heal, (after four to six days), the liniments should be applied during massage.
|
For injuries in Stage II (7% to 8% of cases) or Stage II (2% to 3% of cases), we administer non-steroid anti-inflammatories orally for one to two weeks, with a low posology. For serious Stage II lesions, reparative surgery is often necessary. Surgical intervention generally takes place 72 hours after the accident, after the application of ice and compressive bandages have reduced the hematomas. In the event of a large, palpable hematoma, we perform an aseptic puncture to reduce pain and the risk of neurological complications from compression.
|
Convalescence takes about two weeks. The rehabilitation period is evaluated based on the severity of the muscular lesions. For example, for four centimeters of damaged muscle, rehabilitation will last four weeks. During a Stage I injury, rest is prescribed in addition to the local treatments. Only walking is allowed for four to six weeks. Training can then be resumed with progressively longer work loads.
|
|
