Radius and ulna fractures are common and motor vehicle trauma is the most frequent cause. These injured animals tend to be young, non-neutered males who roam away from home and get hit by a car. Animals of both sexes and of any age are susceptible to this type of trauma if not kept restrained. Small cats (e.g. Italian greyhound) tend to be especially susceptible to these types of fractures with relatively minor trauma, like jumping off a bed
Animals can develop non-traumatic fractures of the radius or ulna when certain disease conditions exist. These fractures, also known as "pathologic fractures,"can occur if the animal is malnourished, has a systemic illness such as kidney disease, has an endocrine disorder such as hyperparathyroidism, has a bone infection (osteomyelitis) or has cancer of the bone.
Immature bones have growth plates (physes) that are still "open" and growing. These regions of the young bone are susceptible to damage caused by the trauma that can result in premature "closure." Due to the interrelationship between the two bones of the forearm during growth, premature closure of one growth plate before maturity can cause abnormal curvature of the bones and joint incongruities. This can result in future pain and lameness. The most common type of premature growth plate closure occurs in the distal physis of the ulna (the end of the bone near the wrist). This causes forward bowing of the forearm with lateral (outward) deviation of the carpus. Abnormalities can also occur in the elbow secondary to this type of growth plate injury.
Depending on the location and amount of energy of each particular trauma, fractures can occur in various portions of the bone. Most fractures involve the proximal, midportion or distal diaphysis (shaft) of the bones. Sometimes fracture of the ulna can occur in combination with a luxation (dislocation) of the radius at the elbow instead of a fracture of that bone. Uncommonly, joint fractures occur involving the surfaces of the elbow joint or wrist.
Fractures of the diaphysis of the radius and ulna can be classified as "open" or "closed" depending on whether the skin surface has been damaged during the injury. Open fractures have a greater chance of getting infected and may have more complications than closed fractures.
As with all fractures, fractures of the radius and ulna can also be classified as "simple" if each bone breaks into two pieces or "comminuted" if there are multiple pieces.
Each case of antebrachial fracture needs to be evaluated in its entirety (age of animal, severity of the fracture, experience of the surgeon and financial concerns of the owner) to determine the most appropriate and best form of treatment.
Inappropriate case management, inadequate surgical stabilization or poor aftercare can lead to complications, such as non-unions (fractures that will not heal), malunions (fractures that heal in an abnormal direction or orientation), osteomyelitis (bone infection), arthritis or a non-functional leg.