FORELIMB INJURIES
Some the most common injuries in sporting dogs involve the shoulder. This is especially true in agility dogs.5 Common shoulder problems include biceps brachii tenosynovitis, supraspinatus insertionopathy, infraspinatus contracture and
bursal ossification, teres minor myopathy, and medial shoulder instability (medial glenohumeral ligament sprain, subscapularis
tendinopathy, and joint capsule laxity).
Other forelimb injuries in sporting dogs, which have been described elsewhere, include shoulder trauma, elbow injuries, and
carpal injuries. Shoulder trauma can result in fracture, osteoarthritis, or luxation. Injuries to the elbow encountered in
canine athletes frequently include luxation, medial and lateral collateral ligament rupture, congenital or traumatic fragmented
medial coronoid process, or osteoarthritis of unknown cause.4
Biceps brachii tenosynovitis
The biceps brachii originates on the supraglenoid tubercle; passes across the shoulder joint, down the humerus in the intertubercular
groove; and inserts on the proximal medial ulna and the proximal cranial radius. Its function is to flex and supinate the
elbow, extend the shoulder, and passively stabilize the shoulder in neutral and flexed positions.6,7 Biceps brachii tenosynovitis is usually a chronic injury of the forelimb that develops over time as the tendon tears slowly
and then subsequently develops dystrophic mineralization.8 On orthopedic examination, pain will be elicited on palpation of the tendon and flexion of the shoulder joint. In some cases,
conservative management will resolve the problem, and some veterinarians recommend rest with one injection of corticosteroids
into the shoulder joint, which is confluent with the tendon bursa; however, to my knowledge, no definitive published reports
have shown efficacy of corticosteroid injections for biceps tendonitis.8
Rehabilitation, without surgery, often includes therapeutic ultrasound, passive range of motion exercises, strengthening exercises,
and underwater treadmill therapy.9
2. A postoperative lateromedial radiograph obtained after arthroscopic tenotomy of the biceps brachii tendon and tenodesis
of the tendon to the proximal humeral diaphysis.
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When surgical treatment is indicated, the tendon is released arthroscopically (tenotomy) and may or may not be fixed to the
proximal humerus.8 I perform fixation in these cases with a lag screw and washer if the dog's owner is planning to return the dog to sporting
activities (Figure 2).10 Rehabilitation, as outlined above, is recommended postoperatively to develop the brachialis muscle that also flexes the
elbow and may prevent continued overload of the biceps brachii muscle when the dog uses it to flex the elbow.11
The prognosis is good to excellent for most dogs treated surgically with either technique, but their level of performance
in athletics after surgery has not been scientifically evaluated.8,10,12 Further research in injured sporting dogs after their performance in athletic competition is needed to determine how well
these dogs regain their function as athletes.
Supraspinatus insertionopathy
3. A lateromedial radiograph of the shoulder showing ossification of the supraspinatus tendon (arrow).
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The supraspinatus muscle originates on the scapula and crosses the shoulder joint cranially to insert on the humerus at the
greater tubercle. It functions to extend the shoulder and is a passive stabilizer of the shoulder joint.6 Supraspinatus insertionopathy or tendinopathy involves the supraspinatus tendon becoming torn or strained over time. This
chronic injury may not result in lameness until there is ossification of the tendon (Figure 3) and impingement on the biceps brachii tendon, but lameness can occur without ossification.13,14 On physical examination, the dog will exhibit pain when the shoulder is flexed and the tendon is palpated cranially over
the shoulder joint; the dog may also exhibit pain when the biceps brachii tendon is palpated.9,15 Supraspinatus tendon injuries can be diagnosed with ultrasonography or magnetic resonance imaging (MRI), and injuries are
often bilateral.14
The decision to treat should be based on a dog's clinical presentation since mineralization of the tendon can be present and
identified as an incidental finding on radiographs without any clinical signs of lameness or pain on palpation. Treatment
can be aimed at surgical removal of the ossified body, but the condition can recur, and, in one report, three of 16 dogs (19%)
had a poor surgical outcome.14 Extracorporeal shock wave therapy, laser therapy, and therapeutic ultrasound have been reported as treatments for the condition,
along with underwater treadmill therapy and exercises to restore shoulder function and resolve pain associated with the condition,
but prospective placebo-controlled trials have not been reported.9,15,16 In horses, various tendon injuries have been treated successfully with platelet-rich plasma and stem cells; this method
of stimulating repair of a strained tendon is currently under investigation in dogs.17-20 For athletes that do not respond to rehabilitation, surgery is recommended to resect the torn or mineralized portion of
the tendon.14
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