Bicipital tenosynovitis

What it is

Bicipital tenosynovitis is inflammation of the tendon of origin of the biceps brachii and of the synovial sheath that surrounds it. It usually results from repetitive strain or partial tears of the tendon, and leads to fibrosis of the tendon and sheath, adhesions and mineralisation. It may also be secondary to other shoulder diseases, such as osteochondral fragments from osteochondritis dissecans that lodge in the sheath, or to mineralisation of the supraspinatus tendon nearby.

Who it affects

Middle-aged to older dogs of medium and large breeds, often active or overweight; the Labrador and golden retriever and the Rottweiler are frequently affected.

Anatomy involved

The biceps brachii (m. biceps brachii) arises from the supraglenoid tubercle of the scapula. Its tendon crosses the shoulder joint and runs distally in the intertubercular groove of the humerus, between the greater and lesser tubercles, held in place by the transverse humeral retinaculum. Its synovial sheath is an extension of the shoulder joint capsule, so diseases of the joint and of the tendon are closely linked. The muscle inserts on the radial and ulnar tuberosities; it flexes the elbow and extends the shoulder.

Clinical signs

Chronic, intermittent thoracic limb lameness, often subtle, that worsens after exercise. The key finding is pain on the biceps test: flexing the shoulder while the elbow is extended and pressing directly on the tendon in the intertubercular groove. Muscle atrophy may develop in long-standing cases.

Diagnosis

• Orthopaedic examination with the biceps test.
• Radiographs of the shoulder, including a skyline view of the intertubercular groove: sclerosis or osteophytes of the groove, mineralisation within the tendon or sheath.
• Ultrasound, arthrography, MRI or arthroscopy to assess the tendon and sheath directly; joint fluid analysis.

Treatment

Conservative treatment first: rest and controlled exercise, weight loss, NSAIDs and physiotherapy; an intra-articular or intra-sheath injection of a corticosteroid is often effective in chronic cases. Dogs that do not respond, or that have a substantial tear, are treated surgically by biceps tenotomy, often arthroscopic, which relieves pain, or by tenodesis, which reattaches the tendon to the proximal humerus. Prognosis is good with either approach.