Triceps Tendon Injection Techniques

Indications and Clinical Considerations

Triceps tendinitis is seen with increasing frequency in clinical practice as exercise and use of exercise equipment have increased in popularity. The triceps tendon is susceptible to the development of tendinitis at its distal portion and its insertion on the ulna. It is also subject to repetitive motion that may result in microtrauma, which heals poorly because of the tendon’s avascular nature. Exercise is often implicated as the inciting factor of acute triceps tendinitis. Tendinitis of the triceps tendon frequently coexists with bursitis of the associated bursae of the tendon and elbow joint, creating additional pain and functional disability. Calcium deposition around the tendon may occur if the inflammation continues, making subsequent treatment more difficult. Continued trauma to the inflamed tendon may ultimately result in tendon rupture ( Fig. 63.1 ). Trauma to the distal triceps tendon may also result in an avulsion fracture that produces a characteristic radiographic finding known as the flake sign ( Fig. 63.2 ).

The onset of triceps tendinitis is usually acute, occurring after overuse or misuse of the elbow joint. Inciting factors may include activities such as playing tennis and aggressive use of exercise machines. Improper stretching of the triceps muscle and triceps tendon before exercise has also been implicated in the development of triceps tendinitis as well as acute tendon rupture. Injuries ranging from partial to complete tears of the tendon can occur when the distal tendon sustains direct trauma while it is fully flexed under load or when the elbow is forcibly flexed while the arm is fully extended. The pain of triceps tendinitis is constant and severe and is localized in the posterior elbow ( Fig. 63.3 ). Significant sleep disturbance is often reported. Patients with triceps tendinitis will exhibit pain with resisted extension of the elbow. A creaking or grating sensation may be palpated when passively extending the elbow. As mentioned, the chronically inflamed triceps tendon may suddenly rupture with stress or during vigorous injection procedures inadvertently injected into the substance of the tendon. With triceps tendon rupture, the patient will not be able to fully and forcefully extend the affected arm.

Plain radiographs and magnetic resonance imaging are indicated for all patients with posterior elbow pain. On the basis of the patient’s clinical presentation, additional testing, including complete blood count, sedimentation rate, and antinuclear antibody testing, may be indicated. Magnetic resonance imaging of the elbow is indicated if joint instability is suspected and to further confirm the diagnosis. Radionuclide bone scanning is useful to identify stress fractures of the elbow not seen on plain radiographs. Ultrasound imaging may also provide the clinician with useful information regarding the condition of the tendon ( Fig. 63.4 ).

Clinically Relevant Anatomy

The triceps brachii muscle is the major extensor muscle of the elbow joint and is the antagonist muscle to the biceps brachii and brachialis muscles. The triceps muscle gains its name from the 3 bundles of muscles that compose it. Each of the 3 muscles has a different origin. The long head of the triceps finds its origin at the infraglenoid fossa of the scapula. The medial head finds its origin at the groove of the radial nerve as well as the dorsal surface of the humerus, at the medial intermuscular septum, and from the lateral intermuscular septum. The lateral head finds its origin at the dorsal surface of the humerus at a point lateral and proximal to the groove of the radial nerve as well as the greater tubercle down to the region of the lateral intermuscular septum. All 3 heads are innervated by the radial nerve, with the long head of the triceps receiving innervation from the axillary nerve in many individuals. The 3 heads of the triceps muscle coalesce into the triceps tendon, which inserts onto the olecranon process and the posterior wall of the capsule of the elbow joint ( Fig. 63.5 ). The tendon is susceptible to the development of tendinitis at its insertion.