Olecranon Bursa Injection Techniques

Indications and Clinical Considerations

Bursae are formed from synovial sacs that allow easy sliding of muscles and tendons across one another at areas of repeated movement. These synovial sacs are lined with a synovial membrane invested with a network of blood vessels that secrete synovial fluid. Inflammation of the bursa results in an increase in the production of synovial fluid with swelling of the bursal sac. With overuse or misuse, these bursae may become inflamed, enlarged, and, on rare occasions, infected. Although there is significant intrapatient variability as to the number, size, and location of bursae, anatomists have identified a number of clinically relevant bursae, including the olecranon bursa. The olecranon bursa lies in the posterior aspect of the elbow between the olecranon process of the ulna and the overlying skin. It may exist as a single bursal sac or in some patients as a multisegmented series of sacs that may be loculated.

The olecranon bursa is vulnerable to injury from both acute trauma and repeated microtrauma. Acute injuries frequently take the form of direct trauma to the elbow when playing sports such as hockey or falling directly onto the olecranon process. Repeated pressure from leaning on the elbow to rise or from working long hours at a drafting table may result in inflammation and swelling of the olecranon bursa. Gout or bacterial infection rarely may precipitate acute olecranon bursitis ( Fig. 64.1 ). If the inflammation of the olecranon bursa becomes chronic, calcification of the bursa may occur with residual nodules, called gravel.

The patient with olecranon bursitis frequently complains of pain and swelling with any movement of the elbow, but especially with extension. The pain is localized to the olecranon area, with referred pain often noted above the elbow joint. Often, the patient is more concerned about the swelling around the bursa than the pain. Physical examination reveals point tenderness over the olecranon and swelling of the bursa, which at times can be quite extensive ( Fig. 64.2 ). Passive extension and resisted shoulder flexion reproduce the pain, as does any pressure over the bursa. Fever and chills usually accompany infection of the bursa. If infection is suspected, then aspiration, Gram stain, and culture of the bursa, followed by treatment with appropriate antibiotics, are indicated on an emergent basis. When the olecranon bursa is infected, rice bodies are often present ( Fig. 64.3 ). Plain radiographs and/or ultrasound imaging of the posterior elbow may reveal calcification of the bursa and associated structures consistent with chronic inflammation ( Fig. 64.4 ).

Clinically Relevant Anatomy

The elbow joint is a synovial, hinge-type joint that serves as the articulation among the humerus, radius, and ulna ( Fig. 64.5 ). The joint’s primary function is to position the wrist to optimize hand function. The joint allows flexion and extension at the elbow, as well as pronation and supination of the forearm. The joint is lined with synovium and covered by a dense capsule that thickens medially to form the ulnar collateral ligament and laterally to form the radial collateral ligaments. These dense ligaments, coupled with the elbow joint’s deep bony socket, make this joint extremely stable and relatively resistant to subluxation and dislocation. The anterior and posterior joint capsule is less dense and may become distended if there is a joint effusion. The olecranon bursa lies in the posterior aspect of the elbow joint between the olecranon process of the ulna and the overlying skin. The olecranon bursa may become inflamed as a result of direct trauma or overuse of the joint.

The elbow joint is innervated primarily by the musculocutaneous and radial nerves, with the ulnar and median nerves providing varying degrees of innervation. At the middle of the upper arm, the ulnar nerve courses medially to pass between the olecranon process and the medial epicondyle of the humerus. The nerve is susceptible to entrapment and trauma at this point. At the elbow, the median nerve lies just medial to the brachial artery and occasionally is damaged during brachial artery cannulation for blood gases.