Ultrasound-Guided Injection Technique for Olecranon Bursitis Pain
The olecranon bursa lies in the aspect of the elbow between the skin and the olecranon process of the ulna (Fig. 60.1). The bursa serves to cushion and facilitate sliding of the musculotendinous unit of the triceps muscle. The bursa is subject to inflammation from a variety of causes with acute elbow trauma and repetitive microtrauma being the most common. Acute injuries to the bursa can occur from direct trauma such as when falling on the ice onto the elbow or from being tackled when playing football or checked when playing ice hockey. Direct pressure on the elbow when pushing oneself up with the elbow or working at a drafting table has also been implicated in the development of olecranon bursitis. If the inflammation of the bursa is not treated and the condition becomes chronic, calcification of the bursa with further functional disability may occur. Gout may also precipitate acute olecranon bursitis as may bacterial, tubercular, or fungal infections.
The patient suffering from olecranon bursitis, which is also known as student’s and baker’s bursitis, most frequently presents with the complaint of severe pain with any movement of the elbow, but extension is often the most painful. Physical examination of the patient suffering from olecranon bursitis will reveal point tenderness over the olecranon process, at the acromion process, as well as in the subacromial region. If there is significant inflammation, rubor and color may be present and the entire area may feel boggy or edematous to palpation (Fig. 60.2). Swelling, which at times can be quite dramatic, is often present (see Fig. 60.2). Passive range of motion, especially extension of the elbow, may exacerbate the pain of olecranon bursitis. If calcification or gouty tophi of the bursa and surrounding tendons are present, the examiner may appreciate crepitus with active range of motion of the affected elbow.
Plain radiographs are indicated in all patients who present with elbow pain to rule out occult bony pathology. Based on the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging or ultrasound imaging of the affected area may also help delineate the presence of other elbow bursitis, calcific tendonitis, tendinopathy, triceps tendonitis, or other elbow pathology (Figs. 60.3 and 60.4). Magnetic resonance imaging or ultrasound imaging of the affected area may also help delineate the presence of calcific tendonitis or other elbow pathology.
Rarely, the inflamed bursa may become infected, and failure to diagnose and treat the acute infection can lead to dire consequences (Fig. 60.5).
CLINICALLY RELEVANT ANATOMY
The elbow joint is a synovial hinge-type joint that allows the distal humerus to articulate with the proximal radius and ulna (Fig. 60.6). The joint allows flexion and extension as well as supination and pronation. The joint’s articular surface is covered with hyaline cartilage, which is susceptible to arthritis and degeneration. This membrane gives rise to synovial tendon sheaths and bursae that are subject to inflammation. The entire elbow joint is surrounded by ligaments, which, coupled with the extremely deep bony articular socket, makes the joint stable throughout its range of motion. The joint capsule is lined with a synovial membrane, which attaches to the articular cartilage. This membrane gives rise to synovial tendon sheaths and bursae that are subject to inflammation and swelling, especially in the anterior and posterior aspects of the joint where the joint capsule is less dense. The olecranon bursa lies in the posterior aspect of the joint, while the cubital bursa lies anteriorly (Fig. 60.7). Both are subject to the development of bursitis with misuse or overuse of the elbow joint. The primary innervation of the elbow joint comes from the musculocutaneous and radial nerves with some lesser contribution from the median and ulnar nerves. As the ulnar nerve passes inferiorly down the upper arm, it courses medially at the mid humerus to pass between the olecranon process and medial epicondyle of the humerus. The nerve is extremely susceptible to entrapment and trauma at this point. Anteriorly, the median nerve lies just medial to the brachial artery and occasionally susceptible to damage during puncture of the brachial artery when drawing arterial blood gasses.