Intra-Articular Injection of the Inferior Radioulnar Joint

Indications and Clinical Considerations

The radioulnar joint is susceptible to developing arthritis from a variety of conditions that all have the ability to damage the joint cartilage. Osteoarthritis of the joint is the most common form of arthritis that results in radioulnar joint pain. However, rheumatoid arthritis, posttraumatic arthritis, and psoriatic arthritis also are common causes of radioulnar pain secondary to arthritis. Less common causes of arthritis-induced radioulnar pain include the collagen vascular diseases, infection, and Lyme disease. Acute infectious arthritis usually is accompanied by significant systemic symptoms, including fever and malaise, and should easily be recognized by the astute clinician and treated appropriately with culture and antibiotics, rather than injection therapy. The collagen vascular diseases generally present as a polyarthropathy rather than a monoarthropathy limited to the radioulnar joint, although radioulnar pain secondary to collagen vascular disease responds exceedingly well to the intra-articular injection technique described later.

The majority of patients who present with radioulnar pain secondary to osteoarthritis and posttraumatic arthritis pain complain of pain localized to the distal forearm. Activity, especially pronation and supination of the joint, makes the pain worse, with rest and heat providing some relief. The pain is constant and is characterized as aching. The pain may interfere with sleep. Some patients complain of a grating or “popping” sensation with use of the joint. Instability of the distal ulna and crepitus may be present on physical examination and can be identified by performing a distal radioulnar joint stress test ( Fig. 77.1 ).

In addition to the previously mentioned pain, patients suffering from arthritis of the radioulnar joint often experience a gradual decrease in functional ability with decreasing radioulnar range of motion, making simple, everyday tasks, such as using a screwdriver, corkscrew, or turning a doorknob, quite difficult. With continued disuse, muscle wasting may occur and an adhesive capsulitis with subsequent ankylosis may develop.

Plain radiographs are indicated in all patients who present with radioulnar pain. Based on the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Ultrasound imaging and magnetic resonance imaging of the distal radioulnar joint are indicated if joint instability or damage to the soft tissues is suspected ( Fig. 77.2 ).

Clinically Relevant Anatomy

The radioulnar joint is a synovial, pivot-type joint that serves as the articulation between the rounded head of the ulna and the ulnar notch of the radius ( Fig. 77.3 ). The joint’s primary role is to optimize hand function allowing pronation and supination of the forearm. It is lined with synovium, and the resultant synovial space allows intra-articular injection. The entire joint is surrounded by a relatively weak capsule.

The radioulnar joint also may become inflamed as a result of direct trauma or overuse of the joint. It is innervated primarily by the anterior and posterior interosseous nerves, and is bounded anteriorly by the flexor digitorum profundus and posteriorly by the extensor digiti minimi.