The distal radioulnar joint is a synovial pivot-type joint whose primary function is to aid in orientation of the hand in space for crucial functions like eating and drinking by allowing pronation and supination of the wrist. The joint’s articular cartilage is susceptible to damage, which, if left untreated, will result in arthritis with its associated pain and functional disability. Osteoarthritis of the joint is the most common form of arthritis that results in distal radioulnar joint pain and functional disability, with rheumatoid arthritis, posttraumatic arthritis, and crystal arthropathy also causing arthritis of the distal radioulnar joint. Less common causes of arthritis-induced distal radioulnar joint pain include the collagen vascular diseases, infection, villonodular synovitis, and Lyme disease. Acute infectious arthritis of the distal radioulnar joint is best treated with early diagnosis, with culture and sensitivity of the synovial fluid, and with prompt initiation of antibiotic therapy. The collagen vascular diseases generally manifest as a polyarthropathy rather than a monoarthropathy limited to the distal radioulnar joint, although distal radioulnar pain secondary to the collagen vascular diseases responds exceedingly well to ultrasound-guided intra-articular injection of the distal radioulnar joint.

Patients with distal radioulnar joint pain secondary to arthritis, gout, synovitis, and collagen vascular disease-related joint pain complain of pain that is localized to the distal forearm and wrist.

Activity, including pronation and supination, makes the pain worse, with rest and heat providing some relief. The pain is constant and characterized as aching. Sleep disturbance is common with awakening when patients roll over onto the affected upper extremity. Some patients complain of a grating, catching, or popping sensation with range of motion of the joint, and crepitus may be appreciated on physical examination. A distal radioulnar stress test may exacerbate the patient’s pain symptomatology and will aid the examiner in identifying instability of the distal radioulnar joint (Fig. 63.1).

Functional disability often accompanies the pain of many pathologic conditions of the distal radioulnar joint. Patients will often notice increasing difficulty in performing their activities of daily living and tasks that require pronating and supinating the forearm such as using a screwdriver and corkscrew or tuning a doorknob. If the pathologic process responsible for the distal radioulnar pain is not adequately treated, the patient’s functional disability may worsen, and muscle wasting and ultimately a frozen distal radioulnar joint may occur.

Plain radiographs are indicated in all patients who present with distal radioulnar joint pain (see Fig. 63.1). 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 (MRI) or ultrasound of the distal radioulnar joint is indicated if fracture, effusion, tendinopathy, crystal arthropathy, joint mice, synovitis, bursitis, or ligamentous injury is suspected (Fig. 63.2).

The distal radioulnar joint is a synovial pivot-type joint that allows the pronation and supination of the forearm to optimize the positioning of the hand (Fig. 63.3). 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 distal radioulnar joint is surrounded by a relatively weak joint capsule. The joint capsule is lined with a synovial membrane, which attaches to the articular cartilage. This membrane gives rise to synovial tendon sheaths and occasionally bursae that are subject to inflammation and swelling. The dorsal and volar distal radioulnar ligaments provide joint stability but are subject to strain and sprain (Fig. 63.4). The radioulnar joint is innervated primarily by the anterior and posterior interosseous nerves. The joint is bounded anteriorly by the flexor digitorum profundus and posteriorly by the extensor digiti minimi.