Definition

Osteoarthritis of the wrist refers to the painful degeneration of the articular surfaces that make up the wrist due to noninflammatory arthritides. It commonly affects the joints between the distal radius and the proximal row of carpal bones. Symptoms include pain, swelling, stiffness, and crepitation. Radiographs will reveal different degrees of joint space narrowing, cyst formation, subchondral sclerosis, and osteophyte formation.

Secondary osteoarthritis resulting from post-traumatic conditions, as can be seen after distal radius fractures, carpal fractures, and carpal instability, is the most common form [1]. Primary osteoarthritis in the wrist is rare. The Framingham study showed a 9-year incidence of only 1% of radiographically significant wrist osteoarthritis in women and 1.7% in men. These rates are significantly lower than the rates of thumb basal joint osteoarthritis (30%), distal interphalangeal joint arthritis (28%-35% in patients older than 40 years), and radiographic hand osteoarthritis in patients 80 years and older (90%-100%) [2]. Rare conditions that may cause wrist osteoarthritis include idiopathic osteonecrosis of the lunate (Kienböck disease) and the scaphoid (Preiser disease). Distal radius fractures that have healed inappropriately (malunited) can also be the cause (Fig. 40.1). In considering malunited fractures of the distal radius, abnormal parameters that have been shown to be associated with wrist arthritis include the following: on an anteroposterior radiograph, an intra-articular step-off of more than 2 mm and radial shortening of more than 5 mm; and on the lateral radiograph, a dorsal angulation of more than 10 degrees [3–5].

Carpal fractures that fail to heal, particularly of the scaphoid, can also be the cause of arthritis [6]. This bone is predisposed to nonunions biologically because of its fragile vascular supply and biomechanically on account of the shear forces it encounters [7,8]. Other factors associated with nonunions include fracture displacement, fracture location, and delay in initiation of treatment [9,10]. Features of a scaphoid nonunion that appear to be associated with arthritis are the displacement of the cartilaginous surfaces and the loss of carpal stability [11,12]. Both of these lead to abnormal loading of the cartilage and consequently to ensuing arthritis. This pattern of arthritis is known as scaphoid nonunion advanced collapse (SNAC) (Fig. 40.2).

Carpal instability can also result in uneven loading of the articular surfaces and subsequent arthritis [13] (Figs. 40.3 and 40.4). The most common form of carpal instability is scapholunate dissociation [14]. It consists of a disruption of the interosseous ligament between the scaphoid and lunate. The resultant abnormal biomechanics lead to abnormal loading and subsequent arthritis, a pattern known as scapholunate advanced collapse [1] (SLAC).

Symptoms

Wrist pain is the presenting symptom in the overwhelming majority of patients. For the most part, this pain is of insidious onset, although many patients will recall a particular event that brought it to their attention. It is diffusely located across the dorsum of the wrist. It may be activity related and may bear little correlation to radiographic findings. Patients may also report inability to do their daily activities because of weakness, but on further questioning, this weakness is often secondary to pain.

Another presenting symptom is stiffness, particularly in flexion and extension of the wrist. Pronation and supination are usually not affected, unless the arthritic process is extensive and also involves the distal radioulnar joint. Motion may also be associated with a clicking sensation or with audible crepitation.

Complaints about cosmetic deformity are also common, particularly after distal radius fractures that have healed with an inappropriate alignment. Swelling is also commonly noted by the patients. This swelling is essentially a representation of the malunited fracture, but in patients with advanced arthritis irrespective of the etiology, it may represent synovial hypertrophy or osteophyte formation. In this situation, the swelling tends to be located in the dorsoradial region of the wrist (Fig. 40.5).

Physical Examination

Examination of the wrist includes a thorough examination of the entire upper limb. Comparison with the opposite side is useful to determine the degree of motion loss, if any. In wrist osteoarthritis, the most obvious finding may be loss of motion. Normal range of motion includes approximately 80 degrees of flexion, 60 degrees of extension, 20 degrees of radial deviation, and 40 degrees of ulnar deviation [15]. Comparison with the opposite side, if it is not involved, is useful to determine the degree of motion loss.

The wrist is palpated for evidence of cysts or tenderness. Tenderness just distal to Lister tubercle may be a sign of pathologic change at the scapholunate joint, including scapholunate dissociation, Kienböck disease, or synovitis of the radiocarpal joint. Tenderness at the anatomic snuffbox may indicate a scaphoid fracture or nonunion and, in early SNAC wrists, may be the site of radioscaphoid degeneration. In the presence of pancarpal arthritis, the tenderness is usually diffuse.

Provocative maneuvers should also be performed to check for signs of carpal instability. The scaphoid shift test of Watson evaluates for scapholunate instability [16]. In this test, the examiner places a thumb volarly on the patient’s scaphoid tubercle, and the rest of the fingers wrap around the wrist to lie dorsally over the proximal pole of the scaphoid. As the wrist is taken from ulnar deviation to radial deviation, the thumb will apply pressure on the scaphoid tubercle and force the scaphoid to sublux out of its fossa dorsally in ligamentously lax patients as well as in those with frank scapholunate instability. Once pressure from the thumb is released, the scaphoid will then shift back into its fossa. This finding is best demonstrated in those who have ligamentous laxity or those with recent injuries. Patients who have chronic injuries often develop sufficient fibrosis to prevent subluxation of the scaphoid out of its fossa. However, they often still have pain that is reproduced with this maneuver. Comparison with the unaffected side is essential, especially if the patient has evidence of generalized ligamentous laxity.

The strength of the abductor pollicis brevis is tested by asking the patient to palmar abduct the thumb against resistance, and it should be compared with the opposite side. Similarly, the strength of the first dorsal interosseus should be checked by asking the patient to radially deviate the index finger against resistance. These tests evaluate for motor deficits of the median nerve and ulnar nerve, respectively. Sensation should also be compared with the opposite side. Whereas static two-point discrimination is an excellent way to test sensation in the office, a more precise evaluation of early sensory deficits can be performed by graduated Semmes-Weinstein monofilaments. Frequently, this test requires a referral to occupational therapists who perform it.

Functional Limitations