Charcot Neuroarthropathy of the Wrist in Type 1 Diabetes

Charcot neuroarthropathy typically affects the joints of the foot and ankle in diabetes (1); neuroarthropathy of the wrist is extremely rare (2,3).

A 53-year-old right-handed white Caucasian woman, who was a rose grower, presented to rheumatology with an uncomfortable, swollen right wrist. She had type 1 diabetes of 23 years’ duration and had undergone right ulnar nerve decompression at the elbow for focal entrapment neuropathy 3 years previously. She had residual wasting of the small muscles of the right hand with mild weakness of the abductor digiti minimi and sensory signs consistent with bilateral ulnar neuropathy (more marked on the right). At the right wrist, there was loss of 50^o of both dorsiflexion and palmar flexion.

Plain X-ray showed cystic changes in the distal radius and carpus with joint space narrowing, which had not been present 3 years earlier at the time of ulnar nerve decompression. Laboratory investigation revealed a markedly elevated alkaline phosphatase (250 units/l [normal range 25–110]) and a normal C-reactive protein (<2 mg/l [normal range 0–10]). No sedimentation rate was recorded. Radioisotope bone scan demonstrated increased uptake in the right radiocarpal joint. A diagnosis of osteoarthritis was made, and she was treated with a splint and nonsteroidal anti-inflammatory drugs with some initial symptomatic benefit. However, she experienced continual wrist swelling, and repeat plain X-ray 2 years later showed further loss of joint space and more subchondral sclerosis but no periarticular osteoporosis (Fig. 1A). This was accompanied by progressive deformity of the right wrist, eventually leading to marked limitation of movement and loss of function. At referral to our clinic, the clinical appearances (Fig. 1B) and sequence of events suggested a probable diagnosis of wrist neuroarthropathy. In addition, there were also signs of a marked peripheral sensorimotor neuropathy affecting the lower limbs and a typical Charcot pattern of deformity affecting the left foot (although it had not previously been recognized as such). This had started with a spiral fracture of the left fibula following minor trauma, with later development of spontaneous fractures of the proximal phalanx of the second toe and the base of the fifth metatarsal, eventually leading to typical clinical and radiological appearances of midfoot neuroarthropathy.

Charcot neuroarthropathy rarely affects joints other than the foot and ankle in diabetes (1). Joint involvement in the upper limb is extremely unusual; only two reports of neuroarthropathy affecting the wrist have been described before (2,3). The likely explanation for the rarity of wrist neuroarthropathy probably reflects the lesser degrees of peripheral sensorimotor and autonomic neuropathy affecting the upper compared with the lower limbs and the fact that the latter possess major weight-bearing joints (especially foot and ankle), which are subjected to continual trauma. Neuroarthropathy likely results from the combination of loss of protective sensation, a direct result of sensorimotor neuropathy, and hemodynamic changes (hyperemia) due to autonomic neuropathy, which eventually lead to osteolysis and demineralization of bone (4), in the presence of recurrent minor joint trauma (5). We believe that within a susceptible milieu (later development of foot neuroarthropathy), the impact of ulnar entrapment neuropathy (6) and the patient’s vocation (rose pruning, which generated recurrent wrist trauma) contributed to the development of wrist neuroarthropathy in this particular case. When neuroarthropathy affects the lower limb, treatment is focused on weight-sparing maneuvers and off-loading of the joint (5). However, this case suggests that the benefits of using casts in neuroarthropathy may not lie solely in weight redistribution/off-loading, but also in reducing the attendant hyperemia by enforced underuse of the limb.

Charcot neuroarthropathy can, albeit rarely, affect joints other than those of the foot (2,3,7). Early recognition is crucially important because joint immobilization combined with the use of bisphosphonates may halt the process of joint disintegration and prevent ensuing joint deformity and loss of function (5,8).