Musculoskeletal ImagingOsteoarthropathy
a disease of the joints and bones.
Hypertrophic osteoarthropathy is characterized by clubbing of the digits of the hands and feet, enlargement of the extremities as a consequence of periarticular and osseous proliferation, and painful and swollen joints. Two categories are recognized, primary (hereditary or idiopathic) and secondary.
Primary hypertrophic osteoarthropathy
, also called
pachydermoperiostosis, is inherited as an autosomal dominant trait. Patients may have the complete syndrome (with pachydermia, periostitis and cutis verticis gyrata), the incomplete form (with sparing of the scalp), or the forme fruste (with pachydermia and minimal or absent periostitis). On radiographs, periostitis predominates. Poorly defined bone outgrowths in the epiphyses of
tubular bones and sometimes also in the axial skeleton are especially characteristic of this disease. Diaphyseal expansion in
tubular bones and sclerosis of the spongiosa in both appendicular and axial skeletal sites are evident. Other features are prominent sinuses, moderate enlargement of the mandible, and
calcification and ossification of ligaments.
Secondary hypertrophic osteoarthropathy
occurs as a consequence of another disease process (Table 1).
Osteoarthropathy, Table 1. Some causes of secondary hypertrophic osteoarthropathy.
In the secondary form, digital clubbing (at times associated with focal areas of tuftal hypertrophy or resorption), joint pain, and tenderness are frequent manifestations. Initially periosteal bone deposition occurs in the diaphyses of the tibiae, fibulae, radii, ulnae, and sometimes the femora, humeri, metacarpals, metatarsals and phalanges. Although periostitis becomes prominent in metaphyses, it does not usually extend into the epiphyses. Among the types of periostitis are a single layer of new bone, laminated or onion peel pattern, and irregular areas of periosteal elevation. A diffuse, symmetric increased uptake on bone scans in the diaphyses and metaphyses of tubular bones along their cortical margins creates a distinctive parallel track sign.
Neuropathic osteoarthropathy occurs in patients with a number of diseases, including syphilis, diabetes mellitus, and syringomyelia. This form of osteoarthropathy is discussed under its specific name.
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