One or more bones of the limbs may be involved, but the spine, ribs, and skull are rarely affected. When the disease occurs along the full length of a limb, however, the hyperostotic process almost always extends to the shoulder girdle or pelvis as well. Pelvic obliquity can ensue from adduction contractures of the hips.

Clinical Manifestations. Patients report pain, stiffness, limitation of motion, and deformity. The pain, usually over the affected bones and joints, can radiate along the limb.

When the hyperostosis extends to the growth plate, growth may be altered, resulting in angular or limb length deformities. Involvement of the articular cartilage leads to osteoarthritis.

Hyperostosis affecting the full length of a limb is almost always accompanied by extensive fibromatosis, with a “ruddy wood” texture on palpation. This soft tissue manifestation lies close to the affected bones and joints (most often the hands and feet), causing contractures, muscle weakness, and limitation of joint motion. Soft tissue changes are often the first evidence of this disorder in children. Hand involvement can evolve into carpal tunnel syndrome.

Diagnostic Studies. Radiographs reveal a broad, irregular linear density along the axes of the long bones. The linear streaks may not be as evident in radiographs taken early in the disease, but they gradually increase in size and density as the child grows. In the epiphyses of the long bones and in the small bones of the hands and feet, the hyperostosis takes the form of spots and patches that resemble osteopoikilosis (see Plate 4-26).

Histologic examination reveals an excessive amount of normal-appearing bone formed by membranous ossification. Thickened, sclerotic, and somewhat irregular laminae surround and almost obliterate the haversian systems (osteons). Ectopic ossification may also occur near the joint or may extend into the soft tissue along the fascial planes.

Treatment. Surgical management of melorheostosis focuses on preventing or correcting deformities. To ameliorate contractures and joint stiffness, excision of the foci, fasciotomy, and capsulotomy are done. For deformities of bone, osteotomy, epiphysiodesis (see Plate 4-35), triple arthrodesis, and, occasionally, amputations of deformed digits are performed. Myelopathy has been rarely reported in those patients with spine involvement. Unfortunately, no medical or surgical treatment can eradicate the pain of this disorder, and close partnership with a pain management team helps to improve patient comfort.