Mucopolysaccharide disorders in orthopaedic surgery.

The mucopolysaccharidoses (MPSs) are a family of disorders characterized by the accumulation of glycosaminoglycans, which is caused by enzyme deficiencies in the lysosomal metabolism of these normal cellular byproducts. Skeletal abnormalities are early and prominent features of MPS, and the orthopaedic surgeon is often the first healthcare provider to raise suspicion for this diagnosis. Recently developed medical therapies for the management of MPS (ie, hematopoietic stem cell transplantation, intravenous enzyme replacement therapy) have led to increased lifespan but have not had much effect on the development of skeletal deformities. Patients must be monitored carefully and treated surgically as necessary. Conditions that may require surgical management include cervical spine and atlantoaxial instability, gibbus deformity, hip dysplasia and osteonecrosis, genu valgum, and carpal tunnel syndrome. The orthopaedic surgeon should have a basic understanding of MPS and of the clinical presentation, musculoskeletal abnormalities, and radiographic findings associated with this group of disorders.