Introduction: Hurler syndrome (mucopolysaccharidosis type I) is an autosomal recessive disorder with characteristic progressive musculoskeletal manifestations termed dysostosis multiplex. These include dorsolumbar kyphosis with gibbus deformity, deficient femoral head ossification and acetabular dysplasia, valgus deformity of the knee, broad hands prone to carpal tunnel syndrome, pes planus and generalised joint contracture. Untreated, death occurs early in childhood. Therapeutic bone marrow transplantation (BMT) has improved life expectancy and now patients attain skeletal maturity. BMT, however, appears to have little influence on skeletal outcome, and optimum orthopaedic management is as yet uncertain.
Methods: Nineteen patients treated by BMT at a mean of 10 months (range 3–19 months), have been followed over a mean of 93 months (range 3–196 months). Five patients are now adolescent. We describe the clinical and radiological features of these patients and detail orthopaedic procedures and their outcome. Descriptive statistical analysis is used, displaying mean values and standard deviation where appropriate.
Results: All patients demonstrate characteristic acetabular dysplasia and failure of ossification of the superolateral femoral head. Nine have undergone bilateral pelvic and femoral derotation osteotomies at a mean of 48 months (range 24–105 months); mean acetabular angle preoperatively was 33 ± 3.8°. Five patients had pelvic osteotomy only. IN the remaining five patients, mean acetabular angle is 25 ± 3.3°. Genu Valgum of variable severity due to failure of ossification of the lateral aspect of the proximal tibial metaphysis is observed early. Four patients underwent medial epiphyseal stapling at a mean of 105 months. While most patients demonstrate thoracolumbar vertebral anomalies peculiar to Hurler syndrome, only five had had progressive scoliosis, two having had anterior spinal fusion at 37 and 72 months. Most patients experience symptoms of carpal tunnel syndrome from about 48 months. Only one patient has significant difficulty mobilising independently.
Conclusions: Our findings reflect the variability of musculoskeletal problems seen in Hurler syndrome. This cohort represents one of the largest available for study, and ongoing review will clarify the natural outcome of the disease and help determine if and when orthopaedic intervention is appropriate.
