Atlanta Case 15

Q.

What are the major orthopaedic concerns with this condition?

A.

This, of course, is Down's syndrome or Trisomy 21 ( 95% trisomy 21; 2% mosaics and 3% translocations). Incidence about 1 in 600 live births falling to 1 in 250 in mothers over 35 years.

There are several orthopaedic problems possible in these children.
1. Atlanto-axial instability. Some 10% show increased atlanta -dens interval ( ADI). They may have Occiput -C1 instability , odontoid hypoplasia, cervical spondylolisthesis and hypermobility of their mid cervical spine.
2. Scoliosis. Occurs in about half the patients and is of an idiopathic nature in most.
3. Hip joint laxity. The generalized ligamentous laxity in these patients probably predisposes them to hip instability and to recurrent dislocation even after open reduction and femoral/pelvic osteotomies. Acetabular dysplasia is very common and can occur into adulthood.
4. Slipped upper femoral epiphyses. The slips are easily missed in this population and therefore are diagnosed later and may be more severe with a higher incidence of AVN. Some have concommitant hypothroidism which increases the risk of slip.
5. Lax ligaments possibly contribute to their genu valgum and patella dislocations. Again recurrences are common despite surgical correction.
6. Several other problems can occur including hallux valgus deformity in these flexible flat feet, a polyarticular arthropathy resembling rheumatoid and leukemia in about 1% which may first present to the orthopaedic clinic. They also are infection prone.

It's little wonder that these gentle children can terrorise the most hardened orthopaedic surgeons with their deguiling smile! This is Down's syndrome or Trisomy 21 ( 95% trisomy 21; 2% mosaics and 3% translocations). Incidence about 1 in 600 live births falling to 1 in 250 in mothers over 35 years.