DISLOCATION OF THE HIP IN CHILDREN WITH DOWN'S SYNDROME

GIUSEPPE SELVA, M.D., Pediatric Orthopaedic Research Fellow

FREEMAN MILLER, M.D., Attending Pediatric Orthopaedic Surgeon

July 25, 1995

CLINICAL CASE PRESENTATION

ORTHOPAEDIC DEPARTMENT

THE ALFRED I. DUPONT INSTITUTE

WILMINGTON, DELAWARE

CASE HISTORY:

PATIENT 1.

• HISTORY: This is a 3 year old female with Down's Syndrome whose mother noticed clicking in the left hip since age 2. At the age of 4 the patient developed a limp after falling from a bicycle. She is otherwise healthy and started walking at 24 months of age. Other significant medical history includes a recurrent otitis media.
• PHYSICAL EXAM: A full range of motion was noted, with instability of the hip. The hip was easily dislocated and reduced.
• XRAYS: The pre-operative x-ray, C T scan and operative arthrogram demonstrate the hip subluxated.

• TREATMENT: At age 5, the patient underwent a left varus derotational osteotomy, left Dega osteotomy and left posterior capsular plication . She was maintained in a spica cast for 6 weeks.
• FOLLOW-UP: At twenty-three months post-operative the hardware was removed, the hip remains stable, the patient has a mild limp and remains pain-free.

PATIENT 2.

• HISTORY: This is a 2.5 year old female with Down's Syndrome whose mother noticed few episodes of "popping in and out" in the right hip with adduction and flexion. These episodes were painless and patient had no limp. She is otherwise healthy and has just started walking. Other significant medical history includes a persistent minor atrioseptal defect and a reccurent otitis media.
• PHYSICAL EXAM: A full range of motion was noted, with instability of the hip. The hip was dislocated with extreme adduction/flexion and easily reduced.
• XRAYS: The pre-operative x-ray demonstrates a seated hip. Intra-operative arthrogram demonstates dislocation with extreme adduction/flexion.
• TREATMENT: Observation was undertaken for 18 months. As the right hip became more unstable, with recurrent episodes of dislocation, at age 4 the patient underwent a right Dega osteotomy and right posterior capsular plication. She was maintained in a spica cast for 6 weeks and in a night time abduction brace for 6 months.
• FOLLOW-UP: At twenty-five months post-operative the hip remains mildly unstable, the patient has had few episodes of dislocation (none in the last year). Patient presents no limp and remains pain-free.

DISEASE PROGRESSION:(Bennet et al, 1982)

1. Initial phase (0-2 years).
• Stable but hypermobile hips Acetabulum is well formed and even deeper than normal.
• (Rarely a child with Down S. presents with DDH.)
2. Dislocation phase (2 -10 years).
• Habitual dislocation hips spontaneously begin to dislocate without trauma.
• Children may present clicking, limping or feeling of giving away. Usually, pain is not present.
• Acute dislocation Dislocation following a minor trauma. Patients present with moderate pain, increased limp and reduced activity.
• Hips are easily reducible under anesthesia, but recurrence is common.
3. Subluxation phase
• Concentric reduction becomes rarer and dysplasia develops.
4. Fixed phase
• The patients can walk with a limp up into the early twenties even in the fixed dislocated hip phase. Pain is not a major complaint.

SELECTED LITERATURE REVIEW:

• Down's Syndrome is one of the most common causes of handicap. It occurs in 1.7 of every 1000 live births.
• Congenital heart abnormalities, orthopedic problems, high susceptibility to infections, G.I. malformations and a relatively high incidence of leukemia are the main health problems of this condition.
• Orthopaedic problems are usually related to hypotonia, ligamentous laxity and hyperflexibility of joints. They include pes planus, genu valgum, dislocation of the patella, scoliosis, spontaneous dislocation of the hip and instability of cervical spine (also related to abnormalities of C. spine).
• The occurrence of dislocation of the hip is hard to evaluate because it can occur throughout the whole life of the patient.
• Anatomy of the hip includes: a thin, weak fibrous capsule such that dislocation occurs without any tear or detachment, moderate to severe femoral neck anteversion and a noted deficiency of posterior superior acetabular rim.

REPORTED POPULATION:

   Reference             Patients and age             % sublux / dislocate            





 Diamond et al.      265 Pts          Children               4.5%           

        1981         +Adults                                                



 Bennet et. al.      220 Pts.         5 to 62                4.5%            

        1982         y.o.                                                   



 Aprin et al.        946 Pts          childhood              1.3%            

        1985         *                                                      



 Hresko et al.       65 Pts           14 to 70               18%             

        1993         y.o.                                                   

*review of records of children with Down S. registered at Children's Hospital of Boston (age 3 to 13).

TREATMENT RECOMMENDATIONS:

• Closed reduction and immobilization are highly unsuccessful. However this treatment is still suggested for patients with first-time dislocation. (Bennet et al., Gore et al., Aprin et al.)

• Surgical treatments include several procedures (performed alone or in combination):
• - Capsular plication
• - VDRO
• - Acetabular procedures (Salter; Dega, Sutherland, Chiari). Exact surgical reconstruction reccommendations can not currently be made due to insufficient data in the literature and limited individual experience.

OUTCOME EXPECTATIONS:

• The overall success rate is about 50%. However, many reported cases have a short follow-up.
• Bennet et al. reported an infection rate of 19% after surgery. They also stated that poor results should be expected when surgery is performed in the "fixed phase" of dislocation.
• THA in adulthood seems effective for pain relief and functional recovering.(Skoff et al.)
• A normal hip at skeletal maturity does not preclude later subluxation and dislocation (as previously thought). (Hresko et al. 1993).
• The development of hip dysplasia or dislocation is associated with loss of function during adult life (degenerative hip disease).

REFERENCES:

1) Aprin H., Zink W. P., Hall J. E. Management of dislocation of the hip in Down Syndrome. J. Pediatr. Orthop. 5: 428; 1985

2) Bennet G.C., Rang M., Roye D. P., Aprin H. Dislocation of the hip in trisomy 21. J. Bone Joint Surg. 64-B: 289; 1982

3) Diamond L.S., Lynne D., Sigman B. Orthopedic disorders in Down's Syndrome. Orthop. Clin. North Am. 12: 57; 1981

4) Gore D. R. recurrent dislocation of the hip in a child with Down's Syndrome. A case report. J. Bone Joint Surg. 63-A: 823; 1981

5) Hrenko M.T., McCarthy J. C., Goldberg M.J. Hip disease in adults with Down Syndrome. Journal Bone Joint Surg. 75-B: 604; 1993

6) Shaw E. D., Beals R. K. The hip joint in Down's Syndrome. Clin. Orthop. 278:101; 1992

7) Skoff H.D., Keggi K. Total hip replacement in Down's Syndrome. Orthopedics 10:485; 1987.