RICKETS IN AN ADOPTED CHILD

RICHARD B. ISLINGER, M.D., Orthopaedic Resident

WILLIAM G. MACKENZIE, M.D., Attending Pediatric Orthopaedic Surgeon

July 15,1996

CLINICAL CASE PRESENTATION

ORTHOPAEDIC DEPARTMENT

THE ALFRED I. DUPONT INSTITUTE

WILMINGTON, DELAWARE

CASE HISTORY:

This patient was first seen here at the age of 2 and 1/2 years. She was referred here with the diagnosis of nutritional rickets.

Significant past medical history included the following:

She was adopted from Russia and according the Russian medical documents was born to a mother who suffered from alcohol abuse. She was born prematurely (gestational age not available) at 2000gms, 44cm, with an apgar of 5/6. Furthermore, she had previously been diagnosed with encephalopathy, anemia, fetal alcohol syndrome and rickets. - Since arriving here in the U.S., the adopted mother had her on vitamin supplements for 7 weeks. The mother states that the child began walking at the age of 27 months.

She was seen by both orthopaedics and pediatrics and her physical exam was as follows:

- She was well below the 5th percentile for both height and weight

- There was delayed psycho-motor and speech development

- Multiple rachitic deformities of the skeleton to include severe bowing of the tibias bilaterally (45 degrees), pigeon chest (pectus carinatum), thickened/widened wrists bilaterally and a trendelenberg gait on the left side.

INITIAL LAB STUDIES:

Ca: 9.7 - nl

PO4: 6.2 - mildly increased

Alk Phos: 401 - mildly increased

UA: WNL

Vit D 1-25: 92 - mildly increased

X-RAY STUDIES:

- "cupping" of the distal radius and distal femur

- widening of the physis

- angular deformities

She was diagnosed with nutritional rickets and was treated with Calciferol 1200ug\day. Her first follow-up was 5 weeks later where she was noted to have a decreased Trendelenburg lurch and a decrease in her wrist thickening. 10 months later on follow-up she had a noticeable decrease in her tibial bowing along with almost complete resolution of the growth plate abnormalities. At her last follow-up on March 4th 1996 (she was 4 + 4yo) she had mild anterior lateral bowing of her tibia bilaterally with a normal thigh-foot angle and a mechanical axis that crossed the midline of her knee.

RICKETS:

Background:
Clinical:
Histology:
Radiographic:
CAUSES:
Management:
SELECTED LITERATURE REVIEW:
Normal development:
  1. The tibiofemoral angle in the newborn and infant is in varus (15 degrees). At 18 to 24 months the tibiofemoral angle becomes more neutral. The tibiofemoral angle then changes to valgus and is at its maximum at age three to four (12 dgrees). It then corrects itself to that of the adult by age 7 (6 degrees in boys, 7 in girls).
  2. Internal tibial torsion often accompanies physiologic genu varus and accentuates the "bowlegs"
  3. Pes planus and external tibial torsion may accompany genu valgum- will accentuate "knock knees"
Rachitic pathology
When caring for rachitic deformities it is of paramount importance to correct the underlying metabolic abnormality first prior to any surgical intervention. If the metabolic abnormality is not corrected, surgical intervention will likely fail.
TREATMENT RECOMMENDATIONS:
OUTCOME EXPECTATIONS:
REFERENCES:
  1. Ferris B, Walker C, Jackson A, Kirwan E.: The Orthopaedic Management of Hypophosphatemic Rickets. J Pediatr Orthop 11:367-373; 1991.
  2. Kling TF Jr.: Angular Deformities of the Lower Limbs in Children. Orthop Clin North Am 18:513-527; 1987.
  3. Paley D, Tetsworth K.: Mechanical Axis Deviation of the Lower Limbs. Clin Orthop 280:65-71; 1992.
  4. Salenius P, Vankka E.: The Development of the Tibiofemoral Angle in Children. J Bone Joint Surg (Am) 57:259-261; 1975.
  5. Stanitski DF.: Treatment of Deformity Secondary to Metabolic Bone Disease With the Ilizarov Technique. Clin Orthop 301:38-41; 1994.
  6. Zaleske DJ. Metabolic and Endocrine Abnormalities. In: Lovell W, and Winter RB, 4th ed. Pediatric Orthopaedics. Philadelphia: Lippincott-Raven, 1996.