Definition
Rickets
- pediatric disorder secondary vitamin D or calcium deficiency
- results in defective mineralization of the growth plate
- widened growth plates
- weak bones with bowing
Physiology of vitamin D
| Generation of vitamin D | Action of vitamin D |
|---|---|
|
Vitamin D3 ingested - activated by sunlight - hydroxylated in liver - activated in kidney under PTH control |
Intestine - increases calcium absorption Kidney - decreases calcium excretion Bone - increases calcium release |
Causes
Acquired or nutritional vitamin D deficiency most common cause world wide
| Vitamin D deficiency | Congenital disease | Vitamin D metabolism |
|---|---|---|
|
Dark skinned children Cold climates Inadequate sunshine Vegetation |
Vitamin D dependent rickets Type 1 - defect in 1 alpha hydroxylase - converts 25 (OH) to biologically active 1,25 (OH)
|
Kidney failure / Renal insufficiency |
| Vitamin D supplementation |
Vitamin D independent rickets Type 2 - mutation in vitamin D receptor
|
Phenytoin |
|
X linked hypophosphataemic rickets - vitamin D resistant rickets - impaired tubular resorption phosphate - increased loss of phosphate via kidneys - treatment phosphate + calcitriol
|
Differential diagnosis
Blounts
Achondroplasia / skeletal dysplasia
Primary hypoparathyrodism
Osteogenesis imperfecta
Clinical presentation
Bowing - develops during periods of rapid growth / toddlers
Osteopenic fractures - recurrent clavicle fractures / stress fractures
Kyphoscoliosis
Short stature - adults < 5 foot
Teeth - delayed formation / cavities
Xray
Classic signs
- widened irregular physis plate
- cupped and flared metaphysis
Tibial and femoral bowing
Valgus malalignment
Other joints
Blood tests
Alkaline phosphatase - increased secondary to low phosphate
Serum 25-hydroxyvitamin D - decreased
Serum phosphate - reduced
Urinary phosphate - elevated in x-linked hypophosphatemai
Management
Angular deformity
Options
Guided growth / temporary hemiepiphysiodesis
Osteotomy
Guided growth
Technique
Eight plate surgical technique PDF
Arthroscopy techniques guided growth PDF
Results
- 26 children with rickets undergoing eight plates to correct angular deformity
- 77% complete correction
- 15% required osteotomy
Grote et al J Pediatr Orthop 2023
- 24 children with rickets treated with hemi-epiphysiodesis versus 37 non rickets control
- in rickets correction up to 36% slower
- rickets less likely to completely correct
- rickets more likely to require secondary procedures
Osteotomy
Indication
Bowing
Results
- deformity correction tibia / femur in 47 children with X-linked hypophosphatemic rickets
- high risk of recurrent deformity with external fixation alone
- reduced risk with external fixation + flexible nails