Counsel the family from the outset about the possibility of amputation
If pre-fracture: clamshell brace - no evidence bracing prevents fracture or deformity
If impending fracture/fracture/pseudoarthrosis: MRI first to see extent and how much to resect
Serial observation + bracing until maturity
Q5What is the '4 in 1 osteosynthesis'?▸
1. Resection of pseudoarthrosis + fibrotic periosteum
2. Correct angular deformity: bone grafting, acute shortening, or bone transport
3. Enhance biology: BMP2,7, periosteal flap, autogenous bone graft +/- bone transport
4. Stable fixation with Ilizarov followed by IMN through the ankle joint (often most difficult - William's rod)
Q6What did the EPOS 2000 (Gill) study recommend?▸
340 patients; pre-fracture clamshell brace
Fracture -> Ilizarov (provides compression, allows lengthening/bone transport) -> IM nail
IM nail options: antegrade rush pin, splint the ankle to control the distal fragment, or William's rod
William's rod through STJ and TTJ if <4 years old; proximalise it 2 years post-op if not grown out of the ankle joint
Amputate after 3 unsuccessful operations, severe LLD (>15cm) or non-functional limb (Symes, prosthesis protects the pseudoarthrosis)
Q7Why is the Ilizarov frame the method of choice and what are the prognostic factors?▸
EPOS study: excellent stability; allows complete resection of the pseudoarthritic area regardless of segment length (lengthening/bone transport)
Enables weight bearing, which stimulates healing of bone and soft tissue
Can transport the fibula distally to avoid valgus ankle deformity
Poor prognostic factors: young age, advanced Crawford staging, NF (not mentioned: fibular pseudoarthrosis); reasonable success between 3-6 years
Amputate after 3 unsuccessful operations, LLD >15cm or non-functional limb (Symes)
Q8What is the argument for the timing of surgery in congenital pseudarthrosis?▸
Older child: difficult to provide stable fixation in a small child even with Ilizarov; difficult to weight bear with the frame, which is needed to stimulate bone growth
Younger child: if delayed, a braced and protected leg cannot develop normally - becomes dysplastic, loses function, shorter from growth retardation
Based on EPOS, reasonable success between 3-6 years (the fibromatosis in the pseudarthrosis area has greater osteolytic activity in smaller children)
Q9Bone transport versus acute shortening - what does the EPOS study suggest?▸
Bone transport has a lower fusion rate
Deep muscles and periosteum move with the transported segment but superficial muscle and fascia move very little
Major vessels lengthen and become tortuous distally, causing kinking
EPOS suggests acute shortening + LLD correction via proximal metaphyseal lengthening after corticotomy
Q10What is the pathology and the functional outcome at maturity?▸
Fibrous hamartoma in pathological periosteum -> strangulation of blood supply, decrease osteogenicity, increased osteoclastic resorption
Dysplastic bone -> failure of new bone formation and segmental weakening
Anterolateral bowing associated with NF (50%), ED syndrome, amnionic band syndrome
At maturity: FWB 40%, LLD 60%, walk unlimited 70%, no ankle 30%, sports <30%
Q11What radiographic patterns are described in the progression of congenital tibial dysplasia?▸
Dense cortex
Narrowed medullary canal (widened cortex)
Cystic lesion
Dysplastic segment
Q12Which classification do these features represent?▸
The Crawford classification of congenital pseudarthrosis of the tibia
Types I-IV: dense canal, widened cortex, cystic, then dysplastic pseudoarthrosis
Q13Describe the clinical and radiographic findings.▸
Left leg bowing with apex posterior
The ankle is not in a normal resting posture
X-ray: tibia and fibula bowing with apex posterior
Correlate clinically and obtain an AP film to see whether the bowing is posteromedial
Q14What is the diagnosis and its natural history?▸
Posteromedial bowing of the tibia
Physiological and commonly associated with intra-uterine malpositioning
Benign course, usually self-remodels
No syndromal correlation
Q15What history and examination findings would you look for?▸