Updated: 6/14/2021

Anterolateral Bowing & Congenital Pseudoarthrosis of Tibia

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
4
0
0
100%
0%
Evidence
6
0
0
Topic
Images
https://upload.orthobullets.com/topic/4056/images/Clinical photo - courtesy Miller_moved.jpg
https://upload.orthobullets.com/topic/4056/images/tibial bowing xray - courtesy Miller_moved.png
https://upload.orthobullets.com/topic/4056/images/Congenital pseudo xray - courtesy Miller_moved.png
https://upload.orthobullets.com/topic/4056/images/Free fibula graft - courtesy Miller_moved.png
https://upload.orthobullets.com/topic/4056/images/indianjorthop_2012_46_6_616_104184_f3.jpg
  • summary
    • Anterolateral Bowing and Congenital Pseudoarthrosis of the Tibia are congenital conditions, most commonly associated with Neurofibromatosis Type 1, that present with a bowing deformity of the tibial.
    • Diagnosis is confirmed with radiographs of the tibia. 
    • Treatment is nonoperative with bracing for patients who are weightbearing without pseudoarthrosis or fracture. Surgical correction is indicated in the presence of pseudoarthrosis or fracture 
  • Epidemiology
    • Incidence
      • Extremely rare
      • 1:140,000-190,000
    • Risk Factors
      • Up to 55% associated with Neurofibromatosis Type 1
      • 15% associated with Fibrous Dysplasia
  • Etiology
    • Pathophysiology
      • pseudoarthrosis in not congenital, but in fact develops post-natally due to fracture non-union
    • Three types of tibial bowing exist in children
      • anterolateral bowing (this topic)
      • posteromedial bowing (physiologic)
      • anteromedial bowing (fibular hemimelia) 
    • Anterolateral bowing is a continuum of disease that can be divided into
      • anterolateral bowing of tibia 
      • congenital pseudarthrosis of tibia 
    • Associated conditions
      • neurofibromatosis type I
        • is found in 50-55% of patients with anterolateral bowing
        • only 6-10% of patients with neurofibromatosis will have anterolateral tibial bowing
  • Classification
    • Numerous classification systems have been proposed (Boyd, Andersen, Crawford) however none guide management or are predictive of outcome
    • Two classification criteria have been proposed to guide treatment:
      • The presence or absence of fracture
      • The age at which fracture occurs
        • "Early onset" < 4 years old
        • "Late onset" > 4 years old
  • Presentation
    • Symptoms
      • majority present with bowing in the first year of life
    • Physical exam
      • deformity
      • careful skin examination for cafe-au-lait spots and other signs of neurofibromatosis
  • Treatment
    • The lesion does not self-resolve, and once fracture occurs there is low likelihood of spontaneous resolution
    • Nonoperative
      • bracing in clamshell orthosis or patellar tendon bearing (PTB) orthosis
        • indications
          • children of ambulatory age (weight bearing)
          • bowing without pseudarthrosis or fracture
            • spontaneous remodeling is not expected
        • goal is to prevent further bowing and fractures
        • osteotomy for bowing alone is contraindicated
        • technique
          • maintained until skeletal maturity
    • Operative
      • surgical fixation
        • indications
          • bowing with pseudarthrosis or fracture
      • amputation
        • indications
          • typically indicated after multiple failed surgical attempts at union
          • severe limb length discrepancy
          • dysfunctional angular deformity
          • Method- Syme or Boyd amputation
  • Techniques
    • Surgical fixation
      • goals
        • resection of pseudarthrosis to grossly normal bone
        • correction of alignment
        • bone grafting and stabilization of the remaining segments
        • intramedullary splinting of the bone is desired
      • techniques
        • intramedullary nailing with bone grafting
          • Resect the pseudarthrosis
          • Tibial shortening
          • Fixation with intramedullary rod
          • Bone graft
        • free vascularized fibular graft (Farmer's Procedure)
          • contralateral fibula is used, ipsilateral is involved in pseudarthrosis
        • Ilizarov or circular frame fixation with lengthening or bone transport
    • Amputation
      • Ankle disarticulation (Boyd or Syme amputation) preferred over resection at pseudoarthrosis site
      • Persistent motion at pseudoarthrosis site managed by prosthetic socket
  • Complications
    • Recurrent fracture
      • seen in 50% or more of patients even after initial union
    • Valgus deformity

    • Limb length discrepancy at skeletal maturity (average 5cm)

    • No treatment is considered to produce results in a predictable and acceptable fashion

Please rate this review topic.

You have never rated this topic.

Thank you. You can rate this topic again in 12 months.

Questions (4)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(SAE07PE.88) Figure 40 shows the radiographs of a 2-year-old boy who has a deformed leg. The patient is ambulatory and has no pain. What is the most appropriate management?

QID: 6148
FIGURES:
1

Observation

60%

(171/287)

2

Patellar tendon bearing (PTB) orthosis

21%

(60/287)

3

Osteotomy to correct the deformity and fixation with an intramedullary rod

16%

(45/287)

4

Vascularized fibular graft from the contralateral leg

2%

(7/287)

5

Amputation

0%

(0/287)

L 5 E

Select Answer to see Preferred Response

(OBQ04.255) Anterolateral tibial bowing is associated with which of the following lower extremity conditions in children?

QID: 1360
1

Calcaneovalgus foot deformity

6%

(187/2977)

2

Congenital pseudoarthrosis of the tibia

67%

(1996/2977)

3

Fibular hemimelia

15%

(449/2977)

4

Congenital talipes equinovarus

6%

(174/2977)

5

Congenital vertical talus

5%

(157/2977)

L 2 D

Select Answer to see Preferred Response

Evidence (6)
EXPERT COMMENTS (18)
Private Note