3. INTRODUCTION
Congenital pseudarthrosis of tibia refers to nonunion of
tibial fracture that develops spontaneously or after trival
trauma in a dysplastic bone segment of tibia diaphysis.
CPT is rare & Usually develops in first 2 yrs of life.
Etiology is unclear.
Incidence is 1: 250,000
There is a strong association of CPT with
neurofibromatosis type 1.
4. CLINICAL FEATURES
Associated with anterolateral
bowing of tibia.
Bowing usually occurs at the
junction of middle & distal third.
Deformity may be associated with
skin dimple, limb shortening,
dysplasia of fibula & ankle valgus.
Usually unilateral.
5. NEUROFIBROMATOSIS
NF-1 occurs due to mutation on the gene coding for
NEUROFIBROMIN on chromosome 17.
Neurofibromin is expressed in a broad range of cells & tissue
type.
It negatively regulates Ras activity ( cell proliferation &
function)
It’s deficiency leads to increased Ras activity.
Affects Ras-dependent MAPK( mitogen activated protein
kinase) activity which is essential for osteoclast function &
survival.
7. DIAGNOSTIC CRITERIA OF
NEUROFIBROMATOSIS
6 or more café-au-lait macules (>5mm before puberty &
>15mm after puberty).
Axillary or inguinal freckling.
2 or more neurofibromas or 1 plexiform neurofibroma.
2 or more Lisch nodules.
Optic glioma.
A distinctive osseous lesion such as sphenoid dysplasia or
thinning of long bone cortex with or without pseudarthrosis.
A first degree relative with NF-1.
8. PATHOLOGY
Unclear
Recent studies have shown that there is hyperplasia of
fibroblast with the formation of dense fibrous tissue.
This invasive fibromatosis is located in the periosteum &
between broken bones ends causing compression,
osteolysis & persistance of pseudarthrosis.
10. PATHOLOGY
Paley et al theorized that pathology of pseudarthrosis is not
bony but rather its periosteal in origin.
This theory was also considered by CODAVILLA a century
ago.
This theory is supported by following observation :-
Thickening with hamartomatous transformation of periosteum.
Appearance of strangulation of bone with atrophic changes
followed by avascular changes.
Failure of remodelling of pin tracts leading to stress fractures.
11. PATHOLOGY
Pathologic analysis of HERMANNS-SACHWEB et al
confirmed that pathologic periosteum is the cause of
CPT.
There finding was :-
Neural cells form a tight sheath around the periosteal
vessels.
Peiosteum undergoes hypoxemic changes resulting in the
formation of a thick fibrous cuff.
Leads to impaired oxygen & nutrient supply to the
subperiosteal bone & atrophic changes are observed.
12. CLASSIFICATION
There is no universally agreed system based on both
clinical features & radiographic findings.
CAMURATI - 1930
ADGLEY - 1952
BOYD - 1958
APOIL - 1970
ANDERSEN - 1973
CRAWFORD - 1986
CRAWFORD - 1999
BOYD & ANDERSEN are commonly used.
13. BOYD CLASSIFICATION
Boyd divided CPT into 6 types :-
Type 1 :-
Pseudarthrosis occurs with anterior
bowing.
A defect in tibia present at birth.
Other congenital deformities may be
present which may affect the
management of pseudarthrosis.
14. BOYD CLASSIFICATION
Type 2 :-
Pseudarthrosis occur with anterior bowing & a hourglass constriction of
the tibia is present at birth.
Spontaneous fractures or after minor trauma.
Commonly occur before 2 yrs of age.
Also known as HIGH RISK TIBIA.
Tibia is tapered, rounded, sclerotic & obliteration of medullary canal.
Most common type.
Associated with NF-1
Poorest prognosis.
15. BOYD CLASSIFICATION
Type 3 :-
Pseudarthrosis develops in a congenital cyst
usually near the junction of middle & distal
third of tibia.
Anterior bowing may precede or follow the
development of fracture.
Recurrance of fracture is less common after
treatment.
16. BOYD CLASSIFICATION
Type 4 :-
Originates in a sclerotic segment of
bone.
Without narrowing of tibia.
Medullary canal is partially or
completely obliterated.
An insufficiency or stress fracture
develops in the cortex of tibia &
gradually extends through the sclerotic
bone.
Prognosis is good.
17. BOYD CLASSIFICATION
Type 5 :-
Pseudarthrosis of tibia occurs with a dysplastic fibula.
Pseudarthrosis of both bone may develop.
Prognosis is good if the lesion is confined to fibula.
If the lesion progress to tibia then the natural h/o usually
resembles type 2.
Type 6 :-
Occurs as an intraosseous neurofibroma or schwannoma
Extremely rare.
18. CRAWFORD CLASSIFICATION
Divided broadly divided into 2 types:-
Non-Dysplastic
Anterolateral bowing with increased density & sclerosis of
medullary canal.
Dysplastic
Anterolateral bowing with failure of tubularization.
Cystic changes.
Frank pseudarthrosis.
21. TREATMENT
Treatment of CPT depends upon age of the patient & type of
pseudarthrosis.
Decision has to be taken whether to attempt to secure union
or amputation is the treatment of choice.
No single treatment approach has proven ideal .
True pseudarthrosis does not heal when treated with casting
alone.
22. TREATMENT
Goals of treatment :-
Complete excision of the soft tissue fibromatosis at the
site of pseudarthrosis.
Correction of angular deformity.
Stimulation of bone healing.
Proper fixation of bone fragments.
Postoperative protection .
23. TREATMENT
Is divided into 2 types :-
Prophylactic :-
Decreased activity.
Orthotics or cast.
Curettage with bone grafting.
Active :-
Surgical treatment
24. TREATMENT
Bone grafting
IM fixation
Ilizarov fixation
Free vascularized fibular grafting
Amputation
Bmp(bone morphogenic proteins).
Electric stimulation.
26. VASCULARISED FIBULA GRAFTING
Advantages :-
Primary bone lengthening
Correction of deformity.
Union occur in a relative short
period.
Disadvantages :-
Development of valgus deformity of
normal ankle.
28. AMPUTATION
Anticipated shortening of more then 2 or 3 inches.
Multiple failed surgical procedure.
Stiffness & decreased function of the limb that will be
more useful after amputation & fitting with prosthesis.
29. BONE MORPHOGENIC PROTEIN
16 different BMP have been identified.
BMP-2 & BMP -7 are the only current available for the
clinical use in non-union & paeudarthrosis.
Clinical studies have shown that BMP-2,6,9 plays an
important role in early differentiation of mesenchymal
progenitor cells to preosteblasts.
BMP-7 promotes early differentiaiton of preosteoblast to
osteoblast.
30. PSEUDARTHROSIS OF FIBULA
Pseudarthrosis of fibula often precedes or
accompanies the same condition in ipsilateral tibia.
Several grades are seen :-
Bowing of fibula without pseudarthrosis.
Pseudarthrosis without ankle deformity.
With ankle deformity.
Fibular pseudarthrosis with latent tibia pseudarthrosis.
Progressive valgus deformity is developed.
32. TREATMENT
Until skeletal maturity –ankle foot orthosis.
At maturity :- supramalleolar osteotomy
Langenskiöld has devised an operation for children to
prevent valgus deformity & halt its progression—
SYNOSTOSIS.
5.7% of pt. with NF-1 develops CPT whereas 40% pt’s of CPT found to have NF-1.
Macroscopy :- Aspect of the pseudarthrosis of the tibia. At the site of insufficient bone healing, white fibrous tissue substitutes the bone. A thickened cuff of periosteum and interruption of the bone compacta are noted.
Microscopy :- Histologic section of the periosteum of the control case with some vessels and small nerves, H&E, 40×. (B) By contrast, the periosteum of CPT patients shows a lot of small blood vessels embedded in proliferating fibrous tissue, H&E, 40×. (C) In the area of pseudarthrosis, cellular proliferating fibrous tissue with immature bone is observed, H&E, 40×. (D) Proliferating fibrous tissue of the periosteum.
The anterolateral bowing is due to the dominant muscular forces on the leg from the posterolateral compartment.
Various classification system based on radiographic & morphology exist.
Patient with type 1 CPT usually presents early in life , before 2 years of age & have a good prognosis with treatment.
Type 2 presents usually in older childern after experiencing the failed surgical t/t, refracture or an osteotomy to correct a bowed tibia. Type 2 have a relative poor prognosis.
Type 3 cases are usually of late onset type which develops as a stress fracture of congenital dysplastic tibia or in a healed tibia after previous bone grafting & has the best prognosis.
The siginificant feature of type 2 is there is presem=nce of dead bone coz of the previous sx.
Prophylactic :- pt. with anterolateral bowing of the tibia at the junction of middle & distal third of diaphysis or beyond ,particularly when accompanied by narrowing ,sclerosis & loss of defination of the medullary canal are considered high risk for developing pathological fractures & nonunion.
The extremity is protracted by an orthosis & the child is guarded against excess activity.
as the longitudinal growth takes places , there is a tendency towards the correction of the deformity though it can take a long time.
The threat of the fractures is ever present untill skeletal maturity.
Ostetomy are prohibited.
If fracture & pseudarthrosis apperas imminent eg. In presence of cyst then curettage & filling with bone grafts.
Sometimes it develop bet. The time of sucessful bone grafting of tibia & skeletal maturity.
Lateral malleolus is shifted proximally so valgus deformity develops.