pseudoarthrosis

1. Congenital pseudoarthrosis of Tibia
(CPT)
Name of the student:
Dr. Saikat Ghosh
M.S (Orthopedic Surgery) Resident, Phase-B
Chattogram Medical College, Chattogram.

9. Introduction
• Congenital pseudarthrosis of the tibia and fibula (CPT)
was first described by Paget in 1891 and is
characterized by a spontaneous fracture that heals
poorly with routine treatment.
• Anterolateral bowing of the tibia, the precursor of CPT, is
present at birth, although the fracture and the ensuing
pseudarthrosis are rarely seen at this time. Although the
term ‘congenital pseudarthrosis’ is thus a misnomer, an
alternative name for the condition has not been
forthcoming.

10. Definition
Pseudoarthrosis: This is defined as a fracture that has
undergone nonunion and a cleft develops between the bone
ends resembling joint formation with end becoming convex and
the other concave.
The cleft or cavity gets filled with fluid and is lined by a
membrane and pseudocapsule. The structure is hypermobile and
has no restraints. Radiographically ,the characteristic appearance
is that of “mortar and pestle”.

11. Pseudoarthrosis of Tibia
• Congenital pseudoarthrosis of tibia (CPT) refers to nonunion
of a tibial fracture that develops spontaneously or after trivial
trauma in a dysplastic bone segment of the tibial diaphysis.
• The pseudoarthrosis usually developes during the first 2 years
of life.
• Normally CPT is unilateral, located at the junction of the
middle and distal thirds of the tibial segment with no
predominance for sex or side.
• The fibula is also affected in more than half the cases.

12. Is congenital pseudoarthrosis really congenital ???
• Congenital pseudoarthrosis of tibia is a misnomer it is
often not a congenital one. The nonunion
(pseudoarthrosis) develops usually after birth due to
congenital ‘defect’ in tibia.
• it is revealed by either pseudarthrosis at birth or by a
pathological fracture presenting in bone with
modifications such as bowing, narrowing of the
medullary canal or a cyst.

13. Etiology
• The exact cause of CPT is not known .Inheritant inability
of the bone to form to form callus at the site of fracture.

14. Epidemiology
• CPT is a rare condition, with a reported incidence ranging
from one in 28,000 in Finland to one in 1,90,000 in the
United Kingdom.

15. Types
• Severe neonatal forms or primary pseudarthrosis, in
which signs are present at birth,
• secondary pseudarthrosis, which is revealed by a
pathological fracture when the child begins walking.

16. Clinical feature
Inspection:
 Anterolateral or anterior angulation /bowing of leg
 Signs of neurofibromatosis
• Foot deformity
• Ankle valgus
• Skin dimple over angulation
Palpation:
• Thinning of tibia at angulation
• Tenderness
• Abnormal mobility (pathological fracture)
• Wasting of calf muscles
• Contracted and prominent tendo Achilles

17. Associated problems
• (i) Leg length discrepancy,
• (ii) multilevel multidirectional tibial deformity,
• (iii) proximal migration of the fibula,
• (iv) fibular nonunion,
• (v) ankle mortise valgus,
• (vi) ankle-joint dorsiflexion,
• (vii) valgus contracture,
• (viii) cavovalgus foot deformity, and
• (ix) persistent dorsiflexion contracture before
surgery.

18. Radiological appearance
• The radiological appearance varies from bowing of the
tibia with failure of formation of a normal medullary
cavity, cystic lesions, and an associated incomplete or
complete fracture of the tibia with atrophy and tapering at
the site of the fracture and pointed distal fragment
depending on stage.
• Lesions associated with neurofibromatosis often show a
typical appearance in which a segment of tibia or tibia
and fibula show hourglass thinning, sclerosis and loss of
the medullary cavity followed by a fracture through the
dysplastic sites.
• In lesions associated with fibrous dysplasia, there is cyst
formation with expansion of the shaft of the bone,
surrounded by sclerosis, ground-glass appearance and
other features of fibrous dysplasia.

20. Pathology
• There is a failure of normal bone formation in the distal half of
the tibia, resulting in segmental defect of bone, anterolateral
angulation and pathological fracture.
• The site of pseudarthrosis is usually surrounded by a
thickened periosteum and a thick, heavy cuff of poorly
perfused hamartomatous fibrous tissue. They are said to
prevent union by a mechanical effect of interposition and be
responsible for defective vascularisation in the bone. The
periosteum could create a fibrous band causing an increase in
local pressure around the bone resulting in reduced
vascularization as well as bone atrophy. The vascularlization
defect could also be secondary to thickening of the vessel
walls in the area of pseudarthrosis .

21. Physiopathology
• Fibrous hamartoma replaces the healthy periosteum.
• Fibrous hamartoma leads to osteolysis and vascular
constriction of the bone.
• The bone is viable despite the osteolysis, atrophy and
hamartomatous constriction.
• Medullary canal obliterated due to sclerosis.
• Osteocytes produce lower levels than normal of BMP.
• Increased osteoclasts and osteoclasis.

22. Neurofibromatosis
• The criteria used by Crawford for diagnosis of
neurofibromatosis requires at least two of the following:
• (i) multiple café-au-lait spots,
• (ii) positive family history of neurofibromatosis,
• (iii) definitive biopsy, or
• (iv) characteristic bony lesions, such as pseudarthrosis
of the tibia, hemihypertrophy, or a short sharply
angulated spinal curvature.
• Café-au-lait spots are typically smooth edged. At least
five spots measuring more than 0.5 cm in diameter are
considered diagnostic of neurofibromatosis.

23. Neurofibromatosis and Pseudoarthrosis
• The association of NF1 in 40 to 60% of the cases of
CPT suggests a genetic cause. NF1 codes for a
ubiquitous protein, neurofibromin, whose functions
include the negative regulation of Ras, a protein involved
in cell differentiation and proliferation . The mutation of
NF1 results in a loss of neurofibromin activity resulting in
the maintenance of the active form of Ras. The loss of
function of neurofibromin can result in a Ras-MAPK
pathway anomaly resulting in defective osteoblastic
differentiation. Over expression of the Ras pathway can
also result in an increase in osteoclast activity and their
precursors, explaining bone resporption in CPT and the
high rate of recurrent fractures.

24. Natural history of CPT
• The natural history of CPT can be divided into primary
and secondary.
• the primary problems in CPT are:
• 1) anterolateral bowing;
• 2) non-healing fracture (pseudarthrosis)
• 3) proximal migration of the fibula
• Most of the secondary conditions are due to the effect of
the primary condition on the surrounding soft tissues and
joints and the secondary effects on growth and
development of the lower limb.

25. Natural history of CPT
• The secondary conditions are
1. atrophy and thinning of the calf muscles
2. calcaneo-cavus deformity of the foot with a pistol grip
heel
3. dorsiflexion contracture of the ankle (calcaneus
deformity of the foot)
4. lateral subluxation of the ankle joint, valgus wedging of
the distal tibial epiphysis and instability of the ankle
5. proximal tibial physis grows into recurvatum and valgus
6. slowing of growth of the distal tibial and fibular physes
and LLD
7. Coxa valga.

29. Investigations
• Although the diagnosis can be made from plain
radiographs, MRI provides excellent details of the extent
of the pathological process.

31. Classification
• There have been several different published classifications of
CPT.
1. Anderson- 1973
2.Boyd-1982
3.Crawford-1986
4.Paley -2007
5. Apoil
None of these classifications considers the status
of the fibula. Choi et alclassified the fibula in CPT with
emphasis on its level of proximal migration.

32. Crawford classification
• The Crawford classification, which is the most
frequently used today . This classification has the
advantage of being descriptive and identifying the
different stages as CPT progresses:
• type I: anterior bowing with an increase in cortical
density and a narrow medulla;
• type II: anterior bowing with narrow, sclerotic
medulla,
• type III: anterior bowing associated with a cyst or
signs of a prefracture,
• type IV: anterior bowing and a clear fracture with
pseudarthrosis often associating the tibia and fibula.

33. Boyd classification
• The Boyd classification with 6 types, which has prognostic
value:
• type I: anterior bowing associated with other congenital
malformations,
• type II: anterior bowing with an hourglass appearance to the
tibia. A fracture usually occurs before the age of 2. The ends
of the bone are thin, rounded and sclerotic with obliteration of
the intramedullary canal. This type is more often associated
with NF1 type III: pseudarthrosis developing from an
intraosseous cyst, usually at the middle and distal third
junction.
• type IV: sclerotic bone with no pathological bowing. The
medullary canal is partially or completely obliterated.
• type V: dyplasic appearance to the fibula. Pseudarthrosis can
be located on either of the two bones of the tibial segment.
• type VI: associated with an intraosseous fibroma or a

36. Anderson classification
1. Dysplastic
2. Cystic
3. Late
4. Clubfoot
5. Angulated

37. Apoil classification
• type I: atrophic pseudarthrosis with thin bone ends. The
ends of the bone are said to look like ‘‘barley sugar’’,
which results in a more or less significant long-term loss
of bone substance, or overlap. The inferior fragment is
often small and aplastic, ending in an atrophic epiphysis.
There is no medullary canal. The fibula has an identical
lesion,
• type II: tight, extensive hypertrophic pseudarthrosis. The
bone ends are dense, wide and the medullary canal has
disappeared, the cortex thickens on the concave side.
The fibula is often bowed and abnormally shaped.

39. Differential Diagnosis
• Congenital postero-medial bowing of the tibia and
antero-medial bowing associated with fibular hemimelia.
• congenital longitudinal deficiency of tibia (paraxial tibial
hemimelia)
• Fracture nonunion
• Osteogenesis imperfecta
• Ehlers Danlos syndrome
• Fibrous dysplasia
• Rickets
• Post osteomyelitic pathological fracture.

40. Lessons prior treatment
• Hamartoma resection should be comprehensive back to
normal fat planes.
• Medullary canal should be recanalized.
• All bone and soft tissue at the CPT site should be alive.
• Autogenous cancellous bone graft contains more stem
cells than autogenous cortical or allograft bone and
produces more bone for the same volume of graft.
• Bone graft is rapidly resorbed.
• Intramedullary fixation helps prevent refracture.
• Rigid fixation is critical to provide mechanical stability at
the CPT site.
• BMP may be helpful to boost decreased BMP production
by the diseased tibia.

41. Lessons
• Zoledronic acid can help prevent osteoclasis at the CPT
site.
• Zoledronic acid given prior to bone graft harvest can
protect the bone graft from resorption after implantation.
• Angular correction at the CPT site is critical.
• Periosteal grafting can help restore healthy periosteum
at the CPT site.14
• Larger cross-sectional area of union at the CPT site has
a lower risk of fracture.10,11
• Cases with accidental cross union between the tibia and
fibula do not refracture.

42. Methods of Treatment
1. Conservative
2. surgical

43. Conservative treatment
• Done for patients without fracture or pseudoarthrosis
(prepseudoarthrosis).
• Total contact plastic clamshell orthosis, AFO (prior to
walking), KAFO (infant starting to walk). Worn indefinitely
full-time; if fracture does not occur tibial bowing usually
gradually improves and reformation of medullary canal
often requires up to 5-10 years. If there is sufficient
straightening of tibia, medullary canal is reformed and
adequate cortical thickness then orthosis may be
discontinued.

44. Goals of surgical treatment
1. Union at fracture site, maintaining union
2. Prevent refracture
3. Correct limb length inequality
4. Correct associated growth abnormalities
5. Prevent ankle deformity and arthritis.

66. Controversies in the management

67. The Cross union concept
• Choi et al (2011) recommended creation of a cross-union
between the tibia and fibula for CPT cases where the fibula
was broken but minimally proximally migrated. They
converged the two fibula bone ends towards the two tibia
bone ends in what they called a ‘4-in-1 Osteosynthesis’.
• They used a cortico-cancellous sheet of the inner table of the
ilium with or without its periosteum and when necessary
additional cortical bone from the contralateral tibia combined
with cancellous bone chips to achieve the cross-union. The
cortical graft was placed posterior to the two bones and then
cancellous chips between the bones and another layer of
cortical bone anterior to the bones.
• They did not recommend this method when the fibula was
intact or when the fibula was significantly proximally migrated.

68. Paley foundation cross union protocol
• Paley (2012) reported preliminary results using combined
pharmacological and surgical management with cross-union.
• The treatment protocol was:
• presurgical infusion of zoledronic acid (ZA)
• hamartoma resection around tibia and fibula with resection of the
interosseous membrane
• tibial rodding with a telescopic growing rod and fibular rodding
with a wire

69. Cross union
• decancellousization of the ilium to harvest a large cancellous
bone graft
• harvest of periosteal graft from the underside of the iliacus
muscle
• application of a three-layer graft composed of 1) periosteum
around the CPT, 2) cancellous bone between and around the
tibia and fibula, and 3) BMP2 posterior and anterior to the
bone graft covered by soft tissues
• application of the Ilizarov apparatus to compress the CPT site
and to give rotational stability .

72. Cross union
• Fig. Reproduced with permission by the Paley Foundation: (a) anterior incision shown from
front and cross section. Note hamartoma encircling tibia and fibula and the interosseous
membrane between them; (b) anterior and deep posterior fasciotomy and muscle reflection
to expose tibia, interosseous membrane, and fibula, allow resection of the membrane under
direct vision without damage to the neurovascular bundles; (c) circumferential resection of
the tibial fibrous hamartoma is carried out over the planned length of the cross-union. The
same is done for the fibular hamartoma; (d) the tibial bowing is straightened and the bone
ends overlapped and resected; (e) a customized Fassier-Duval telescopic nail is inserted and
the male end locked with a wire into the distal epiphysis and the female end screwed into the
proximal epiphysis; (f) a small diameter locking plate is fixed medially to the tibia with six
screws; (g) the fibular ends can now be cut and the fibula fixed with a wire in its medullary
canal; (h) a periosteal graft is harvested from the undersurface of the iliacus muscle. It is then
expanded by passing it through the skin graft mesher; (i) decancellousization of the ilium is
done by first splitting the two cortical tables of the ilium down to the roof of the acetabulum,
triradiate cartilage, sciatic notch, posterior spines and sacro-iliac joint; (j) the periosteal graft
is wrapped around the congenital pseudarthrosis site and bone morphogenic protein-2
(BMP2) collagen sponges are inserted overtop the posterior muscles behind the tibia and
fibula (left). The cancellous bone is inserted between the tibia and fibula (left centre). The
BMP2 sponges are placed overtop the bone graft (right centre). The anterior muscles lie over
the BMP2. The interosseous space has a sandwich of cancellous bone between layers of
BMP2 and its overlying soft tissues; (k) the cross-union forms between the bones by three
months after surgery. The bone is well fixed with the telescopic rod in the tibia, the wire in
the fibula and the plate on the tibia (left). Growth may occur despite the hardware leading to
telescopic expansion of the male and female rods. The fibular wire descends with growth
(left).

73. Prognostic Factors
• Factors reported to negatively affect union: 1)
neurofibromatosis; 2) age at treatment less than three
years; 3) previous failed surgery; and 4) years of follow-
up after treatment. Neurofibromatosis is often touted to
be a negative prognostic indicator.

76. Jannatul Ferdous, 9 years old child
3 years ago had
cellulitis in her right leg
Abscess formation
Incomplete drainage of abscess
Development of osteomyelitis
Maltreatment of osteomyelitis

77. After being admitted in CMCH
• Sequestrum in tibia is excised
• Cortical graft taken from ipsilateral fibila without periosteum
• Grafted portion is fixed within gap of tibia by multiple screws
and cerclage wires
• Finally, external fixation is given
• Ex-fix is removed after 6months .