CONGENITAL PSEUDO ARTHROSIS OF TIBIA- CPT

Dr. Rejul K Raj, CMC Ludhiana

INTRODUCTION.

• Type of non union.

• Present at birth or incipient.

• rare pathology. 1 in 2,50,000 live births.

• neurofibromatosis.

• Cause- unknown.

• Most commonly in disal tibia.

Introduction – contd.

• extremely unfavorable.

• Poor healing potential at the pseudoarthrosis.

• there is a little or no tendency for the lesion to heal spontaneously.

• It is challenging to treat effectively

• Hamartomatous thickened fibrous tissue with limited vascular ingrowth.

• thin and atrophic tibial bone

• pointed distal fragment.

• The false joint is in the distal third of the shaft.

• The fibula is affected

• Untreated CPT

Problems- Primary

1. Obtaining union

2. Shortening of the limb –

1. At birth itself.

2. Pseudarthrosis remains ununited.

3. Repeated unsuccessful operations

3. Tendency for refracture- diminishes with skeletal maturity.

Problems- secondary deformitiesa) abnormal inclination of the proximal tibial physis

b) posterior bowing of the proximal third of the tibial diaphysis

c) proximal migration of the lateral malleolus

d) fibular hypoplasia

e) fibular pseudarthrosis

f) ankle valgus and calcaneus deformity

CLASSIFICATIONS

• Andersen's classification – 1973

• Boyd's classification- 1982

• Crawford's classification- 1986

• EI-Rosasy-Paley-Herzenberg's classification- 2007

BOYD’S- 1982, 6 types

• Type I - anterior bowing with tibial defect. • Type II – Most common

– with hour glass constriction– spontaneous fracture– HIGH RISK TIBIA ( tapered ,rounded, sclerotic ,

obliterated )– Poorest prognosis.

• Type III - with congeital cyst• Type IV- with sclerotic segments, sterss fractures.• Type V -with dysplastic fibula. • Type VI- an intraosseous neurofibroma or

schwannoma is evident

Crawford's classification- 1986

• Type I-– the medullary canal is preserved and cortical

thickening at the apex of the deformity might be observed

– good prognosis;

• Type II –– presence of thinned medullary canal, cortical

thickening, and trabeculation defect.

• type III -– cystic lesion, which may be fractured; patients

with this type of pseudarthrosis tend to experience early fracture and, therefore, require early treatment.

• Type IV-– pseudarthrosis is present with tibial and possibly

fibular nonunion.

EI-Rosasy-Paley-Herzenberg'sclassification- 2007

1. patient's condition at time of presentation (relation to previous treatment),

2. radiological (atrophic or hypertrophic), 3. mobility of pseudarthrosis site (stiff or mobile).

• Type 1– Atrophic (narrow) bone ends– Mobile pseudarthrosis– No previous surgery

• Type 2– Atrophic (narrow) bone ends– Mobile pseudarthrosis– Previous unsuccessful surgery

• Type 3– Hypertrophic (wide) bone ends– Stiff pseudarthrosis

AIMS

1. Achieve union

2. Prevent refracture

3. Correct limb length inequality

4. Correct associated growth abnormalities

5. Prevent ankle deformity and arthritis.

1. Strategies to achieve union

1. Microvascular free fibular transfer.

2. the Ilizarov technique

3. Bone grafting with intramedullary nailing.

• Excision of the pseudarthrosis should be an integral part of the procedure.

2. Strategies for minimizing the risk of refracture

• Splint the limb in an orthosis until skeletal maturity.

• Retain an intramedullary nail until skeletal maturity.

3. Strategies for dealing with shortening of the limb

● Minimize the extent of shortening by obtaining union of the pseudarthrosis as early as possible.

● Established shortening can be addressed by limb equalization procedures

4. Strategies for minimizing valgusdeformity of the ankle

● Ensure union of the fibular pseudarthrosis.

● Retaining an intramedullary rod that crosses the ankle joint can also prevent ankle deformity although the motion is lost.

IMAGING

Magnetic resonance imaging• extent of the disease • preoperative planning in that the borders for resection can be

defined precisely. • The area of the pseudarthrosis is hyper intense on fat-suppressed

and T2-weighted images and slightly hypo intense on T1-weighted images with contrast enhancement after administration of gadolinium.

Computed tomography scan

Confirm radiographic findings.

Total bone scintigraphy

Level of the pseudarthrosis .

PATHOGENESIS• exhibits insufficient mechanical strength and osteogenetic

capability.

• An abnormal highly cellular fibrovascular tissue grows at expense of the bony cortex.

• incoordinate osteoclastic bone resorption that does not have a normal bone modeling purpose.

• Reactive changes leads to excess trabecular bone and hence medullary sclerosis.

• Excessive bone resorption accounts for intracortical cysts.

• Impaired vascularization

• L shaped excision specimen pseudoarthrosis, left tibia

Pujani M, Madan NK, Shukla S. Congenital pseudoarthrosis tibia with fibrous hamartoma in a child with neurofibromatosis. J Lab Physicians 2013;5:68-9

Histopathology

• Fibrous hamartoma is the key pathology = low osteogenicity and high osteoclastogenicity.

• The soft tissue at the pseudarthrotic site is composed of variable admixture of fibrous tissue, fibrocartilage, and hyaline cartilage with evidence of enchondral ossification.

• marrow spaces are devoid of hematopoiesis.

• This invasive fibromatosis is located in the periosteum and between broken bone ends and surrounds the tibia causing compression, osteolysis, and persistence of pseudarthrosis

• Figure 2: Tissue section from site of pseudoarthrosisshowing mature lamellar bone along with soft tissue showing spindle cell proliferation: Fibrous hamartoma (H and E, ×400

Pujani M, Madan NK, Shukla S. Congenital pseudoarthrosis tibia with fibrous hamartoma in a child with neurofibromatosis. J Lab Physicians 2013;5:68-9

TREATMENT HISTORYShah H, Rousset M, Canavese F. Congenital pseudarthrosis of the tibia: Management and complications. Indian

J Orthop 2012;46:616-26

• Charnley (1956) first treated cases of CPT with intramedullary rod.

• Coleman added autogenous iliac bone graft to intramedullary rod for the treatment of CPT.

• In 1974, Ostrup et al. demonstrated the presence of active osteocytes in vascularized bone graft and their absence in nonvascularized bone graft.

• Taylor et al. (1975) succeeded in grafting the first vascularized fibula and 3 years later, the same technique was applied by Weiland et al. for treating patients with CPT.

• Shah et al. used cortical bone grafting with intramedullary nailing for the treatment of the CPT.– Cortical bone grafting from contralateral tibia resist resorption better than cancellous

bone hence primary union rate is higher with use of cortical bone graft.

SURGICAL OPTIONS

1. Vascularized fibular graft

2. External fixation

3. Intramedullary rod

4. Amputation

1. Vascularized fibular graft

• The procedure entails harvesting a long segment of the opposite fibula along with its vascular pedicle.

• This is transferred into the gap created after radical excision of the pseudarthrotic segment. • The vessels of the transferred fibula are anastomosed to the local vessels. The transferred

fibula is fixed securely to the tibia.

1. Vascularized fibular graftCharnley-Williams technique • the intramedullary rod in tibia was inserted along with

vascularized fibular graft according to the technique described by O'Brien.

• The goal is to obtain bone union, by mixing propitious biological environment with the vascularized bone graft, and the intramedullary rod is responsible for stability.

•The high success rate of primary and secondary union are the distinct advantage of vascularised fibular graft.

The limitations of this technique are • cost, technical complexity, poor protection against re-fracture,

failure to correct limb length discrepancy, and deformities of leg and ankle simultaneously at time of primary surgery.

2. External fixation

• Circular external fixation as the treatment of choice of CPT

• allows total resection of pathological tissue

• ensures stability regardless of the amount of resected tissue

• allows extension of the member, correction of axial deformities

• full support immediately after the intervention

• The Ilizarov frame is applied,

• the pseudarthrosis is excised.

• the fragments are compressed.

3. Intramedullary rod

• provides stability and does not disturb distal tibial epiphysis.

• Intramedullary rod prevents refracture; therefore, it is inadvisable to remove the rod after union

3. Intramedullary rod

• 1. Excision of the pseudarthrosis

– until fresh bleeding.

– the thick periosteum is excised.

• 2. Bone grafting - autogenous bone grafting facilitates union

• 3. Intramedullary rodding

Three struts of cortical bone are placed around the site of the excised pseudarthrosis after ensuring that the fragments are well apposed.

4. Amputation

• For resistant pseudarthrosis when other extensive surgical procedures have not achieved a functional extremity

• either due to persistent nonunion or due to dysfunctional angular deformity, shortening, atrophy, and stiffness, the amputation is entirely appropriate.

5. Ultrasound-Low-Intensity pulsed ultrasound

stimulation (LIPUS) • Okada et al. reported a case of CPT of the tibia (Boyd type IV)

successfully treated with low-intensity pulsed ultrasound stimulation (LIPUS) administered for 20 min/day.

• The treatment was continued for 1 year until solid fusion on radiographs and subsequent full-weight-bearing was achieved.

•

• The underlying mechanisms of action of LIPUS remain unclear. However, in experimental studies conducted in rats, LIPUS application facilitates union and increase mechanical strength of bone

complications

1. Refracture

2. Malalignment of the tibia

3. Limb length discrepancy

4. Ankle valgus

5. Ankle stiffness

1. Refracture.

• 14% to 60%.

• Anatomic alignment of the tibia and fibula minimize the risk of re-fracture.

• Intramedullary rod and external bracing must be continued as effective protection against re-fractures.

2. Malalignment of the tibia

• Diaphyseal malalignment of the tibia (procurvatum or valgusdeformity) are progressive and do not remodel

3. Limb length discrepancy

• Residual limb length discrepancy following successful union is a major problem.

• Growth abnormalities of the tibia, fibula, and the ipsilateral femur abnormalities are also noted with CPT

• which include inclination of the proximal tibial physis, posterior bowing of the proximal third of the tibial diaphysis, proximal migration of the lateral malleolus.

4. Ankle valgus

4. Ankle valgus

• Compromises functional outcome.

• Progressive ankle valgus is a problematic postoperative donor-site morbidity of a vascularized fibular graft in children.

•

• Tibiofibular metaphyseal synostosis (the Langenskiöldprocedure)

5. Ankle stiffness

• progressively regresses once intramedullaryrod is removed from ankle.

• Pain secondary to degenerative changes of the ankle can be treated with limitation of activity and shoe modification.

• Severe pain may require ankle arthrodesis

Follow up.

• till skeletal maturity to identify and rectify residual problems.

Take Home message.

• Rare.• The natural history of the disease is extremely unfavorable and

• Little or no tendency for the lesion to heal spontaneously. • challenging to treat effectively• Aims to obtain a long term bone union, to prevent limb length discrepancies,

to avoid mechanical axis deviation, soft tissue lesions, nearby joint stiffness, and pathological fracture.

• The key to get primary union is to excise hamartomatous tissue and pathological periosteum.

• Age at surgery, status of fibula, associated shortening, and deformities of leg and ankle play significant role in primary union and residual challenges after primary healing.

• Surgical options such as intramedullary nailing, vascularized fibula graft, and external fixator, have shown equivocal success rate in achieving primary union

• Amputation must be reserved for failed reconstruction, severe limb length discrepancy and gross deformities of leg and ankle..

Refereneces.

• Shah H, Rousset M, Canavese F. Congenital pseudarthrosis of the tibia: Management and complications. Indian J Orthop 2012;46:616-26

• Campbell’s – 12th edition.

• Paediatric orthopaedics –A system of decision making, by Benjamin Joseph.

THANK YOU.