Keywords induced membrane technique - segmental bone defects - free vascularized fibular flap
The management of bone defects, especially segmental bone defects, is a challenge
for orthopedic surgeons. The most commonly used methods for the reconstruction of
segmental bone defects are the free vascularized fibula flap, Ilizarov bone transport
technique, and induced membrane technique.[1 ]
[2 ]
[3 ] Every method has its own shortcomings.[1 ]
[2 ]
[3 ] The combination of these methods may overcome their shortcomings. However, there
were few reports on the combined use of these methods.[4 ] The present case report describes a case of severe acute femoral bone loss managed
by an induced membrane technique combined with a free vascularized fibula flap.
Case Report
A 41-year-old woman was admitted after a motorcycle accident. The patient presented
with a Gustilo IIIA left femur meta-epiphyseal fracture (AO 32-C and 33-C) and left
patellar fracture ([Fig. 1 ]). The length of femoral bone loss was 15 cm (12 cm medially and 18 cm laterally).
Fig. 1 A 41-year-old woman was admitted with a Gustilo IIIA left femur meta-epiphyseal fracture
(AO 32-C and 33-C) and left patellar fracture. The length of femoral bone loss was
15 cm (12 cm medially and 18 cm laterally).
Thorough debridement was performed. Tissue samples were collected for microbiological
culture. The intercondylar fracture was fixed with K-wires, and an external fixator
bridged the knee joint (Hoffman II external fixation system, Stryker, Kalamazoo, MI).
The bone defect was then filled with antibiotic cement spacer, which was premixed
with gentamycin (Smith & Nephew, Memphis, TN) ([Fig. 2 ]). The patellar fracture was fixed with two screws. The open wound was primarily
closed.
Fig. 2 First step of the Masquelet technique. (A ) The femoral bone defect was filled with a cement spacer. (B ) X-ray of the cement spacer in an anteroposterior view. Proper alignment and length
of the limb obtained with external fixation.
Intravenous antibiotic therapy with vancomycin 500 mg × 4 daily was started immediately
postoperatively. Weight bearing was not allowed postoperatively. The microbiological
cultures were negative and the wound healed uneventfully. Antibiotic therapy was discontinued
after 1 week, and the patient was discharged after 9 days.
Blood examinations (erythrocyte sedimentation rate [ESR], C-reactive protein [CRP],
and white blood cell [WBC] count) were checked routinely during follow-up and normalized
after 1 month. The external fixator was removed and the limb was braced in a cast
1.5 months after the initial procedure. The second step of the Masquelet technique
was performed 2 months after the trauma.
A lateral approach to the femur was used. The induced membrane was opened and the
antibiotic cement was removed. Samples for microbiological culture were collected.
A free vascularized fibula (18 cm) was harvested from the contralateral leg. The donor
peroneal artery was anastomosed to the branch of the femoral artery by the end-to-end
technique. The peroneal veins were anastomosed to the venae comitantes of the recipient
artery and the saphenous vein. The residual bony defect was filled with morcellized
cancellous autologous bone graft from iliac crests. Then, the induced membrane was
closed. The femur was fixed by internal fixation with the less invasive stabilization
system (LISS) ([Fig. 3 ]). A superficial drainage was placed and subcutaneous and skin layers were sutured.
Fig. 3 X-ray showed the composite graft and plate in an anteroposterior (A ) and lateral (B ) views. A complete filling of the defect was obtained, maintaining correct limb alignment
and length.
One week after surgery, antibiotic therapy (vancomycin 500 mg × 4 daily) was discontinued
on the basis of negative microbiological cultures. Weight bearing was not allowed
for the first 2 months. Partial weight bearing started at 3 months, was progressive
at 4 months, and full at 5 months. At 6 months, the graft appeared completely integrated
on the X-ray ([Fig. 4 ]). It was interesting that significant hypertrophy of the transferred fibula was
not found at 3 years follow-up ([Fig. 4 ]). We thought that the hypertrophy of the fibula was not needed because the fibula
had a surrounding consolidated morcellized cancellous autograft.
Fig. 4 X-ray follow-up. (A, B ) Six months. Integration of the graft on both sides. (C, D ) Three years. Remodeling of the morcellized cancellous autograft and hypertrophy
of the transferred fibula were not significant because of the consolidation of the
morcellized cancellous autograft.
Literature Review and Conclusion
Between 1986 and 1999, Masquelet et al[5 ]
[6 ] have developed the induced membrane technique, and 35 patients with segmental bone
defects were treated with the induced membrane technique. The bone defects ranged
from 5 to 25 cm. In 20 cases, the defect exceeded 10 cm. Soft tissue repair by flaps
was performed in 28 cases. Three patients failed due to the failures of free flaps,
and bone healing was obtained by open-air grafting or bone transport. One amputation
was performed before bone healing. The other 31 patients, obtained bone healing at
an average 4 months and normal walking without devices were allowed at an average
of 8.5 months. Delayed stress fractures were noted in four patients, two at 6 months
and two at 2 years. Healing was obtained by simple cast immobilization. All infections
had healed without recurrence upon long-term follow-up.
The induced membrane technique was performed in two stages[3 ]: The first stage includes radical debridement and insertion of an antibiotic cement
spacer into the bone defects. The bone was stabilized always with an external fixator.
Soft tissue was repaired by flaps when needed. The second stage was performed 6 to
8 weeks later. The spacer was removed; a cancellous autograft was placed within this
membrane. The induced membrane technique does not require specialized equipment; it
can be performed easily by surgeons with various capabilities and experience; and
it is applicable to diaphyseal, metaphyseal, or epiphyseal bone defects. Therefore,
the induced membrane technique, as described by or modified from Masquelet, seems
to have gained popularity recent years due to the management of segmental bone defects.[7 ]
[8 ]
[9 ]
[10 ]
[11 ]
[12 ]
[13 ]
In the present case, the induced membrane technique was initially chosen for the management
of segmental bone defects. However, for second-stage management, the autologous bone
graft seemed insufficient due to the large meta-epiphyseal bone defects in the femur.
Additional grafting material was required. However, the ideal ratio of bone substitutes
and autograft was not determined, although the ratio of 1:3 (allograft:autograft)
was suggested.[3 ] Therefore, the autologous bone graft combined with a free vascularized fibula flap
was chosen in the present study.
The clinical outcomes of the vascularized free fibula flap for the management of large
bone defects are favorable.[2 ] However, the femur, especially the distal segment, is a large-caliber bone and is
under severe stress during weight bearing. Significant hypertrophy must occur for
the transferred fibula to be able to support the body weight. This hypertrophy can
take a long period of time in adults and still may not provide sufficient strength
to allow weight bearing. Therefore, the fracture of a single strut of fibula placed
in the femur is common.[14 ] An alternative is to use folded or double free vascularized fibula flaps.[15 ] The third option for the femur is the free fibula used in conjunction with allografts.[16 ] The induced membrane technique combined with the free vascularized fibula flap used
in the present case may be a fourth option, or a modified method to a single free
vascularized fibula flap to reconstruct segmental bone defects in the femur.
Pelissier et al[17 ] demonstrated that the induced membranes have an abundant vascular network and secrete
growth factors and osteoinductive factors. With the aforementioned characteristics,
the membranous pocket prevents resorption of the contained graft and supports the
revascularization and consolidation of the bone graft. Free vascularized fibula flap
always has a reliable effect on the bone union because of its vessel-rich characteristics.[2 ] Therefore, this combined method was reasonable as an alternative method for the
reconstruction of segmental bone defects in femurs. The present case demonstrated
that this combined method could be successfully used for the reconstruction of segmental
femoral bone defects.
