Free Fibular Flap and Fibular Graft Double-Strut Tunneling to Fill a Large Tibial Plateau Defect

Skeletal defects secondary to osseous tumors, trauma, and chronic osteomyelitis present numerous challenges for surgeons due to the avascular nature of the remaining tissue postresection¹. Taylor et al first described an approach to bone defects using a free vascularized fibular graft as a structural and vascular donor.² These vascularized segments are commonly and correctly known as free fibular flaps (FFFs). FFFs offer an excellent solution for reconstructing bony defects. Since its original description, the use of FFFs has become a viable option in limb-sparing bone reconstruction, providing options other than amputation.³ Much of the advantages of using FFFs come from its distinctive large-caliber peroneal vessels. Transplanted with FFFs, those vessels allow for improved vascularity compared with nonvascular osseous grafts.^4,5 As such, the indications of FFFs have encompassed a broad array of applications within orthopedics and reconstructive surgery. In lower limb defects, FFFs have been used in the treatment of avascular osteonecrosis of the femoral head and midfoot reconstruction, among other applications.³ In this report, the authors present a case of FFFs tunneled within the proximal tibial plateau in combination with a nonvascularized fibular graft and morselized autografted bone to fill a large bony defect secondary to chronic osteomyelitis.

A 60-year-old male presented with an infected proximal tibial nonunion and bony defect following an open reduction and internal fixation of a traumatic left tibial plateau fracture due to a motor vehicle collision. Initially, the patient was managed at an outside institution with serial debridement and antibiotic spacers and was considered a candidate for amputation. The patient was transferred to the center, and the authors elected to proceed with a limb salvage procedure. The first stage included removal of hardware, debridement of infected and necrotic bone of the tibial plateau, and placement of an antibiotic-eluting cement spacer (Figure 1 and Figure 2). A left medial hemigastrocnemius and hemisoleus flap along with fasciocutaneous flaps were used to reconstruct the proximal tibial soft tissue defect. Multiple bone biopsies were sent to be cultured to ensure infection resolution, and the patient received parenteral antibiotics for a period of 6 weeks. 

Following preoperative discussions with the orthopedic and plastic surgery teams, the decision was made to perform an FFF with the idea of introducing vascularized bone into the defect to optimize healing potential. An incision was made on the lateral aspect of the leg to expose the peroneal muscles, which were then elevated and meticulously dissected circumferentially around the fibular bone. An osteotomy was performed leaving approximately 7 cm of fibular bone both proximally at the knee and distally at the ankle. The interosseous septum was divided. Once the peroneal vessels were identified, the dissection proceeded cephalad to create a fibular flap that was elevated from the surrounding tissue on its pedicle. The cement spacer was removed from the defect, and a 4.5 mm proximal tibia plate was contoured to match the shape of the patient’s proximal tibia. After contouring and femorotibial alignment were optimized, the FFF was osteotomized to match the defect. The length-adjusted FFF was tunneled through the soft tissues and inserted into the tibial defect. A proximal portion of the fibula bone was also used as a bone graft to fill the gap, effectively creating a double-strut fibular flap and fibular graft within the tibial space. A combination of 100 mL of autograft, 10 mL of allogenic bone with cellular bone matrices (ViviGen, DePuy Synthes), and remaining fragments of the fibula were packed to fill the rest of the defect. Fluoroscopic imaging was used to confirm the alignment and safe positioning of all implants (Figure 3). The previous soft tissue flaps were reapproximated to cover the bone and orthopedic hardware. An additional split-thickness skin graft from the left thigh measuring approximately 150 cm² was used to cover the remaining open left leg wounds.

At approximately 4-months postoperatively, the patient’s incisions appear well-healed, and bony consolidation at the FFF insertion site is exhibited (Figure 4). The patient’s overall limb alignment is in slight valgus; however, successful progress was made from partial weight-bearing of the operative extremity to weight-bearing as tolerated. No postoperative complications have been noted thus far with minimal pain, and the flap appears to be well-perfused.

Reconstruction of large bone defects (defects > 6 cm) can prove quite challenging for orthopedic and plastic surgeons. In defects secondary to tumor resection, chronic osteomyelitis, and high energy trauma, a patient-specific management strategy is planned. Many factors play a role in the technique used for reconstruction, including the surgeon’s preference, host factors, and location, as well as the size and nature of the defect.^6-9 Therefore, multiple treatment strategies have been devised to fill bone defects, each with its own advantages and shortcomings. Various options include distraction osteogenesis, induced membrane technique, and autograft and allograft, all of which can be supplemented with a variety of biologic augments. This case report is unique in that it represents an innovative FFF technique that further expands the applications of the fibula flaps. The FFF displayed important characteristics necessary to fulfill the treatment requirements for this patient’s large bony defect. 

To achieve appropriate healing, 3 basic requirements need to be achieved: stability of the fixation, bony union, and a healthy soft-tissue envelope. The FFF is an excellent strategy that satisfies all 3 requirements. Vascularized grafts such as the FFF heal with a different modality when compared with nonvascularized grafts.^10,11 Vascularized bone segments maintain osteocyte viability due to intact endosteal and periosteal vascular flow, while nonvascularized bone grafts fuse by “creeping substitution” requiring over 2 years for complete integration.^12,13 This cellular viability provides mechanical support and biological stimulation, inducing hypertrophy of the osseous flap in response to stress.¹⁴ The FFF is a well-recognized source of vascularized bone; however, it may provide insufficient length and stability for many long bone defects. It requires significant preoperative planning including determination of pedicle length and identification of recipient vessels. The free fibula bone is mechanically weak and is prone to fracture if weight- bearing is initiated before full integration has occurred.

In this patient, the authors utilized a combination of the FFF, a nonvascularized fibular graft, morselized autograft, and allogeneic allograft with viable cells. Compared to a conventional single-strut vascularized fibular graft, a double-strut complex can support more mechanical stress as well as higher torque.¹⁵ Since this technique was first used by Jupiter et al in 1987, it became widely adopted for reconstructing defects in the lower extremities, including avascular necrosis of the femoral head.^16,17 The presented tibial defect was also packed with morselized autograft collected from the remaining segments of the fibula. The use of bone grafting is shown to be associated with superior results in smaller defects.¹⁸ The combination of FFFs with a nonvascularized bone graft along with autografted morselized bone provides both biological stimulation, as well as solid structural support for the tibial plateau, ensuring hypertrophy and osteogenesis, while maintaining the integrity of the construct. This approach further expands the various uses of FFFs in a combined construct to fill a large bony defect of the tibial plateau secondary 

The versatility of the FFF has allowed for the expansion of its application to reconstruct a tibial plateau defect created by infected nonunion. As such, this technique should be considered as a reconstructive option for the treatment of challenging large defects of the tibial plateau. 

Authors: Fadi J. Hamati BA^a, Charalampos Siotos MD^a, E. Bailey Terhune MD^b, Joel C. Williams MD^b, Amir H. Dorafshar MD^a

Affiliations: ^aDivision of Plastic and Reconstructive Surgery, Rush University Medical Center, Chicago, IL; ^bMidwest Orthopaedics at Rush, Rush University Medical Center, Chicago, IL

Correspondence: Amir H. Dorafshar, Professor and Chief, Division of Plastic and Reconstructive Surgery, Rush University Medical Center, Chicago, IL; amir_dorafshar@rush.edu.

Financial disclosure: Dr. Dorafshar receives royalties from Elsevier and KLS Martin and indirect research support from De Puy Synthes.