Orthopedics

Case Report 

Tibia Stress Fracture and Subsequent Nonunion Associated With High Morbidity Following Vascularized Fibula Graft Harvest

Benjamin J. Main, DO; Aaron J. Seidman, DO; Alfred M. Faulkner, DO

Abstract

There is little in the literature about tibial stress fracture after partial fibulectomy. As fibula strut grafting and vascularized fibula flap grafting becomes more common in the field of reconstructive surgery, the incidence of this complication will likely rise. The authors present the case of a 54-year-old woman with tibial stress fracture and subsequent nonunion following vascularized fibula graft harvest. The aim of this case report is to present a unique tibial stress fracture and nonunion following vascularized fibula flap for mandibular reconstruction and a discussion of the orthopedic management of this uncommon injury. The authors' goal is to educate both surgeons and patients about the altered biomechanics and subsequent risks associated with fibula strut graft harvest, from an orthopedic surgery perspective. By increasing physician awareness and obtaining better informed consent preoperatively, better health care outcomes associated with fibular graft harvesting can be obtained. [Orthopedics. 2021;44(x):xx–xx.]

Abstract

There is little in the literature about tibial stress fracture after partial fibulectomy. As fibula strut grafting and vascularized fibula flap grafting becomes more common in the field of reconstructive surgery, the incidence of this complication will likely rise. The authors present the case of a 54-year-old woman with tibial stress fracture and subsequent nonunion following vascularized fibula graft harvest. The aim of this case report is to present a unique tibial stress fracture and nonunion following vascularized fibula flap for mandibular reconstruction and a discussion of the orthopedic management of this uncommon injury. The authors' goal is to educate both surgeons and patients about the altered biomechanics and subsequent risks associated with fibula strut graft harvest, from an orthopedic surgery perspective. By increasing physician awareness and obtaining better informed consent preoperatively, better health care outcomes associated with fibular graft harvesting can be obtained. [Orthopedics. 2021;44(x):xx–xx.]

Vascularized fibula flap grafting is gaining popularity in reconstructive jaw surgery because of its unique properties. The fibula flap is large, well vascularized, able to withstand mastication, and somewhat resistant to peri-implant reabsorption.1,2 These grafts are not without disadvantages. Fibula graft harvest poses the risk of altering the normal biomechanics of the lower extremity, specifically redistributing loading mechanics of the ankle. Tibia stress fracture after vascularized fibula graft is a rare complication, but it has been reported in the literature.3,4 The aim of this case report is to present a unique tibia stress fracture and nonunion after vascularized fibula flap for mandibular reconstruction and a discussion of the orthopedic management of this injury.

Case Report

A 54-year-old woman with a history of congenital hypoplastic mandible had mandibular reconstruction with left fibula flap graft for severe mandibular atrophy, foreign body reaction, and stress fracture. Approximately 10 cm of the patient's fibula was harvested per recommended technique. The patient had an extensive history of mandibular stress fracture with malocclusion requiring multiple surgeries beginning in 1999. Of note, she also underwent left total knee arthroplasty 14 months following her partial fibulectomy.

The patient had an uneventful perioperative course. Approximately 22 months postoperatively from her fibula flap graft, she presented to the emergency department with left lower extremity pain. The patient felt a sharp pain when planting her left foot. Radiographs of the left tibia demonstrated a nondisplaced distal third tibial shaft fracture (Figure 1). The patient was placed in a short leg cast, made non-weight bearing, given crutches, and instructed to follow up with the orthopedic surgeon who had performed her total knee arthroplasty. The cast was removed at 12 weeks, when the fracture was deemed healed on radiograph and by clinical examination. Approximately 2 weeks after cast removal, the patient presented to the emergency department with left leg pain and deformity sustained during atraumatic normal gait. Radiographs of the left tibia demonstrated an impending open displaced transverse fracture of the distal third tibia with significant sclerosis (Figure 2). The amount of callus formation at the fracture site prevented adequate closed reduction, and operative management of the patient's fracture was recommended. The patient's fracture was further complicated by the presence of an ipsilateral total knee arthroplasty, complicating the preferred treatment modality of intramedullary nail fixation.

Anteroposterior (A) and lateral (B) radio-graphs of the left tibia obtained in the emergency department showing a subtle nondisplaced distal third tibial shaft fracture. The patient reported pain with palpation of the distal tibia.

Figure 1:

Anteroposterior (A) and lateral (B) radio-graphs of the left tibia obtained in the emergency department showing a subtle nondisplaced distal third tibial shaft fracture. The patient reported pain with palpation of the distal tibia.

Anteroposterior (A) and oblique (B) radiographs of the left tibia showing an impending open displaced transverse fracture of the distal third tibia with significant sclerosis.

Figure 2:

Anteroposterior (A) and oblique (B) radiographs of the left tibia showing an impending open displaced transverse fracture of the distal third tibia with significant sclerosis.

The patient underwent open reduction and internal fixation for her distal third tibia fracture (Figure 3). The fracture was readily identified, with significant sclerosis and poor tissue envelope surrounding the tibia fracture site noted. The fracture site was thoroughly irrigated and debrided of sclerosis, devitalized tissue, and hematoma. The proximal and distal fracture sites were drilled and burred to remove sclerosis to create a surface amenable to fracture reduction. A 10-hole 4.5-mm plate was contoured to the tibia. Alignment was confirmed fluoroscopically, and the plate was fixated using locking screws. The wound was closed. The patient was managed postoperatively with splint immobilization and made non-weight bearing for 6 weeks. She was seen 6 weeks postoperatively and showed good clinical improvement and routine radiographic healing.

Postoperative anteroposterior (A) and lateral (B) radiographs after open reduction and internal fixation of the left tibia.

Figure 3:

Postoperative anteroposterior (A) and lateral (B) radiographs after open reduction and internal fixation of the left tibia.

The patient presented to the emergency department 1 week later, which was 7 weeks following open reduction and internal fixation. She had sustained a fracture through her distal tibial plate and previous nonunion site. At that time, laboratory analysis was not suggestive of infectious nonunion. Hardware was removed and a spanning Taylor Spatial Frame (Smith & Nephew) was applied in conjunction with a negative pressure wound vacuum dressing for inadequate and tenuous soft tissue coverage. Subsequently, the patient developed a deep infection. The patient required multiple surgical irrigations and debridement with chronic intravenous antibiotics suppression therapy. Unable to suppress the infection, the patient elected to undergo below knee amputation less than 2 years removed from her tibial stress fracture and subsequent nonunion.

Discussion

To the authors' knowledge, only one study has documented the incidence of tibia stress fracture after vascularized fibula graft harvest. Han et al3 evaluated the results of vascularized fibula grafting for use in skeletal reconstruction. Of 132 cases in which vascularized fibula transfer was used, 1 patient was noted to have sustained a stress fracture of the ipsilateral tibia. The authors noted that the patient had long-standing diabetes mellitus and osteopenia.3 Emery et al4 reported 5 cases of tibial stress fracture after fibula strut graft harvest for use in spine surgery. The authors also commented on the presence of osteopenia in 3 of the 5 patients, suggesting its role in tibial stress fracture following fibulectomy.4

Multiple studies have suggested that the length of the residual fibula after graft harvest is important for ankle stability.5–8 Weiland et al5 originally proposed that an arbitrary value of 6 cm of distal fibula be preserved for ankle stability. A cadaveric biomechanical study by Pacelli et al8 suggested that only 10% (3.9 cm) of the distal fibula remain intact before ankle instability (>2 mm of motion) was observed. The study also observed significant axial migration of the fibula in neutral ankle position.8 The authors suggested that this axial migration may have a role in ankle pain following partial fibulectomy. A study by Gore et al6 found that 41% of patients reported mild to severe pain at 2-year follow-up after partial fibulectomy.

The biomechanics of the fibula has been extensively studied, and it is clear that the fibula plays a role in load bearing.8–10 A study by Goh et al11 compared the weight-sharing role of the fibula before and after in vitro fibula graft harvest. The authors demonstrated an average load transmission of 7.12% for the fibula with the ankle at neutral. The load through the fibula was increased during dorsiflexion and eversion. When the fibula was removed, the distal fibula only accounted for 0.62% to 0.81% of the load-sharing responsibility, thereby transmitting an additional 6% of load bearing of the lower extremity through the tibia. The use of a syndesmotic screw from fibula remnant to tibia was shown to partially restore load-sharing responsibility, ranging from 1.71% to 5.14%.11

The fibula also affects the load-bearing properties of the knee. A cadaveric study by Yazdi et al12 demonstrated that a 2-cm fibulectomy at 12 cm proximal to the lateral malleolus resulted in a 5.2% increase in lateral compartment contact pressures. Total knee replacement alters knee biomechanics. The patient underwent total knee arthroplasty 8 months prior to tibial stress fracture. To the current authors' knowledge, there have been no studies discussing total knee arthroplasty in patients with fibulectomy. Further research is necessary to understand the effect of fibulectomy on proper component positioning related to joint reactive forces.

In this case, a 54-year-old woman had a distal tibia stress fracture 22 months after fibula graft harvest for mandibular reconstruction. The patient was managed with cast immobilization and was non-weight bearing for 12 weeks. She subsequently fractured her distal tibia at the level of the original stress fracture. The patient went on to have a devastating course of multiple attempts at fracture fixation with subsequent deep infections.

Conclusion

Although tibia stress fracture after partial fibulectomy is rare, with a rate of 0.76% reported in the literature,3 this complication is likely under-reported and, as demonstrated in this case, can be associated with high morbidity. The goal of this case report was to educate both surgeons and patients about the altered biomechanics and subsequent orthopedic risks associated with partial fibulectomy. Patient education prior to consent for harvest and development of a safe post-harvest protocol is important in optimizing associated health care outcomes. Deficiencies in patient bone metabolism should be investigated and optimized prior to the index procedure. Further research is needed to address the perioperative management of patients' status after partial fibulectomy.

References

  1. Shen Y, Li J, Ow A, Wang L, Lv MM, Sun J. Acceptable clinical outcomes and recommended reconstructive strategies for secondary maxillary reconstruction with vascularized fibula osteomyocutaneous flap: a retrospective analysis. J Plast Reconstr Aesthet Surg. 2017;70(3):341–351. doi:10.1016/j.bjps.2016.11.020 [CrossRef] PMID:28063782
  2. Gbara A, Darwich K, Li L, Schmelzle R, Blake F. Long-term results of jaw reconstruction with microsurgical fibula grafts and dental implants. J Oral Maxillofac Surg. 2007;65(5):1005–1009. doi:10.1016/j.joms.2006.06.294 [CrossRef] PMID:17448854
  3. Han CS, Wood MB, Bishop AT, Cooney WP III, . Vascularized bone transfer. J Bone Joint Surg Am. 1992;74(10):1441–1449. doi:10.2106/00004623-199274100-00002 [CrossRef] PMID:1469003
  4. Emery SE, Heller JG, Petersilge CA, Bolesta MJ, Whitesides TE Jr, . Tibial stress fracture after a graft has been obtained from the fibula: a report of five cases. J Bone Joint Surg Am. 1996;78(8):1248–1251. doi:10.2106/00004623-199608000-00016 [CrossRef] PMID:8753718
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  7. Lang CJ, Frederick RW, Hutton WC. A biomechanical study of the ankle syndesmosis after fibular graft harvest. J Spinal Disord. 1998;11(6):508–513. doi:10.1097/00002517-199812000-00010 [CrossRef] PMID:9884296
  8. Pacelli LL, Gillare J, McLoughlin SW, Buehler MJ. A biomechanical analysis of donor-site ankle instability following free fibular graft harvest. J Bone Joint Surg. 2003;85(4):597–603. doi:10.2106/00004623-200304000-00002 [CrossRef] PMID:12672832
  9. Lambert KL. The weight-bearing function of the fibula: a strain gauge study. J Bone Joint Surg Am. 1971;53(3):507–513. doi:10.2106/00004623-197153030-00007 [CrossRef] PMID:5580009
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  11. Goh JC, Mech AM, Lee EH, Ang EJ, Bayon P, Pho RW. Biomechanical study on the load-bearing characteristics of the fibula and the effects of fibular resection. Clin Orthop Relat Res. 1992;(279):223–228. doi:10.1097/00003086-199206000-00028 [CrossRef] PMID:1600659
  12. Yazdi H, Mallakzadeh M, Mohtajeb M, Farshidfar SS, Baghery A, Givehchian B. The effect of partial fibulectomy on contact pressure of the knee: a cadaveric study. Eur J Orthop Surg Traumatol. 2014;24(7):1285–1289. doi:10.1007/s00590-013-1381-0 [CrossRef] PMID:24318306
Authors

The authors are from the Department of Orthopedics, Beaumont Hospital, Farmington Hills, Michigan.

The authors have no relevant financial relationships to disclose.

Correspondence should be addressed to: Benjamin J. Main, DO, Department of Orthopedics, Beaumont Hospital, 28050 Grand River Ave, Farmington Hills, MI 48336 ( benjamin.main@beaumont.org).

Received: June 17, 2019
Accepted: November 17, 2019
Posted Online: November 25, 2020

10.3928/01477447-20201119-04

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