Suprasyndesmotic Fixation: Can It Have An Impact In Neuropathic Diabetic Ankle Fractures?

Using the example of a bimalleolar ankle fracture in a 61-year-old woman with diabetes, these authors say suprasyndesmotic fixation can be beneficial for patients when instability and non-adherence are potential issues.

Type 2 diabetes mellitus is a worldwide epidemic directly correlated with the rise in obesity, which is particularly worse in the United States. In 2014, the World Health Organization has estimated 422 million people are living with diabetes mellitus, a significant increase from 108 million in 1980.^1,2

With this dramatic increase in diabetes mellitus also comes an increase in patient comorbidities, most prominently vasculopathies, neuropathies and delayed tissue healing due to the physiologic and metabolic abnormalities present in the disease. Multiple studies have demonstrated a 10- to 20-fold increased risk of undergoing a lower extremity amputation in this population in comparison to patients without diabetes.2 This presents challenges for the foot and ankle surgeon when patients have elective surgery or suffer a traumatic event.

Supination-external rotation ankle fractures present a challenge in patients affected by diabetes with a loss of protective sensation due to peripheral neuropathy, particularly when syndesmotic disruption has occurred. Post-traumatic patients with diabetic neuropathy and increased hemoglobin A1C levels >8 pose a greater risk for complications. Complications include delayed wound healing, postoperative infection, nonunion, delayed union, malunion, Charcot arthropathy and hardware failure.² Due to demineralization (osteopenia) and compromised soft tissue healing potential, an increase in osteosynthesis is required. To increase the rigidity of the fixation, one should use multiple tetracortical suprasyndesmotic screws, locking plates, and external fixators.

Accordingly, we present a case study demonstrating the use of supra-syndesmotic fixation for a supination-external rotation level IV neuropathic ankle fracture with multiple tetracortical suprasyndesmotic screws and a locking plate, bicortical medial malleolar fixation and a Steinmann pin for tibiotalar stabilization.

What You Should Know About The Patient’s Ankle Fracture

A 61-year-old patient with type 2 diabetes and peripheral neuropathy presented to the emergency department after suffering a bimalleolar right ankle fracture. Surgeons reduced and splinted the ankle fracture in the emergency department and admitted the patient for potential open reduction and internal fixation (ORIF). However, due to concern for soft tissue compromise, the surgeon decided to have the patient transported to a skilled nursing facility in the splint and delay ORIF until the soft tissue was stable.

While the patient was in the skilled nursing facility, the ankle became dislocated despite splinting. She then developed signs of soft tissue breakdown along the medial malleolus of the ankle. At this time, the patient got a referral to the senior author for further evaluation and surgical management.

At five weeks post-injury, the patient had ORIF of the bimalleolar ankle fracture. Due to the marked instability of the ankle and the patient’s medical history, surgeons used multiple tetracortical screws for fixation along with percutaneous bicortical fixation of the medial malleolus and an axial Steinmann pin to provide additional stability to the tibiotalar joint.

Due to the patient’s history of a first ray amputation of the left foot, we recommended the use of a wheelchair instead of external fixation so as not to tax the opposite extremity. We extended the non-weightbearing period from the traditional six weeks to 12 weeks.

How Suprasyndesmotic Fixation Can Benefit Patients With Diabetes

Surgeons should utilize suprasyndesmotic fixation in the neuropathic diabetic supination-external rotation level IV ankle fractures in the presence of gross instability, when there is a concern for non-adherence and when there is a clinical demonstration of a loss of protective sensation.

Researchers have reported high complication rates including transtibial amputation in both operative and conservative treatment in this patient population.^3-6 Costigan and colleagues (2007) performed a retrospective study of 84 patients with diabetes who had standard fixation for acutely injured, closed and reduced ankle fractures.⁷ The authors noted a 14 percent complication rate including infection, development of Charcot arthropathy, nonunion and peripheral vascular compromise. In another study, Haddix and coworkers (2018) observed an increase in complications in patients with type 1 versus type 2 diabetes as well as insulin-dependent patients versus non-insulin dependent patient populations.⁸

In the aforementioned patient populations, foot and ankle surgeons should consider additional rigid fixation supraconstructs that extend fixation beyond the zones of injury. These constructs reduce the risk of hardware failure, which stresses the soft tissue and can lead to subsequent postoperative complications such as infection, wound dehiscence and the development of Charcot arthropathy. Multiple tetracortical syndesmotic fixation provides additional rigidity to the construct for non-adherent patients with unstable diabetic neuropathic ankle fractures, improving the likelihood of achieving a favorable outcome in a challenging patient population.

It is no longer the standard of care to address neuropathically involved ankle fractures — whether they occur in patients with or without diabetes — with traditional osteosynthesis. Supraconstructs that advance rigidity in osteopenic bone and extend fixation beyond the zones of injury have now become the standard.

Dr. Visser is the Director of the SSM Health DePaul Hospital Foot and Ankle Surgery Residency in St. Louis. He is a Fellow of the American College of Foot and Ankle Surgeons.

Dr. Wolfe is a third-year resident with the SSM Health DePaul Hospital Foot and Ankle Surgery Residency in St. Louis.

Dr. McKeey is a second-year resident with the SSM Health DePaul Hospital Foot and Ankle Surgery Residency in St. Louis.

Dr. Keeter is a second-year resident with the SSM Health DePaul Hospital Foot and Ankle Surgery Residency in St. Louis.

References

1. World Health Organization. Global report on diabetes. 2016; 978:8. Available at https://www.who.int/diabetes/global-report/en/ .
2. Guyer AJ. Foot and ankle surgery in the diabetic population. Orthop Clin N Am. 2018; 49(3):381-387.
3. Flynn JM, Rio Fr, Piza PA. Closed ankle fractures in the diabetic patient. Foot Ankle Int. 2000;21(4):311-319.
4. Lovy AJ, Dowdell J. Keswani A, et al. Nonoperative versus operative treatment of displaced ankle fractures in diabetics. Foot Ankle Int. 2017; 38(3):255-260.
5. Schon LC, Easley ME, Weinfeld SB. Charcot neuroarthropathy of the foot and ankle. Clin Orthop Relat Res. 1998; 349:116-131.
6. McCormack Rg, Leith JM. Ankle fractures in diabetics. Complications of surgical management. J Bone Joint Surg Br. 1998; 80(4):689-692.
7. Costigan W, Thordardson D, Debnath U. Operative managementof ankle fractures in patietns with diabetes mellitus. Foot Ankle Int. 2007; 28(1):32-37.
8. Haddix K, Clement C, Tennat J, et al. Complications following operatively treated ankle fractures in insulin and non-insulin dependent diabetic patients. Foot Ankle Specialist. 2018; 11(3):206-216.