Ankle fractures in patients with diabetes and documented neuropathy present a significant challenge to the clinician. The majority of literature has indicated that ankle fractures in this particular patient population are often difficult to manage and complication rates are reportedly quite high. These poor outcomes are similar for both conservative and surgical treatment.
There are several factors implicated in the high complication rates one sees in the management of ankle fractures in patients with diabetic neuropathy. Many of these patients have significant osteopenia. The combination of the osteopenia with neuropathy can often result in significant problems. Treatment for these patients is often very labor-intensive and ideal therapeutic options have yet to be determined when it comes to managing ankle fractures in patients with diabetic neuropathy.
Indeed, outcomes have been shown to be generally poor and some factors that have been implicated are beyond the physician’s control. Standard approaches to treating these fractures in non-diabetic patients do not result in good outcomes when one applies these approaches to patients with diabetic neuropathy. Clinicians should also be aware of significant medical and legal issues surrounding the treatment of diabetic ankle fractures.
What You Should Know About The Risk Factors
Cavanaugh, et. al., presented a study evaluating radiographic abnormalities in patients with diabetic neuropathy. They noted a substantial number of neuropathic fractures in a large number of these patients and also pointed out that a significant number of patients went on to develop a Charcot process. The authors of the study concluded that one should have a high index of suspicion for neuropathic fractures and conditions such as Charcot deformity when managing patients with diabetes and established neuropathy.1
Reddy, et. al., evaluated the mechanical integrity of bone in experimental diabetes. This study determined there was a 37 percent decrease in maximal load, a 25 percent decrease in deformation and maximal load and a 38 percent increase in bending stiffness in comparison to non-diabetic subjects. They concluded that diabetic bone was stiffer and bore less of a load, thus decreasing its energy absorption capacity.2
Ivers, et. al., evaluated 3,654 patients over a two-year period. They tried to determine risk factors that were associated with fractures in patients with diabetes mellitus. They concluded that diabetes-related factors that are significantly associated with an increased risk of fractures include the presence of neuropathy, a duration of diabetes mellitus greater than 10 years and insulin treatment. The authors found that spontaneous fractures develop in this patient population and are often undiagnosed due to the lack of pain sensation.3
Bibbo, et. al., looked at risk factors for complications in diabetic ankle fractures. This study determined that age, hypertension, weight and fracture type were not significant factors in the development of these complications. However, his study demonstrated that neuropathy and peripheral vascular disease were significant factors that resulted in complications.4
Another major problem among patients with diabetes is the development of Charcot after a fracture. Young, et. al., tried to determine which factors were associated with the development of Charcot arthropathy in diabetes. However, this study determined that certain factors including sex, age, insulin use, the duration of diabetes, retinopathy, proteinuria, the level of hemoglobin A1c, weightbearing status and history of previous ulceration provided no statistical value for predicting the development of Charcot arthropathy.5
Complications: What The Literature Reveals
When it comes to the surgical management of ankle fractures in patients with diabetes, potential complications include infection, malunion, nonunion and Charcot arthropathy. These complications can be rather difficult to manage and have significant morbidity.
In particular, when one is managing diabetic ankle fractures, the treating physician should have a high index of suspicion for the development of Charcot. The incidence of Charcot arthropathy is relatively high following fracture in patients with diabetes mellitus. There are clearly factors other than mechanical overload that are involved. Unfortunately, these patients have abnormal bone metabolism, which results in significant bone resorption and often rapid disintegration. Following an ankle fracture, this can result in progressive destruction over a relatively short period of time.
The literature on the management of ankle fractures in patients with diabetes has shown outcomes to be generally poor. McCormick and Leith evaluated ankle fractures in 26 patients with diabetes mellitus and compared them to a group of non-diabetic patients. They found a 42.3 percent incidence of complications in patients with diabetes mellitus as opposed to no complications in the non-diabetic group. They concluded that conservative management may be preferable to surgical treatment in view of the high risks associated with management of ankle fractures with diabetes mellitus.6
However, Flynn, et. al., evaluated 98 patients with ankle fractures, 25 of whom had diabetes mellitus. The infection rate was 32 percent in the diabetes mellitus group. Interestingly, those patients with diabetes mellitus treated with conservative therapy had a greater tendency to become infected over those treated with open reduction internal fixation (ORIF). This study concluded that the diabetic patients who were poorly compliant and had evidence of neuropathy and severe edema are very difficult to manage.7
Key Considerations For Treating Patients With Diabetes
Indeed, it is important to emphasize tight metabolic control for patients with diabetes mellitus who sustain the ankle fractures. Beam, et. al., studied the effects of blood glucose control on fracture healing. This study demonstrated decreased bone formation and mechanical stiffness in patients with poorly controlled diabetes mellitus. However, when blood glucose levels were tightly controlled with insulin, the fracture healing was similar to the non-diabetic controls. They concluded that insulin treatment with improved blood glucose control will ameliorate early and late complications of fracture healing in patients with diabetes mellitus.8
From a medical/legal standpoint, it is important to document and enter into the chart any objective assessment that has established that these patients have diabetic neuropathy. Informed consent is also very important in this group of patients, whether one is treating them in the emergency department or the clinic. One should educate these patients about potential complications that might ensue following operative or nonoperative care. Complications may include the development of a Charcot process, severe deformity and potential limb loss.
A Pertinent Review Of Conservative Care Options
Given these risk factors and treatment considerations in this patient population, clinicians may want to review conservative treatment options. Conservative care for these patients should include an extensive period of non-weightbearing. Ideally, one should emphasize a non-weightbearing period that is twice as long for these patients as opposed to a non-diabetic patient with an ankle fracture. In other words, if a patient with diabetes sustains a non-displaced supination-external rotation fracture that requires six weeks of non-weightbearing in a non-diabetic, then he or she should wear a non-weightbearing, short-leg cast for 12 weeks.
It is also recommended to utilize casts that are very well padded or a total contact cast. One must emphasize protection for any osseous prominences in areas that are predisposed to irritation or breakdown. Additionally, frequent cast changes are recommended so clinicians may regularly inspect these areas. This facilitates early diagnosis and treatment of any iatrogenic wounds.
One should also instruct the patient to protect the contralateral extremity while he or she is wearing the cast. It is recommended to wrap the contralateral limb lightly in an elastic bandage up to the knee and utilize a pillow in between the legs during sleep. This helps avoid the development of iatrogenic wounds on the contralateral extremity. We also recommend limiting activity in order to avoid problems in the contralateral extremity that are secondary to excess weightbearing or overuse.
We have considered prophylactic bisphosphonate therapy in diabetic patients with established neuropathy when they have sustained ankle fractures. Bisphosphonates are bone metabolism regulators that inhibit osteoclastic activity and bone resorption. Bisphosphonates are indicated for metabolic bone disease and seem to be well tolerated with very few side effects. The objective with bisphosphonate therapy in diabetic patients with ankle fractures is to limit bony destruction during the acute phase of Charcot. Bisphosphonates have been well established for use in early stage Charcot.9,10 One may consider bisphosphonates as a prophylactic measure in this particular group of patients in order to minimize the incidence of Charcot.
Pertinent Pearls On Managing Open And Unstable Fractures
Open fractures are an especially challenging problem in diabetic patients with established neuropathy. White, et. al., evaluated the treatment of 14 fractures in 13 patients. They achieved complete bony union without complication in only three patients.11
For unstable ankle fractures and significant deformity in patients with diabetes, one should consider surgical management. Surgical options may include ORIF or closed reduction with percutaneous and/or external fixation. As with any type of surgical management, surgeons should emphasize certain precautions. One should allow for a preoperative decrease in edema after the injury before proceeding with surgical treatment. This allows a more healthy soft tissue envelope that might be less prone to soft tissue complications.
Surgeons should also develop an adequate fixation construct for these patients due to the incidence of osteopenia and neuropathy. The construct must provide adequate stiffness. We recommend utilizing multiple lag screws, if possible, when fixing a lateral malleolar fracture. We recommend fully threaded cancellous screws below the level of the ankle joint, especially in the presence of osteopenia.
We also recommend that surgeons use multiple transsyndesmotic screws through the plate when possible. These transsyndesmotic screws should engage all four cortices. One should also place the medial malleolar screws in such a way that four cortices are engaged as opposed to depending on cancellous bone to support the screws. There have been some other specialized techniques recommended for this particular group of patients. This includes the use of intramedullary screws and intramedullary nails for the fibular fracture.12
Additionally, we often consider employing a supplemental external fixator to neutralize any forces that might affect the internal fixation construct. It is recommended to perform cast changes every seven to 14 days in order to facilitate early recognition of any soft tissue complications. We also recommend obtaining serial radiographs on a more frequent basis in patients with diabetes. Doing so enables one to detect any osseous complications early in the postoperative period. Again, it is recommended to utilize a well-padded or total contact cast following surgery.
A Closer Look At Surgical Treatment Outcomes
Jani, et. al., established a protocol for treating unstable ankle fractures with transarticular fixation. The goal was to develop a minimally invasive technique to manage these patients and accordingly limit the risks associated with ORIF. They treated 18 ankle fractures in patients with diabetes mellitus. They performed closed reduction followed by percutaneous fixation and protective weightbearing. They reported a major complication rate of 25 percent with two below-knee amputations.13
In unpublished data gathered at the Western Pennsylvania Hospital, we have retrospectively studied the outcomes of ankle fracture treatment in 27 patients with diabetes and 27 non-diabetic patients via a case/control design. We reviewed demographic and outcome data. We performed statistical analysis comparing the diabetic and control group and also compared outcomes in patients with type 1 diabetes and those with type 2 diabetes.
The overall complication rate was 30 percent for the diabetic group and 7 percent for the control group. Peripheral vascular disease (p=.010), peripheral neuropathy (p=<.001) and higher patient weight (p=.039) were the only comorbid conditions that were statistically different when we compared patients with diabetes versus a non-diabetic control group (p=.010, p=<.001, respectively). Data analysis revealed the length of hospital stay was the only outcome that was statistically different between the diabetic and control groups (p=<.001).
This outcome data included assessments of ankle fracture type and severity, time to full weightbearing and fracture union, and the incidence of nonunion and wound problems. There was also no statistical difference between the demographic and outcome data of patients with type 1 diabetes and the results among those with type 2 diabetes.
Overall, there were no major complications of Charcot arthropathy, limb loss or death in this study population. This study demonstrates a low complication rate for the surgical treatment of diabetic ankle fractures relative to the existing literature.
An ankle fracture in a patient with longstanding diabetes mellitus can be a calamity for the patient and the physician who treats this fracture as a routine injury. Therefore, one should manage these patients with special precautions. In order to help achieve the best outcomes, it is essential to consider key factors that may predispose patients with diabetic neuropathy to complications resulting from an ankle fracture.
Dr. Catanzariti is the Director of the Residency Training Program within the Division of Foot and Ankle Surgery at the Western Pennsylvania Hospital in Pittsburgh. He is a Fellow of the American College of Foot and Ankle Surgeons.
Dr. Mendicino is Chief of the Division of Foot and Ankle Surgery at the Western Pennsylvania Hospital in Pittsburgh. He is a Fellow and Past President of the American College of Foot and Ankle Surgeons, and is a Clinical Professor of Surgery at the Western Campus of the Temple University School of Podiatric Medicine.
Dr. Sautter is a Chief Resident of Foot and Ankle Surgery at Western Pennsylvania Hospital in Pittsburgh.
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