Diabetic Ankle Fractures: A Review of the Literature and an Introduction to the Adelaide Fracture in the Diabetic Ankle Algorithm and Score

Diabetics who have acquired an ankle fracture may be easily missed given their atypical presentation. As such, it is not infrequently seen that these patients are either initially misdiagnosed or ineffectively managed resulting in unnecessary hospital length of stay and procedures. Multiple review articles and retrospective studies have been previously published in the literature, but complete guidelines to assist in accurate diagnosis and cost-effective management for this complex problem do not currently exist. Through a critical analysis of the current literature, a proposed diagnostic and management algorithm and scoring system that can be used to quantify risks in the surgical management are presented for consideration.


Introduction
Both diabetes and ankle fractures are increasing in incidence worldwide. In 2003, it was estimated that 194 million people in the world have been diagnosed with diabetes and this is predicted to exponentially increase to over 333 million by 2025 [1]. Ankle fractures are amongst the most common injuries encountered by orthopaedic surgeons, with its incidence on the rise in parallel with general life expectancy [2,3]. Extrapolated from this data, the incidence of diabetic ankle fractures will inevitably increase. There is, however, a lack in a standardized diagnostic and treatment guidelines for diabetic ankle fractures. Additionally and not uncommonly, diabetic ankle fractures have been misdiagnosed resulting in delayed management. For these reasons, we propose a diagnostic and management algorithm that incorporates a quantitative scoring system in hope to achieve a practical approach to this complex and challenging problem.

Materials and Methods
Publications were identified by conducting a comprehensive keyword search of Medline, EMBASE, and CINAHL databases between the months of September 2010 to March 2011 by the primary author (Joshua Yee). Search terms included "diabetes, " "ankle, " and "fracture. " Available abstracts of all articles (i.e., no date restriction to search results) published in the English language in the above databases searched within the above timeframe where included for initial review to determine suitability. Inclusion criteria for full-text review were that articles must be relevant to diabetic ankle fracture diagnosis and management. Manual search of the all the references in the full-text publications was also completed to further identify additional publications for potential inclusion. All included full-text publications for review were further defined as either a notable or supportive. A publication was defined to be notable if the study design (i.e., cohort, retrospective, case control, and case series) and level of prognostic strength (i.e., level IV or higher) were met. Notable publications were subjected to further critical analysis. Exclusion criteria were the following: publications not published in English; all conferences, lectures, review articles, and publications that were neither published nor published in the above databases. Duplicate results that occurred in different databases were truncated to a single result.

Results
A total of 352 abstracts were initially screened. From these abstracts, 59 articles met our inclusion criteria for further full text review. 293 articles were excluded. Nine additional articles were found after reviewing all the full-text references ( Figure 1). Nineteen notable papers were identified for further critical analysis (Tables 1 and 2). From these results, we propose the Adelaide Fracture in the Diabetic Ankle (AFDA) algorithm and score (Figures 2 and 3, Table 3).

Discussion
The AFDA algorithm consists of two parts: a diagnostic and management part (Figures 2 and 3), having its own respective goals. The diagnostic part is targeted for primary care physicians and nurse practitioners with a goal to accurately and timely provide a diagnosis to any presentation of ankle redness, swelling, and/or pain; and if such a presentation is encountered, the algorithm progresses to assess or screen for the presence and risks for diabetes. Risk factors for diabetes include previous history of impaired glucose intolerance; high-risk ethnic groups (i.e., Retrospective study 2 SooHoo et al. [21] Ganesh et al. [3] Case control study 6 McCormack and Leith [22] Jones et al. [23] Flynn et al. [24] Blotter et al. [25] Kristiansen [26] Bibbo et al. [27] Case series 7 Costigan et al. [28] Ayoub [14] Holmes and Hill [29] Kline et al. [30] White et al. [31] Schon et al. [32] Low and Tan [33] Asian, African, and Hispanic); positive family history or gestational diabetes; age greater than or equal to 45 with either a body mass index (BMI) greater or equal to 25 or presence of hypertension; and established cardiovascular risk factors or disease. If risk factors are present, screening for diabetes is suggested using either HBA1c (greater or equal to 6.5%), two-hour plasma glucose (greater or equal to 11.1 mmol/L) during an oral glucose tolerance test, or fasting blood glucose (greater or equal to 7.0 mmol/L) [4].
If the presence of diabetes has been excluded, other causes of ankle redness, swelling, and/or pain should be considered, which can include: gout, infection, septic arthritis, deep vein thrombosis (DVT), and haemarthrosis [5,6]. Furthermore, if there is an absence of systemic signs of infection (i.e., fever, elevated white cell count, or CRP), then infection is unlikely [6].  Since the introduction of the Ottawa ankle rules [7], there has been a significant increase in cost efficiency to plain radiograph usage in assessing acute ankle injuries. However, there has been question of whether the Ottawa ankle rules apply in diabetics [8,9]. If there is a history of diabetes or newly diagnosed diabetes, we suggest that plain radiographs can be acquired independent of the Ottawa ankle rules. This should be interpreted for presence of a fracture, dislocation, and/or Charcot's arthropathy. Because of the possibility of an insensate lower limb, the patient's history may be difficult to elicit which has occurred first: the fracture or acute Charcot's. However, if any of these are present, the AFDA management algorithm and score can be applied.
The AFDA management algorithm and score will assist the treating specialist in the optimal decision making for managing diabetic ankle fractures. If a fracture requires fixation, the AFDA score (Table 3) can be considered to differentiate between managing it as a primary ORIF or primary rigid fixation/arthrodesis. Ganesh et al. [3] have, in an analysis of a nationwide inpatient database, concluded that there are significant increases in in-hospital length of stay and costs for diabetics with ankle fractures compared with nondiabetics. Having a decision from the outset can potentially decrease these factors and, furthermore, allow the patient to return to their usual activities earlier and save them from unnecessary revision surgery. Rigid fixation/arthrodesis is reserved for patients who are at high risk of amputation or failure if primary ORIF is used. Comparing techniques of rigid fixation/arthrodesis is beyond the scope of this discussion, but options include retrograde intramedullary nailing [10,11], posterior blade plate [12], external ring fixators [13], and cross-screw techniques [14].
If Charcot's arthropathy is present in conjunction with the diabetic ankle fracture, Eichenholtz's [15] staging should also be considered. As Eichenholtz stage I has traditionally been considered to be the acute fragmentation stage, the current literature recommends that this stage can be managed nonoperatively in the interim, with nonweight bearing and serial total contact casting. Additionally, frequent followup and further patient optimization through multidisciplinary review and management can be considered. Endocrine input for consideration of intravenous bisphosphonate therapy (i.e., Pamindronate) has been shown to inhibit the increased osteoclastic activity that weakens bones during this acute stage [16,17]. Optimization of diabetic control, nutrition, and vascular status whilst this stage progresses will likely achieve a better outcome. Once Eichenholtz's staging progresses outside of stage I, progression for fixation consideration is suggested. Postoperatively and independent from the surgical fixation technique, the literature suggests that all patients undergo prolonged nonweightbearing for 12 weeks, protected or partial weight bearing for another 8 to 12 weeks, with frequent outpatient followup with plain radiographs initially fortnightly for the first six weeks, then monthly thereafter [18]. The AFDA scoring system (Table 3) is based on assessable patient factors. Two points have been allocated to factors more readily seen in the notable publications to suggest either poor outcomes of standard internal fixation or better outcomes with rigid fixation/arthrodesis. A Semmes Weinstein monofilament 10 g/5.07 at the plantar aspect of either the great toe, first, third, or fifth metatarsal head can be used to assess presence of neuropathy [18]. Presence of vasculopathy can be defined as peripheral oxygen saturations consistently less than 95% or an ABI of less than 0.65 [19]. Obesity can be defined as a BMI of greater than 30. Smoking has not been included as a factor because it increases general surgical risk, independent of fixation technique.   Two points each One point each (i) Peripheral neuropathy/loss of protective sensation [2,23,24,28,33] (ii) Presence of vasculopathy [2,14,28] (iii) Insulin dependence with poor compliance [23][24][25]30] (iv) Previous or coinciding history of Charcot's arthropathy in any joint [2,14,23] (i) Diabetic history of greater than 20 years [14,23] (ii) Presence of nephropathy or retinopathy [6] (iii) Obesity [14,30] (iv) Poor patient compliance With the use of AFDA algorithm, it can hopefully provide a standardized approach and guide to management for diabetic ankle fractures. The scoring system, in particular, can assist in objectively quantifying risk for both the patient and affected ankle joint so as to allow the treating specialist to have confidence in achieving the best possible outcome. As the score increases, the risks of failure in standard fixation methods increase and consideration of more robust and rigid fixation techniques or fusion should be incorporated. From our review of the literature, we suggest that if the patient scores five or more, rigid fixation/arthrodesis should be considered from the outset. If rigid fixation/arthrodesis fails, despite adequate measures in hope for an optimal outcome, amputation can be considered.
The current evidence of which AFDA is derived from is based primarily on heterogeneous study designs and our center's experience. As such, it will require further validation reviews or trials, incorporating followup and functional outcome scores. Once validated, AFDA can be used as a protocol and research tool for the diagnosis and management of diabetic ankle fractures.