Essential Pearls On Treating Diabetic Ankle Fractures

Keith D. Cook, DPM, FACFAS, Carl Brandon Lindberg, DPM, and Joseph Genualdi, DPM

   The rate of fracture healing in patients with diabetes also appears to be dependent on blood glucose levels. Recent studies by Liu and colleagues have shown that ankle fractures in patients with diabetes with HbA1c levels greater than 6.5% had poor radiologic outcomes and a lower American Orthopaedic Foot and Ankle Society score in comparison to patients with an HbA1c less than 6.5%.14 Elevated blood glucose levels have also been associated with wound healing complications.15 This is due to a number of combined systemic effects such as macro- and microvascular disease, accumulation of glycosylation byproducts in the tissue, and poor healing secondary to an increase in inflammatory cytokines.11 One must educate the patient on the importance of glycemic control during the initial encounter to decrease complications.

   Patients with diabetic neuropathy who suffer ankle fractures have a higher risk of developing Charcot neuroarthropathy secondary to the direct injury sustained. Charcot first described neuropathic osteoarthropathy in 1868 and Johnson published the neurotraumatic theory of developing Charcot foot in 1967.16 Reportedly 5 to 10 percent of all patients with diabetes who sustain an ankle fracture develop Charcot neuroarthropathy.11 There is an increased risk for developing Charcot in a neuropathic patient who is not immobilized or in whom a delay in immobilization takes place. Once clinical and radiographic healing have occurred with a neuropathic ankle fracture, we advise bracing with a Charcot Restraint Orthotic Walker (CROW). One should also direct attention to the non-injured limb as patients with Charcot have a greater risk of developing neuroarthropathy on the contralateral side due to the increased weightbearing requirements.

A Closer Look At Treatment Options

The question of when to perform surgery on diabetic ankle fractures should depend on the patient’s comorbidities and fracture type. When it comes to a stable, non-displaced ankle fracture, one can provide conservative treatment and educate the patient regarding blood glucose control, immobilization and strict adherence to the non-weightbearing protocol.3,14,15,17 In 1998, Schon and coworkers reported the outcomes of conservative treatment for 15 patients with non-displaced ankle fractures.3 The authors found casting and/or bracing of the non-displaced fractures for three to nine months resulted in favorable outcomes.

   For closed, displaced ankle fractures, the timing of surgical intervention can become more difficult. A literature search revealed no prospective controlled trials comparing treatment modalities for displaced diabetic ankle fractures. Compounding the problem is that not all displaced ankle fractures are equal and the degree of comorbidities may be different from patient to patient.

   In a study of patients with peripheral neuropathy, Schon and coworkers reported the outcomes of conservative treatment for four patients with displaced ankle fractures and surgical treatment for nine patients with displaced ankle fractures.3 All of the patients in the conservative treatment group had a non-union or malunion, requiring late open reduction and internal fixation (ORIF) in one case and ankle arthrodesis in the remaining three patients. In the surgical treatment group, seven out of the nine patients had favorable outcomes with ORIF and immobilization for three months.

   In a meta-analysis by Lillmars and Meister, the authors compared ankle fracture outcomes in 140 patients with diabetes with 223 non-diabetic controls.4 The authors reported an overall complication rate of 30 percent for patients with diabetes who had surgical treatment, 77 percent for patients with diabetes who received conservative care and 7 percent for non-diabetic controls.

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