Ankle fractures in patients with diabetes present a great challenge for the foot and ankle surgeon. Indeed, there is an abundance of literature documenting the difficulty of managing diabetic ankle fractures. Surgical treatment can be fraught with complications such as delayed bone and wound healing, and the development of Charcot neuroarthropathy.
When it comes to treating diabetic ankle fractures, complication rates are high, especially in patients with neuropathy. One reason for this is the altered osteogenesis in patients with diabetes in comparison to that of people without diabetes. In 1988, Loder evaluated the influence of diabetes mellitus on the healing of closed fractures. The study found the overall osseous time to union to be 163 percent longer in the diabetic population. Furthermore, the study found that displaced fractures requiring open reduction internal fixation (ORIF) had a 187 percent longer healing time in patients with diabetes.1
Reddy, et al., studied the mechanical strength of bone in patients with diabetes. The study revealed 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 patients without diabetes. The authors concluded that diabetic bone was more inflexible and bore decreased loads. Accordingly, they noted that diabetic bone has decreased energy absorbing capacity.2
Cavanaugh, et al. evaluated radiographic abnormalities in patients with diabetic neuropathy. The study demonstrated a substantial number of neuropathic fractures in many of these patients. Moreover, they noted that a significant number of these patients went on to develop Charcot arthropathy.3
An Overview Of The Pathophysiology Of Charcot Arthropathy
Charcot neuroarthropathy is largely associated with longstanding diabetes mellitus. Two main theories exist regarding the development of Charcot joint disease. The first theory, neurotraumatic destruction (also known as the German theory), postulates that the breakdown is a result of cumulative mechanical trauma in a joint that has been rendered insensitive to proprioception and pain.
The joint insult may be major or minor, recognized or unrecognized. Often, when unrecognized microtrauma from abnormal gait causes increased plantar pressure in an insensate limb, this leads to Charcot arthropathy.
The theory of neurovascular destruction hypothesized that a lack of vasomotor tone leads to ligamentous weakening and bone resorption. The neurally stimulated vascular reflex is interpreted as an “autosympathectomy” and eventually induces joint disintegration. While the exact cause of Charcot athropathy is unclear, it is likely that both theories contribute to the pathophysiology of the disease.
Weighing The Various Treatment Options And Potential Complications
The literature shows controversy when it comes to surgical versus non-surgical treatment in this patient population.4-7 McCormack and Leith reported increased infection rates, delayed bone healing and an increased incidence of Charcot joint disease with overall complication rates approaching 47 percent in the surgical treatment of 19 diabetic ankle fractures.8 Bibbo, et al., reported that 5 to 10 percent of all patients with diabetes who sustain an ankle fracture will develop Charcot joint disease.4 More recent studies have shown increases in severe complications, most notably Charcot joint disease and infection, in the non-surgical group.9
Appropriately selected patients with diabetes undergoing surgical treatment can have a successful outcome. To maximize positive outcomes, tight glucose control is preferable. In addition, signs of peripheral vascular disease warrant the intervention of a vascular specialist, preferably before the definitive surgery takes place. There is a benefit with these patients to follow the general rule of thumb to double the fixation, double the non-weightbearing time and double the number of post-op visits.6
Fixation options vary widely and are dependent on the severity of osteopenia, the presence of peripheral vascular disease and the integrity of the soft tissue envelope. The fixation options include percutaneous techniques such as Kirshner wires, Rush rods, percutaneous screws and external fixation as well as traditional open techniques such as lateral and anti-glide plating, and intramedullary nails.4-8,10-12
Locking plate technology has further enhanced our ability to maintain reduction with rigid fixation in patients with poor bone stock. One may use external fixation alone or to augment internal fixation. With the overall goals being rigid internal fixation and the prevention of further postoperative complications, the foot and ankle surgical community has turned its attention to the fibula-pro-tibia technique. Accordingly, let us take a closer look at this technique as an option for obtaining a rigid internal fixation construct to decrease the likelihood of late stage Charcot breakdown.
What You Should Know About The Fibula-Pro-Tibia Technique
Hahn first described the fibula-pro-tibia technique in 1884 as a means to support tibial discontinuity. The procedure involved a transfer of the proximal fibula to the proximal tibia to improve load sharing. The technique was modified throughout the years and surgeons used it to manage large tibial defects, delayed union, non-union and osteomyelitis.13-15
In 1995, Schon and Marks discussed the use of this procedure for the treatment of neuropathic ankle fracture/dislocation in the patient with diabetes.7 They modified the procedure to include multiple transsyndesmotic screws through a fibular plate in order to create a rigid ankle joint complex that promotes osseous healing and decreases the incidence of post-traumatic Charcot joint disease. Since then, other authors have published additional articles espousing the usefulness of this technique, or modifications thereof, in treating diabetic ankle fractures.4,6,11,12
We use a standard approach for ORIF of a lateral malleolar fracture. Once we have achieved reduction of the fracture via bridge plating or interfragmental compression, we fill the remaining holes in the fibular plate with 3.5-mm or 4.0-mm fully threaded screws. One may deliver the transsyndesmotic screws proximal to fractures near the ankle joint level or they may span higher fibular fractures with or without comminution present. We advocate the purchase of four cortices to reinforce the construct.
Furthermore, delivering multiple locking transsyndesmotic screws increases rigidity and decreases the chance of screw failure or the backing out of screws. Multiple transsyndesmotic screw delivery have the advantage of fixation “backup.” In other words, a break in one or two screws will not lead to a failure of the entire construct.12 Additionally, in cases that involve a medial malleolar fracture, we advocate far lateral tibial cortex screw purchase.
Is there a biomechanical tradeoff? Delivering multiple transsyndesmotic screws across the distal tibiofibular articulation theoretically eliminates its natural motion. Controversy exists on whether syndesmotic fusion interferes with restoration of normal ankle joint anatomy and motion. Studies have shown that 6 degrees of rotatory motion and 1.1 mm of mediolateral translation occur at the distal fibular interosseous site. Lack of this motion is not a significant detriment to a patient’s normal walking ability.16,17 This finding was similar to the report by DeOrio, who noted no deleterious effect on gait after five patients underwent fusion of the distal tibia and fibula via a fibula-pro-tibia technique.14
Navigating The Potential Complications Of The Fibula-Pro-Tibia Technique
This surgical approach is not without its own inherent complications.4,6,7,11,12 Additional hardware may lead to prominence and subsequent wound complications, or the need for second surgery hardware removal. If one uses a relatively longer lateral incision to deliver the proximal fixation, wound healing issues may arise. To avoid this longer skin incision, one may deliver the fibular plate subperiosteally through a smaller incision. One may then deliver the proximal screws percutaneously with the aid of intraoperative fluoroscopy.
There is always the potential for complications with surgical treatment and one must determine if the benefits outweigh the risks. This decision is no different when implementing the fibula-pro-tibia technique for diabetic ankle fractures. With appropriately selected patients, we believe this operative technique can provide a stable, braceable limb, reduce the risk of late stage joint breakdown and return patients to being community ambulators.
Ankle fractures in the patient with diabetes involve a large realm of potential complications. Factors such as ambulatory status, quality of bone, glucose control and vascular status, just to name a few, are imperative for the foot and ankle surgeon to consider.
The fibula-pro-tibia technique has been adapted to treat high-risk ankle fractures, specifically in patients with neuropathy, diabetes mellitus, and/or Charcot arthropathy. This technique involves delivering multiple transsyndesmotic screws through a fibular plate and into the distal tibia to form a “one bone” lower leg. The goal is to create a rigid construct in the face of osteoporotic bone in order to neutralize the deforming forces that lead to a Charcot joint event in the high-risk patient population.
Dr. Reeves is an Attending Physician at the Florida Hospital East Orlando Residency Training Program in Orlando, Fla. He is a Fellow of the American College of Foot and Ankle Surgeons.
Dr. MacGill is the Chief Resident of Foot and Ankle Surgery at Florida Hospital East Orlando.
Dr. Shane is an Attending Physician with the Florida Hospital East Orlando Residency Training Program. She is an Associate of the American College of Foot and Ankle Surgeons.
Dr Conte is an Attending Physician with the Florida Hospital East Orlando Residency Training Program. He is in private practice in Orlando.
Dr. Steinberg is an Assistant Professor in the Department of Plastic Surgery at the Georgetown University School of Medicine in Washington, D.C. Dr. Steinberg is a Fellow of the American College of Foot and Ankle Surgeons.
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2. Reddy GK, Stehno-Bittel L, Hamade S, Enwemeka CS. The biomechanical integreity of bone in experimental diabetes. Diabetes Res Clin Pract. 54(1):1-8, 2001.
3. Cavanaugh PR, Young MJ, Adams JE, Vickers KL, Boulton AJ. Radiographic abnormalities in the feet of patients with diabetic neuropathy. Diabetes Care. 17(3):201-209, 1994.
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