Treating Complicated Ankle Fractures

Tackling complicated ankle fractures can be a difficult dilemma, which from time to time requires atypical surgical techniques to obtain a perfect repair. In today’s ever changing world, we are seeing more patients with underlying comorbidities, which can lead to difficult management of what would be a routine fracture in a healthy patient. Likewise, with an ever-growing population of people participating in exercise and extreme sports, we also are seeing more devastating comminuted-type fractures of the ankle.

Comorbidities are taking their toll on postoperative outcomes of surgical repairs. These comorbidities include diabetes mellitus, peripheral vascular disease, vitamin D deficiency and the systemic disease ramification of chronic disease management with high side effect medications.

We believe the use of improper closed reduction techniques in some emergency rooms may be another factor associated with an increased number of patients with atypical fracture patterns along with increased morbidity to the soft tissue envelope and articular damage. In our experience, these incidents have increased the difficulty level of treatment.

Ankle biomechanics has taught us the importance of not only obtaining anatomical length of the fibula but, equally as important, the need for syndesmotic alignment.

The literature has shown that even with the slightest malalignment of 1 mm of lateral talar displacement, there is a 42 percent reduction of the contact area.¹ There is also a big focus on proper syndesmotic reduction. Studies have shown that malreduction of the syndesmosis can be present in up to 50 percent of surgical repairs of ankle fractures and have worse functional outcomes.^2,3 Understanding the importance of proper anatomical reduction is of utmost importance in the ankle joint in order to prevent posttraumatic arthritis and disability.

In this article, we will discuss in detail each anatomical aspect involved in complicated ankle fracture repair and share our techniques and tips for proper treatment.

Key Pearls On Distal Fibular Fixation

Meticulous dissection for lateral malleolar reduction is essential due to encountering the superficial peroneal nerve, which usually emerges from the crural fascia approximately 10 to 12 cm from the distal tip of the fibula.⁴ Surgeons must also take caution during dissection to prevent injury to the peroneal tendons. This is followed by subperiosteal dissection of the fibular fracture with adequate curettage of the hematoma from the fracture interface to allow for proper healing.

When treating ankle fractures with delayed open reduction internal fixation (ORIF), a more extensive dissection is required to “mobilize” the distal fibular fragment. It is important to allow soft tissue swelling to subside if one performs ORIF in the acute phase, due to the increased postoperative risk of dehiscence and infection.

In reducing the fibular fracture, it is important to bring the fibula out to length. We gauge this by the classic radiographic dime sign, the talocrural angle, Shenton’s line and, most importantly, confirmation that the ankle mortise is in anatomical alignment with equally distributed joint space.

Some distal fibula fractures are more difficult than others to reduce. Fractures that are significantly comminuted or have multiple butterfly fragments become difficult, and important factors to remember include reducing the main fracture fragments. After stabilization, reduce the small fragments to the main fragments. One can fixate these with multiple smaller lag screws or bridge plates for severely comminuted fractures.

With more proximal oblique or transverse fibular shaft fractures, there may be significant shortening, which makes reduction very difficult. Tips for reduction include using reduction forceps at a stable portion of the proximal and distal fragment, and manually distracting to gain reduction. When this attempt fails at reduction, the “push-pull screw” technique may be useful. This entails affixing the plate to the distal fragment. Place a 3.5 mm screw in the lateral aspect of the proximal fragment. Then place a lamina spreader between the 3.5 mm screw and the proximal end of the plate, and apply distraction. This will bring the fibula out to length.⁵

With fixation of the distal fibular fracture, practice the proper AO lag technique. Under-drilling initially may facilitate easier visualization and placement of the lag screw directed to the posterolateral aspect of the distal fibula.

Upon examination of the fracture, it is important to identify and address Wagstaffe and Tillaux fractures. Repairing these fragments will aid in stabilization of the syndesmosis. Due to the fracture fragment size, Wagstaffe and Tillaux fractures will usually require small screw fixation or even buried Kirschner wire fixation.

Fixating Medial Malleolar Fractures

In addressing medial malleolar fractures, dissection to this area must be meticulous to prevent any injury to the neurovascular structures or adjacent soft tissue structures. Cadaveric studies have illustrated the safe zone for medial malleolus dissection and screw fixation.⁶ Creating a slightly anterior incision for the medial malleolar ORIF will prevent iatrogenic injury to the posterior tibial tendon but surgeons must take care to avoid the saphenous vein and nerve.

With screw fixation of the medial malleolus fracture, it is important to achieve compression and examine the fracture under fluoroscopy. Surgeons must ensure that the periosteal and capsular tissue do not become impinged between the screw head and cortical bone, creating an under-compressed fixation. One should examine medial malleolus fixation under fluoroscopy to ensure the proper alignment and placement of fixation. It is prudent to drill a hole and insert the first screw before drilling for the second screw due to possible loss of reduction and rotation of the unstable fracture.

When treating patients who have multiple comorbidities such as diabetes mellitus or present with osteoporotic bone, bicortical lag by technique fixation may be more appropriate due to its increased torque and decreased fixation loosening.⁷ For patients with smaller comminuted fractures of the medial malleolus that are not amenable to screw fixation, one may apply fixation with a hook plate.

What You Should Know About Syndesmotic Stabilization

Upon placement of the syndesmotic screw, it is important to understand the spatial relationship of the fibula to the tibia. Studies have shown that placement of the screw in the tibia is of utmost importance as syndesmotic malreduction may result when the screw is in a more posterior position in comparison to central or anterior position.⁸

The use of fluoroscopy during fixation is a very important visual tool. Obtaining proper anterior posterior, mortise and lateral views during fixation placement will ensure proper reduction occurs.

Do you leave the screw in or take it out? There have been many different trains of thought regarding every aspect of syndesmotic stabilization. In a study performed by Song and colleagues, 36 percent of patients had malreduction of the syndesmosis on postoperative computed tomography (CT) scans.⁹ Of these patients, surgeons removed syndesmotic fixation and 89 percent had spontaneous reduction of the syndesmosis.

With our patients who have poorly controlled diabetes, present with osteoporotic bone or are more prone to failure of conventional fixation, we augment syndesmotic stabilization with additional transsyndesmotic screws.

A Guide To Posterior Malleolar Fixation

Posterior malleolar fractures can be difficult to address due to their anatomic location and surrounding soft tissue structures. Haraguchi and colleagues had categorized posterior malleolar fractures into three types: type 1 (posterolateral), type 2 (medial extension) and type 3 (small shell type).¹⁰

Radiographic imaging may not display posterior malleolar fractures accurately and may obscure die-punch fragments, significant step-offs, plafond impaction, or fractures that are larger in size than the X-ray indicates.

A recommended imaging modality for preoperative planning of trimalleolar ankle fractures is a CT scan. These are not necessary for all ankle fractures but one should reserve CT scans for the complex ankle fractures (trimalleolar, comminuted, severe dislocation). Studies have shown that surgeons changed operative planning in 29 percent of trimalleolar fractures after CT scan evaluation.¹¹

As the complexity of the fracture increases, other approaches may allow better exposure for proper anatomical reduction. The posterolateral and posteromedial approaches to access posterior malleolar fractures may be favorable incisional techniques.

Make the posterolateral incision at the interval between the posterior fibula and Achilles. Retract the peroneal tendons anteriorly. Carry dissection down between the flexor hallucis longus tendon and the peroneal tendons. This will give access to the posterolateral aspect of the tibia to allow for reduction and fixation of the posterior malleolar fracture.

The posteromedial incision may be more useful for fractures with a large medial extension. Make the incision just posterior to the medial malleolus. Carry dissection down to the posterior tibial tendon. Make an incision through the sheath and create an interval between the posterior tibial tendon and flexor digitorum longus tendon. Retract the flexor digitorum longus tendon posteriorly, which will also protect the neurovascular structures. This interval will provide access to the posteromedial aspect of the tibia.

Alternatively, using a transmalleolar approach may address the posterior malleolar fracture through the malleolar fracture. Insert a bone hook through the medial malleolus fracture and direct it toward the posterior tibia to help with posterior malleolus fracture reduction. One can also use a transmalleolar approach on the lateral malleolus. Surgeons may use a lamina spreader to distract and open up the lateral malleolar fracture, which will create exposure and allow for reduction of a posterolateral tibia fracture.

In Conclusion

As our patient population presents with increased comorbidities, which subsequently create more challenges for treatment of complicated ankle fractures, innovation with advanced techniques is required to address these fractures properly. We have described a few helpful tips and techniques that may aid in proper repair of these more advanced, complicated ankle fractures when the routine conventional techniques do not suffice. It is important to understand the biomechanics of the ankle to achieve proper anatomical reduction and prevent posttraumatic arthritis.

Dr. Hofbauer is a Diplomate of the American Board of Foot and Ankle Surgery, and a Fellow of the American College of Foot and Ankle Surgeons. He is a member of The Orthopedic Group in Pittsburgh.

Dr. Lai is a Fellow at the Orthopedic Group in Pittsburgh.  

References

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4. Blair J, Botte M. Surgical anatomy of the superficial peroneal nerve in the ankle and foot. Clin Orthop Relat Res. 1994; 305:229-238.
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