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CHAPTER 64 • Ankle Fractures

Most patients have good outcomes following ankle fracture, but there are a range of potential complications (Table 64-4). Assessment of the frequency at which these occur depends on the patient and injury groups evaluated. While rates of wound infection of up to 32% 113 have been reported in diabetic patients and high rates of fixation failure reported in elderly patients, 29 for most patients recovery will be completed without complication. Osteoarthritis of the ankle is most commonly caused by trauma with 39% of cases in a recent series found to be secondary to ankle fracture. 393 AO/OTA type C fracture patterns, high BMI, dislocation, and increased age are risk factors for the development of osteoarthritis. 223 Assessing those at risk is a major challenge as osteoarthritis may occur even following perfect reduction, pre- sumably because of cartilage damage at the time of injury. 77 An interesting study by Stufkens et al. found that cartilage damage was a predictor of posttraumatic osteoarthritis at a mean of almost 13 years follow-up. No correlation was found between the number of lesions and the outcome but worse outcomes were found with deeper lesions and those on the anterior or lateral talus or the medial malleolus. 364 A further investigation of the articular cartilage assessment using arthroscopy found the most common site of damage to be the talus followed by the distal tibia and fibula and finally the medial malleolus. 152 Further long-term outcome studies may be necessary particularly as we now know that osteoarthritis following ankle fracture may take a number of years to become apparent, with Horisberger finding a mean time from ankle fracture to end-stage osteoarthritis of 21 years. 393 As might be expected, postoperative complications have been shown to result in significantly worse patient-reported outcomes. Høiness et al. 154 found a significant difference in patient-reported outcomes when those with minor, major, and no postoperative complications were compared. Interestingly, Horisberger 160 was also able to demonstrate a correlation between complications and development of osteoarthritis. Less common complications include CRPS, 77 compartment syndrome, 19,303,428 and pulmonary embolism. 58,403 While these are significant complications, their rarity is highlighted by the small number of case reports. The most common complications of wound infection, symptomatic metalwork, and failure of fix- ation remain the biggest challenges in the management of ankle fractures. Removal of metalwork results in an improvement in patient-reported outcomes in only 50% of patients. 48

TABLE 64-4. Complications Following Ankle Fractures

Complication

Rate and Management

Early Wound infection/ dehiscence

1%–10%. Superficial infections can often be treated with antibiotics and dressings. Deep infections may respond to suppression antibiotics until the fracture has united but then usually require surgery to debride the wound and obtain bacteriologic specimens. Exposed hardware may require removal and the use of a spanning external fixator until the infection is eradicated. Loss of reduction 0%–2%. This is most common in conservatively treated, unstable fractures. In surgically treated fractures this may be related to inadequate initial reduction, inadequate fixation, poor bone stock, peripheral neuropathy or psychiatric illness. Malunion increases the risk of osteoarthritis. Thromboembolism DVT 3%, PE 0.3%. Chemoprophylaxis is of uncertain efficacy

Late Symptomatic hardware

Varies depending on the type and location of the fixation device. Removal is effective in 50%. Rare in low-energy fractures but up to 30% of unstable patterns. May take several decades to become evident. Higher when anatomical reduction of the mortise is not achieved, other cases probably related to chondral injury at time of injury. May require functional bracing or an arthrodesis. Most commonly encountered after nonoperative treatment. Often asymptomatic, but if painful may require (revision) fixation and possibly bone grafting. Rare, associated with high-energy fractures. The superficial peroneal, sural, and saphenous nerves are all at risk in the subcutaneous layer and injury may result in a patch of anesthetic, or worse, dysesthetic skin.

Osteoarthritis

Nonunion

Compartment syndrome

Neuroma

Annotated References Reference

Annotation

Cherney SM, Cosgrove CT, Spraggs-Hughes AG, et al. Functional outcomes of syndesmotic injuries based on objective reduction accuracy at a minimum 1-year follow-up. J Orthop Trauma. 2018;32(1):43–51. Kristensen KD, Hansen T. Closed treatment of ankle fractures: Stage II supination–eversion fractures followed for 20 years. Acta Orthop Scand. 1985;56(2):107–109. Michelson JD, Hamel AJ, Buczek FL, et al. Kinematic behavior of the ankle following malleolar fracture repair in a high-fidelity cadaver model. J Bone Joint Surg Am. 2002;84-A(11):2029–2038.

The authors aimed to correlate accuracy of syndesmosis reduction and clinical outcome. They found no difference between clinical outcome and malreductions of up to 3 mm.

Classic paper describing 95% good outcomes after nonoperative treatment of SER2 fractures after a mean of 21 years.

Much of our understanding of ankle biomechanics is based upon rather artificial, static models and this probably explains the inconsistency between these models and clinical results. This paper demonstrates the importance of muscular control in ankle stability.