What is an Evans osteotomy?

Evans Osteotomy: Definition and Clinical Applications

An Evans osteotomy is a lateral column lengthening procedure performed approximately 10 mm proximal to the calcaneocuboid joint, primarily used in the surgical treatment of adult and pediatric pes planus (flatfoot) deformity. 1

Anatomical Considerations

• The optimal location for an Evans osteotomy is exactly 10 mm proximal to the calcaneocuboid joint, which helps avoid damage to the anterior or middle subtalar facets 1
• The osteotomy is directed from posterolateral to anteromedial to minimize the risk of violating the calcaneal facets and sustentaculum tali 2
• Several structures are at risk during the procedure, including the sural nerve, peroneus longus tendon, and peroneus brevis tendon 1
• Medial soft tissues consistently pass in the line of the Evans osteotomy and require careful protection 1

Biomechanical Effects and Indications

• The Evans osteotomy corrects abduction, improves talar head coverage, decreases forefoot and rearfoot valgus, and improves medial column arch height 2
• It has become an important surgical option for treating adult pes planus deformity of multiple causes 1
• The procedure is frequently implemented in flatfoot reconstructive surgery for correction of planar deformity 3
• It is particularly valuable in the correction of pediatric collapsing pes planovalgus 4

Fixation Considerations

• The original description of the Evans osteotomy involved no internal fixation, and debate has existed regarding the necessity of fixation 3
• Studies show an acceptably low rate of nonunion (1.4%) for unfixated, isolated Evans calcaneal osteotomies 3
• When performed without fixation, the anterior process shows initial dorsal displacement (average 1.21 mm at 6 weeks) that typically diminishes over time 4
• Modern techniques often utilize locking plates to stabilize the osteotomy and allograft material 5

Potential Complications

• Hardware-related complications can occur, with females twice as likely as males to develop symptoms after locking plate application 5
• Hardware removal may be required in approximately 30% of cases due to soft-tissue irritation 5
• Displacement of the anterior process can occur, though studies show this typically resolves without significant clinical impact 4
• Careful attention to anatomical structures is necessary to avoid damage to the sural nerve and peroneal tendons 1

Clinical Outcomes

• The procedure produces clinically and statistically significant improvements in the calcaneal inclination and talar declination angles 4
• Complete pain relief is typically reported after hardware removal when hardware-related complications occur 5
• The Evans osteotomy provides effective correction of flatfoot deformity when properly executed 2

Surgical Pearls

• Patients, especially females, should be counseled about potential hardware-related pain and possible follow-up procedures to remove hardware 5
• The osteotomy should be performed with careful attention to nearby anatomical structures to minimize complications 1
• When using the Evans osteotomy as part of flatfoot reconstruction, it should be considered in the context of the overall deformity correction plan 2