Percutaneous Dwyer and Lateral Displacement Calcaneal Osteotomy

Jonathan R. M. Kaplan

♦ INTRODUCTION

The calcaneal osteotomy has a long-standing history of use in various disorders of the foot and ankle. While traditionally performed through a 4- to 6-cm incision, advancements in minimally invasive technique and technology have allowed the calcaneal osteotomy to be performed through 1- to 2-mm “keyhole” incisions. Through these minimally invasive techniques, excellent correction is achieved while minimizing soft-tissue disruption.

Both the lateral displacement calcaneal osteotomy and the Dwyer lateral closing wedge osteotomy can be used to correct a hindfoot varus deformity.¹ The author prefers to perform a combination of the Dwyer and lateral closing wedge osteotomy in order to achieve sufficient correction. Additionally, if needed, proximal translation of the calcaneus can also be performed in order to achieve three-dimensional correction of the deformity when needed.

♦ INDICATIONS AND CONTRAINDICATIONS

The primary indication for the lateral displacement calcaneal osteotomy is to correct a hindfoot varus deformity. This includes primarily correction of the cavovarus foot or subtle hindfoot varus. Other indications may include treatment of Mueller-Weiss syndrome in which there is hindfoot varus with a compensatory flatfoot² (Figure 16.1). Additionally, this calcaneal osteotomy can be considered as part of the treatment algorithm in patients undergoing surgery for a fifth metatarsal fracture, peroneal tendon pathology, or ankle instability with associated hindfoot varus. Furthermore, the minimally invasive calcaneal osteotomy is beneficial for preserving the soft tissues. Examples include relatively close adjacent incisions such as a concomitant lateral ligament reconstruction incision (Figure 16.2), patients at risk for infection (tobacco use, diabetes, corticosteroid usage), or nearby prior surgical scars.

Contraindications to a lateral displacement calcaneal osteotomy include neutral hindfoot alignment or hindfoot valgus. Additionally, it should be avoided in patients with active infection in the hindfoot. Lastly, in patients with a rigid hindfoot deformity, consideration should be made for arthrodesis-type procedures to correct the deformity instead of periarticular osteotomies; however, this is a relative contraindication as a calcaneal osteotomy can be performed in addition to a hindfoot arthrodesis procedure if needing to achieve additional correction.

♦ PATIENT HISTORY AND PHYSICAL EXAMINATION

A thorough history and physical examination is critical to determine the need for a lateral displacement calcaneal osteotomy. On the history, patients with hindfoot varus may report an array of symptoms related to lateral ankle and foot overload. Patients may occasionally develop pain and callosities along the lateral column of the foot; however, more often patients will present with symptoms related to other pathology that are related to having a hindfoot varus alignment. This includes pain or weakness related to peroneal tendon pathology, recurrent ankle sprains or ankle instability, symptoms related to hindfoot or midfoot arthritis, or even fifth metatarsal stress fracture symptoms due to their alignment and chronic lateral foot overload.

The physical examination should include assessment of the patient in both the standing and seated position. The author prefers to first start with having the patient stand facing away from the examiner to best evaluate the hindfoot alignment. Additionally, Coleman block testing can be performed while the patient is standing so as to assess for a forefoot-driven hindfoot varus. If the hindfoot corrects into physiologic valgus, the deformity is flexible and secondary to plantarflexion of the first ray. In this case, a first metatarsal osteotomy is better indicated for correction rather than a lateral displacement calcaneal osteotomy. With the patient in a seated position, the hindfoot deformity should be assessed to determine if it is passively correctable. If the deformity is not passively correctable, an arthrodesis-type procedure would be more likely indicated than a calcaneal osteotomy. Finally, thorough examination of the foot and ankle should

be completed including soft-tissue evaluation, strength and sensory testing, palpation of pulses, range of motion of the ankle and hindfoot joints, as well as diagnosis-specific examination.

Figure 16.1 A. AP foot radiograph of a patient with Mueller-Weiss syndrome with comma-shaped dysplastic navicular. B. Lateral foot radiograph of a patient with Mueller-Weiss syndrome with flatfoot appearance including decreased calcaneal pitch as well as dysplastic navicular. C. Hindfoot alignment radiograph of a patient with Mueller-Weiss syndrome showing hindfoot varus. D. Postoperative lateral foot radiograph of a patient with Mueller-Weiss syndrome with healed calcaneal osteotomy. E. Postoperative hindfoot alignment radiograph of a patient with Mueller-Weiss syndrome with laterally translated calcaneal osteotomy.

Figure 16.2 Intraoperative image showing planned incision for lateral ligament reconstruction (full line) and adjacent completed calcaneal osteotomy (dotted line).

♦ IMAGING STUDIES

Radiographs

Weight-bearing radiographs should be obtained if possible as they are better indicators of true alignment compared to non-weight-bearing radiographs. Three views of the ankle, including anteroposterior (AP), oblique, and lateral, and three views of the foot, including AP, oblique, and lateral, should be obtained. Additionally, a Saltzman hindfoot alignment view should be obtained to allow for better assessment of the extend of hindfoot varus deformity³ (Figure 16.3).

Pertinent findings on the AP and oblique ankle radiographs would include any presence of ankle arthritis as well as potential varus or compensatory valgus deformity of the ankle. On the lateral radiographs of the foot and ankle, there may be evidence of increased calcaneal pitch, metatarsal stacking, increased sinus tarsi visualization, and posterior appearance of the fibula due to a cavovarus deformity, as well as potential hindfoot arthritis across the triple joint complex. The AP and oblique radiographs of the foot may show associated adduction deformity across the transverse tarsal joint and/or metatarsus adductus, or midfoot arthritis across the tarsometatarsal joints. Furthermore, specific pathologic abnormalities should be considered on the radiographs such as the presence of Mueller-Weiss syndrome with talonavicular arthritis and avascular changes to the navicular associated with hindfoot varus and compensatory flattening of the arch.

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