Key Pearls Of Calcaneal Osteotomies

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Continuing Education Course #108 — May 2003

I am very pleased to introduce the ninth article, “Key Pearls Of Calcaneal Osteotomies,” in our CE series. This series, brought to you by HMP Communications, consists of regular CE activities that qualify for one continuing education contact hour (.1 CEU). Readers will not be required to pay a processing fee for this course.

In this month’s article, Kieran T. Mahan, DPM, offers key indications, pertinent pearls and specific pointers for performing three common calcaneal osteotomies, including the Dwyer, Evans and sliding calcaneal ostetomies.

Dr. Mahan, the Associate Dean for Research at the Temple University School of Podiatric Medicine, also provides insights into modifications that may help facilitate treatment outcomes.

At the end of this article, you’ll find a 10-question exam. Please mark your responses on the postage-paid postcard and return it to HMP Communications. This course will be posted on Podiatry Today’s Web site (www.podiatrytoday.com) roughly one month after the publication date. I hope this CE series contributes to your clinical skills.

Sincerely,

Jeff A. Hall
Editor-In-Chief
Podiatry Today

INSTRUCTIONS: Physicians may receive one continuing education contact hour (.1 CEU) by reading the article on pg. 67 and successfully answering the questions on pg. 72. Use the postage-paid card provided to submit your answers or log on to www.podiatrytoday.com and respond electronically.
ACCREDITATION: HMP Communications, LLC is approved by the Council on Podiatric Medical Education as a sponsor of continuing education in podiatric medicine.
DESIGNATION: This activity is approved for 1 continuing education contact hour or .1 CEU.
DISCLOSURE POLICY: All faculty participating in Continuing Education programs sponsored by HMP Communications, LLC are expected to disclose to the audience any real or apparent conflicts of interest related to the content of their presentation.
DISCLOSURE STATEMENTS: Dr. Mahan has disclosed that he has no significant financial relationship with any organization that could be perceived as a real or apparent conflict of interest in the context of the subject of his presentation.
GRADING: Answers to the CE exam will be graded by HMP Communications, LLC. Within 60 days, you will be advised that you have passed or failed the exam. A score of 70 percent or above will comprise a passing grade. A certificate will be awarded to participants who successfully complete the exam.
TARGET AUDIENCE: Podiatrists.
RELEASE DATE: May 2003.
EXPIRATION DATE: May 31, 2004.
LEARNING OBJECTIVES: At the conclusion of this activity, participants should be able to:

• discuss proper indications for the Dwyer osteotomy, the Evans osteotomy and the sliding calcaneal ostetomy;
• describe the aforementioned osteotomy procedures;
• discuss the impact of using allogeneic grafts for an Evans ostetomy; and
• discuss post-op considerations for patients who undergo the aforementioned osteotomies.

Sponsored by HMP Communications, LLC.

After you’ve reflected the extensor digitorum brevis distally, perform the Evans osteotomy through and through, I cm proximal to the calcaneaocuboid joint.
Proceed to insert the lamina spreader and measure the desired correction.
After measuring the desired correction, insert the graft and gently tap it into place.
Here is an inferior view of the calcaneus prior to the shift medially.
Here is the inferior view of the calcaneus showing the medial shift.
Note this inferior view of the calcaneus after fixation with a Steinmann pin. The pin outside the foot shows the angle of the pin. Using two pins may be advantageous to prevent rotation.
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Author(s): 
By Kieran T. Mahan, DPM

Calcaneal osteotomies have been a mainstay of foot and ankle surgery for many years, and are critical in the realignment of significant foot deformities. Both varus and valgus deformities often require calcaneal deformities for correct alignment. Although a large number of calcaneal osteotomies have been described in the literature over the years, there are a few principal ones that tend to be more commonly used than others.
One would perform the Dwyer osteotomy for frontal plane deformity of varus in the cavus foot. Surgeons often perform the Evans osteotomy for realignment of the adolescent valgus foot, but it is also used during adult flatfoot repairs. The sliding calcaneal osteotomy is commonly used to treat adult flatfoot. Each of these procedures has a unique powerful way of realigning the position of the heel with respect to the ground.
Calcaneal osteotomies exert their effect through realigning the position of the heel at the time of heel strike. The Dwyer takes the heel out of varus by wedging the calcaneus from the lateral side of the heel. The Evans has multiple effects. It realigns the heel (taking it out of valgus) and reduces the abduction of the midtarsal joint. It plantarflexes the forefoot on the rearfoot. Correction occurs in all three planes. The sliding calcaneal osteotomy serves to center the valgus heel back under the leg. You can modify the procedure by using a varus opening wedge to produce frontal plane correction.
Each of these procedures is technically straightforward. Understanding the proper indications for each of the procedures is essential. Yet there are also some key technical elements that can make a large difference in the outcomes. In order to ensure the best results for your patients, let’s take a closer look at these procedures, starting with the Dwyer osteotomy.

How The Dwyer Osteotomy Works
Dwyer described this osteotomy as both an opening medial osteotomy and a lateral closing wedge osteotomy. Either way, the procedure is designed to take the heel out of varus. Knowing this, the calcaneal axial X-ray would seem to be ideal for determining when you should perform this procedure. Although the X-ray may be useful, performing the Coleman block test is even more useful. It helps you differentiate between structural varus and varus created by plantarflexion of the first ray. In many cavus feet, it is the plantarflexion of the first ray that causes the inversion appearance of the heel that we see in stance.

In order to perform the Coleman block test, you place a block under the lateral portion of the forefoot to neutralize the effect of first ray plantarflexion. If there is no true structural varus, the heel will come out of varus to a vertical position.
Be aware that performing the Dwyer alone in these patients with a plantarflexed first ray will create increased stress beneath the sesamoids with focal pain. If you perform the Dwyer along with a dorsiflexory osteotomy in these patients, it will lead to excessive pronation and collapse of the foot. Worse than the poorly performed Dwyer is the unnecessary Dwyer osteotomy. Indeed, the indication must be very specific.

Pertinent Pointers Of The Procedure
The technique is based upon a lateral approach. The primary concern is the sural nerve, which splits into an anterior and posterior branch superiorly. Entrapment of the sural nerve is a complication that is truly disconcerting to the patient on a long-term basis. Although some bruising of the nerve is not uncommon and may result in short-term paresthesias, entrapment of the nerve often creates sufficient pain that the result is unsuccessful, regardless of the structural outcome.
Make the curved incision from the superior surface of the calcaneus, 1 to 2 cm proximal to the upper margin of the bone, extending distally past the lower margin of the calcaneus. Carry the dissection down through the superficial fascia, which is mobilized enough to create room for resection of the wedge and possible insertion of staples.

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