Essential Insights On Treating Fifth Metatarsal Fractures

Start Page: 76

Continuing Education Course #140 — April 2006

I am pleased to introduce the latest article, “Essential Insights On Treating Fifth
Metatarsal Fractures,” in our CE series. This series, brought to you by the North American Center for Continuing Medical Education (NACCME), 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.

The incidence of fifth metatarsal fracture is somewhat common in active patients and such fractures can be complicated in nature. With this in mind, Nicholas Romansky, DPM, and Todd Becker, DPM, provide an essential guide to classification systems for these types of fractures. They also review key diagnostic pearls and pertinent treatment considerations for facilitating optimal outcomes.

At the end of this article, you’ll find a 10-question exam. Please mark your responses on the enclosed postcard and return it to NACCME. 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
Executive Editor
Podiatry Today

INSTRUCTIONS: Physicians may receive one continuing education contact hour (.1 CEU) by reading the article on pg. 77 and successfully answering the questions on pg. 82. Use the enclosed card provided to submit your answers or log on to www.podiatrytoday.com and respond via fax to (610) 560-0502.
ACCREDITATION: NACCME 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 NACCME are expected to disclose to the audience any real or apparent conflicts of interest related to the content of their presentation.
DISCLOSURE STATEMENTS: Drs. Romansky and Becker have disclosed that they have 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 their presentation.
GRADING: Answers to the CE exam will be graded by NACCME. 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: April 2006.
EXPIRATION DATE: April 30, 2007.
LEARNING OBJECTIVES: At the conclusion of this activity, participants should be able to:
• demonstrate a thorough knowledge of fifth metatarsal fractures;
• discuss common causes and diagnostic characteristics of cervical fractures, capital fractures and shaft fractures of the fifth metatarsal;
• review the Delee and Torg classification systems for Jones fractures;
• review key treatment considerations with Jones fractures; and
• discuss the diagnosis and treatment of tuberosity fractures of the fifth metatarsal.

Sponsored by the North American Center for Continuing Medical Education.

This is a spiral shaft fracture that resulted from a twisting injury. Note the medial displacement and shortening of the distal fragment.
Here one can see a spiral shaft fracture after open reduction internal fixation. The large surface area along the fracture site lends itself to healing. The authors used two 2.7 mm lag screws and standard AO technique with cerclage wire to reinforce the f
Here one can see an acute Jones fracture following intramedullary screw fixation with a 4.0 mm partially threaded cancellous screw. This treatment maintains periosteal blood supply and allows for rigid fixation and earlier weightbearing.
(Illustration courtesy of Maria McBride)
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Author(s): 
By Nicholas Romansky, DPM, and Todd Becker, DPM

Can You Spur An Earlier Return To Play For Athletes?
In athletes, almost all fifth metatarsal fractures require surgical treatment. Given the high rates of delayed union, non-union or recurring fracture, early surgical intervention via ORIF or intramedullary fixation is strongly recommended.
When pursuing these surgical options, the surgeon should ensure the patient is in a supine position on the OR table with the knee maximally flexed and the foot adducted on the surface of the OR table. This key position makes it very easy to place the guide or K-wire through the fracture site. Always aim down and inward to avoid hitting the lateral metatarsal cortex. Early surgical intervention helps avoid deconditioning of the athlete and typical prolonged bouts of immobilization. Modified activity or “relative rest” of activity can begin three days after the procedure.
Both of the above options facilitate an earlier return to play for athletic patients. However, one should closely monitor these athletes as the rate of fracture recurrence can be 12 percent or higher.

A Primer On Fifth Metatarsal Anatomy
A thorough understanding of the anatomy is crucial to the successful treatment of fifth metatarsal fractures due to variations within the metatarsal. The fifth metatarsal is a long bone consisting of a capitum, cervical neck, diaphyseal shaft, a metaphyseal-diaphyseal junction as well as the distinctive tuberosity at the base. Researchers have shown that the narrow distal canal, thicker dorsal and plantar cortices, and lateral bowing of the metatarsal are all potential factors in fixation failure.1

Ligamentous attachment to the fifth metatarsal base includes a portion of the long plantar ligament as well as the short plantar ligament, an interosseous ligament between the fourth and fifth metatarsal bases. Ligamentous attachment also includes the medial, lateral, dorsal and plantar cuboid-fifth metatarsal ligaments. The peroneus brevis and peroneus tertius tendons also insert onto the base of the fifth metatarsal.
Along the shaft of the bone is the origin of the three muscles, including the abductor digiti quinti brevis, the dorsal interosseous (which aids in interosseous stability due to its bipennate nature) and plantar interosseous muscles. While most of these muscular attachments play only a limited role in acute fractures, the peroneus brevis has been shown to be a major force in inversion injuries lending to styloid fractures. There is also a slip of the lateral plantar aponeurosis that attaches to the base of the metatarsal.
The nutrient artery to the fifth metatarsal enters the shaft at the middle and proximal one-third junction, and divides into a short proximal and longer plantar branch. This network of arteries accounts for approximately 60 to 65 percent of the blood supply to the bone. The other 30 percent comes from the periosteum and 5 percent comes from the joint interface.
There is an area of relative avascularity that exists at the juncture of the divergence of the proximal terminal branch of the nutrient artery and the metaphyseal arteries that lends itself to the high non-union rate of Jones fractures. This area tends to become even more avascular once a fracture has occurred due to the increase in cortical thickening and loss of medullary canal. Accordingly, proteins and nutrients necessary for bone healing cannot reach the fracture site, leading to a high rate of non-unions.
It is also necessary to have a good working knowledge of the path of the sural nerve when undertaking surgical correction of proximal fifth metatarsal fractures. In 1999, Donley demonstrated through cadaveric dissection that one must give particular attention to the dorsolateral branch of the sural nerve when fixating these fractures due to its proximity to the insertion site of the screw.2

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