Essential Insights On Treating Fifth Metatarsal Fractures

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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)
82
Author(s): 
By Nicholas Romansky, DPM, and Todd Becker, DPM

Other Insights On The Treatment Of Jones Fractures
Portland, et. al., found union rates of 6.2 weeks for acute Jones fractures and 8.3 weeks for stress fractures treated with intramedullary screw fixation. In their study, all 22 of the patients achieved complete union.9 In 1999, Pietropaoli found no biomechanical difference between the use of 4.5 mm malleolar screws and 4.5 mm partially threaded cannulated screws.10 In 2001, Shah determined there is no difference in fixation rigidity based on the size of the partially threaded cannulated screw used (4.5 mm vs. 5.5 mm) and may actually increase the risk of intraoperative or postoperative fracture.11
Conversely, Kelly, et. al., found that fifth metatarsal fractures can accommodate 6.5 mm screws and that they had greater pull-out strength and greater purchase than 5.5 mm screws.12 They also found that using a large screw did not result in greater fracture stiffness but did result in a high rate of fracture with insertion. They suggest using a 6.5 mm screw but recommend using smaller screws for canals with diameters less than 5 mm.
Husain and DeFronzo compared the use of intramedullary screw fixation with bicortical screw fixation.13 They found a greater resistance to load failure in the bicortical screw when they compared it to intramedullary screw fixation. However, there was also a high propensity for failure at the medial aspect of the screw’s exit through the stress riser.
Other ORIF modalities include tension banding, percutaneous pinning and inlay bone grafting. Torg described the use of inlay bone grafting as the treatment of choice for stage II and III stress fractures.4

Tuberosity Fractures: What You Should Know
Fractures to the styloid process occur proximal to the fourth/fifth intermetatarsal articulation and are believed to be the result of tensile mediated avulsion by the lateral cord of the plantar aponeurosis and/or peroneus brevis.
Stewart classified these fractures based on their anatomic site and articular involvement.6 Type I fractures correspond to the aforementioned Jones fracture. Type II is an intraarticular fracture of the base of the metatarsal. Type III is an extraarticular fracture of the styloid process. Type IV is an intraarticular comminuted fracture of the metatarsal. Type V represents an injury to the apophysis in children.
In adolescents, it important to remember that the apophysis is also the site of a secondary growth plate and may actually be apophysitis. One can easily determine this by the presence of a radiolucent line parallel to the shaft of the metatarsal. This apophysis is most common among girls aged 9 to 11 and boys aged 11 to 14. It disappears two to three years after it first appears.
One must also be aware of the possibility of a possible secondary ossicle that mimics symptoms of a base fracture. It is important to obtain contralateral films to rule out an os vesalianum or os peroneum.
Proximal fifth metatarsal fractures typically demonstrate minimal displacement and heal very well conservatively with a short leg cast for two weeks followed by a progressive return to shoe gear for another two to four weeks.
Joint displacement greater than 5.0 mm, the presence of a lateral prominence, comminution or delayed union are all indications for ORIF with intramedullary screws, tension band wiring or fragment excision with tendon repair (if the fragment is small).
In a frozen cadaveric study, Husain, et. al., compared 4.0 mm partially threaded screws to two 0.062 K-wire tension band wirings. They found the screw construct had greater strength and three times the load resistance of the tension band technique.12 Postoperative treatment includes a walking cast or Cam walker for four to six weeks postoperatively.

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