Most metatarsal fractures are due directly to a crushing injury from a heavy object dropped onto the foot or indirectly from traumatic twisting of the forefoot into plantar flexion and inversion. The first, fourth, and fifth metatarsal bones are the ones most frequently fractured. This is due to their increased mobility in relation to the second and third metatarsals, which act as the relatively fixed center of the foot.
Metatarsal fractures are classified on the basis of anatomy (
Fig. 65.1):
Class A: metatarsal neck fractures
Class B: metatarsal shaft fractures
Class C: proximal fifth metatarsal tubercle fracture (Jones fracture)
Fractures may be nondisplaced, displaced, or comminuted.
Metatarsal fractures will usually present with pain and swelling over the dorsal midportion of the foot (Class A and B) or with pain localized to the lateral portion of the foot (Class C). Class C fractures are often associated with an injury history suggestive of a sprained ankle.
Obtain radiographs of the forefoot in all cases of suspected metatarsalfracture.
Treatment of metatarsal fractures is based upon classification. Significantly displaced or comminuted Class A or B fractures should be splinted andreferred urgently to a consultant. Nondisplaced Class A, B, and C fractures may be treated conservatively by splinting or casting until the patient isseen by a consultant. Generally, the splint or cast may remain in place for6 to 8 weeks for optimal results. If an appropriate consultant is not immediately available, you may need to reduce a displaced fracture as outlinedlater.
What You Need
Stockingette, cast padding, elastic bandages
Three- or 4-inch plaster slabs, OR plaster rolls 4-inch width, OR fiberglass casting tape 4-inch width
If Reduction Is Required,
1% or 2% lidocaine without epinephrine
5-mL syringe, 18- and 25-gauge needles
Finger traps and counterweights
Clinical Technique
Obtain history of the injury and perform a physical examination of the foot. Document the neurologic and vascular status of the foot. Obtain an appropriate radiograph and identify and classify any fractures. If a fracture is present, is it Class A, B, or C? Displaced, nondisplaced, or comminuted?
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Decide on a plan of therapy, discuss this with the patient, and obtain consent.
Class A Fractures:
Displaced or comminuted: splint and refer urgently.
Nondisplaced: splint or cast. Refer for
follow-up.
Class B Fractures:
Displaced or comminuted: splint and refer urgently, or reduce and cast if no consultant available.
Nondisplaced: splint or cast. Refer for
follow-up.
Class C Fractures:
Displaced: splint or cast. Refer for
follow-up.
Nondisplaced: elastic bandage wrap dressing; may need to cast or splint for comfort. Refer for
follow-up.
Apply splint (posterior slab and stirrup) or short-leg cast as required.
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Provide crutches, appropriate analgesia, and follow-up arrangements.
If Reduction Is Required (Displaced Class B Fractures):
Draw up 5 mL of 1% or 2% lidocaine without epinephrine into 5-mL syringe with the 18-gauge needle. Remove the 18-gauge needle and attach the 25-gauge needle. Palpate over the fracture site of the metatarsal, and identify this spot on the skin with a pen mark.
Place stockingette for cast over foot, and push it up over the ankle. Cleanse skin with alcohol wipe over the marked site.
Raise a skin wheal with the lidocaine. Insert needle deeper until it reaches the fracture site. Aspirate; if you are in the right location, a small bit of blood will return; otherwise reposition the needle. Once a small bit of blood is aspirated, you are in the fracture site hematoma. Inject 3 to 4 mL of anesthetic. Allow 5 to 10 minutes for full anesthetic effect.
Place the toe(s) of the fractured metatarsal(s) and the next toe medially into the finger traps. Have the patient lie supine on a table and position the finger traps to keep the foot 18 inches or more off the table. Apply a 5- or 10-pound counterweight to the tibia. Allow foot to hang in this traction for 10 minutes.
After this length of time, gently manipulate the fracture fragments through the skin into rough apposition. Remove the counterweights.
Pull stockingette back over foot, apply cast padding, and apply cast material from metatarsal heads to just beyond the ankle. Remove toes from finger traps, and extend the casting to just below the knee.
Provide crutches, give appropriate analgesia, and arrange follow-up.
Follow-Up:
Arrange follow-up with an appropriate consultant within 24 to 48 hours of injury, if possible.
If a cast was applied, 24-hour follow-up is necessary to check the cast for fit.
Nondisplaced fractures may be followed by the primary care physician, if appropriate. Follow-up times should be the same as listed earlier.
