Fracture, Fifth Metatarsal (Avulsion, Jones Fractures)



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Fracture, Fifth Metatarsal (Avulsion, Jones Fractures)
Mark E. Lavallee
R. Michael Galbraith
Basics
Description
  • Fractures of the proximal 5th metatarsal of the foot occur at different locations, often with different etiologies. Prognosis and treatment differ vastly, and there is potential to have chronic pain and instability of the foot if not treated properly. Proximal 5th metatarsal fractures are classified into 3 types by region, especially in relation to the joint at the base of the 4th/5th metatarsals (1,2,3,4):
    • Avulsion fracture of the tuberosity:
      • Near splayed insertion of the peroneus brevis tendon (within 0.5 cm from proximal tip of 5th metatarsal)
      • Located extra-articular and do not extend into the joint between the 4th and 5th metatarsal (cubometatarsal joint)
    • Jones fracture (metaphyseal–diaphyseal junction):
      • Fracture line extends into or towards the articulation between the bases of the 4th and 5th metatarsals (measuring from the proximal tip of the 5th metatarsal, >0.5 cm and <1.5 cm)
      • Have relative poor blood supply, heal more slowly, and are prone to delayed union and nonunion
    • Diaphyseal stress fractures:
      • Most commonly occur just distal to the 4th and 5th intermetatarsal articulation to midshaft
      • Result of chronic, repetitive microtrauma, especially in younger athletes
      • Heal most slowly and have greatest risk of delayed union, nonunion, and recurrence
    • Subtypes according to healing potential (5):
      • Type I (acute): Acute without prior pain. X-rays show clean fracture without sclerosis.
      • Type II (delayed union): Involve prior symptoms or a known stress fracture. X-rays show medullary sclerosis and a widened fracture line.
      • Type III (nonunion): Involves prior symptoms or a known stress fracture. X-rays show evidence of repeated trauma, widened fracture line, and exuberant sclerosis (suggesting fracture nonunion).
  • Synonym(s): Dancer's or tennis fracture: avulsion fracture of base of the 5th metatarsal
Epidemiology
  • Fractures of the proximal 5th metatarsal are common foot fractures.
  • Avulsion fractures are the most common type of fracture.
  • Diaphyseal stress fractures are the least common type of fracture.
Risk Factors
  • Previous fracture to the proximal 5th metatarsal
  • Lateral ankle instability
Commonly Associated Conditions
  • Lateral ankle sprain: Tuberosity avulsion fractures are commonly associated with ankle sprains with the foot inverted and plantar flexed. The anterior talofibular and calcaneofibular ligaments often are injured, and there may be swelling and ecchymosis just anterior and distal to the lateral malleolus.
  • Proximal 5th metatarsal stress fracture: Patient may have had a previously undiagnosed and slightly symptomatic stress fracture of the proximal 5th metatarsal.
  • There is a high incidence of delayed union, nonunion, and refracture with Jones and diaphyseal stress fractures.
Diagnosis
Postreduction views are only applicable when clinician attempts to reduce a significantly displaced fracture of the 5th metatarsal. Most displaced fractures are best treated operatively. Views would be anteroposterior, lateral, and oblique
History
  • How and when did it occur? Mechanism of injury is important to determine.
  • Did athlete injure this foot previously? Determine presence of fracture of the 5th metatarsal.
  • Was there a recent history of ankle sprain prior to this injury? Loss of proprioception and reflex inhibition may have predisposed athlete to this injury.
  • History of other medical conditions? Diabetes or other causes of peripheral neuropathy.
Physical Exam
  • Patient may complain of pain over the lateral aspect of foot, especially when weight-bearing on plantar-flexed foot.
  • Jones fractures often occur as a result of a pivot in the direction opposite the planted foot.
  • Patient is tender to palpation over the proximal 5th metatarsal.
  • Often there may be swelling or ecchymosis of the proximal 5th metatarsal.
  • Check neurovascular status: Posterior tibial and dorsalis pedis pulses and normal capillary refill
  • Palpate the peroneus brevis tendon to assess its integrity.
  • Resisted external rotation of foot activates the peroneus brevis muscle and checks its strength.
  • Full examination of the distal fibular, lateral ligaments, and foot helps identify associated ankle or foot injury.
  • Check sensation: If decreased around lateral aspect of foot, the lateral dorsal cutaneous nerve, a branch off the sural nerve, may be injured.
Diagnostic Tests & Interpretation
Imaging
Standard x-ray films: Anteroposterior (AP), lateral, and oblique views of the foot. If findings are suggestive of ankle trauma meeting the Ottawa criteria for radiographs, ankle films (AP, lateral, and oblique views) also should be taken. The Ottawa Ankle rules state that radiographs are indicated for patients between the ages of 15 and 55 yrs old with inability to walk 5 steps after an ankle injury OR tender over posterior 3rd of distal fibula.
Differential Diagnosis
  • Peroneus brevis tendon injury
  • Apophysis (secondary ossification center closes between ages 9 and 11 yrs in girls, 11 and 14 yrs in boys)
  • Apophysitis (Iselin disease)
  • Accessory ossicles
  • Hematoma of lateral proximal foot
  • Midshaft diaphyseal fracture of the 5th metatarsal
  • Sprain of the cubometatarsal joint

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Ongoing Care
Follow-Up Recommendations
  • Orthopedic referral for surgery as indicated above and for avulsion fractures that are displaced (rare), comminuted (rare), or involve >30% of the cubometatarsal articulation
  • Patients not responding to home exercise programs after immobilization is complete may benefit from referral to physical therapy.
  • Type I Jones or diaphyseal stress fractures should be referred to an orthopedist if patient prefers surgery in order to return to play quicker or the fracture is displaced or comminuted.
References
1. Brown SR, Bennett CH. Management of proximal 5th metatarsal fractures in the athlete. Curr Opin Ortho 2005;16:95–99.
2. Fetzer GB, Wright RW. Metatarsal shaft fractures and fractures of the proximal 5th metatarsal. Clin Sports Med. 2006;25:139–150, x.
3. Hatch RL, Alsobrook JA, Clugston JR. Diagnosis and management of metatarsal fractures. Am Fam Physician. 2007;76:817–826.
4. Mologne TS, Lundeen JM, Clapper MF, et al. Early screw fixation versus casting in the treatment of acute Jones fractures. Am J Sports Med. 2005;33:970–975.
5. Torg JS, Balduini FC, Zelko RR, et al. Fractures of the base of the 5th metatarsal distal to the tuberosity. Classification and guidelines for non-surgical and surgical management. J Bone Joint Surg Am. 1984;66:209–214.
Codes
ICD9
  • 733.94 Stress fracture of the metatarsals
  • 825.25 Fracture of metatarsal bone(s), closed
  • 825.35 Fracture of metatarsal bone(s), open


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