Fracture, Stress: Metatarsal, Navicular
Stephen Simons
Gordon Givan
James Robinson
BasicsDescription
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Overload, repetitive stress injury to bone
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Manifest as fatigue fractures to otherwise normal bone
Epidemiology
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Stress fractures account for 0.7–15.6% of athletic injuries (1).
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Metatarsal fractures are the second most common stress fractures; most frequent in track, running, and dance (1).
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Tarsal navicular stress fractures were thought to be rare, but they may be more common than first thought. They occur mostly in running and jumping sports, with 73% occurring in track (2).
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Tarsal navicular stress fractures have been reported in athletes as young as 13 (3).
Risk Factors
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Training errors: Number, frequency, intensity, and duration of strain cycles
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Impact attenuation: Muscle fatigue, training surfaces, footwear
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Gait mechanics: Foot type, lower extremity alignment, altered gait
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Bone health: Nutrition, genetics, hormones, bone disease
DiagnosisHistory
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Pain onset acute or insidious? Usually insidious.
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Pain location? Site of fracture; forefoot for metatarsal stress fractures and dorsomedial midfoot for tarsal navicular stress fractures. Some patients may report ankle pain related to the tarsal navicular stress fractures.
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Associated findings? There is usually minimal or no swelling with stress fractures.
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Does pain improve or worsen during the activity?
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Tendinitis pain often improves as the injured tissue warms up, but stress fracture pain persists or worsens during the activity.
Physical Exam
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Metatarsals: Forefoot pain that progressively worsens with activity
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Tarsal navicular: Vague, dorsal midfoot pain sometimes radiating along the medial arch or into the ankle
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Minimal or no forefoot swelling
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Tenderness at the base, head, or midshaft of the metatarsal
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Axial load applied to head of the metatarsal causes pain at the fracture site and distant to the examination site.
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Examine callous patterns, which may clue the examiner to excessive loads to individual metatarsals.
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Tender over the dorsum of the navicular at the “N” spot in the space between the anterior tibial tendon and the extensor hallucis longus tendon
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Biomechanical examination, joint range of motion, strength, and flexibility to assess predisposing conditions
Diagnostic Tests & Interpretation
Imaging
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Radiographs:
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Metatarsals: Anteroposterior and lateral radiographs are often initially normal; 2–3 wks following symptom onset, periosteal thickening and sometimes a radiolucent line can be appreciated (1,4)[A].
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Tarsal navicular: Plain radiographs often are normal throughout the course of a navicular stress fracture (5,6,7)[A].
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Bone scan:
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Metatarsals: Very sensitive, but necessary only if a diagnosis is needed quickly, as with a competitive athlete. Not specific and must be correlated with clinical history and examination (1).
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Navicular: Characteristically show radioactive uptake throughout the entire navicular (5,8)[B]
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CT scan:
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Metatarsals: Not helpful
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Navicular: Thin sliced cuts in the plane of the talonavicular joint reveal the curvilinear fracture extending from the dorsal cortex surrounded by exuberant bony sclerosis. CT is helpful to determine an incomplete fracture vs a complete dorsoplantar transection of the navicular. CT scan can also help differentiate between navicular stress fracture and a stress reaction (5,7)[A].
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MRI:
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Although generally not necessary, metatarsals will demonstrate intramedullary edema.
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For tarsal navicular, alternative to bone scan considering cost and ionizing radiation. MRI may distinguish an active tarsal navicular stress fracture from a mature fracture as sometimes seen on CT.
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Pathological Findings
Navicular fracture types (5):
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Type I fractures involve only the dorsal cortex.
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Type II fractures are fractures that extend into the navicular body.
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Type III fractures traverse the entire navicular and extend into the plantar cortex.
Differential Diagnosis
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Tendinitis
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Tendon rupture, partial or complete
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Metatarsalgia
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Symptomatic accessory ossicle
P.257
Treatment-
Metatarsals (1,4,9)[A]:
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Cease sporting activities
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Non-weight-bearing only needed for pain control
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Rest period, average 6 wks
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Navicular:
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Non-weight-bearing on crutches with below-the-knee cast or removable brace for 6–8 wks. High failure rate with weight-bearing rest (6,7,10)[A].
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Studies continue to show poorer outcomes with early weight-bearing (7)[B].
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Follow-up clinical assessment for tenderness at the “N” spot. Radiographic assessment not helpful. Continued tenderness should extend non-weight-bearing another 2–3 wks (6)[B].
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Surgery/Other Procedures
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Surgery is rarely required for metatarsal stress fractures (1,4,9)[B].
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90% of navicular stress fractures can be managed with non-weight-bearing cast. However, type III fractures should be referred for surgical management [C].
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Surgical fixation with internal screw, bone grafting, or both is necessary for fractures not clinically healed by nonoperative means.
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Recent studies show comparative long-term outcomes between conservative non-weight-bearing and surgery (10,2)[B].
Ongoing Care-
Metatarsals (1)[C]:
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Non-weight-bearing aerobic training by swimming and pool running during the rest period
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Advance to biking and stair climbing before running
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Return to progressive gradual training only after pain-free walking and no local tenderness at the fracture site.
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Consider biomechanical control with custom orthotic to address excessive lesser metatarsal loading.
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Navicular (8)[C]:
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1st 2 wks following cast removal: Activities of daily living, swimming, water running
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2nd 2 wks: Assess “N” spot; if nontender, then 5 min jogging on grass every other day. Gradually increase to 10 min per session.
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3rd 2 wks: Assess “N” spot; if nontender, then faster running for short distances, ie, 50 meters on alternate days. Gradual speed increase.
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4th 2 wks: Assess “N” spot; if nontender, then gradual return to full training over several weeks. Average time to return to sport is 5–6 mos from diagnosis.
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Attention throughout the rehabilitation time to soft-tissue massage and joint mobilization to the talocrural, subtalar, and midtarsal joints.
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Strength training to reverse the atrophy acquired during immobilization
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Follow-Up Recommendations
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Metatarsal stress fractures not healing in a reasonably expected period should be referred to orthopedic surgery or podiatry. Consider referring for biomechanical evaluation for recurrent stress fractures.
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Navicular: Refer the persistently symptomatic navicular stress fracture that does not heal by the above outlined protocol.
References
1. Brukner P, Bennell K, Matheson G, eds. Stress fractures. Champaign, IL: Human Kinetics, 1999.
2. Potter NJ, Brukner PD, Makdissi M, et al. Navicular stress fractures: outcomes of surgical and conservative management. Br J Sports Med. 2006;40:692–695; discussion 695.
3. Ostlie DK, Simons SM. Tarsal navicular stress fracture in a young athlete: case report with clinical, radiologic, and pathophysiologic correlations. J Am Board Fam Pract. 2001;14:381–385.
4. Hatch RL, Alsobrook JA, Clugston JR. Diagnosis and management of metatarsal fractures. Am Fam Physician. 2007;76:817–826.
5. Kiss ZS, Khan KM, Fuller PJ. Stress fractures of the tarsal navicular bone: CT findings in 55 cases. AJR Am J Roentgenol. 1993;160:111–115.
6. Khan KM, Brukner PD, Kearney C, et al. Tarsal navicular stress fracture in athletes. Sports Med. 1994;17:65–76.
7. Burne SG, Mahoney CM, Forster BB, et al. Tarsal navicular stress injury: long-term outcome and clinicoradiological correlation using both computed tomography and magnetic resonance imaging. Am J Sports Med. 2005;33:1875–1881.
8. Quirk R. President's guest lecture: stress fractures of the foot. Ankle Int. 1998;19:494–496.
9. Wienfeld SB, Haddad SL, Myerson MS. Metatarsal stress fractures. Clin Sports Med. 1994;16:319–338.
10. Torg J, Moyer J, Gaughan J. Management of tarsal navicular stress fractures—conservative vs. surgical treatment: a meta-analysis. Presented at the AOSSM 2009 Annual Meeting.
CodesICD9
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733.94 Stress fracture of the metatarsals
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733.95 Stress fracture of other bone
Clinical Pearls
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Risk factors for stress fractures include overuse or training errors, biomechanical factors, choice or age of shoe, nutrition, and menstrual issues for women.
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Careful attention to the risk factors, particularly training errors, will minimize the risk of reinjury.
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Surgery is rarely indicated for metatarsal and tarsal navicular stress fractures.