CASE REPORT

Navicular stress
fracture

R V P de Villiers
MMed (RadD) SA

Department of Radiology, Tygerberg Academic
Hospital and University of Stellenbosch,

Tygerberg, W Cape

Abstract
The diagnosis of a navicular fracture is
difficult and often delayed due to a
nonspecific clinical presentation and
subtle imaging findings. Initial radi-
ographs are often negative.
Historically isotope bone scans were
recommended, but now CT and MR
imaging are suggested due to the
higher specificity.Imaging of both feet
allows internal comparison and may
also detect an asymptomatic or
unsuspected contralateral fracture.
CT is a reliable indicator of fracture
healing. The imaging evidence of frac-
ture healing usually lags behind the
clinical picture.

Introduction
Navicular fractures commonly

occur in elite athletes, including run-
ners, gymnasts and football players.

Clinical
The diagnosis is often delayed for

months. Clinically the onset is insidi-
ous with nonspecific signs and symp-
toms. The interval between symptoms
and the diagnosis may be from 7

weeks to 4 months or longer,'
Clinically the patient complains of

pain along the dorsomedial aspect of
the midfoot. On examination there
may be pain to palpation along the
medial longitudinal arch or dorsum
of the foot. Foot anomalies that may
be associated with navicular stress
fractures are a short first metatarsal
and a relatively long second ray,'

Pathology
Most navicular stress fractures

involve the middle third of the navic-
ular. This is due to a relative avascu-
larity of the middle third of the navic-
ular. Fractures may be complete or
incomplete. Incomplete fractures
involve the dorsal 5 mm of the navic-
ular adjacent to the talonavicular
joint.'

Fig. 1. Plain X-ray of subtle fracture of navicular
bone.

34 SA JOURNAL OF RADIOLOGY • August 2003

Imaging
Imaging of a suspected stress frac-

tures starts with radiographs of the
foot. The initial radiographs are often
negative (Fig. 1). Historically isotope
bone scans were recommended, but
now CT and MR imaging are suggest-
ed due to the higher specificity
(Fig. 2). Should an early fracture be
suspected, fat-saturated MRl tech-
niques (STIR or fatsat T2/proton den-
sity) are used to assess for bone mar-
row oedema of the stress response
(Fig. 3). As the fracture is linear and
located in the middle third of the
bone, CT imaging must be performed
perpendicular and parallel to the mid-

/

Fig. 2. Isotope bone scan of foot showing increased
tracer uptake in navicular suggestive of a stress
fracture.

Fig. 3. MRI of the foot. Sagittal STIR image. Note
increased signal intensity in the navicular with asso-
ciated fracture line compatible with occult fracture.
No fracture was present on the plain X-ray.



CASE REPORT

Fig. 4. Coronal CT of navicular. Note fracture line
surrounded by sclerosis

Fig. 5. Coronal CT of both navicula. Stress fracture
of right navicular with complete fracture and dis-
placement.

Fig. 6. Axial CT mult/planar image chip fracture of
navicular.

foot (Fig. 4). Imaging of both feet
allows internal comparison and may
also detect an asymptomatic or
unsuspected contralateral fracture
(Fig 5). Multislice CT with multipla-
nar reformatting is the method of
choice (Fig. 6). CT is a reliable indica-
tor of fracture healing. The imaging
evidence of fracture healing usually
lags behind the clinical picture.'

Treatment
Navicular stress fractures are treat-

ed with cast immobilisation. This
treatment results in a successful out-
come in 80% of patients and most
athletes return to sport in 5 - 6
months.'

References
J. Georgen T. Venn-Watson E. Rossman D. et al.

Tarsal navicular stress fractures in runners. AfR
1981; 136: 339-346.

2. Pavlov H. Torg J. Freiberger R. Tarsal navicular
stress fractures: radiographic evaluation.
Radiology 1983; 148: 641-645.

3. Spitz DJ. Newberg AH. Imaging of stress frac-
tures in the athlete. Radiol Clin North Am 2002;
40: 324-326.

4. Khan K. Fuller P. Bruckner P. Outcome of con-
servative and surgical management of navicular
stress fractures in athletes. Am f Sports Med
1992; 20: 657-666.

35 SA JOURNAL OF RADIOLOGY • August 2003