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Introduction
  • Navicular fractures can be
    • traumatic
      • navicular avulsion fractures
        • mechanism is plantar flexion
      • navicular tuberosity fractures
        • mechanism is eversion with simultaneous contraction of PTT
        • may represent an acute widening/diastasis of an accessory navicular
      • navicular body fractures
        • mechanism is axial loading
    • stress fracture  
      • mechanism of injury is usually due to chronic overuse 
      • often seen in athletes running on hard surfaces
      • also common in baseball players 
      • considered a high risk injury due to risk of AVN
      • most common complications include delayed union and non-union  
Anatomy
  • Articulations
    • navicular bone articulates with
      • cuneiforms
      • cuboid
      • calcaneus
      • talus
  • Biomechanics
    • navicular bone and its articulations play an important role in inversion and eversion biomechanics and motion
Classification
 
Sangeorzan Classification of Navicular Body Fractures
(based on plane of fracture and degree of comminution)
Type I Transverse fracture of dorsal fragment that involves < 50% of bone.
No associated deformity
  
Type II Oblique fracture, usually from dorsal-lateral to plantar-medial.
May have forefoot aDDuction deformity.
 
Type IIII Central or lateral comminution.
ABDuction deformity.
  
 
Presentation
  • Symptoms
    • vague midfoot pain and swelling
  • Physical exam
    • midfoot swelling
    • tenderness to palpation of midfoot
    • usually full ROM of ankle and subtalar joint
Imaging
  • Radiographs
    • may be difficult to see and are often missed
    • oblique 45 degree radiograph 
      • best to visualize tuberosity fractures
  • CT
    • more sensitive to identify fracture than radiographs 
  • MRI
    • will show signal intensity on T2 image due to inflammation 
Treatment of Stress Fractures
  • Nonoperative
    • cast immobilization with no weight bearing  
      • indications
        • any navicular stress fracture, regardless of type, can be initially treated with cast immobilization and nonweight bearing for 6-8 weeks with high rates of success 
  • Operative
    • open reduction and internal fixation
      • indications
        • high level athletes
        • nonunion of navicular stress fracture
        • failure of cast immobilization and non weight bearing
Treatment of Traumatic Fractures
  • Nonoperative
    • cast immobilization with no weight bearing
      • indications
        • acute avulsion fractures 
        • most tuberosity fractures
        • minimally displaced Type I and II navicular body fractures
  • Operative
    • fragment excision
      • indications
        • avulsion fractures that failed to improve with nonoperative modalities
        • tuberosity fractures that went on to symptomatic nonunion
    • open reduction and internal fixation
      • indications
        • avulsion fractures involving > 25% of articular surface
        • tuberosity fractures with > 5mm diastasis or large intra-articular fragment
        • displaced or intra-articular Type I and II navicular body fractures 
      • technique
        • medial approach
          • used for Type I and II navicular body fractures
    • ORIF followed by external fixation VS. primary fusion
      • indications
        • Type III navicular body fractures 
      • technique
        • must maintain lateral column length
 

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Questions (3)

(OBQ12.256) A 21-year-old recreational baseball player presents for evaluation of anterior ankle pain that has been persistent for the past 6-8 weeks. On physical exam he is tender over the midfoot, but has full strength with dorsiflexion, plantarflexion and inversion. His radiographs are read as normal; radiographs are shown in Figure A. Representative MRI sequences are shown Figures B and C. What is the most appropriate treatment for this patient? Review Topic

QID:4616
FIGURES:
1

Observation alone

5%

(84/1864)

2

Cortisone injection in to the anterior tibial tendon sheath

1%

(12/1864)

3

Partial weight bearing in a boot

13%

(246/1864)

4

Non-weightbearing in a cast for planned 6-8 weeks

78%

(1447/1864)

5

Open reduction internal fixation of the fracture

4%

(69/1864)

Select Answer to see Preferred Response

PREFERRED RESPONSE 4

Based on the clinical history and imaging shown, the patient has a navicular stress fracture of the foot. The most appropriate treatment for this patient is to place the patient into a non-weightbearing cast with outpatient follow up in 6-8 weeks.

Tarsal navicular stress fractures are often the result of overuse, particularly while running on hard surfaces. They are common in baseball players. Patients often present with vague, midfoot pain, swelling and localized tenderness. Immobilization and non-weight bearing can be used to treat most navicular stress fractures, even in high level athletes.

Fowler et al. review the treatment options for stress fracture for the tarsal navicular. They indicate that diagnosis can be difficult because of the high false negative rate of standard radiographs. While surgical intervention has become increasingly popular, they recommend that initial management should be conservative non-weight bearing for these injuries.

Torg et al. discuss a meta-analysis of the efficacy of surgical versus conservative management of tarsal navicular stress fractures. They found no statistically significant difference between conservative (non-weight bearing) and surgical intervention in terms of overall outcome; however there was a trend favoring use of conservative management. They recommend immobilization with non-weight bearing as the standard of care for tarsal navicular stress fractures.

Figure A shows an AP and oblique radiograph of a right foot. While hard to discern on the AP radiograph, a step-off is visualized at the dorsal and proximal aspect of the navicular. Some mild comminution is seen as well. Figures B and C show representative sequences from a T2 weighted MRI of the foot. The minimally displaced injury is appreciated through the axial and sagittal sequences seen.

Incorrect Answers
Answer 1: Observation is not indicated as treatment for this patient
Answer 2: This patient does not have evidence of anterior tibial tendinitis
Answer 3: Torg et al. have reported worse outcomes when partial weight bearing was used
Answer 5: Outcomes do not support use of operative intervention as the first line of treatment, even in high level athletes.


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(SBQ07.35) What is the most common complication associated with the injury seen in Figure A? Review Topic

QID:1420
FIGURES:
1

Malunion

8%

(230/3063)

2

Non-union

80%

(2457/3063)

3

Infection

1%

(17/3063)

4

Longitudinal arch instability

11%

(329/3063)

5

Neurovascular injury

1%

(17/3063)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

Figure A shows a navicular stress fracture. Of the available answers, the most common complication associated with this injury is fracture non-union.

Navicular stress fractures occur commonly in running athletes. Repetitive loads on navicular bone can manifest as incomplete or complete fractures. The vast majority (~83%) of fractures are incomplete at initial presentation and those that are complete are often non displaced. Non union and delayed union are the two most common complications of both conservative and surgical treatment.

Torg et al. (1982) looked as a series of navicular stress fractures in 19 patients. They noted an average period of 7 months between the onset of symptoms and the diagnosis of navicular stress fracture. In their cohort, 7 out of the 10 patients treated non-surgically with casting were complicated by non-union, delayed union or re-fracture.

Torg et al. (2010) reviewed the outcomes and effectiveness of conservative versus surgical management of navicular stress fractures. They found no significant advantage between surgery and non-weight bearing (NWB) conservative immobilization in terms of fracture healing time and return to activity. Weight-bearing (WBAT) conservative management was found to be the least effective treatment. They suggest that NWB immobilization should be considered the standard of care for tarsal navicular stress fractures.

Figure A is a CT scan image showing a complete navicular fracture of the left foot.

Incorrect Answers:
Answer 1: Navicular stress fractures are typically nondisplaced and are very rarely associated with malunion.
Answer 3: Navicular stress fractures are rarely complicated by deep infection, unless there is an open fracture, which is not typical in these chronic fractures.
Answer 4: The navicular bone helps to support the medial column of the longitudinal arch. Only displaced fractures or navicular dislocation has been shown to cause arch instability.
Answer 5: Neuromas may occur with navicular stress fractures and non-union, but this is rare.


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(OBQ06.61) A 24-year-old female who is training for her first marathon presents with six weeks of increasing foot pain. An AP radiograph and representative axial cut of her CT scan of her injury are seen in figures A and B. Management should consist of which of the following? Review Topic

QID:172
FIGURES:
1

Weight bearing as tolerated in a hard soled shoe

6%

(81/1347)

2

Non weight bearing cast immobilization

71%

(961/1347)

3

Fragment excision and posterior tibial tendon advancement

1%

(20/1347)

4

Percutaneous screw fixation

15%

(204/1347)

5

Open reduction with autologous bone graft

6%

(79/1347)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

The patient presents with symptoms and imaging studies consistent with a navicular stress fracture. Initial mangement of these injuries consists of non weight bearing cast immobilization.

Khan et al found that patients managed with a minimum of 6 weeks of non weight bearing (NWB) had significantly improved rates of return to sport (86%) compared with patients that were allowed to weight bear as tolerated (26%). After failure of weight bearing management, 6/7 patients who were then NWB in a cast were able to return to sports.

Lee et al review the clinical presentation, evaluation, and treatment of navicular stress fractures. The authors advocate for initial management with NWB immobilization and note that CT and MRI may be useful to determine the chronicity of the injury.

Torg et al performed a meta-analysis of the existing literature regarding treatment of navicular stress fractures. The authors note that no difference has been seen in patient outcomes between NWB and operative management and they state that NWB cast immobilization should be the initial treatment for navicular stress fractures.

Incorrect Answers:
Answer 1: Weight bearing as tolerated in a hard soled shoe is less effective than NWB cast immobilization for navicular stress fractures
Answer 3: Fragment excision and tendon advancement is not a described technique to manage these injuries
Answer 4: Percutaneous screw fixation may be indicated after failure of 6-8 weeks of non weight bearing
Answer 5: Open reduction, with or without bone grafting, is not the preferred initial management


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