Tarsal Navicular Fractures

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 is usually 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

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
    - acute injury in recreation athlete and no linear line seen on xray
Operative
- open reduction and internal fixation
  - indications
    - high level athletes
    - linear black line is present
    - chronic injury
    - nonunion of navicular stress fracture

Treatment of Traumatic Fractures

Nonoperative
- cast immobilization with no weight bearing
  - indications
    - acute avulsion fractures
    - most tuberosity fractures
    - minimally displace 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 involves > 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

TAG

(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? Topic

Review Topic

FIGURES: A

1. Weight bearing as tolerated in a hard soled shoe
2. Non weight bearing cast immobilization
3. Fragment excision and posterior tibial tendon advancement
4. Percutaneous screw fixation
5. Open reduction with autologous bone graft

PREFERRED RESPONSE ▶

DISCUSSION: 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

Illustrations: A

REFERENCES:

1. Khan KM, Fuller PJ, Brukner PD, Kearney C, Burry HC. Outcome of conservative and surgical management of navicular stress fracture in athletes. Eighty-six cases proven with computerized tomography. Am J Sports Med. 1992 Nov-Dec;20(6):657-66. PMID:1456359 (Link to Abstract)

2. Lee S, Anderson RB. Stress fractures of the tarsal navicular. Foot Ankle Clin. 2004 Mar;9(1):85-104 PMID:15062216 (Link to Abstract)

3. Torg JS, Moyer J, Gaughan JP, Boden BP. Management of tarsal navicular stress fractures: conservative versus surgical treatment: a meta-analysis. Am J Sports Med. 2010 May;38(5):1048-53 PMID:20197494 (Link to Abstract)

Question Authors:

Brian Weatherford MD, John Badylak MD, Ben Taylor MD,

Please Rate Educational Value!

4.0

Average 4.0 of 9 Ratings

Level of Evidence 1 (Randomized Control Trial)

Torg JS, Moyer J, Gaughan JP, Boden BP. Management of tarsal navicular stress fractures: conservative versus surgical treatment: a meta-analysis. Am J Sports Med. 2010 May;38(5):1048-53 PMID:20197494 (Link to Abstract)

Level of Evidence 4 (Case Series)

Khan KM, Fuller PJ, Brukner PD, Kearney C, Burry HC. Outcome of conservative and surgical management of navicular stress fracture in athletes. Eighty-six cases proven with computerized tomography. Am J Sports Med. 1992 Nov-Dec;20(6):657-66. PMID:1456359 (Link to Abstract)

Level of Evidence 5 and Other Journal Articles (includes Case Reports, Expert Opinions, Personal Observations, and Biomechanic Studies)

Lee S, Anderson RB. Stress fractures of the tarsal navicular. Foot Ankle Clin. 2004 Mar;9(1):85-104 PMID:15062216 (Link to Abstract)

Textbooks

Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012
AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009
Orthopaedic Knowledge Update 10, John M Flyn. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2011
Hoppenfeld SP. Surgical Exposures in Orthopaedics: The Anatomic Approach. Lipponcott, Williams, and Wilkins, Philadelphia, PA, Copyright 2009
Orthopaedic In-training Examination (OITE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Self-Assessment Examination (SAE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012

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