October 24, 2021
Navicular stress fractures cover

A Review of Navicular Stress Fractures

Introduction

Navicular stress fractures are frequently encountered in athletes. First described by Town in 1970,[1]Towne LC, Blazina ME, Cozen LN. Fatigue fracture of the tarsal navicular. J Bone Joint Surg Am. 1970;52:376-378. they represent up to ⅓ of all stress fractures and are almost exclusively seen in athletes (98%).[2]Bennell KL, Malcolm SA, Thomas SA, Wark JD, Brukner PD. The incidence and distribution of stress fractures in competitive track and field athletes. A twelve-month prospective study. Am J Sports Med. … Continue reading Stress fractures are an overuse syndrome where repetitive foot strikes during exercise or running result in microfractures with inadequate rest and recovery time. The navicular is particularly susceptible due to the middle ⅓ being relatively avascular. As a side note, Mueller-Weiss syndrome is a rare presentation of navicular avascular necrosis seen in middle aged adults with chronic midfoot pain which can present similarly.

Clinical Vignette

You are evaluating a 37 year old long distance runner who presents with an insidious onset of mid foot pain. She has rapidly increased her distance as she trains for an ultra marathon. The pain is located at her midfoot where she has point tenderness over the dorsomedial foot. Which of the following imaging modalities has the highest diagnostic yield for the most likely diagnosis?

A) Radiographs
B) CT
C) MRI
D) Ultrasound

Image 1. Anatomy of the foot with the navicular bone highlighted in red (click to enlarge).

Navicular stress fractures are most commonly seen in track and field athletes, who account for 59% of navicular stress fractures, as well as runners and basketball players. [2] Other risk factors are similar to those associated with general stress fractures including history of stress fractures, female athlete triad, relative energy deficiency in sport, poor nutritional status, excessive training, poor footwear or biomechanics.[3]Wright AA, Taylor JB, Ford KR, Siska L, Smoliga JM. Risk factors associated with lower extremity stress fractures in runners: a systematic review with meta-analysis. Br J Sports Med. … Continue reading

Evaluation

Patients typically report insidious onset of symptoms that initially begin only after long periods of exercise and eventually can occur even at rest. Diagnosis is typically delayed 4 – 7 months from onset of symptoms.[4]Gross CE, Nunley JA., 2nd Navicular stress fractures. Foot Ankle Int. 2015;36(9):1117–22. Patients endorse pain, swelling of the midfoot worse with push off, running and jumping. On exam, there is typically swelling and tenderness over the navicular. The “N” spot, described as a nickel-sized area in the center of the proximal dorsal navicular, is tender in 81% of patients.[5]Torg JS, Pavlov H, Cooley LH, et al. Stress fractures of the tarsal navicular. A retrospective review of twenty-one cases. J Bone Joint Surg Am. 1982;64:700-712. Standing on toes or single leg hop can also reproduce symptoms but is non-specific. [6]Fitch KD, Blackwell JB, Gilmour WN. Operation for nonunion of stress fracture of the tarsal navicular. J Bone Joint Surg Br. 1989;71:105-110.

Image 2. Illustration of the ‘N spot’, located on the navicular between the Tibialis Anterior tendon and EHL tendon[7]Ostlie, Daniel K., and Stephen M. Simons. “Tarsal navicular stress fracture in a young athlete: case report with clinical, radiologic, and pathophysiologic correlations.” The Journal of … Continue reading

Radiographs of the foot should be routinely obtained to evaluate undifferentiated midfoot pain, although it is only 33% sensitive for navicular stress fractures. [8]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 … Continue reading Note that accessory navicular bone can be seen and can be mistaken for a fracture. MRI is the imaging modality of choice and is the most sensitive study for identifying navicular stress fractures. Bone scintigraphy is 100% sensitive but is not routinely utilized and lacks anatomic resolution of the injury.

Image 3. Two view xray of the foot showing a longitudinally oriented sclerotic band in the lateral aspect of the navicular bone consistent with a stress fracture.[9]Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 7202

Image 4. Foot MRI demosntrating marrow edema involving the central navicular (white arrows), consistent with a stress reaction.[10]Harris, Guy, and Craig Harris. “Imaging of tarsal navicular stress injury with a focus on MRI: A pictorial essay.” Journal of medical imaging and radiation oncology 60.3 (2016): 359-364.

Image 5. Foot MRI showing bilateral navicular stress fractures.[11]Constantinou, Demitri, Nikiforos P. Saragas, and Paulo N. Ferrao. “Bilateral Navicular Stress Fractures with Nonunion in an Adolescent Middle-Distance Athlete: A Case Report.” Current … Continue reading

Management

In nondisplaced stress fractures, nonoperative management is generally considered first line therapy although it would be fair to say that this is somewhat controversial. Nonoperative management primarily revolves around discontinuing offending activities, immobilization in a cast and non-weight bearing status for 6 – 8 weeks. Bone stimulator, shock wave therapy, vitamin D and calcium supplementation and teriparatide can also be considered depending on the clinical context.
Indications for surgical management include: (a) displaced navicular stress fractures, (b) nondisplaced complete fractures with sclerotic changes, (c) comminuted fractures, (d) athletes who fail conservative management, (e) athletes who cannot tolerate a prolonged recovery course. Standard surgical approach is open reduction, internal fixation. Bone marrow aspirate concentrate (BMAC) seems to be a promising adjunct in early studies.[12]Adams SB, Lewis JS, Jr, Gupta AK, Parekh SG, Miller SD, Schon LC. Cannulated screw delivery of bone marrow aspirate concentrate to a stress fracture nonunion: technique tip. Foot Ankle Int. … Continue reading
There are several studies comparing conservative management to surgical management which are best summarized in a 2010 meta analysis by Torg et al.[13]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;38: 1048-1053. They found no advantage in surgical intervention when compared with cast immobilization and complete non–weight bearing (P = .6441). However, there was a nonsignificant trend favoring the success of nonoperative management (96%) over surgery (82%). Weight bearing with or without immobilization had significantly worse clinical outcomes compared to non– weight bearing or surgery.

Rehabilitation & Return to Play

As the athlete comes out of the cast, rehabilitation generally revolves around range of motion, proprioception and strengthening. Full return to sport typically takes 6 to 12 months. Sport specific training can begin earlier, around 4-6 months but depends on the clinical picture, progress and demands of the sport. Complications include progression to full cortical break and non-union, which may be as high as 20% based on one study of post-operative CT imaging.[14]McCormick JJ, Bray CC, Davis WH, Cohen BE, Jones CP, 3rd, Anderson RB. Clinical and computed tomography evaluation of surgical outcomes in tarsal navicular stress fractures. Am J Sports Med. … Continue reading

Case Conclusion

Answer is C, MRI. The patient in this vignette is a female distance runner with insidious onset of midfoot pain with point tenderness of the dorsal midfoot. Number one on your differential should be navicular stress fracture, although the differential is more broad. Standard radiographs are only 33% sensitive for navicular stress fractures, and although first line imaging, do not have the highest diagnostic yield. CT scan can be used to better evaluate a fracture if previously identified, but is not necessary initially. Ultrasound may have a role in some stress reactions or fractures, but in the navicular it’s role is not well defined.

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;20: 657-666.

Read More

References[+]

Leave a Reply

Your email address will not be published. Required fields are marked *