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A 24-year-old elite gymnast with foot pain
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A 24-year-old female elite gymnast presented to clinic after experiencing the insidious onset of right foot pain during exercise. Initial radiographs, CT scan and MRI of the right foot 6 months earlier were all reportedly read as negative at an outside institution.
She was taken off training and rehabilitation, but her pain progressive worsened to cause discomfort even during normal activities. The patient was placed in a CAM boot for immobilization with crutches for ambulation. Of note, the patient desired to return to high-level gymnastics as quickly as possible.
Sanjeev Bhatia
Andrew R. Hsu
Examination and imaging
On examination, the patient’s right foot was well aligned with no significant deformity or abnormality. There was no significant swelling or edema over the foot. She had full range of motion of the tibiotalar and subtalar joints with no mechanical symptoms or crepitus. She had tenderness directly over the dorsal midfoot to direct palpation. She had no pain over the anterior or posterior tibial tendons, peroneals tendons or lateral ligamentous complex. She had mild discomfort with single-limb stance on the right foot that worsened with single-limb hopping.
New weight-bearing radiographs and MRI of the right foot were obtained (Figures 1a-1f).
Shown are baseline AP (a), oblique (b) and lateral radiographs (c) of the right foot of a 24-year-old female elite gymnast along with coronal (d), axial (e) and lateral T2-weighted (f) MRIs.
Images: Bhatia S, Hsu AR
What is your diagnosis?
See answer on next page.
Navicular stress fracture
Navicular stress fractures can be difficult to both diagnose and treat with vague presenting symptoms. Standing radiographs of the patient’s right foot demonstrate a fracture line best seen on oblique view with mild callus and sclerosis suspicious for a chronic injury to the navicular bone. MRI scans show a vertically oriented fracture line through the middle third of the navicular and also show bone marrow edema within the navicular bone and adjacent soft tissue. There is cortication of the fracture fragments suggesting injury chronicity.
The patient has a navicular stress fracture likely chronic in nature secondary to overuse from her activity as a high-level gymnast and the history of symptoms. Navicular body fractures result from axial loading, and stress fractures are often seen in explosive athletes who participate in running and jumping activities on hard playing surfaces. These fractures are considered high-risk due to their vascular and biomechanical properties and propensity to result in displacement, avascular necrosis and nonunion.
Simon Lee
The central third of the navicular body is the zone of maximal shear stress and is also the area lacking direct blood supply. Patients typically present with full range of motion of the ankle and subtalar joint, but with vague midfoot pain and swelling. There is tenderness to palpation directly over the mid-portion of the navicular body known as the “N spot.” They are often times initially diagnosed as anterior or posterior tibial tendinitis or an ankle sprain.
Radiographic findings are subtle and often do not show a discrete fracture line early in the process and, therefore, advanced imaging with CT or MRI is warranted for further evaluation. The clinician should have a low index of suspicion and threshold to obtain advanced imaging when entertaining this diagnosis. Oblique (inverted) 45° radiographs can help delineate tuberosity fractures since the navicular lies in an oblique direction relative to the floor. It is critical to obtain weight-bearing radiographs to better detect acute pathology. CT is more sensitive to identify fracture lines and cystic changes, and MRI shows increased signal intensity on T2-weighted images due to edema and inflammation. Bone scan (Tc-99m) is sensitive, but not specific for navicular stress fractures.
Immediate postoperative AP (a), oblique (b) and lateral radiographs (c) show fracture fixation with two 4-mm cannulated partially threaded screws, one directed medial to lateral and the other lateral to medial.
In the present case, suspicion was high for a navicular stress fracture given the patient’s activity history, insidious onset of pain and physical exam findings. Pain to palpation over the navicular bone along with difficulty with one-legged stance and hop further indicated a tarsal stress fracture. Advanced imaging confirmed the injury along with fracture pattern and chronicity.
Discussion and management
Repeat CT scan at 3 months after surgery
shows fracture union without hardware failure
on coronal (a) and axial (b) cuts.
Treatment of navicular stress fractures has been a topic of recent debate. Recently, nonoperative management with strict non-weight-bearing cast immobilization for 6 weeks to 8 weeks followed by functional rehabilitation has been indicated for any navicular stress fracture regardless of type. Historically, and within a subset of orthopedic surgeons treating high demand patients, there has been a trend toward operative treatment with open reduction and internal fixation (ORIF), especially in high-level athletes and patients with discrete, chronic or displaced fracture lines seen on radiographs.
Early surgical intervention has been reported to have good clinical outcomes and a quicker return to athletic activity, as nonoperative management often can be unpredictable with continued pain after immobilization. If fractures are chronic and displaced, fixation may be supplemented with allograft or autologous bone grafting. Complications of nonoperative and operative management include delayed union, nonunion, refracture, persistent pain and talonavicular arthritis. Salvage of a poor outcome in a navicular stress fracture typically requires a talonavicular arthrodesis, which results in significantly altered foot biomechanics.
Typically, surgical fixation is performed with two cannulated or solid 4-mm partially threaded screws perpendicular to the axis of the fracture line. Patients are made non-weight-bearing in a CAM boot with compression stocking for 6 weeks with gentle range of motion out of the boot starting at 2 weeks. Weight-bearing status is advanced to partial at 6 weeks and full at 9 weeks in a CAM boot with the initiation of strengthening exercises as tolerated. Patients are gradually returned to activity at 10 weeks with a medial arch support as needed. Fracture union is evaluated at 3 months with a CT scan and if united, patients are allowed to return to impact activities.
Treatment plans must be tailored to individual patients and based on their history, exam and functional demands. In the present case, the patient is a high-level elite gymnast with a need to return to impact activities as quickly as possible. The patient must be counseled appropriately about the risks and benefits of nonoperative and operative treatments and the costs associated in terms of opportunities, and of not being able to train and compete.
After the diagnosis was made, the patient was educated about her injury as well as the full risks and benefits of surgical intervention. The patient elected to undergo navicular stress fracture open reduction and internal fixation. A successful fixation with two 4-mm cannulated partially threaded screws was performed (Figures 2a-2c) with return to full weight-bearing in a CAM boot at 8 weeks. Repeat CT scan 3 months after surgery showed fracture union without hardware failure (Figures 3a-3b). She returned to gymnastics 3 months postoperatively without complications or further symptoms.
References
Lee S. Stress fractures of the tarsal navicular. Foot Ankle Clin. 2004;9(1):85-104.
Torg JS. Am J Sports Med. 2010; doi:10.1177/0363546509355408.
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Disclosures: Hsu and Bhatia have no relevant financial disclosures. Lee receives royalties, financial or material from SLACK Incorporated.