Title: Tarsal Navicular Stress Injury: Long-term Outcome and Clinicoradiological Correlation Using Both Computed Tomography and Magnetic Resonance Imaging
Authors: Burne SG, Mahoney CM, Forster BB, Koehle MS, Taunton JE, Khan KM
Source: American Journal of Sports Medicine 33(12): 1875-1881, 2005.
PODIATRIC RELEVANCE:
The navicular stress injury is a condition that potentially can be challenging to foot and ankle surgeons, even those specializing in Sports Medicine, since these injuries are rather infrequent. It is imperative that clinicians are current with the treatment protocols that result in optimal outcomes and patient satisfaction. This article examines available treatments and their long-term outcomes, as well as the clinical and radiographic correlation at long-term follow-up.
METHODS:
This was a retrospective cohort study of 19 patients treated for a navicular stress injury between 1996 and 2002, were identified from a computer registry with baseline clinical and imaging data extracted by chart review. Patients who had received care from a university sports medicine center and had one of the following final diagnoses: navicular stress fracture (NSF), defined as appropriate foot pain and tenderness, a positive delayed bone scan result and the presence of fractures lines on CT or radiographs; or navicular stress reaction (NSR), defined as above but with no fracture line on radiographs or CT. All had undergone a bone scan and CT imaging during their initial evaluation, but the baseline images were not available for the study.
Excluded from the study were those who sustained original injury from acute trauma, those who had other significant abnormalities present in the foot and ankle at the time of injury and those who were pregnant during follow-up.
Participants followed up with a sports medicine physician who had not been directly involved in patient treatment, and were presented with a questionnaire to obtain symptoms on a visual analog scale (VAS). Each participant’s sporting success, defined as return to the specific pre-injury sporting level of competition; recurrence, defined as symptoms returning such that they initiated a physician follow up; and questions regarding pain and function were included in the questionnaire. Tenderness was assessed via pressure applied to the area by an algometer, and also by functional testing. Imaging assessment was done on all patients by CT of both feet and MRI of the affected side.
RESULTS:
Fewer than half of the patients in the study had been treated with non-weightbearing rest, and only 18% received a minimum of 6 weeks of non-weightbearing cast immobilization, which is the standard of care recommended from previous case series. 55% of patients with NSF reported complete sporting success at the long term follow-up. Imaging studies revealed that 7 patients initially diagnosed with NSR developed clinical fracture symptoms and demonstrated evidence of nonunion on CT scans during long-term follow-up. Only 3 patients originally diagnosed with NSF had a normal appearing CT scan at the long-term follow-up. Clinical variables of pain score, sporting success or recurrence were not statistically associated with CT or MRI parameters. Participants who still had CT-proven fractures at long-term follow-up had a significantly longer duration of symptoms after treatment than did those without proven fractures. CT detected more fractures than did MRI, but MRI detected a higher proportion of medullary extension in detected fractures.
COMMENTS:
As foot and ankle specialists, we should always try to provide our patients with the most proper and up-to-date method of treatment. Findings in this article suggest that many practitioners often do not follow the recommended treatment protocol as recommended by previous studies. In this particular study, the reasons for allowing patients with navicular fractures to be weightbearing are uncertain. This was the largest published study in the past decade, with the longest minimum follow-up period but the number of participants in the study was low. Nonetheless, we should take note of the findings in this study, and those before it, and make certain that patients with navicular symptoms receive a thorough CT imaging evaluation and non-weightbearing status for at least 6 weeks as part of their a treatment. Finally, possibilities of a larger, multi-institution study of navicular stress injuries and their treatment should be explored.
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Disclaimer:
Scientific Abstract Monthly postings are submitted by podiatric surgical residents. The ideas presented are not the opinions of the American College of Foot and Ankle Surgeons (ACFAS), nor are they presented as facts. ACFAS presents this information without any warranty of any kind, expressed or implied, and is not liable for its accuracy nor for any loss or damage caused by the user's reliance on information obtained in these areas.