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CASE REPORT
Bilateral First Metatarsal Stress Fractures in a Field Hockey Player

John P. Metz, MD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 33 - NO. 10 - OCTOBER 2021

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In Brief: First metatarsal stress fractures are uncommon in young athletes, and to have them occur bilaterally is even more unusual, as in this case of a 14-year-old female field hockey player. The patient sought treatment after several days of bilateral foot pain with swelling and tenderness to palpation over the proximal aspect of the first metatarsals. Initial plain x-rays were negative, but a subsequent bone scan and MRI revealed bilateral first metatarsal stress fractures. The patient was successfully treated with relative rest and rigid-soled shoes. Clinicians should be aware that initial x-rays may not reveal first metatarsal stress fractures, and further imaging may be needed.

Stress fracture of the metatarsal is somewhat common among athletes. About 90% of all metatarsal stress fractures involve the second, third, or fourth metatarsals.1 Stress fractures of the first metatarsal, however, are uncommon.1-5 Studies of military recruits suggest first metatarsal stress fractures account for about 1% of all metatarsal stress fractures. Radiologic studies suggest a higher incidence but lack clinical correlation. Bilateral first metatarsal stress fractures in two patients were mentioned in one report,1 but no further details were given. To our knowledge, this is the first detailed case report in the literature of bilateral first metatarsal stress fractures.

Case Report

A 14-year-old female field hockey player came to our office with increasing bilateral foot pain that was worse in the right foot. The pain was increased by running, relieved by rest, and had been occurring for 5 days. The patient reported that over-the-counter doses of ibuprofen had little effect on her symptoms. Three days prior to the onset of pain, she had started high school field hockey practice on a grass field and had worn a pair of new field hockey cleats that did not have any padding or insoles added to them after purchase. At the time of presentation, her symptoms were limiting her ability to participate in athletic activities.

The patient did not recall any trauma or injuries to her feet in the recent or distant past nor any other history of bone disease or problems with physical activity. She had not participated in any kind of training or exercise program in the summer months before the onset of her symptoms, a fact confirmed by her mother. She had no other medical problems, and was not taking any other medications or supplements. Her menses occurred monthly and had not changed in the last year. She did not have a fever, recent weight loss, or night pain. She denied any bingeing, purging, or dietary restriction behavior.

Physical exam. The patient was 5 ft 4 in. tall and weighed 161.5 lb (body mass index = 27.7 kg/m2). Her right foot appeared normal and was slightly cavus. Mild swelling without erythema was seen over the medial dorsum of the foot, and point tenderness to palpation was noted in this area as well, specifically at the proximal aspect of the first metatarsal but not at the navicular. Passive motion of the first metatarsal reproduced the patient's symptoms, but no other areas were tender to palpation. The pain did not increase with passive or active ankle motion or great toe plantar flexion or dorsiflexion. The left foot exam was essentially the same as the right foot, except the degree of swelling and tenderness to palpation was somewhat less. Both feet demonstrated normal circulatory and neurologic findings.

Imaging. X-ray examinations of both feet were normal. A triple-phase bone scan obtained approximately 1 week later showed increased accumulation in all three phases at the bases of both first metatarsals, possibly consistent with bilateral stress fractures. The nature of the patient's diagnosis was unusual, and, after discussion with several sports medicine colleagues, confirmatory magnetic resonance imaging (MRI) of both feet was obtained approximately 6 to 7 weeks after her symptoms began (some delay occurred because of her health insurance preapproval process). The only treatment during the waiting period was relative rest.

Diagnosis. In the left foot (figure 1), MRI revealed a fracture at the base of the first metatarsal with bone marrow edema extending from the base into the shaft, consistent with stress fracture. The radiologist also noted bone marrow edema of the middle cuneiform and third metatarsal base consistent with bone bruising and/or trabecular microfracture. The right foot images (figure 2) showed a fracture of the dorsal base of the first metatarsal with associated bone marrow edema.

Treatment. The patient was treated with bilateral postoperative shoes. She was allowed to walk, because this was relatively pain free at the time of diagnosis, but restricted from running, jumping, and other lower extremity impact activity. She was also instructed to use ice and over-the-counter analgesics as needed. The patient responded well to treatment and was pain free at rest and with walking within about 1 week.

She continued to wear the postoperative shoes for about 6 weeks and then made a transition to tennis shoes. Because of her unusual diagnosis, at this time she was referred to a podiatrist to see if she would require any special orthoses to prevent reinjury upon return to athletic activity. The podiatrist recommended continued restriction of athletic activity but no special footwear modifications. He believed that such modifications would be warranted only if her symptoms recurred. After her consultation with the podiatrist, she was, unfortunately, lost to follow-up.

Historical Perspective

The diagnosis of first metatarsal stress fracture is unusual and has even been described as rare. Most large studies of this entity come from the military medicine literature. In 1944, Bernstein and Stone2 reported 3 first metatarsal stress fractures among 307 military recruits with stress fractures of the foot. Two years later, Bernstein et al3 reported 2 first metatarsal stress fractures in 724 total metatarsal stress fractures in army recruits. In 1954, a 15-month review4 of 148 metatarsal stress fractures revealed none involving the first metatarsal. Another report in 19665 summarized 12 years of data from two military training centers and showed only 6 cases involving the first metatarsals among 265 cases of stress fractures of the metatarsals and calcaneus. In total, these four military studies reported a total of 11 first metatarsal stress fractures among 1,444 total stress fractures in the foot, an incidence of just less than 1%. Treatment in all these studies consisted of relative rest, installing a steel shank in the soles of the soldiers' boots to provide rigidity, and gradual return to activity.

Two studies in the radiology literature suggest that first metatarsal stress fractures may be more common than in the previously mentioned studies. Levy6 reported x-ray evidence of first metatarsal stress fracture in 8 of 142 (7.8%) consecutive Irish military recruits who had stress fractures in the foot. Meurman7 reported an 11% (15 of 135) incidence of first metatarsal stress fractures among Finnish army recruits who had stress fractures in the foot. In both studies, it was unclear if the patients had specific evidence of first metatarsal stress fracture on physical exam, thus casting doubt on whether the x-ray findings correlated with the patient's symptoms and signs noted.

A Closer Look

Stress fractures of the first metatarsal occur in the cancellous bone at the base near the medial cuneiform and are compression fractures, similar to stress fractures found in the calcaneus.8,9 First metatarsal stress fractures are often missed on initial x-rays, but they are better seen 10 to 14 days later when dense linear sclerosis is evident at the base of the metatarsal, typically without periosteal reaction. Oblique views are sometimes needed to see the fracture.6 Some authors6,9 suggest that the incidence of first metatarsal stress fractures may be higher than earlier reports indicated, because follow-up x-rays were not obtained 10 to 14 days later if initial x-rays were negative, and because many clinicians did not recognize the radiographic changes of this injury.

Our patient's presentation was somewhat unusual in that her symptoms began a few days after starting field hockey practice, without any other preceding overuse or stress. In the study by Bernstein et al,3 the first cases did not appear until the third week of training, and the highest incidence was in the seventh week.

Bernstein and Stone2 diagnosed 31 metatarsal stress fractures in 307 recruits within the first 19 days of military training (two on the first day). No mention was made of how many of these were first metatarsal stress fractures or what kind of training the patients in the study had done before beginning their military training. Granted, these cases were all men, but one would presumably expect a similar pattern in women, as long as they didn't have risk factors related to the female athlete triad.

Our patient also did not have any other apparent risk for stress fracture, such as decreased menstruation or other stress fractures in her history. Whether her cavus feet contributed to her injury is unclear, and it is unknown if altered biomechanics affected other patients in studies as well. Patients who have cavus feet have increased loading of the first metatarsal head, but they do not have an increased incidence of stress fracture of the metatarsal bone.1 Anderson10 claimed an association between first metatarsal stress fracture and hyperpronation of the foot, but also mentions that it is surprising "that it is so rare when the hyperpronating foot is so common."

The remainder of our patient's presentation (ie, localized pain increased with weight-bearing physical activity, focal tenderness, swelling, relief of symptoms with rest, and use of a stiff-soled shoe) was typical of other, more common, metatarsal stress fractures, such as those of the second or third metatarsals. Return-to-play guidelines for this injury follow the recommendations for other more common metatarsal stress fractures. Relative rest is used with gradual pain-free return to full activity expected over 4 to 6 weeks.1

No data exist on prevention of first metatarsal stress fractures, but common sense would suggest that properly fitted shoes with appropriate traction, support, and stability would be appropriate, especially if playing field hockey on hard surfaces, such as artificial turf. Starting and increasing training appropriately would also help prevent injury.

Future Considerations

The true incidence of stress fractures of the first metatarsal is still in question, because no recent reports of these injuries are available in large numbers. Reports are also lacking for first metatarsal stress fractures diagnosed by using more sensitive radiographic techniques, such as bone scans or MRI. These studies, if they are ever done, would need to include clinical correlation with physical exam findings, because extremely sensitive radiographic studies may overestimate the incidence of stress fractures. For example, the radiologist interpreted the MRI to show bone bruising versus trabecular microfracture in the third metatarsal and middle cuneiform bones, even though our patient had no symptoms or physical finding referable to those areas.

Stress fracture of the first metatarsal bone is unusual, but it should be considered in a patient whose symptoms include pain, swelling, and focal tenderness that increase with activity. Dense linear sclerosis at the first metatarsal base on plain x-ray is the typical finding, but it may be easily missed. Further studies, such as bone scan or MRI, may be useful if x-ray findings are inconclusive. Treatment with a rigid-soled shoe and relative rest for 4 to 6 weeks should provide relief of symptoms. The patient may need some type of orthosis, and the orthotic fitting may require a more specialized evaluation.

References

  1. Weinfeld SB, Haddad SL, Myerson MS: Metatarsal stress fractures. Clin Sports Med 1997;16(2):319-338
  2. Bernstein A, Stone JR: March fracture: a report of three-hundred and seven cases and a new method of treatment. J Bone Joint Surg 1944:26(4):743-750
  3. Bernstein A, Childers MA, Fox KW, et al: March fractures of the foot: care and management of 692 patients. Am J Surg 1946;71(3):355-362
  4. DeVan WT, Carlton DC: The march fracture persists. Am J Surg 1954;87:227-231
  5. Gilbert RS, Johnson HA: Stress fractures in military recruits: a review of twelve years' experience. Milit Med 1966;131:716-721
  6. Levy JM: Stress fractures of the first metatarsal. AJR Am J Roentgenol 1978;130(4):679-681
  7. Meurman KO: Less common stress fractures in the foot. Br J Radiol 120211;54(637):1-7
  8. Devas M: Stress Fractures. New York City, Churchill Livingstone, 1975, pp 155-173
  9. Lucas MJ, Baxter DE: Stress fracture of the first metatarsal. Foot Ankle Int 1997;18(6):373-374
  10. Anderson EG: Fatigue fractures of the foot. Injury 1990;21(5):275-279

Dr Metz is an assistant director of the Family Medicine Residency program at JFK Medical Center in Edison, New Jersey. He holds a certificate of added qualifications in sports medicine. Address correspondence to John P. Metz, MD, JFK Medical Center, 65 James St, Edison, NJ 08818; e-mail to [email protected].

Disclosure information: Dr Metz discloses no significant relationship with any manufacturer of any commercial product mentioned in this article. No drug is mentioned in this article for an unlabeled use.


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