Bilateral pathologic mid-tibial stress fractures

Discussion

The fundamental approach to treating a stress fracture involves understanding the pathophysiologic forces contributing to the fracture. Initial treatment that includes strict non–weight bearing for up to 6 months with close clinical and radiologic follow-up is often reasonable if the practitioner is comfortable with management. Otherwise, concurrent referral to sports medicine subspecialists or orthopedic surgeons is warranted, especially in refractory stress fractures or if the patient has a history of recurrent low-energy fractures. Further workup, including BMD, biochemistry, and metabolic panel, should also be considered.¹⁰ Patel et al provide a concise algorithm for diagnosis and referral that can aid family physicians in managing care of a stress-type injury.¹¹ In our case, J.C. was neither an elite athlete nor had he made any abrupt changes to his training regimen. He had no evident anatomic abnormalities and, similar to the circumstances surrounding the injury, the location of the fracture was atypical. Therefore, workup for underlying pathogenesis was initiated. Of note, this case was managed by an experienced sports and exercise medicine physician and that, along with the fact that J.C.’s clinical symptoms remitted each time he was on strict rest, resulted in a longer period before orthopedics consultation was required.

The patient’s normal BMD, combined with a lack of other end organ involvement, raised the question of whether this case actually represented an incidental fracture in the presence of asymptomatic PHPT rather than a pathologic fracture. The literature suggests that BMD can be preserved for up to the first 8 years of parathyroid disease and might not always be a good predictor of fracture risk in early stages.¹² It is generally accepted that severe PHPT increases risk of fracture: epidemiologic studies have shown that the relative fracture risk is increased in untreated PHPT starting as early as 10 years before diagnosis, but some controversy exists around risk in milder disease.¹³ However, there are few cases in the literature that support the pathologic fracture hypothesis presented in this case. One case in BMJ Case Reports and another in the Pan African Medical Journal described traumatic and stress-type fractures, both in the context of severe PHPT in young men.^14,15 Another case in the Journal of Pediatric Orthopaedics discusses an adolescent baseball pitcher with secondary hyperparathyroidism and 2 upper extremity stress fractures.¹⁶ None of these cases definitively discuss pathologic stress fractures in young patients secondary to mild or previously asymptomatic PHPT. However, we argue that this case is a first presentation of symptomatic PHPT and that subsequent early definitive management was prudent and warranted. The delayed healing, along with the similar contralateral stress fracture, might further support this conclusion. Furthermore, once the underlying pathology was corrected, conservative measures eventually began to show success. One caveat is that it is difficult to separate the effects of the reversal of metabolic disease from success of ultrasound therapy.

As of the writing of this report, J.C. continues to undergo LIPUS therapy and has demonstrated clinical improvement. He has not yet returned to activity.