Disclosures: Christopher T. Ha, DO: No financial relationships or conflicts of interest

Case Diagnosis: Bilateral bisphosphonate-associated atypical femoral fractures

Case Description: A 78-year-old female with lumbar spinal stenosis status post L5-S1 decompression and fusion and osteoporosis presented with persistent leg pain. The spine surgery she underwent alleviated her back pain, but not her leg pain. She also received several epidural corticosteroid injections without benefit. The pain was located in bilateral buttocks and radiated to anterior thighs. It was worse with weight-bearing. On physical exam, back extension reproduced axial pain and rotation and side-bending elicited symptoms in the buttocks though not in the thighs. Passive range of motion of the lower extremities including internal/external rotation and FABER maneuver reproduced lateral thigh pain. She had isolated hip abductor weakness bilaterally.

Setting: Large academic hospitalAssessment/

Results: Given her exam did not correspond with spine pathology, X-ray imaging was obtained and revealed bilateral incomplete transverse stress fractures involving the lateral cortex of the proximal femoral shafts. The pattern was consistent with that seen in bisphosphonate use. The patient underwent urgent bilateral intramedullary rod placement with improvement in her symptoms.

Discussion: Atypical femoral shaft fractures are a newly defined, rare phenomenon. According to the American Society for Bone and Mineral Research, they are found in the subtrochanteric or shaft region, are transverse in configuration, noncomminuted, associated with cortical thickening, and often atraumatic in nature (1). The literature suggests a possibility that most of these fractures are due to bisphosphonate use (2), secondary to long-term suppression of bone remodeling.

Conclusion: This case highlights the importance of the physical exam in patients with spinal pathology with ongoing symptoms despite surgery or epidural steroid injections. Clinicians should recognize atypical femoral shaft fractures as a cause of lower extremity pain, especially in patients on bisphosphonate therapy. If sufficient clinical suspicion, further imaging with X-ray or MRI is warranted with consideration of orthopedic surgery for treatment.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/what-pathology-did-the-spinal-injectionist-miss-persistent-leg-pain-after-multiple-epidural-steroid-injections-and-spinal-stenosis-surgery-a-case-report/