Sequential stress fractures of the ulna and radius in a patient with neurofibromatosis type 1: A case report.

Stress fractures of the forearm are uncommon, and to our knowledge, sequential involvement of both the ulna and radius has not been well characterized. Neurofibromatosis type 1 is associated with increased bone fragility and delayed fracture healing due to impaired osteoblastic differentiation, reduced mineralization capacity, and increased osteoclastic activity. We report the case of a woman in her early 60s with neurofibromatosis type 1 and lower-extremity weakness who relied on upper-extremity weight-bearing ambulation. She initially developed a nondisplaced transverse stress fracture of the proximal ulnar shaft with delayed union, which subsequently achieved union following conservative treatment, including teriparatide. Approximately 24 months after the initial ulnar fracture, she developed a new nondisplaced stress fracture of the radial shaft, suggestive of a possible stress-transfer phenomenon related to altered load distribution across the forearm. Repeated conservative treatment with strict weight-bearing restriction resulted in radiographic union with restoration of functional forearm motion. This case highlights the importance of recognizing altered forearm load distribution to reduce the risk of secondary stress injury.