Introduction This article describes a clinical case of a stress fracture of the distal tibial metaepiphysis following a high-energy tibial shaft fracture stabilized with interlocking intramedullary (IM) nail to identify an underlying cause of the traumatic event. Objective To demonstrate the occurrence of a stress fracture after adequate interlocking IM nailing of a traumatic fracture due to systemic osteoporosis that presented no clinical manifestations prior to injury. Material and methods Magnetic resonance imaging was performed to diagnose the stress fracture. Bone mineral density and laboratory markers of bone metabolism were measured to identify underlying causes of the stress fracture. Consolidation of the traumatic fracture fixed with interlocking IM nail was re-evaluated with a radiograph of the fracture site. Results The stress fracture was seen off the IM nail on MRI scans. Osteoporosis was diagnosed with bone densitometry using dual energy X-ray absorptiometry, and deoxypyridinoline, a bone resorption marker and vitamin D deficiency were identified with laboratory tests. No signs of fracture union were seen radiologically. Conclusion A stress fracture of the distal tibial metaepiphysis detected 3 months after a tibial shaft fracture fixed with interlocking IM nail can be considered an insufficiency fracture caused by primary (idiopathic) systemic osteoporosis that was asymptomatic prior to the high-energy injury.