We report a case of a healthy 38-year-old man presenting with insufficiency fracture of proximal tibia associated with unrecognized osteoporosis. Radiologic bone DEXA (Dual Energy X-ray Absorptiometry) assessment revealed osteoporosis, but the patient displayed no apparent risk factors for insufficiency fractures and osteoporosis except for a history of smoking. Following right proximal tibial open reduction and internal fixation, the patient commenced smoking cessation and began taking alendronate.The patient was treated for gait rehabilitation, which included quadriceps strengthening exercises and his condition improved with independent walking. This report highlights an unusual site of proximal tibial insufficiency fractures and the potential effect of smoking on low bone mineral density in a young male patient.