Case Report: Management of tibial fracture nonunion: a case study of treatment failure and lessons learned.

UNLABELLED: Concept of "mechanical-biological balance" is fundamental to successful fracture healing; disruption of either component can lead to healing failure. Fractures of the middle and distal tibia are commonly encountered in clinical practice, particularly when associated with comminution. Managing fracture nonunion requires a comprehensive assessment of infection status, skeletal alignment, bone defect, implant stability, and host biological characteristics. This case report aims to explore the etiological factors of tibial nonunion and to reflect upon the biomechanical mechanisms underlying internal fixation failure. The findings demonstrate that failure to restore structural stability rendered subsequent biological repair measures ineffective. CASE PRESENTATION: A 49-year-old perimenopausal woman developed tibial nonunion after internal fixation with a medial locking plate, screws, and titanium cables for a comminuted mid-to-distal tibiofibular fracture. Despite subsequent revision with PRP injection and autologous iliac crest bone grafting without addressing the underlying mechanical instability, the nonunion persisted and ultimately resulted in plate fatigue fracture. CONCLUSION: This case underscores that mechanical stability is a prerequisite for the biological cascade of fracture healing. In the absence of an adequate mechanical environment, even the most advanced biological augmentation cannot ensure successful union.