Unstable Osteosynthesis of a Humeral Diaphyseal Fracture as a Cause of a Pseudoarthrosis and an Extensive Bone Defect (A Case Report)

Relevance . The causes of the formation of a humeral diaphyseal pseudarthrosis can be various risk factors and their combination, including iatrogenic, associated with osteosynthesis technique non-compliance. This leads to instability of the metal constructions with the destructive consequences for the bone tissue and the injured limb function in general. Case presentation . A 60-year-old woman received a right humeral diaphyseal fracture with displacement (АО/АSIF 12-A3) and underwent locking intramedullary osteosynthesis. Subsequently, the fixation failure developed. In 3 years after the primary surgery, a combination of two complications was diagnosed: a nonunion and a defect of the humerus with the formation of a traumatic bone cyst in the distal part. The patient was reoperated: resection of the pseudarthrosis, removal of the right humerus cyst, and revision plate osteosynthesis with bone autografting. A positive result of treatment was obtained: fracture consolidation, reparation of the distal humerus bone structure and restoration of the right upper limb function. Conclusion . The presented clinical case demonstrates the importance of careful preoperative planning of osteosynthesis: the selection of an appropriate implant size, and adequate intraoperative blocking of the intramedullary nail to create a stable “bone-fixator” system. The careful outpatient follow-up of the patient, early detection of possible complications and timely surgical removal of the unstable implant with revision osteosynthesis are required.