Hybrid Osteosynthesis for Septic Humeral Shaft Nonunion in a Patient with Obesity: A Case Report

Septic humeral shaft nonunion represents a complex reconstructive challenge in orthopedic surgery, particularly in patients with obesity, in whom increased lever arms and greater mechanical loading of the upper extremity substantially compromise fixation stability.Recurrent failure of isolated fixation constructs, including intramedullary nails or compression plates, necessitates hybrid strategies that combine enhanced biomechanical stability with effective eradication of microbial infection.This article presents the case of a middle-aged man with obesity and a history of a left humeral shaft fracture initially treated with intramedullary nailing in December 2020 who developed persistent nonunion.Following revision surgery with dynamic compression plating, fixation failure occurred secondary to implant fatigue.A second revision procedure was performed through a posterior approach, including nerve neurolysis, extensive debridement, and hybrid fixation using a 240 x 8 mm Targon™ H intramedullary nail (B.Braun, Melsungen, Germany) combined with a narrow 4.5-mm dynamic compression plate (DCP; DePuy Synthes, Warsaw, IN, USA).Cancellous bone chip grafting was also performed.Intraoperative cultures yielded Staphylococcus epidermidis, establishing the diagnosis of septic nonunion, and targeted oral clindamycin therapy was initiated.Despite transient postoperative radial neuropraxia, which resolved with pregabalin treatment and structured physical rehabilitation, the patient achieved complete osseous union, eradication of infection, and an Upper Extremity Functional Scale (UEFS) score of 69/80, corresponding to 86% of maximal functional capacity.In conclusion, hybrid fixation combining an intramedullary nail with a narrow 4.5-mm DCP, together with pathogen-directed antimicrobial therapy, provides excellent axial and rotational stability and represents an effective salvage strategy for septic humeral shaft nonunion in patients with increased biomechanical demands.