PubMed^® Literature Review

Despite advancements in surgical techniques and implant designs, achieving optimal results remains challenging due to the complexity of fracture patterns, patient-specific factors, and potential complications [1][2][3].

Intramedullary nailing has been widely adopted as a viable option for treating humeral shaft fractures due to its minimally invasive nature and the biomechanical stability it provides [4]. However, concerns regarding nonunion rates have prompted investigations into factors influencing union outcomes post-IMN.

Nonunion rates after IMN vary across studies but are generally reported within a range suggesting comparable efficacy between IMN and other fixation methods such as plate osteosynthesis [5][6]. Amer et al.'s systematic review highlighted no significant difference in nonunion rates between plating (1.8%) versus nailing (3.9%), though they noted an increased risk of iatrogenic radial nerve injury with plating [7]. This finding underscores the importance of technique refinement and surgeon experience in minimizing complications associated with each method.

Several factors contribute to the risk of nonunion following IMN. Patient-related factors include advanced age, smoking status, comorbidities like diabetes mellitus or osteoporosis that impair bone healing capacity [8]. Fracture-related variables encompass comminution degree, fracture site displacement severity at presentation—particularly oblique fractures near the proximal third—and open versus closed fracture status [1][9].

Surgical technique also plays a pivotal role; improper nail size selection or inadequate stabilization can lead to micromotion at the fracture site impeding bone healing processes leading towards nonunion development [10]. The necessity for distal locking remains debated; Egrise et al.'s study suggested that distal locking might not be required for all cases if primary stability is achieved through proper nail impaction within the medullary canal except certain distal third fractures where it may still be necessary [11].

Treatment strategies for addressing established nonunions involve rigorous debridement back to healthy bleeding bone edges followed by stable fixation often combined with autologous bone grafting or alternative biologic enhancers aimed at stimulating osteogenesis at the nonunion site [12][13].

In conclusion, while intramedullary nailing offers many advantages including preservation soft tissue envelope integrity around humerus allowing early mobilization post-operatively; careful consideration must be given towards optimizing both patient selection surgical approach minimize risks associated particularly concerning issue such as nonunions which despite being relatively infrequent when they do occur present significant challenges both patients surgeons alike necessitating sometimes complex revision procedures ensure successful outcome ultimately achieved.