Despite great advances in orthopedic technology, surgeons still encounter patients with humeral shaft nonunion who have already undergone repeated failed surgeries. In some circumstances, repeated operative failures to obtain union coupled with soft tissue maladaptation and deformity have left the patient with a profound disability and an abandonment of optimism, especially for patients with poor financial conditions [2, 3, 7, 10, 20]. Several methods have been designed to treat humeral shaft nonunion by providing adequate fixation across the fracture site and improving the local biomechanical environment or blood supply, but each method has its drawbacks. Well recognized revisions for humeral shaft nonunion include interlocking nail fixation, Ilizarov external fixation, and internal plate fixation with an autologous iliac crest bone graft or vascularized fibular graft; of these methods, plating with bone grafting is generally considered the first choice for nonunion of the humeral shaft [9, 10, 12].
Interlocking intramedullary nails have been widely used in acute humeral fractures, pathologic fractures, and nonunions of the tibia or femur shaft [3]. For humeral shaft nonunion, nailing or exchange nailing reportedly improves the biomechanical stability via the use of a nail at least 1 mm thicker than the shaft diameter and fosters a healing environment by transporting mesenchymal stem cells into the nonunion sites during the reaming procedure [2, 21]. However, the healing rate of nailing for humeral shaft nonunion varies from 40 to 95.6% [22,23,24]. A poor outcome might result from a lack of cyclical loading due to weight-bearing and a higher amount of distractive and torsional loads on the humerus [23]. As most of the patients in the present study had erosion, osteopenia, and sclerotic bone, it was difficult to achieve adequate fixation with good rotational control using exchange nailing; furthermore, as most patients had stiffness in the neighboring joints, exchanging nailing might have caused subacromial impingement and rotator cuff injury, which would have worsened the function of those joints [25]. Therefore, exchange nailing or nailing was not performed in the current study.
External fixation provides good stability and compression of the nonunion sites to achieve bony consolidation. Traditionally, Ilizarov ring fixators are used for distraction osteogenesis and bone transport in patients with infected nonunion of the tibia or femur. Several studies report that this technology yields a high union rate in patients with nonunion of the humeral shaft [26, 27]. However, the disadvantages of external fixation include a long fixation time, risk of pin-tract infection, and patient discomfort, making it an unreliable and unnecessarily complex option for non-infected nonunion [10].
Plating combined with bone grafting is the method most widely used to treat humeral shaft nonunion, as it achieves precise correction of the deformity and absolute stability, and enables the use of biologic augmentation [5, 13]. One study reported a healing rate of 97% for anterior augmentation plating of aseptic humeral shaft nonunion [28], and a review of 36 studies found that plating with autologous bone grafting achieves a union rate of up to 98% in patients with humeral shaft nonunion [29]. Furthermore, plate fixation and bone grafting is recommended for recalcitrant humeral shaft nonunion following initial operative fixation of the index fracture [30]. In the present study, double plate fixation combined with autologous iliac crest structural bone grafting achieved excellent or good outcomes in patients with recalcitrant humeral shaft nonunion after prior failed surgeries. This treatment might have the following advantages. Firstly, besides attaining precise deformity correction and absolute stability, fixing a second plate vertically to the anterior portion of the bone graft for structural support maintains intimate contact between the bone graft and both nonunion segments, maximizing the osteoconductive, osteogenic, and osteoinductive properties of autologous bone. Secondly, double-plate technology is very effective in restoring the intact compressive and torsional stiffness of humeral shaft segments [31, 32]; thus, postoperative functional rehabilitation was able to be started on the next postoperative day without the use of external immobilization, facilitating limb function restoration.
The plating technique also has complications, such as screw back-outs, peripheral nerve paralysis, and infection [31]. In the present study, there were two patients with nerve palsy (one with ulnar nerve palsy and one with radial nerve palsy) and one with a superficial wound infection. Fortunately, both patients with nerve palsy only had persistent finger numbness without movement dysfunction. For patients with abundant scar tissue from multiple surgeries, surgeons must protect the nerves as much as possible during neurolysis. No patients had implant failure at final follow-up.
Few studies have focused exclusively on the treatment of recalcitrant humeral shaft nonunion. Borus et al. [2] performed uniform surgical repair with 4.5-mm compression plating in combination with bone grafting in seven patients with humeral diaphyseal nonunion following at least two failed prior surgical procedures, and reported that all nonunions had healed with good function of the affected extremity at final follow-up. Marti et al. [8] reported a series of 51 patients with humeral shaft nonunion, 10 of whom had undergone at least two prior surgical procedures; all patients were treated with plating and autogenous bone grafting, and all achieved union at 1 year postoperatively, with 96% of patients achieving excellent or good function. Adani et al. [33] performed plate fixation and fibular transplantation in 13 patients with an average humeral defect length of 10.5 cm who had undergone at least two surgeries; nine patients healed primarily, three required additional bone grafting, and one required a second fibular transplant. In the current study, each patient had previously undergone at least one failed operation for nonunion before the index intervention procedure. Double plating and autologous bone grafting resulted in a bone healing rate of 100%, with a mean bone healing time of 6.4 ± 1.8 months. At final follow-up, each patient showed significantly improved function of the affected limb and significantly reduced pain. Thus, the outcomes of the present study are consistent with the above mentioned studies.
The limitations of the present study are related to its retrospective nature and small sample size. We were also unable to directly compare plate fixation with other fixation strategies. Finally, because of the rarity and complexity of this specific situation, it was not possible to include a control group. Despite these limitations, the present study demonstrates that double plating in combination with autologous bone grafting achieved successful outcomes for recalcitrant humeral shaft nonunion. To the best of our knowledge, this is the largest series of patients who had undergone multiple surgeries for nonunion and were then treated using double plating technology.