Despite the great advance in orthopedic technology, a surgeon still encounters a patient with humeral shaft nonunion who had already undergone repeated surgery for nonunion. 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]. A number of methods have been designed to treat humeral shaft nonunion in order to provide adequate fixation across the fracture sites and improve the local biomechanical environment or blood supply, and each method has its drawbacks. Well recognized revisions for humeral shaft nonunion include interlocking nail, Ilizarov external fixator, and internal plate supplied with auto- iliac crest bone graft or vascularized fibular graft [9,10,12].
Interlocking intramedullary nails have been widely used in acute humeral fractures, pathologic fractures and nonunions of the tibia or femur shaft, as for humerus fixation, they have the advantages over plates of fewer tissue traumas, fewer circulatory impairments and lower risk of radial nerve injury [3]. Nailing or exchange nailing for humeral shaft nonunion had been successfully reported by some authors, the concept of this technology is improving nonunion segments biomechanical stability by using of a nail being at least one millimeter thicker than its diameter and fostering healing environment by transporting mesenchymal stem cells into the nonunion sites during reaming procedure [2,21]. However, the heal rates varied differently. Lin et al.[22] addressed 23 humeral nonunions with revision exchange nailing, 22 patients (95.6%) showed a bony union. Whereas, McKee et al.[23] achieved union after exchange nailing in only four (40%) of ten patients and Flinkkilä et al.[24] in six (46.2%) of thirteen. The reason might be 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 cases in this study presented with erosion, osteopenia, and sclerotic bone, it was difficult to get adequate fixation with good rotational control by fixation with exchange nailing, also, as most cases had stiffness in the neighboring joints due to repeated prior surgeries, exchanging nailing might cause subacromial impingement and rotator cuff injury which in fact worsen the function of those joints [25]. All of these factors put together made the authors avoid using exchange nailing or nailing to treat cases in the current study.
External fixation for nonunion treatment offers high stability and compression to the nonunion sites to achieve bony consolidation. Traditionally, Ilizarov ring fixators were used for distraction osteogenesis and bone transport in cases with tibia or femur infected nonunion. This technology has been used by several authors in the management of humeral nonunion shaft and yielded a high union rate [26,27]. However, its disadvantages include long fixation time, risks of pin-tract infection, and patient discomfort, these make it an unreliable and rather unnecessarily complex option in non-infected nonunion [10].
Our previous studies had proved that LCP combined with autologous iliac structural bone grafting can effectively treat aseptic limb nonunions[5,13], and many researchers advocated this treatment strategy. Gessmann et al.[28] reported a 97% healing rate of anterior augmentation plating for aseptic humeral shaft nonunions after antegrade or retrograde intramedullary nailing. Also, after reviewed 36 articles, Peters et al.[29] found that plating with auto-bone grafting could achieve a union rate of up to 98% for cases with humeral shaft nonunion. In this study, we used double plate fixation combined with auto-iliac crest structural bone graft to treat patients with recalcitrant un-united humeral shaft who had failed to repeated prior surgeries and finally got a good outcome. This treatment might have the following advantages. Firstly, plate fixation is the most widely used method for long bone fixation due to economic constraints and surgeons’ preference in China, and as most patients in this study showed varying degrees of misalignment or pseudarthrosis, the use of LCP fixation could achieve a high degree of cortex-to-cortex stability with compression of the bone segments while correcting deformities. Secondly, repeated prior surgeries might result in a poor biological environment for fracture repair in cases in this study, a second plate fixing vertically to the anterior of the bone graft for structural support could maintain intimate contact between the bone graft and both nonunion segments, maximizing osteoconductive, osteogenic and osteoinductive properties of autologous bone, this is consistent with the founding of Konda et al.[30], where humeral shaft nonunions following initial operative fixation of the index fracture were more resistant to achieving union when compared to nonunions forming after initial non-operative treatment. And they recommended plate fixation and bone graft for recalcitrant humeral shaft nonunion. Moreover, double-plate technology could obtain absolute stability, thus postoperative functional rehabilitation could be started on the next postoperative day without any external immobilization. This had already been confirmed by other researchers. In a biomechanical study of Kosmopoulos and Nana [31], they found that 90° dual locking plate configurations were more effective in restoring the intact compressive and torsional stiffness for humeral shaft fracture. And, Martinez et al.[32] reported the use of a two-plate construct in the treatment of 22 cases of humeral shaft nonunion with a 100% healing rate.
Meanwhile, the plating technique also has complications of screw back-outs, peripheral never paralysis, and infection [31]. However, we only saw two cases with never palsy (one with ulnar nerve palsy and one radial nerve) and one super wound infection. And at the final follow-up, implant failure did not happen.
Few papers have focused exclusively on the treatment of recalcitrant humeral shaft nonunions. Borus et al.[2] performed uniform surgical repair with 4.5mm compression plating in combination with bone grafting on 7 patients with humeral diaphyseal nonunions following at least two failed prior surgical procedures, at follow-up, all nonunions healed with a good function of the affected extremity. And, Marti et al.[8] reported a series of 51 cases of humeral shaft nonunion, ten of which had undergone at least two prior surgical procedures, all patients were applied with plating and autogenous bone grafting, all got union at one year with 96 percent excellent or good shoulder and elbow function. Also, in a report of Adani et al.[33], 13 patients with an average length of the humeral defect of 10.5 cm who had at least 2 surgeries were treated by plate and fibular fixation, nine patients healed primarily, 3 required additional bone grafting, and 1 had a second fibular transplant. The mean period to radiographic bone union was 6 months. In this current study, before the index intervention procedure, each patient had undergone at least once failed operation for nonunion. We treated them by double plating and auto bone graft resulting in a bone healing rate of 100%, with a mean bone healing time of 6.4±1.8 months. At the final follow-up, each case showed a significantly improved function of the affected limb and a significantly reduced pain. The outcomes of this study were consistent with the above reports.
Limitations of this study are related to its retrospective nature and small patient numbers. In addition, we are unable to make a direct comparison between plate fixation and other fixation strategies. Because of the rarity and complexity of this specific situation, it was not possible to include a control group. Despite its limitations, this series demonstrates that double plating in combination with auto-bone graft achieves successful outcomes in recalcitrant humeral shaft nonunion. And, to the knowledge of the authors, this is the largest series of patients who had undergone multi-surgeries for nonunion treated by double plating the technology.