Despite considerable progress in orthopaedic 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 combined with soft tissue maladaptation and deformity have left the patient with a profound disability and an abandonment of optimism, especially for patients with poor economy [2, 3, 7, 10, 20]. Numerous treatments have been devised for treatment of humeral shaft nonunion, aiming at providing adequate fixation across the fracture sites and improving the local biomechanical environment or blood supply, each 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].
Some authors had successfully reported use nailing or exchange nailing for humeral shaft nonunion, which relies on the concept of improvement of biomechanical stability by the use of a nail being at least one millimeter thicker than its diameter, as well as mesenchymal stem cells transporting into the nonunion site following 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 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. Interlocking intramedullary nails have been widely used in acute humeral fractures, pathologic fractures and nonunions of the tibia or femur shaft, for humerus fixation, they have the advantages over plates of fewer tissue traumas, fewer circulatory impairments and lower risk of radial nerve injury [3]. However, 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]. The other reason why exchange nailing or nailing is not successful in humeral nonunion was lack of cyclical loading due to weight-bearing and a higher amount of distractive and torsional loads on the humerus [23]. All of these factors put together made exchange nailing or nailing was not the best way for 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, it requires long fixation time and risks of pin-tract infection and patient discomfort because of the large size of the frame, which makes it an unreliable and rather unnecessarily complex option in non-infected nonunion [10].
Plate fixation with bone grafting for humeral shaft nonunion has been the most common practice, this technique is easy to use by all surgeons. Gessmann et al.[28] reported a 97% success rate of anterior augmentation plating after antegrade or retrograde intramedullary nailing. In a systematic review of 36 articles, Peters et al.[29] found that plate fixation with autogenous bone grafting achieved a union rate of up to 98%. The cases in this study lived in northwest China, where plate fixation remains the preferred method of long bone fixation due to economic constraints and the level of medical care available. As most patients showed varying degree of misalignment, implant broken and/or loosen, or pseudarthrosis, use of LCP fixation could achieve a high degree of cortex-to-cortex stability with compression of the bone segments and correction of the deformities for those cases. Also, repeated prior surgeries might result in a poor biological environment for fracture repair in cases during this study, 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. Although plating technique has complications of screw back-outs, peripheral never paralysis and infection [31]. 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.
A second plate fixing vertically to the anterior of the bone graft for structural support could maintain intimate contact between the autogenous bone graft and both nonunion fragments, maximizing osteoconductive, osteogenic and osteoinductive properties of autologous bone, resulting in bone healing rates reaching 100% in this study. More, double-plate technology could obtain absolute stability, thus postoperative functional rehabilitation could be started from 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 placement of the anterior and lateral plates at 90° was found to be the best configuration for dual plating. In a clinic study, Martinez et al.[32] reported the use of two-plate construct in the treatment of 22 cases of humeral shaft nonunion with a 100% rate.
Although many authors have reported on the successful treatment of primary humeral diaphysis nonunions, few papers have focused exclusively on revision procedures for salvaging persistent nonunions following failed initial nonunion interventions. Borus et al.[2] reported a series of 7 patients with humeral diaphyseal nonunion following at least two failed surgical procedures, these patients underwent uniform surgical repair with 4.5 mm compression plating and application of autogenous bone grafting. All nonunions healed with a good function of the affected extremity. 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 of 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. All 15 patients achieved bone healing at an average 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 problem, 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.