Plate Fixation of Proximal Humerus Fractures: How to Get It Right and Future Directions for Improvement

Modified-tension band suturing: 'the pulling the reins technique' - a technique for displaced proximal humeral fracture with medial column instability

Fractures of the proximal humerus with medial column instability are challenging and present an unacceptable rate of complications and reoperations. Despite good results reported with the use of locking plates and augmentation techniques using bone graft or a second plate, varus subsidence and fixation failure have been frequently reported. We describe the case of a patient presenting with a complex, multifragmentary proximal humerus fractures successfully treated with open anatomic reduction and internal fixation using a locking plate augmented with lateral traction using three bone anchors in the humerus head. After 18 months, the patient reported fully recovering the mobility and functionality of the operated shoulder. The use of bone anchors pulling the humeral in three different directions like three vectors applied from medial to lateral, posterior to anterior and lateral to anterior help to reduce the most important deformities (varus and retroversion) by applying the tension band principle. This is an interesting approach to avoid primary and secondary reduction loss of the proximal fractures of the humerus with postero-medial cortical defect. The procedure is a good alternative to be used in patients with failure or insufficiency of the medial wall and marked varus.

[Research progress on valgus impacted proximal humeral fractures]

Objective

To review the advancement made in the understanding of valgus impacted proximal humeral fracture (PHF).

Methods

The domestic and foreign literature about the valgus impacted PHF was extensively reviewed and the definition, classification, pathological features, and treatment of valgus impacted PHFs were summarized.

Results

PHF with a neck shaft angle ≥160° is recognized as a valgus impacted PHF characterized by the preservation of the medial epiphyseal region of the humeral head, which contributes to maintenance of the medial periosteum's integrity after fracture and reduces the occurrence of avascular necrosis. Therefore, the valgus impacted PHF has a better prognosis when compared to other complex PHFs. The Neer classification designates it as a three- or four-part fracture, while the AO/Association for the Study of Internal Fixation (AO/ASIF) categorizes it as type C (C1.1). In the management of the valgus impacted PHF, the selection between conservative and surgical approaches is contingent upon the patient's age and the extent of fracture displacement. While conservative treatment offers the advantage of being non-invasive, it is accompanied by limitations such as the inability to achieve anatomical reduction and the potential for multiple complications. Surgical treatment includes open reduction combined with steel wire or locking plate and/or non-absorbable suture, transosseous suture technology, and shoulder replacement. Surgeons must adopt personalized treatment strategies for each patient with a valgus impacted PHF. Minimally invasive surgery helps to preserve blood supply to the humeral head, mitigate the likelihood of avascular necrosis, and reduce postoperative complications of bone and soft tissue. For elderly patients with severe comminuted and displaced fractures, osteoporosis, and unsuitable internal fixation, shoulder joint replacement is the best treatment option.

Conclusion

Currently, there has been some advancement in the classification, vascular supply, and management of valgus impacted PHF. Nevertheless, further research is imperative to assess the clinical safety, biomechanical stability, and indication of minimally invasive technology.

Cyclic Stability of Locking Plate Augmented with Intramedullary Polymethyl Methacrylate (PMMA) Strut Fixation for Osteoporotic Humeral Fractures: A Biomechanical Study

The locking plate may provide improved fixation in osteoporotic bone; however, it has been reported to fail due to varus collapse or screw perforation of the articular surface, especially in osteoporotic bone with medial cortex comminution. Using bone graft as an intramedullary strut together with plate fixation may result in a stronger construct. However, the drawbacks of bone grafts include limited supply, high cost, and infection risk. PMMA (so-called bone cement) has been widely used for implant fixation due to its good mechanical properties, fabricability, and biocompatibility. The risk of donor-site infection and the drawbacks of allografting may be overcome by considering PMMA struts as alternatives to fibular grafts for humeral intramedullary grafting surgeries. However, the potential effects of intramedullary PMMA strut on the dynamic behaviour of osteoporotic humerus fractures remain unclear. This study aimed to investigate the influence of an intramedullary PMMA strut on the stability of unstable proximal humeral fractures in an osteoporotic synthetic model. Two fixation techniques, a locking plate alone (non-strut group) and the same fixation augmented with an intramedullary PMMA strut (with-strut group), were cyclically tested in 20 artificial humeral models. Axially cyclic testing was performed to 450 N for 10,000 cycles, intercyclic motion, cumulated fragment migration, and residual deformation of the constructs were determined at periodic cyclic intervals, and the groups were compared. Results showed that adding an intramedullary PMMA strut could decrease 1.6 times intercyclic motion, 2 times cumulated fracture gap migration, and 1.8 times residual deformation from non-strut fixation. During cycling, neither screw pull-out, cut-through, nor implant failure was observed in the strut-augmented group. We concluded that the plate-strut mechanism could enhance the cyclic stability of the fixation and minimize the residual displacement of the fragment in treating osteoporotic proximal humeral unstable fractures. The PMMA strut has the potential to substitute donor bone and serve as an intramedullary support when used in combination with locking plate fixation. The intramedullary support with bone cement can be considered a solution in the treatment of osteoporotic proximal humeral fractures, especially when there is medial comminution.