Novel Technical Factors Affecting Proximal Humerus Fixation Stability

Comparison of the ALPS and PHILOS plating systems in proximal humeral fracture fixation - a retrospective study

BACKGROUND

Open reduction and plate osteosynthesis are considered as a successful technique for the treatment of proximal humerus fracture (PHF) despite high complication rates. The objective of our study was to review the clinical outcome and complications of the Anatomic Locking Plate System (ALPS) and compare it to the Proximal Humeral Internal Locking System (PHILOS). Our hypothesis was that ranges of motion (ROM) were superior and complication rates were lower with ALPS.

METHODS

Twenty patients treated with ALPS for PHF were retrospectively compared to 27 patients treated with PHILOS. Union, ROM and complications were clinically and radiologically assessed at 6 weeks, 3, 6, 12 and 18-24 months post-operatively.

RESULTS

Mean age was 52 ± 14 in the ALPS group and 58 ± 13 in the PHILOS group. Last follow-ups were conducted at a mean of 20.6 ± 4.8 months. Mean shoulder abduction was superior with ALPS by 14° (p-value = 0.036), 15° (p-value = 0.049), and 15° (p-value = 0.049) at 3, 6, and 12 months respectively. Mean shoulder external rotation was superior with ALPS by 11° (p-value = 0.032), 15° (p-value = 0.010) and 12° (p-value = 0.016) at 6 weeks, 3 and 6 months respectively. At the end of the follow-up, ROM remained better with ALPS, but not significantly. Complication rates over 21 months reached 20% with ALPS and 48% with PHILOS (p-value = 0.045). Implant removal rates reached 10% with ALPS and 37% with PHILOS (p-value = 0.036). Avascular necrosis was the only cause for hardware removal in the ALPS group.

CONCLUSION

The ALPS group showed better clinical outcomes with faster recovery in abduction and external rotation, although no difference in ROM remained after 21 months. Additionally, the complications rate was lower at last follow up. In our experience, the ALPS plating system is an effective management option in some PHF.

A Standardized Operative Protocol for Fixation of Proximal Humeral Fractures Using a Locking Plate to Minimize Surgery-Related Complications

The current literature suggests that up to 55% of complications after plate osteosynthesis treatment for patients with proximal humerus fractures are attributed to the surgical procedure. The hypothesis of this study was that a standardized surgical protocol would minimize surgery-related adverse events. This prospective cohort study included 50 patients with a mean age of 63.2 (range 28-92) years treated by one single surgeon using a previously published standardized surgical protocol. Clinical and radiological follow-up examinations were conducted for up to 24 months using Constant-Murley Score (CS), Subjective Shoulder Value (SSV) and radiographs in true anteroposterior, axial and y-view. Finally, CS was 73.9 (standard deviation [SD]: 14.0) points (89% compared to the uninjured shoulder), and SSV was 83.3% (SD: 16.7) at two years of follow-up. Postoperative radiologic evaluation revealed no primary surgical-related or soft-tissue-related complications (0%). The main complications were secondary, biological complications (20%), largely represented by avascular necrosis (8%). Eight patients underwent revision surgery, mainly for implant removal. In addition, a total of four patients were revised using a hemiarthroplasty (n = 2), reverse shoulder arthroplasty (n = 1) or re-osteosynthesis. The use of our standardized surgical technique on proximal humerus fractures improves fixation with regard to primary stability and prevents primary, surgical-technique-related complications. The subjective grading of a high level of difficulty surgery was associated with more complications.

Application of a lateral intertubercular sulcus plate in the treatment of proximal humeral fractures: a finite element analysis

Background

Inversion deformities caused by insufficient medial support are especially common when the PHILOS locking plate is used to treat proximal humeral fractures. Using finite element analysis, we aimed to compare the biomechanical properties of a PHILOS locking plate (PLP) and a PLP combined with a lateral intertubercular sulcus plate (PLP-LSP) in the fixation of proximal humeral fractures with loss of the medial column.

Methods

After creating a three-dimensional finite element model of a proximal humeral fracture with loss of the medial column, three implant models were established. A full-screw PLP was used in Group A, a PHILOS plate lacking medial screw support and an additional steel plate (MPLP-LSP) were used in Group B, and a full-screw PLP-LSP was used in Group C. The three fixation models were applied to the proximal humeral fracture model, following which horizontal, compressive, and rotational loads were applied to the humerus model. We evaluated structural stiffness and stress distribution in the implant and compared displacement and angle changes among the three models.

Results

Displacement and angle changes were smallest in Group C (PLP-LSP). The implant model used in Group C also exhibited greater structural rigidity, endured less von Mises stress, and was more stable than the models used in Group A and Group B.

Conclusion

An LSP placed at the intertubercular sulcus provides effective lateral and medial support, thereby reducing stress on the PLP and providing better stability with proximal humeral fractures.