Biomechanical Study of the Fixation Strength of Anteromedial Plating for Humeral Shaft Fractures

Abstract

Background:Open reduction and internal fixation with plate and screws are the gold standard for the surgical treatment of humeral shaft fractures, this study was to compare the mechanical properties of anteromedial, anterolateral, and posterior plating for humeral shaft fractures.Methods:A distal third humeral shaft fracture model was constructed using fourth-generation sawbones (#3404, composite bone). A total of 24 sawbones with a distal third humeral shaft fracture was randomly divided into three Groups: A, B, and C (n = 8 in each group) for anteromedial, anterolateral, and posterior plating, respectively. All sawbones were subjected to horizontal torsional fatigue tests, horizontal torsional and axial compressive fatigue tests, four-point bending fatigue tests in anteroposterior (AP) and mediolateral (ML) directions and horizontal torsional destructive tests.Results:In the horizontal torsional fatigue tests, the mean torsional angle amplitude in Groups A, B, and C were 6.12°, 6.53°, and 6.81°. In horizontal torsional and axial compressive fatigue tests, the mean torsional angle amplitude in Groups A, B, and C were 5.66°, 5.67°, and 6.36°. The mean plate displacement amplitude was 0.05 mm, 0.08 mm, and 0.10 mm. Group A was smaller than Group C (P < 0.05). In AP four-point bending fatigue tests, the mean plate displacement amplitude was 0.16 mm, 0.13 mm, and 0.20 mm. Group B was smaller than Group C (P < 0.05). In ML four-point bending fatigue tests, the mean plate displacement amplitude were 0.16 mm, 0.19 mm, and 0.17 mm. In horizontal torsional destructive tests, the mean torsional rigidity in Groups A, B, and C was 0.82, 0.75, and 0.76 N·m/deg. The yielding torsional angle was 24.50°, 25.70°, and 23.86°. The mean yielding torque was 18.46, 18.05, and 16.83 N·m, respectively.Conclusions:Anteromedial plating was superior to anterolateral or posterior plating in all mechanical tests except in AP four-point bending fatigue tests compared to the anterolateral plating group. We can suggest that anteromedial plating is a clinically safe and effective way for humeral shaft fractures.

Treatment of humeral shaft fractures: a new minimally-invasive plate osteosynthesis versus open reduction and internal fixation: a case control study

“…This approach may also increase the stability of fixation, especially in cases of severe osteoporosis, periprosthetic fractures, and pathological fractures requiring biplanar fixation. Biomechanical studies of the human skeleton have shown that anteromedial plates provide better stability than anterolateral or posterolateral plates in the treatment of mid-humeral fractures, and that the anteromedial minimally-invasive approach is not suitable for the treatment of proximal humeral fractures due to the lack of adequate fixation sites [ 26 ]. A dual plate can be used in combination with an anterolateral or lateral approach to reconstruct the medial and lateral columns of the distal humerus while preserving blood supply to the surrounding soft tissues and hastening fracture healing [ 9 ].…”

Biomechanics of Upper Extremity Double Plating

“…No significant biomechanical difference between fixations with 2 or 3 locking screws per fracture segment were found [34]. A biomechanical study by Zheng et al assessed the various plate positions using artificial bone (antero-medial, antero-lateral und posterior) but detected no relevant differences [35].…”

Shaft of humerus fracture managed by anteromedial plating through anterolateral approach.

“…Plates and screws are treated as the ideal fixation device despite the recent advances in the implants. 12 Humerus has been approached through different approaches, and each of them has its advantages and disadvantages. 13 Concerning the shape and structure of humerus, the anterior and anteriormedial surface of humerus is flat, allowing accurate seating of plate compared to the lateral surface, which contains the attachment of deltoid muscle limits proper seating of plate over it.…”