ReviewHow to enhance the stability of locking plate fixation of proximal humerus fractures? An overview of current biomechanical and clinical data
Introduction
Fractures of the proximal humerus are the fourth-most common fracture among geriatric patients after distal radius, proximal femur and vertebral fractures [1], [2]. Because the geriatric population is growing continuously, an increase in the incidence of these fractures should be expected [3]. Locking plate fixation is a standard procedure for the treatment of proximal humerus fractures [4]. However, complication rates of up to 49% have been reported [4], [5], [6], [7], [8], [9]. A low bone mineral density (BMD) and a lack of medial support have been identified as the two most important factors for the stability of locking plate fixation [10], [11], [12]. In their clinical study, Krappinger et al. demonstrated that low BMD is associated with a significantly higher risk of implant failure and loss of reduction after locking plate fixation [12]. With regard to medial support, Gardner et al. were the first to describe the correlation between a lack of medial support and a loss of reduction after fixation of proximal humerus fractures [10]. Accordingly, Jung et al. found significantly worse results after locking plate fixation of fractures with medial comminution [13].
To overcome these problems, many efforts have been made in recent years, and clinical and biomechanical studies have focussed on three principles to increase the stability of locking plate fixation of proximal humerus fractures: augmentation of screw tips in regions of low BMD, the use of medial support screws (calcar screws) and autograft or allograft augmentation in fractures with comminution of the medial column [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26].
The aim of the present article is to give an overview of current biomechanical and clinical studies that focus on how to increase the stability of locking plate fixation of proximal humerus fractures in order to help develop a standardised treatment strategy for this complex and challenging injury.
Section snippets
Methods
The Medline database was searched using the keyword ‘proximal humerus fracture’ in combination with either ‘stability’, ‘medial support’, ‘augmentation’, ‘cement’, ‘bone graft’, ‘autograft’ or ‘allograft’. Only those articles published in the English language were included. After screening, the eligible articles were separated into three groups: (1) medial support screws, (2) cement augmentation and (3) bone grafts. In addition, they were further subdivided into biomechanical and clinical
Medial support screws
Gardner et al. suggested parameters to define whether medial support of a proximal humerus fracture was restored during surgery [10]. A fracture is considered to have medial support if (1) the medial column is intact, anatomically reduced and not comminuted; (2) the shaft is impacted into the head fragment; or (3) an oblique locking screw is placed directly into the inferomedial quadrant of the proximal humeral head fragment to within 5 mm of the subchondral bone. Because medial comminution can
Discussion
The aim of this overview was to present current biomechanical and clinical data on measures to enhance the stability of locking plate fixation of proximal humerus fractures. Literature research revealed that the use of medial support screws, cement augmentation and bone grafts are currently the most frequently used and assessed tools to increase the stability of locking plate constructs. Although the evidence is low and prospective randomised clinical trials on the use of either technique are
Source of funding
None.
Conflict of interest statement
All other authors, their immediate families and any research foundation with which they are affiliated did not receive any financial payments or other benefits from any commercial entity related to the subject of this article.
There is no conflict of interest.
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