The Position and Number of Screws Influence Screw Perforation of the Humeral Head in Modern Locking Plates: A Cadaver Study

*Department of Orthopaedic Surgery, Cantonal Hospital St. Gallen, St. Gallen, Switzerland †Fremantle Orthopaedic Unit, University of Western Australia, Fremantle, Western Australia, Australia ‡Department of Orthopaedic Surgery, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
Journal of orthopaedic trauma (Impact Factor: 1.8). 02/2012; 26(10):e188-92. DOI: 10.1097/BOT.0b013e31823db922
Source: PubMed


: Screw perforation of the humeral head in locking plate osteosynthesis occurs in up to 30% of cases. The current study compared different fixation possibilities (eg, number and position of screws) to reduce screw perforation in the humeral head.
: A humeral head fracture with a missing medial support was created in 30 fresh-frozen cadavers and fixed with a polyaxial locking plate (NCB PH; Zimmer, Warsaw, IN). The constructs were loaded with increasing force and the number of cycles until screw perforation was recorded. Four different fixation methods were tested: group 1 five screws with fixed angle, group 2 five screws in polyaxial position according to bone strength, group 3 three screws, and group 4 five screws with 1 as an inferomedial support screw.
: More screws in the humeral head significantly increased the number of cycles before screw perforation. An inferomedial support screw further increased the number of cycles. Polyaxial screw placement compared with fixed-angle placement had no effect on the screw perforation phenomenon.
: We recommend to position an inferomedial support screw, and at least 5 screws in the head fragment, when using a locking plate in proximal humerus fractures with disrupted medial hinge.

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    • "Another recent finding is the importance of an inferomedial support screw in fixed angle plating of proximal humeral fractures. In a biomechanical study by Erhardt et al. a screw placed obliquely in the inferomedial region of the humeral head significantly increased the number of cycles before loss of fixation occurs and usage of more screws additionally enhanced the fixations strength.16 However, to the authors’ knowledge, despite biomechnical studies, no clinical study could verify these findings in a larger cohort of patients. "
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    ABSTRACT: The aim of the study was to examine the correlation between the chosen position of screws and the complications observed in patients who underwent locked plating of proximal humeral fractures. We evaluated radiographs of 367 patients treated by locked-plating for proximal humeral fractures. Radiographs were taken at one day, 6 weeks, 3 months and 6 months after surgery, and were analyzed for secondary fracture displacement, loss of fixation, cutting out of screws and necrosis of the humeral head. Secondary loss of fixation occurred in 58 cases (15.8%) and among those cutting out of screws was observed in 25 cases (6.8%). In cases of secondary loss of fixation a mean of 6.7 screws were used to fix the fracture (vs 6.6, P=0.425). There was neither significant correlation between position of screws and the occurrence of postoperative loss of fixation in Spearman correlation nor relationship from backward logistic regression analysis. Loss of fixation following locked plating of proximal humeral fractures does not relate to the number of screws and their positions in the humeral head. In consequence, anatomic fracture reduction and restoration of the humeral head-shaft angle are still important factors and should not be disregarded.
    Orthopedic Reviews 04/2014; 6(2):5336. DOI:10.4081/or.2014.5336
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    ABSTRACT: The treatment of complex proximal humeral fractures remains challenging, especially in patients with osteoporosis. Locking plate fixation has become a standard in stabilizing these fractures; however, complication rates are still high. In particular, loss of reduction with varus misalignment and subsequent cut-out of the proximal screws is frequent. Recently the restoration of medial support has been named as the primary aim of operative treatment. This article describes an alternative technique using intramedullary augmentation on the basis of a case report and explains the concept of medial support in locking plate fixation of proximal humeral fractures. Options, findings and recommendations of different procedures are presented in this respect. The importance of correct reduction of the medial cortices, the use of calcar screws, the double-plate fixation method as well as the presented technique of intramedullary augmentation are discussed.
    Obere Extremität 11/2012; 8(3). DOI:10.1007/s11678-012-0189-6
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    ABSTRACT: The treatment of proximal humerus fractures continues to evolve. While the many of these injuries can be managed nonoperatively, a certain percentage require operative treatment. Open reduction internal fixation can offer excellent outcomes when performed in the appropriate patient and utilizing proper techniques. This article reviews the most up-to-date literature regarding all phases of proximal humerus fracture osteosynthesis, including diagnosis, imaging, anatomic considerations, surgical indications, fixation, and surgical outcomes.
    Current Reviews in Musculoskeletal Medicine 01/2013; 6(1). DOI:10.1007/s12178-012-9150-y
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