Screw augmentation reduces motion at the bone-implant interface: a biomechanical study of locking plate fixation of proximal humeral fractures

Schliemann, Benedikt; Seifert, Robert; Roßlenbroich, Steffen; Theisen, Christina; Wähnert, Dirk; Raschke, Michael J.; Weimann, André

doi:10.1016/j.jse.2015.06.028

Cited by 43 publications

(31 citation statements)

References 21 publications

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“…The locking plate combined with bone grafting provides direct double-column support and partial torsional stability without direct medial fixation, while the double plate system provides direct lateral fixation plus indirect medial support [20,21]. Our results indicated that use of a fixing method in combination with a medial support provided more effective double-column support and anti-rotational stability, and better fixation of complex fractures.…”

Section: Discussionmentioning

confidence: 71%

The biomechanics of combined lateral and posterior plates for treating proximal humerus fractures with medial column defects

Zhang

Yuechao

Wang

et al. 2020

Preprint

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KEYWORDSproximal humeral fracture, locking plate, internal fixation, biomechanics, finite element analysis 2 Abstract Background. We investigated the therapeutic effects associated with the combined use of lateral and posterior plates for treating complex proximal humerus fractures. Methods. We used in vitro biomechanical experiments and computer three-dimensional finite element analyses to investigate the biomechanical properties of combined lateral and posterior plates when treating proximal humerus fractures. Eighteen left SAWBONE (Pacific Research Labs) humerus bones were randomly divided among three groups. We established a medial column defect model for surgical neck fractures in each bone specimen and achieved fixation using a proximal humerus locking plate. Each of the three groups used a different fixation method. Group A used a Proximal Humerus Internal Locking System (PHILOS) plate support only. Group B used the PHILOS plate with a posterior locking plate (but without medial column support screws). Group C used the PHILOS plate with both the posterior locking plate and medial column support screws. We subjected three sets of specimens to axial compression, torsion, shear compression, model failure, fatigue testing, and micro-strain analyses.Results and conclusions. In vitro biomechanical analysis and three-dimensional finite element analyses showed that the PHILOS plate, in combination with the posterior locking plate and medial column support screws (Group C), had significantly enhanced biomechanical properties when compared with traditional single plate supports.

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Section: Discussionmentioning

confidence: 71%

The biomechanics of combined lateral and posterior plates for treating proximal humerus fractures with medial column defects

Zhang

Yuechao

Wang

et al. 2020

Preprint

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“…Loading only the humeral head is a limitation to the study as there are currently no available in vivo studies, describing screw perforating from such a perspective, but only from in vitro testing . On the basis of in vivo loading data, biomechanical testing setups that load from 25° lateral angulation have been developed, inducing primary varus bending . However, the related failure mode was screw cut‐out type failure rather than screw perforation .…”

Section: Discussionmentioning

confidence: 99%

Secondary Perforation Risk in Plate Osteosynthesis of Unstable Proximal Humerus Fractures: A Biomechanical Investigation of the Effect of Screw Length

Ciric

Mischler

Qawasmi

et al. 2019

Journal Orthopaedic Research

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Secondary perforation of screws into the joint surface is a commonly reported mechanical fixation failure mode in locked plating of proximal humerus fractures (PHF). This study investigated the influence that screws tip to joint distance (TJD) has on the biomechanical risk of secondary screw perforation and the stability of PHF. Ten pairs of cadaveric proximal humeri with a wide range of bone mineral density were used. Each specimen was osteotomized and instrumented with the PHILOS plate, simulating a highly unstable 3-part fracture. Bones were randomized into a long screw group (LSG) with 4 mm TJD, or a short screw group (SSG) with 8 mm TJD. A custom biomechanical setup was used to test the samples to failure cyclically with a constant valley load and an increasing ramp. The number of cycles to the initial screw loosening event was significantly higher for the LSG (mean ± standard deviation: 17,532 ± 6,458) compared with the SSG (11,102 ± 5,440) (p < 0.01). The mode of failure during testing was lateral-inferior displacement combined with varus collapse, with calcar screws perforating first. The number of cycles to failure event for LSG (27,849 ± 5,648) was not significantly different compared with SSG (28,782 ± 7,307) (p = 0.50). Screws that purchase closer to the joint had better initial stability and resistance against loosening. Placing longer screws, within limits dictated by the surgical guide, is expected to decrease the risk of secondary perforation failures in unstable PHF. These findings require clinical corroboration.

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“…52 In-vitro studies have shown that filling the fracture void with calcium triphosphate cement using PMMA augmentation with plates and nails decreases the risk of screw pull-out and loss of reduction. [53][54][55] Fibula struts show promise, although clinical studies in the current literature are of a small sample size. 56,57 Femoral head allograft augmentation has shown similar results in a group of ten patients, with an average post-op constant score of 72 at 28 months, and one non-union (10%).…”

Section: Augmentationmentioning

confidence: 96%

Management of complex proximal humerus fractures in the elderly: what is the role of open reduction and internal fixation?

et al. 2019

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The ultimate goal of management of proximal humeral fractures in the elderly patient is to get the patient independently mobile. This article will review the current literature regarding this cohort of patient. Recent Cochrane reviews and a large multicentre randomised study question the role of surgical intervention. Implant design is evolving rapidly, and many elderly patients now behave more like the younger patient. There remains little compelling evidence to guide decision-making for the complex proximal humeral fracture in the elderly, and the decision needs to be made on a case-by-case basis taking into account the patient's comorbidities, the fracture pattern and characteristics, the attending surgeon's skill sets, and the availability of equipment.

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Screw augmentation reduces motion at the bone-implant interface: a biomechanical study of locking plate fixation of proximal humeral fractures

Cited by 43 publications

References 21 publications

The biomechanics of combined lateral and posterior plates for treating proximal humerus fractures with medial column defects

The biomechanics of combined lateral and posterior plates for treating proximal humerus fractures with medial column defects

Secondary Perforation Risk in Plate Osteosynthesis of Unstable Proximal Humerus Fractures: A Biomechanical Investigation of the Effect of Screw Length

Management of complex proximal humerus fractures in the elderly: what is the role of open reduction and internal fixation?

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