gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018)

23.10. - 26.10.2018, Berlin

Does intramedullary grafting increase stability of plated proximal humerus fractures?

Meeting Abstract

  • presenting/speaker Boyko Gueorguiev - AO Research Institute Davos, Davos, Switzerland
  • Lyubomir Rusimov - University Hospital for Emergency Medicine 'N. I. Pirogov', Sofia, Bulgaria
  • Ivan Zderic - AO Research Institute Davos, Davos, Switzerland
  • Dian Enchev - University Hospital for Emergency Medicine 'N. I. Pirogov', Sofia, Bulgaria
  • Mihail Rashkov - University Hospital for Emergency Medicine 'N. I. Pirogov', Sofia, Bulgaria
  • Mariya Hadzhinikolova - University Hospital for Emergency Medicine 'N. I. Pirogov', Sofia, Bulgaria
  • Geoff Richards - AO Research Institute Davos, Davos, Switzerland
  • Asen Baltov - University Hospital for Emergency Medicine 'N. I. Pirogov', Sofia, Bulgaria

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018). Berlin, 23.-26.10.2018. Düsseldorf: German Medical Science GMS Publishing House; 2018. DocGF17-356

doi: 10.3205/18dkou493, urn:nbn:de:0183-18dkou4932

Veröffentlicht: 6. November 2018

© 2018 Gueorguiev et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe http://creativecommons.org/licenses/by/4.0/.


Gliederung

Text

Objectives: Incidence of proximal humerus fractures is steadily increasing in elderly patients. Although plating is established as standard treatment of such fractures, postoperative complication rates remain remarkably high, with varus collapse reported as the most common complication after fixation with locking plates. Supplemental augmentation of the medial column with intramedullary bone graft may alleviate the problems and result in superior clinical outcomes. The aim of this study was to investigate the biomechanical competence of PHILOS plating augmented with supplemental intramedullary graft and compare it to conventional PHILOS fixation for treatment of normal and osteoporotic fractures at the proximal humerus.

Methods: Complex four-part proximal humerus fractures were created in thirty artificial humeri assigned to three groups. Fracture pattern in group 1 was characterized by gap-like loss of medial support. In contrast, the specimens in group 2 were with intact medial support, but with hollowed-out inner matrix of the humeral head simulating aggravated bone quality. The fracture model in group 3 was combination of the pattern in groups 1 and 2. Following fracture reduction, each specimen was first instrumented with a PHILOS plate. Non-destructive biomechanical testing was performed in 25° lateral angulation under axial loading ranging up to 400N. Anteroposterior X-rays were shot between 150N and 400N loads in 50N increments. Subsequently, all biomechanical tests were repeated with an additional 3D-printed cylindrical polylactide graft inserted into each specimen to simulate intramedullary fibula grafting and augmented plate fixation. Axial stiffness and varus tilting of the humerus head were evaluated.

Results and conclusion: Axial stiffness (N/mm) without/with intramedullary graft was on average 157.7/217.5 in group 1, 188.8/209.1 in group 2, and 132.7/209.8 in group 3. Intramedullary grafting resulted in significantly higher stiffness in groups 1 and 3 (p< 0.001), but not in group 2 (p=0.120). In addition, non-grafted specimens represented significantly higher stiffness in group 2 compared to groups 1 and 3 (p=0.002), whereas no differences were detected among the three groups in grafted state (p >0.999). Varus tilting (°) under 150N axial load without/with graft was 0.13/0.01 in group 1, 0.05/0.01 in group 2 and 0.08/0.01 in group 3. It decreased significantly in each group post graft insertion (p< 0.045). Furthermore, the non-grafted specimens in group 2 showed trend to lower varus tilting than those in groups 1 and 3 (p=0.068). No significant differences were registered among the three groups after grafting (p >0.999). Consistent results were observed with respect to varus tilting under 200N, 250N, 300N, 350N, and 400N loading. PHILOS plating augmented with supplemental intramedullary graft has the potential to significantly increase stability against varus collapse in unstable proximal humerus fractures, when compared to conventional PHILOS fixation.