Download PDF
Vet Comp Orthop Traumatol 2016; 29(06): 466-474
DOI: 10.3415/VCOT-15-11-0192
Original Research
Schattauer GmbH

Pullout strength of monocortical and bicortical screws in meta -physeal and diaphyseal regions of the canine humerus

Denty Paul Vaughn
1   Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi, USA
,
Jason Alan Syrcle
1   Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi, USA
,
John E. Ball
2   Department of Electrical and Computer Engineering, College of Engineering, Mississippi State University, Mississippi, USA
,
Steven H. Elder
3   Department of Agricultural and Biological Engineering, College of Engineering, Mississippi State University, Mississippi, USA
,
Jennifer Michele Gambino
1   Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi, USA
,
Russell L. Griffin
4   Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, USA
,
Ronald M. McLaughlin
1   Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi, USA
› Author Affiliations Financial support: This research [Project AOVET–15–09V] was supported by a grant from the AO Foundation.
Further Information

Publication History

Received: 27 November 2015

Accepted: 15 July 2016

Publication Date:
19 December 2017 (online)

    Permissions and Reprints

Summary

Objective: Monocortical screws are commonly employed in locking plate fixation, but specific recommendations for their placement are lacking and use of short monocortical screws in metaphyseal bone may be contra indicated. Objectives of this study were to evaluate axial pullout strength of two different lengths of monocortical screws placed in various regions of the canine humerus compared to bicortical screws, and to derive cortical thickness and bone density values for those regions using quantitative computed tomography analysis (QCT).

Methods: The QCT analysis was performed on 36 cadaveric canine humeri for six regions of interest (ROI). A bicortical, short monocortical, or 50% transcortical 3.5 mm screw was implanted in each ROI and axial pullout testing was performed.

Results: Bicortical screws were stronger than monocortical screws in all ROI except the lateral epicondylar crest. Short monocortical metaphyseal screws were weaker than those placed in other regions. The 50% transcortical screws were stronger than the short monocortical screws in the condyle. A linear relationship between screw length and pull-out strength was observed.

Clinical significance: Cortical thickness and bone density measurements were obtained from multiple regions of the canine humerus using QCT. Use of short monocortical screws may contribute to failure of locking plate fixation of humeral fractures, especially when placed in the condyle. When bicortical screw placement is not possible, maximizing monocortical screw length may optimize fixation stability for distal humeral fractures.

Keywords

Canine humerus - screw pullout strength - bone mineral density - monocortical screw fixation - quantitative computed tomography
 

  • References

  • 1 Kraus KH, Ness MG. SOP interlocking plate system. Standard operating procedure [Company Product Information]. Version 1.4 Orthomed (UK) ltd; October 2007 [Cited on June 24, 2014]. Pg. 1-20 Available from: http://www.orthomed.co.uk/pdf-downloads.html
    PubMedGoogle Scholar
  • 2 Khalid M, Theivendran K, Cheema M. et al. Biomechanical comparison of pull-out force of unicortical versus bicortical screws in proximal phalanges of the hand: a human cadaveric study. Clin Biomech (Bristol, Avon) 2008; 23: 1136-1140.
    CrossrefPubMedGoogle Scholar
  • 3 Gautier E, Sommer C. Guidelines for the clinical application of the LCP. Injury 2003; 34 (Suppl. 02) B63-76.
    CrossrefPubMedGoogle Scholar
  • 4 Seebeck J, Goldhahn J, Stadele H. et al. Effect of cortical thickness and cancellous bone density on the holding strength of internal fixator screws. J Orthop Res 2004; 22: 1237-1242.
    CrossrefPubMedGoogle Scholar
  • 5 Hurt RJ, Syrcle JA, Elder S. et al. A biomechanical comparison of unilateral and bilateral string-of-pearls locking plates in a canine distal humeral metaphyseal gap model. Vet Comp Orthop Traumatol 2014; 27: 186-191.
    Article in Thieme ConnectPubMedGoogle Scholar
  • 6 Diederichs G, Issever AS, Greiner S. et al. Three-dimensional distribution of trabecular bone density and cortical thickness in the distal humerus. J Shoulder Elbow Surg 2009; 18: 399-407.
    CrossrefPubMedGoogle Scholar
  • 7 Seebeck J, Goldhahn J, Morlock MM. et al. Mechanical behaviour of screws in normal and osteoporotic bone. Osteoporos Int 2005; 16 (Suppl. 02) S107-111.
    CrossrefPubMedGoogle Scholar
  • 8 Lenz M, Perren SM, Gueorguiev B. et al. Mechanical behaviour of fixation components for periprosthetic fracture surgery. Clin Biomech 2013; 28: 988-993.
    CrossrefPubMedGoogle Scholar
  • 9 Lenz M, Perren SM, Gueorguiev B. et al. A biomechanical study on proximal plate fixation techniques in periprosthetic femur fractures. Injury 2014; 45 (Suppl. 01) S71-75.
    CrossrefPubMedGoogle Scholar
  • 10 Engelke K, Libanati C, Liu Y. et al. Quantitative computed tomography (QCT) of the forearm using general purpose spiral whole-body CT scanners: accuracy, precision and comparison with dual-energy X-ray absorptiometry (DXA). Bone 2009; 45: 110-118.
    CrossrefPubMedGoogle Scholar
  • 11 Park SH, Kim SJ, Park BC. et al. Three-dimensional osseous micro-architecture of the distal humerus: implications for internal fixation of osteoporotic fracture. J Shoulder Elbow Surg 2010; 19: 244-250.
    CrossrefPubMedGoogle Scholar
  • 12 Tingart MJ, Lehtinen J, Zurakowski D. et al. Proximal humeral fractures: regional differences in bone mineral density of the humeral head affect the fixation strength of cancellous screws. J Shoulder Elbow Surg 2006; 15: 620-624.
    CrossrefPubMedGoogle Scholar
  • 13 ASTM F 543-13., Standard Specification and Test Methods for Metallic Medical Bone Screws, ASTM International, West Conshohocken, PA, 2013 Available from: http://www.astm.org/cgi-bin/resolver.cgi?F543-13
    PubMed
  • 14 Chan TF, Vese LA. Active contours without edges. IEEE Trans Image Process 2001; 10: 266-277.
    CrossrefPubMedGoogle Scholar
  • 15 Sahiner B, Chan HP, Petrick N. et al. Computerized characterization of masses on mammograms: the rubber band straightening transform and texture analysis. Med Physics 1998; 25: 516-526.
    CrossrefPubMedGoogle Scholar
  • 16 Huber MB, Carballido-Gamio J, Bauer JS. et al. Proximal femur specimens: automated 3D trabecular bone mineral density analysis at multidetector CT—correlation with biomechanical strength measurement. Radiology 2008; 247: 472-481.
    CrossrefPubMedGoogle Scholar
  • 17 Adams JE. Quantitative computed tomography. Eur J Radiol 2009; 71: 415-424.
    CrossrefPubMedGoogle Scholar
  • 18 Krappinger D, Roth T, Gschwentner M. et al. Preoperative assessment of the cancellous bone mineral density of the proximal humerus using CT data. Skeletal Radiol 2012; 41: 299-304.
    CrossrefPubMedGoogle Scholar