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 OJO  Vol.5 No.1 , January 2015
Does the Location of the Cutting Flute of Self-Tapping Screws in Bony Substrate Affect the Removal Torque?
David James Chapman Graham1*, Alistair Spiers1, Eric Swarts2, Colin Whitewood3
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Abstract: Introduction: An observation was made that when removing self-tapping cortical screws from patients bones, stripping or shearing of the head of the screw occurred more often in screws whose cutting flutes sat in cortical bone compared with screws that had penetrated the distal cortex with flutes exposed. Method: A model was designed to simulate screws with their cutting flutes either in contact with cortical bone or deep to cortical bone. Screws were grouped depending on the location of their cutting flutes and removal torque was measured. Results: Eighteen screws were included in final analysis. There was a statistically significant difference in average initial removal torque and average maximal removal torque with screws with their cutting flutes in substrate requiring significantly more torque to remove. Conclusion: We conclude that self-tapping cortical screws whose cutting flutes sit in cortical substrate require more torque to remove and are therefore more likely to fail. This finding may be used as a guide in pre-operative planning for removal of metalwork from patients.
Keywords: Stainless Steel Screws, Removal Failure, Metalwork Removal, Self-Tapping Screws
Cite this paper: Graham, D. , Spiers, A. , Swarts, E. and Whitewood, C. (2015) Does the Location of the Cutting Flute of Self-Tapping Screws in Bony Substrate Affect the Removal Torque?. Open Journal of Orthopedics, 5, 1-5. doi: 10.4236/ojo.2015.51001.
References

[1]   Canale, S. and Beaty, J. (2007) Campbell’s Operative Orthopaedics. 11th Edition, Mosby/Elsevier, USA.

[2]   Ansell, R. and Scales, J. (1968) A Study of Some Fractures Which Affect the Strength of Screws and Their Insertion and Holding Power in Bone. Journal of Biomechanics, 1, 279-302.
http://dx.doi.org/10.1016/0021-9290(68)90023-7

[3]   Baumgart, F.W., Morikawa, C.K., Morikawa, S.M., et al. (1993) AO/ASIF Self-Tapping Screws (STS). AO/ASIF Research Institute, Davos.

[4]   Busam, M.L., Esther, R.J. and Obremskey, W.T. (2006) Hardware Removal: Indications and Expectations. Journal of the American Academy of Orthopaedic Surgeons, 14, 113-120.

[5]   Jamil, W., Allami, M., Choudhury, M.Z., Mann, C., Bagga, T. and Roberts, A. (2008) Do Orthopaedic Surgeons Need a Policy on the Removal of Metalwork? A Descriptive National Survey of Practicing Surgeons in the United Kingdom. Injury International Journal of the Care of the Injured, 39, 362-367.
http://dx.doi.org/10.1016/j.injury.2007.10.028

[6]   Jago, E.R. and Hindley, C.J. (1998) The Removal of Metalwork in Children. Injury, 29, 439-441.
http://dx.doi.org/10.1016/S0020-1383(98)00080-1

[7]   Webb, J.A., Almaiyah, M., McVie, J. and Montgomery, R.J. (2008) Proximal Femoral Osteotomies in Children Using the Richards Hip Screw: Techniques, Outcome and Subsequent Removal. Journal of Children’s Orthopaedics, 2, 417-423.
http://dx.doi.org/10.1007/s11832-008-0127-8

[8]   Schatzker, J. (1995) Osseointegration of Metal. Canadian Journal of Surgery, 38, S49.

[9]   Hanser, D. and Jensen, J.S. (1992) Additional Mechanical Tests of Bone Cements. Acta Orthopaedica Belgica, 58, 268-271.

[10]   Rua, J.Y., Ashman, R.B. and Turner, C.H. (1993) Young’s Modulus of Trabecular and Cortical Bone Material: Ultrasonic and Microtensile Measurements. Journal of Biomechanics, 26, 111-119.
http://dx.doi.org/10.1016/0021-9290(93)90042-D

 
 
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