The effect of screw insertion angle and thread type on the pullout strength of bone screws in normal and osteoporotic cancellous bone models

被引:91
作者
Patel, Purvi S. D. [1 ]
Shepherd, Duncan E. T. [1 ]
Hukins, David W. L. [1 ]
机构
[1] Univ Birmingham, Sch Mech Engn, Birmingham B15 2TT, W Midlands, England
关键词
Bone screws; Osteoporosis; Pullout strength; Screw insertion angle; PEDICLE SCREWS; FIXATION STRENGTH; MINERAL DENSITY; IN-VITRO; BIOMECHANICAL ANALYSIS; CALCIUM-PHOSPHATE; FINITE-ELEMENT; APATITE CEMENT; LUMBAR SPINE; AUGMENTATION;
D O I
10.1016/j.medengphy.2010.05.005
中图分类号
R318 [生物医学工程];
学科分类号
0831 ;
摘要
Screw fixation can be extremely difficult to achieve in osteoporotic (OP) bone because of its low strength. This study determined how pullout strength is affected by placing different bone screws at varying angles in normal and OP bone models. Pullout tests of screws placed axially, and at angles to the pullout axis (ranging from 10 degrees to 40 degrees), were performed in 0.09 g cm(-3), 0.16 g cm(-3) and 0.32 g cm(-3) polyurethane (PU) foam. Two different titanium alloy bone screws were used to test for any effect of thread type (i.e. cancellous or cortical) on the screw pullout strength. The cancellous screw required a significantly higher pullout force than the cortical screw (p<0.05). For both screws, pullout strength significantly increased with increasing PU foam density (p<0.05). For screws placed axially, and sometimes at 10 degrees, the observed mechanism of failure was stripping of the internal screw threads generated within the PU foam by screw insertion. For screws inserted at 10 degrees, 20 degrees, 300 and 40 degrees, the resistance to pullout force was observed to be by compression of the PU foam material above the angled screw; clinically, this suggests that compressed OP bone is stronger than unloaded OP bone. (c) 2010 IPEM. Published by Elsevier Ltd. All rights reserved.
引用
收藏
页码:822 / 828
页数:7
相关论文
共 55 条
[1]  
An Y.H., 2002, Internal fixation in osteoporotic bone
[2]  
[Anonymous], 1980, IDENTIFICATION OUTLI, DOI DOI 10.1007/978-94-015-3994-4
[3]   Cancellous bone screw thread design and holding power [J].
Asnis, SE ;
Ernberg, JJ ;
Bostrom, MPG ;
Wright, TM ;
Harrington, RM ;
Tencer, A ;
Peterson, M .
JOURNAL OF ORTHOPAEDIC TRAUMA, 1996, 10 (07) :462-469
[4]  
ASTM International, 2001, F183901 ASTM INT
[5]  
Barber JW, 1998, J SPINAL DISORD, V11, P215
[6]   Experimental evaluation of the holding power/stiffness of the self-tapping bone screws in normal and osteoporotic bone material [J].
Battula, Suneel ;
Schoenfeld, Andrew ;
Vrabec, Gregory ;
Njus, Glen O. .
CLINICAL BIOMECHANICS, 2006, 21 (05) :533-537
[7]   Assessment of different screw augmentation techniques and screw designs in osteoporotic spines [J].
Becker, S. ;
Chavanne, A. ;
Spitaler, R. ;
Kropik, K. ;
Aigner, N. ;
Ogon, M. ;
Redl, H. .
EUROPEAN SPINE JOURNAL, 2008, 17 (11) :1462-1469
[8]  
Bland M., 1995, INTRO MED STAT, V2nd
[9]  
*BRIT STAND I, 1991, 3531531991 BS BRIT S
[10]   Primary pedicle screw augmentation in osteoporotic lumbar vertebrae - Biomechanical analysis of pedicle fixation strength [J].
Burval, Daniel J. ;
McLain, Robert F. ;
Milks, Ryan ;
Inceoglu, Serkan .
SPINE, 2007, 32 (10) :1077-1083