Effect of Contouring on Bending Structural Stiffness and Bending Strength of the 3.5 Titanium SOP Implant


Corresponding Author

Scott Rutherford, BVMS CertSAS MRCVS, Croft Veterinary Hospital, Northumberland Business Park West, Cramlington, Northumberland, NE23 7RH, UK

E-mail: s.rutherford@croftvets.co.uk



To compare the bending structural stiffness (BSS) and bending strength (BS) of the 3.5 titanium (Ti) string of pearls (SOP) plate and the 3.5 316LVM stainless steel SOP plate; and the effect of contouring on the BSS and BS of the 3.5 Ti SOP plate.

Study Design

In vitro experimental static 4-point bending materials testing.

Sample Population

Twenty-five 3.5 mm Ti and five 3.5 mm 316LVM stainless steel SOP locking bone plates.


Each plate was tested in 4-point bending until 10 mm of displacement was achieved. BSS and BS were then calculated for each plate. A 2-sample t-test was used to compare the mean BSS and BS of the different groups.


The 3.5 Ti SOP plate had lower mean BSS (0.00263 Nm2) but similar mean BS (12.8 Nm) when compared to the 3.5 316LVM SOP (0.00402 Nm2, 13.0 Nm). Prebending the 3.5 Ti SOP diminished its mean BSS (0.00224 Nm2) and mean BS (9.4 Nm) when compared to the Ti control. Pretwisting the 3.5 Ti SOP increased its mean BSS (0.00273 Nm2) but decreased its mean BS (12.4 Nm) when compared to the Ti control.


The 3.5 Ti SOP is less stiff but of similar strength to the 3.5 316LVM stainless steel SOP. Prebending the Ti SOP significantly lowers its stiffness and strength. Pretwisting the SOP actually increases its stiffness but slightly lowers its strength.