Mechanical characteristics of three staples commonly used in foot surgery

Abstract

Background: Bone staples are an accepted method of fixation in foot surgery. They reduce operating time and trauma in surgical procedures. A variety of memory staples are available but their properties compared to standard staples are not known. We carried out a study comparing two popular types of memory staples and a standard stainless steel staple.

Evaluation of Nitinol Staples for the Lapidus Arthrodesis in a Reproducible Biomechanical Model

“…While not directly comparable due to the different areas of contact and measurement methods, the single 20 × 20 TI Speed staple in the present study produced a contact force of 97.8 N. This drastic improvement is due to evolution in SMA staple design with a wider, low-profile bridge. These improvements are also evident from another study by Rentham et al ( 18 ) comparing the mechanical performance of different staples in four-point bending. They reported a bending moment of 0.51 Nm in a 14 × 12 Memoclip staple at 10° of bending.…”

“…While a number of other studies have evaluated the biomechanical properties of different fixation methods for the Lapidus arthrodesis ( 3 , 5 , 9 , 17 , 18 , 21 – 28 ), variations in models and testing methods make meaningful comparison difficult. When comparing the rigidity of crossed-screw constructs with locking plates in a cadaveric study, Gruber et al ( 21 ) reported peak loads in four-point bending of 110.8 and 120.4 N, respectively.…”

“…Due to their superelastic and shape memory characteristics, SMA staples have the ability elastically recover from large deformations, which may occur in vivo , imparting a dynamic compressive capability not possible in conventional mechanical staples. This has been demonstrated in a number of in vitro biomechanical studies which have reported that SMA staples generate a greater compression across a simulated osteotomy compared to mechanical staples ( 11 , 17 ), and resist permanent deformation, fully recovering their shape following loading ( 18 ).…”

Assessing the performance characteristics and clinical forces in simulated shape memory bone staple surgical procedure: The significance of SMA material model

“…For instance, there are varieties of Shape Memory Alloy (SMA) bone staples (ranging from "simple" to more "sophisticated" shapes) in the market for utilization. Different studies [5][6][7][8][9][10] have highlighted some of advantages achieved from using SMAs for design of medical devices over their traditional material counterparts. Moreover, newer (also known as "next generation") bone staples (making use of barbs, serration along the staple legs, etc.)…”

“…In particular, after judicious selection of a specific size and type of staple, a systematic numerical simulation could furnish surgeons with the pertinent information needed at each critical step in the "yet-to-beperformed" surgical operation [9]. Accurate prediction of the anticipated compressive stress/force and its variation with time will help to estimate the viable activation conditions needed for the effective application of a selected SMA bone staple device, viz.…”