Biomechanical Measurement Error Can Be Caused by Fujifilm Thickness: A Theoretical, Experimental, and Computational Analysis

Abstract

This is the first study to quantify the measurement error due to the physical thickness of Fujifilm for several material combinations relevant to orthopaedics. Theoretical and experimental analyses were conducted for cylinder-on-flat indentation over a series of forces (750 and 3000 N), cylinder diameters (0 to 80 mm), and material combinations (metal-on-metal, MOM; metal-on-polymer, MOP; metal-on-bone, MOB). For the scenario without Fujifilm, classic Hertzian theory predicted the true line-type contact width as WO = {(8FDcyl)/(πLcyl)[(1 − νcyl2)/Ecyl + (1 − νflat2)/Eflat]}1/2, where F is compressive force, Dcyl is cylinder diameter, Lcyl is cylinder length, νcyl and νflat are cylinder and flat Poisson's ratios, and Ecyl and Eflat are cylinder and flat elastic moduli. For the scenario with Fujifilm, experimental measurements resulted in contact widths of WF = 0.1778 × F0.2273 × D0.2936 for MOM tests, WF = 0.0449 × F0.4664 × D0.4201 for MOP tests, and WF = 0.1647 × F0.2397 × D0.3394 for MOB tests, where F is compressive force and D is cylinder diameter. Fujifilm thickness error ratio WF/WO showed a nonlinear decrease versus cylinder diameter, whilst error graphs shifted down as force increased. Computational finite element analysis for several test cases agreed with theoretical and experimental data, respectively, to within 3.3% and 1.4%. Despite its wide use, Fujifilm's measurement errors must be kept in mind when employed in orthopaedic biomechanics research.

Experimental Methods for Studying the Contact Mechanics of Joints

“…To date, most of these comparative investigations have been focused on Fujifilm or Tekscan. For instance, Fujifilm has been compared to Tekscan [10,25,31,36], castings [21,22,39], dyes [22,39], e-coating [35], proximity [39], ultrasound [19], Hertzian theory [31], and finite element models [28,29,31,33]. Similarly, several studies compared Tekscan vs. a mechanical tester's load cell [36], a Hertzian solution [7], and a finite element model [7], as well as a Tekscan system with lower vs. higher resolution [48].…”

“…Fujifilm. This device is made of 2 thin flexible films made of polyester, namely, a transfer film that has surface microcapsules of 2 to 26 μm diameter and a developer film (Figure 2(a) and Table 1) [6,8,10,19,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. This is the most commonly used mechanochemical method for studying the contact mechanics of joints.…”

Evaluation of the contact surface between vertebral endplate and 3D printed patient-specific cage vs commercial cage

“…Nonetheless, there are limitations to this study. First, pressure-sensitive films are widely used for orthopedic biomechanics research, but they have several limitations related to handling, image processing, temperature and moisture sensitivity, and pressure thresholding 19 . For this study, an "Ultra super low" Fujifilm was used, and the pressure range was from 0.19 to 0.6 MPa.…”

Finite Element Analysis of Contact Stress Distribution on Insert Conformity Design of Total Knee Arthroplasty

“…Previous studies revealed the accuracy of Fuji film techniques assessed the contact stress distribution of the TKA displayed in a range of 6 % to 36% [30], [33]. Although the Fujifilm technique was variable, the significant advantage has been reviewed numerous times and is satisfied with various applications [34]. The FE analysis using computer simulation is a beneficial and widely accepted tool, especially varied conditions and investigated outcomes in biomedical applications.…”