Background & Objectives:
Patient and Observer Scar Assessment Scale (POSAS) and Cutometer® are the most frequently used assessment tools to investigate pliability of burn scars. 
We aimed to explore the correlations between the subjective POSAS pliability items and the objective (visco-) elastic properties of scarred skin measured with the Cutometer®. These results could provide information necessary to determine minimal clinically important differences (MCID) for POSAS pliability items and Cutometer®. 
Methods: 
Twenty patients with burn (n=17) or surgical (n=3) scars, scars ranging between 3 and 24 months from date of injury, were recruited at OSCARE in Antwerp, Belgium. Fifty-eight scars on the trunk or extremities were selected. Measurements were repeated at one month (T1) and two months (T2) following the initial measurement (T0). 
Patients completed the POSAS-P (stiffness item), whilst observers assessed pliability using POSAS-O and the maximum amplitude (R0 or Uf) of Cutometer® (350 mbar vacuum load, aperture 8 mm). 
Results:
Twenty patients (11 men and 9 women) with a mean age of 36 years old and scars with a median scar age at T0 of 8 months old are included. 
Correlations between POSAS-P-stiffness, POSAS-O-pliability and Cutometer® R0  are presented (table).
When correlating the POSAS-O-pliability scores with the R0 Cutometer® values, a downwards trend is shown (figure).
Discussion:
The Cutometer® is a valid instrument for measuring the pliability characteristic, as the R0 parameter correlates significantly with both the  observer- (r=-0.597) and patient-reported (r=-0.358) scores. A cut-off of ≥ 0.3 has been stipulated for selection of a valid anchor. However, the latter correlation (r=-0.358) is rather low, probably due to the discrepancy between the procedure to assess stiffness in POSAS-P (without explanatory notes) and the working mechanism of the Cutometer® (vertical deformation).
The significant but imperfect correlation (r=0.443) between the observer- and patient-reported pliability scores suggests that observers and patients do not perceive pliability in the same way. A difference in the assessment protocol (pliability vs. stiffness) for the observer and the patient could explain this.
The presence of ‘levels’ of change suggests that observers can distinguish between ‘levels’ of severity, but the differences between certain scores appears arbitrary. 
Conclusion:
Based on the correlations, the Cutometer® is a valid instrument for measuring the characteristic of pliability when using the R0 parameter, and can serve as an anchor to determine the MCID for POSAS pliability.

Correlation of pliability with (Visco-) elastic properties of burn scars