Use of Tekscan K-Scan Sensors for Retropatellar Pressure Measurement Avoiding Errors during Implantation and the Effects of Shear Forces on the Measurement Precision

Table 2

Percentage decrease of the measured retropatellar parameters in 12 consecutive measurement cycles without changing the experimental setup.

	Torque 30 Nm
	Cyclus 1	Cyclus 2	Cyclus 3	Cyclus 7	Cyclus 8	Cyclus 9
Force	0%	−1.6% ± 1.3	−3.3% ± 1.4	−9.5% ± 4.7	−10.6% ± 4.1	−12.3% ± 3.9
Area	0%	−0.7% ± 1.0	−1.5% ± 0.9	−5.9% ± 4.2	−6.2% ± 3.4	−7.6% ± 2.9
Pressure	0%	−1.0% ± 0.7	−1.8% ± 1.0	−3.8% ± 2.1	−4.6% ± 2.0	−5.0% ± 2.1
Max. force	0%	−1.2% ± 1.0	−2.2% ± 1.3	−3.8% ± 2.2	−4.5% ± 2.4	−5.1% ± 2.4
Max. pressure	0%	−1.1% ± 0.9	−2.1% ± 1.2	−3.8% ± 2.2	−4.4% ± 2.4	−5.0% ± 2.4
	Torque 40 Nm
	Cyclus 4	Cyclus 5	Cyclus 6	Cyclus 10	Cyclus 11	Cyclus 12
Force	0%	−0.8% ± 1.0	−2.6% ± 1.9	−8.1% ± 3.1	−8.7% ± 1.8	−10.1% ± 3.1
Area	0%	−0.7% ± 0.9	−1.8% ± 2.1	−4.2% ± 2.4	−5.2% ± 2.3	−6.2% ± 1.7
Pressure	0%	−0.2% ± 0.8	−1.0% ± 0.8	−3.7% ± 2.2	−3.8% ± 1.8	−4.5% ± 2.6
Max. force	0%	−0.3% ± 1.7	−1.2% ± 2.1	−2.8% ± 1.4	−3.5% ± 1.9	−4.2% ± 2.9
Max. pressure	0%	−0.3% ± 1.6	−1.2% ± 2.1	−2.8% ± 1.4	−3.4% ± 1.9	−4.2% ± 2.9