Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

Table 1

Average and standard deviation of the torsion axis location in the inferosuperior and mediolateral directions for the data without and with error (and different cut-off angles); 𝑃 value of comparison to data without error and combined 𝑃 value of location in 𝑦 and 𝑧 (based on Fisher’s combined probability); (number) in first column represents amount of samples included in analysis.

	Location in inferosuperior direction [mm]	Location in mediolateral direction [mm]	Fisher’s combined probability
No error	−25.45±0.00	3.05±0.00
Cut-off 0° (300)	−45.10±320.03	7.70±66.98
𝑃 value	0.29	0.23	0.25
Cut-off 1° (296)	−29.59±134.83	3.22±45.50
𝑃 value	0.60	0.95	0.89
Cut-off 2° (282)	−23.41±61.24	4.81±32.66
𝑃 value	0.58	0.37	0.54
Cut-off 3° (263)	−26.18±45.00	4.24±28.41
𝑃 value	0.79	0.50	0.76
Cut-off 4° (244)	−24.41±43.49	5.41±25.47
𝑃 value	0.71	0.15	0.34
Cut-off 5° (224)	−25.19±13.69	4.22±23.16
𝑃 value	0.78	0.45	0.72
Cut-off 6° (197)	−25.28±11.49	3.48±19.55
𝑃 value	0.83	0.76	0.92
Cut-off 7° (179)	−25.60±10.14	2.94±18.44
𝑃 value	0.84	0.94	0.98
Cut-off 8° (162)	−25.60±9.54	3.45±17.39
𝑃 value	0.84	0.77	0.93
Cut-off 9° (139)	−25.47±9.45	2.40±16.08
𝑃 value	0.98	0.63	0.92
Cut-off 10° (119)	−25.17±8.16	1.09±15.73
𝑃 value	0.71	0.18	0.38