Table 1.
Gait parameters assessed via CatWalk in the rodent models of arthritic disorders included in this review.
| Categories | Parameter | Explanation | References | Times assessed |
|---|---|---|---|---|
| I | Print Length (distance unit) | Length of the paw print | (32–39) | 8/41 (20%) |
| I | Print Width (distance unit) | Width of the paw print | (32, 33, 35–38) | 6/41 (15%) |
| I | Stride Length (distance unit) | Distance between two successive placements of the same paw | (32, 33, 35–38, 40–42) | 9/41 (22%) |
| I | Base of Support (distance unit) | Distance between hindpaws or forepaws | (37) | 1/41 (2%) |
| I | Print Area (distance unit2) | Area of the complete paw print | (32, 33, 35–38, 40, 42–53) | 19/41 (46%) |
| I | Maximum Print (Contact) Area (distance unit2) | Maximum area of the paw in contact with the glass floor | (35–38, 50, 53–55) | 8/41 (20%) |
| II | Total Paw Print Intensity (arbitrary units) | Total intensity of the paw print (Mean pixel intensity × number of pixels) | (56–62) | 7/41(17%) |
| II | Swing Time (seconds) | Duration of the swing phase of the paw | (35, 36, 40, 45, 50, 51, 63–65) | 9/41 (22%) |
| II | Stand Time (seconds) | Duration of the stand phase of the paw | (32, 33, 35, 36, 40, 42, 44, 45, 49, 51, 52, 66) | 12/41 (29%) |
| II | Duty Cycle (%) | Percentage of the stand phase in a step cycle: [Stance time/(Stance time + Swing time)] x 100 | (35–37, 40, 41, 43–46, 50, 52, 63, 64, 67, 68) | 15/41 (37%) |
| II | Mean Intensity (arbitrary units) | Mean intensity of the paw print | (34, 42, 45, 69–72)1,2,3 | 7/41 (17%) |
| II | Maximum Intensity (arbitrary units) | Maximum intensity of the paw print | (38, 42, 44, 53) | 4/41 (10%) |
| II | Mean Intensity at Maximum Contact (arbitrary units) | Mean intensity of the paw print at maximum contact of the paw | (33, 36, 40, 44, 48, 73, 74)4,5,6 | 7/41 (17%) |
| II | Maximum Intensity at Maximum Contact (arbitrary units) | Maximum intensity at maximum contact of the paw | (53, 66) | 2/41 (5%) |
| II | Arthritic Paw Load (%) | Weight load (area x pressure) distribution between ipsilateral and contralateral paws | (75) | 1/41 (2%) |
| II | Initial Contact Time (seconds) | Time from the start of the run to first contact of the paw with the glass plate | (35, 36) | 2/41 (5%) |
| II | Maximal Contact Time (seconds) | Time from the start of the run to maximum contact of the paw with the glass plate | (35, 36) | 2/41 (5%) |
| II | Anchor Paw Print Intensity ratio (%) | Calculated extent of anchor limb loading during walking | (65) | 1/41 (2%) |
| II | Target Paw print Intensity ratio (%) | Calculated extent of target limb loading during walking | (65) | 1/41 (2%) |
| II | (Dynamic) Weight bearing (arbitrary units) | Calculated force of a paw against the glass floor during walking, measured separately for all paws | (41, 52, 68) | 3/41 (7%) |
| II | (Dynamic) Weight Bearing (%) | Percent weight bearing of one paw relative to all four paws | (41, 52, 68) | 3/41 (7%) |
| II | (Dynamic) Guarding Index (%) | Difference in weight bearing (%) between the two hindpaws. Represents the shift in weight bearing between the two hindpaws. | (41, 52, 68) | 3/41 (7%) |
| III | Normal Step Sequence Patterns (NSSP) | Specific sequences of paw placements during a step cycle | (38) | 1/41 (2%) |
| III | Regularity Index (RI) (%) | Percentage of NSSP in the total number of paw placements (PP) | (37, 38, 40, 41, 46, 47, 49, 68) | 8/41 (20%) |
| III | Phase Lags / Phase Dispersions (%) | Temporal relationship between footfalls of two different paws within a step cycle. It relies the initial contact of one paw (the Target) to the stride cycle of another paw (the Anchor). | (37, 38, 52) | 3/41 (7%) |
| III | Phase Lag Variability (%) | Measure of the accuracy in the interlimb coordination | (37) | 1/41 (2%) |
| IV | Step Cycle (seconds) | Duration of Stand Time + Swing Time of a paw | (37) | 1/41 (2%) |
| IV | Print Positions/ Relative Paw Placements (distance unit) | Distance between the position of the hindpaw and the previously placed forepaw on the same side | (37, 38) | 2/41 (5%) |
| IV | Single Stance (seconds) | Duration of contact with the glass plate with only one paw | (51, 52) | 2/41 (5%) |
| IV | Swing Speed (centimeter /s) | Speed of the paw during the swing phase | (32, 33, 35–38, 40, 41, 43–45, 52, 54, 55, 63, 64) | 16/41 (39%) |
| IV | Run Duration (s) | Total duration of the walkway crossing | (32, 33, 42) | 3/41 (7%) |
| IV | Walking Speed/ Average Speed (centimeter/second) | Average speed during walkway crossing | (32, 33, 41, 45, 68) | 5/41 (12%) |
| IV | Stand Index (%) | Speed at which the paw loses contact with the floor | (35, 36) | 2/41 (5%) |
| IV | Paw Angle* (degrees) | Angle of the paw long axis against the horizontal plane | (35) | 1/41 (2%) |
| IV | Paw Angle Movement Vector (degrees) | Angle between paw long axis and walking direction | (36) | 1/41 (2%) |
| IV | Limb Idleness Index (LII) (%) | Index for OA associated pain, product of anchor and target print as well as swing time ratio | (65, 76) | 2/41 (5%) |
I: General, II: Pain-related, III: Coordination-related, IV: Other.
Note that the table does not include all parameters assessable via CW, but all of these which have been assessed by the researchers whose studies are included in this work. We excluded two studies which only listed significantly altered CW parameters but did not report all gait parameters which were analyzed (69, 77). Percentages presented are rounded.
Fouasson-Chailloux et al. (45): described as Paw Print Intensity in the study, not further specified, therefore assumed to be Mean Intensity.
Zahoor et al. (36): described as intensity, not further specified, therefore assumed to be Mean Intensity.
Fang et al. (73): described as Paw Intensity, not further specified, calculated as Log (Paw Intensity/weight), assigned to Mean Intensity.
Zahoor et al. (35): described as Paw Print Intensity in the study, not further specified, therefore assumed to be Mean Intensity at Max Contact.
Caglar et al. (32): described as Maximum Contact Intensity (%), not further specified, therefore assigned to Mean Intensity at Max Contact.
Kara et al. (33): described as Maximum Contact Intensity (%), not further specified, therefore assigned to Mean Intensity at Max Contact.
*Paw Angle against the horizontal plane can be assumed as both Paw Angle Movement Vector or Paw Angle Body Axis, not further specified.