Evaluation of a pressure plate for detection of hind limb lameness in cats

Abstract

Detection of lameness in cats can be very time-consuming and frustrating. Feline studies have shown that the success of treatment can be evaluated by measurement of the ground reaction force (GRF). However, the possibility of multiple limb involvement or the presence of a compensatory mechanism has not been investigated. Furthermore, there has been no research in cats on possible differences in GRFs between those with stifle problems and those with hip problems, as reported in dogs. In this study, we compared temporospatial parameters and GRFs in 20 lame cats after femoral head and neck ostectomy (FHO) or stifle disease to those in 15 healthy cats. An orthopedic examination was performed in all cats and radiographs were obtained to confirm the disease. GRFs, including peak vertical force (PFz), vertical impulse (IFz), time to PFz, and temporospatial parameters, including step length, paw contact area, and stance phase duration, were calculated. We also calculated the symmetry index (SI) in the forelimbs and hind limbs. The GRFs were normalized to total force (% TF). We found that the IFz (% TF) and PFz (% TF) were lower in the affected limb than in the other limbs in the lame cats. When the lame cats were compared with the sound cats, this difference was only significant for IFz (% TF). The SI values for the PFz and IFz were significantly higher in the hind limbs than in the forelimbs in the lame cats group but there was no difference in the SI according to whether the problem was in the hip or stifle. There were also differences in stance phase duration and paw contact area in both the forelimbs and hind limbs between the sound group and the lame group. There was no difference in PF Z (% TF) or IF Z (% TF) in the affected limb between the lame cats with stifle and those after FHO; however, there were changes in time to PFz and step length. In conclusion, mild to moderate lameness can be detected and measured in cats using pressure plates. The compensatory mechanisms in cats at a walk appear to involve shifting the weight to the other three legs without favoring either the contralateral or the diagonal limb.

Measurement of ground reaction forces in cats 1 year after femoral head and neck ostectomy

“…This finding has also been described in a recent study, where the SI(IFz) in the hindlimb was always higher in a group of lame cats than in a group of sound cats. 28 Additionally, we saw that there was a positive correlation between the age at the time of surgery and the SI in the forelimb. It seems that the older the cats were at the time of surgery, the less equal the distribution of forces were over the other three legs at least 1 year after the surgery; these cats were also more likely to compensate for the change in the hindlimbs by using their forelimbs.…”

“…Nevertheless, we think that this fact is clinically relevant, as it is well known that orthopaedic examinations can overlook gait abnormalities, while GRF measurements can detect low-grade hindlimb lameness in cats. 28…”

Changes in Ground Reaction Forces and Center of Pressure Parameters of Paws When Wearing Dog Boots in Dogs

“…For both parameters, a symmetry index was calculated to describe the percent degree of deviation from symmetry in the front and hind limbs (10). The formula is given here based on an example for the calculation of IFz modified from Budsberg et al (33):…”

“…Several methods are applicable for studying motion sequences. One of them is the measurement of the so-called ground reaction forces, where participants walk and trot over force ( 7 , 8 ) or pressure plates ( 9 , 10 ). Force plates directly measure the acting forces in newtons (N), and these generated forces describe the summation of those that act on the limbs during the stance phase, and are divided into vertical, craniocaudal, and mediolateral forces.…”

Ground Reaction Forces and Center of Pressure within the Paws When Stepping over Obstacles in Dogs

“…It provides objective data on the forces created between the limb and the ground during the stance phase, in a noninvasive manner. It has been used as a method of normal movement assessment in various healthy animals [15][16][17][18], as an objective diagnostic tool for lameness [19,20], and to evaluate various treatments [21][22][23][24]. Many parameters can be obtained during a gait analysis, including peak vertical force (PFz), which is the maximum force exerted in the vertical direction, vertical impulse (IFz), which is the area under the force-time curve that takes into account the force and contact time [25], and the time to PFz, which is the time during the stance phase where PFz is reached (TPFz), for each limb [25,26].…”