Page 180 - Adams and Stashak's Lameness in Horses, 7th Edition

146 Chapter 2

Front Front
VetBooks.ir Secondary Secondary 1°

LF RF LF RF

Secondary 1° Secondary

LH RH LH RH
Hind Hind
A B
Figure 2.134. Suspected secondary lameness patterns. (A) lameness will equally frequently overload the opposite forelimb
Primary hindlimb lameness will most frequently overload opposite and/or the opposite hindlimb, but infrequently overload the
forelimb, less frequently overload the opposite hindlimb, and opposite forelimb.
infrequently overload the ipsilateral forelimb. (B) Primary forelimb

Quantification of Asymmetry Quantification of Asymmetry
Stride Rate: 1.4 Strides Assessed (fore/hind): 23/22 Stride Rate: 1.5 Strides Assessed (fore/hind): 23/23
Forelimb Strides Hindlimb Strides Forelimb Strides Hindlimb Strides
60 –30 Left Hind Lameness Right Hind Lameness 30 60 –30 Left Hind Lameness Right Hind Lameness 30
Pushoff Pushoff Pushoff Pushoff
Right Fore Lameness Right Fore Lameness
40 Midstance –20 20 40 Midstance –20 20
Pushoff Impact – Diff Max (mm) + Diff Max (mm) Pushoff Impact – Diff Max (mm)
20 –10 10 20 –10 10
Diff Min (mm) 0 0 0 Diff Min (mm) 0 0 0

–20 –10 10 –20 –10 10
Pushoff Impact Pushoff
Impact
–40 – Diff Min (mm) + Diff Min (mm) –40 – Diff Min (mm)
Midstance –20 20 Midstance –20 20
Left Fore Lameness Left Fore Lameness
Impact Impact Impact Impact
–60 –30 30 –60 –30 30
–60 –40 –20 0 20 40 60 0 5 10 15 20 0 5 10 15 20 –60 –40 –20 0 20 40 60 0 5 10 15 20 0 5 10 15 20
Diff Max (mm) Stride Stride Diff Max (mm) Stride Stride
Lameness Metrics Lameness Metrics
Thresholds for Max/Min Head: ±6 mm Thresholds for Max/Min Pelvis: ±3 mm Thresholds for Max/Min Head: ±6 mm Thresholds for Max/Min Pelvis: ±3 mm
Diff Max Head: Mean: 14.1 mm SD: 13.2 mm Diff Max Pelvis: Mean: 6.8 mm SD: 3.1 mm Diff Max Head: Mean: –21.6 mm SD: 11.1 mm Diff Max Pelvis: Mean: –9.4 mm SD: 2.7 mm
Diff Min Head: Mean: 8.6 mm SD: 11.5 mm Diff Min Pelvis: Mean: 4.4 mm SD: 3.8 mm Diff Min Head: Mean: –19.7 mm SD: 6.2 mm Diff Min Pelvis: Mean: –14.2 mm SD: 4.1 mm
Threshold for Total Diff Head: 8.5 mm Threshold for Total Diff Head: 8.5 mm
Total Diff Head (Vector Sum): 16.6 mm Total Diff Head (Vector Sum): 29.2 mm
Q Score (fore): R 16.6 Imp Q Score (hind): R 6.8 Push / R 4.4 Imp Q Score (fore): L 29.2 Imp Q Score (hind): L 9.4 Push / L 14.2 Imp
Figure 2.135. Lameness Locator® reports of multiple limb lameness. Both are examples of first part of the law of sides, which
lameness. Left report: Right hindlimb pushoff and impact lameness is primary hindlimb lameness with compensatory (false) ipsilateral
and ipsilateral (right) forelimb lameness. Right report: Left hindlimb forelimb lameness.
pushoff and impact lameness and ipsilateral (left) forelimb
In about 700 horses measured with multiple limb hindlimb lameness and compensatory forelimb lame­
lameness, this was the second most common type, ness (the first principle in the “law of sides”). Horses
occurring in about 19% of all initial evaluations of with this type of multiple limb lameness had a (62%)
multiple limb cases. The simplest explanation of this definitive diagnostic rate, but with 66% ultimately
type of multiple limb lameness is primary hindlimb determined to have only a hindlimb diagnosis and
lameness with compensatory forelimb lameness (the another 20% having both a hindlimb and a forelimb
first principle in the “law of sides”). Horses with this diagnosis. Only 11% ultimately were diagnosed with
type of multiple limb lameness had a high definitive a primary forelimb lameness.
diagnostic rate (82%) with 73% ultimately deter­ 3. Forelimb lameness with ipsilateral hindlimb lame­
mined to have only a hindlimb diagnosis and another ness that is only decreased impact (Figure 2.137).
14% having diagnoses in both hindlimb and front This type was uncommon, occurring in less than
limb. Less than 11% ultimately were diagnosed with 10% of all multiple limb lameness cases. Equally
primary forelimb disease/abnormality. legitimate explanations for this type of multiple limb
2. Forelimb lameness with ipsilateral hindlimb lame­ lameness are primary hindlimb lameness with com­
ness that is only decreased pushoff (Figure 2.136). pensatory forelimb lameness, and vice versa, or pri­
This type was seen in about 10% of all cases of mary forelimb lameness with compensatory hindlimb
multiple limb lameness. The simplest explanation of lameness. This type of multiple limb lameness had a
this type of multiple limb lameness is primary 78% definitive diagnosis rate, but 4% had only a