the less than obvious lameness and the horse that travel unevenly dr. olivier simon, dmv diplomate...

EHPC- The University of Adelaideadelaide.edu.au

Olivier Simon, DMVDiplomate ECVS

The less than obvious lameness and the horse

that travel unevenly

Northern Horse Forum – Roseworthy 20/04/2017


Facts

• Lameness is one of the major causes of poorperfomance in (any level of) horse sport

• It has a major impact on finance and enjoyment

• Horses are not able to speak our language

• Not all lamenesses are foot abscesses


What do we consider as lameness?

• Any gait or stance abnormality resulting in asymmetry

• Includes:– Shifting body weight - Head nodding

– Unloading - Hip hikes

– Relieve - Hip dips

– Alleviate

– Drifting

– Dragging

– Falling on one leg


What do we consider as lameness?

• Any gait or stance abnormality resulting in asymmetry

• Includes:– Shifting body weight - Head nodding

– Unloading - Hip hikes

– Relieve - Hip dips = LAMENESS

– Alleviate

– Drifting

– Dragging

– Falling on one leg


Semi-quantitative

• AAEP (5 grades) lameness scale– Grade 0: not perceptible under any circumstances– Grade 1: Difficult to observe and not consistently

apparent regardless of the circumstances– Grade 2: Difficult to observe at a walk or when

trotting on straight line but consistently apparent under certain circumstances

– Grade 3: Consistently observable at at trot under all circumstances

– Grade 4: Obvious at a walk– Grade 5: minimal weight bearing in motion or at

rest/complete inability to move


Semi-quantitative / subjective

• AAEP (5 grades) lameness scale– Grade 0: not perceptible under any circumstances– Grade 1: Difficult to observe and not consistently

apparent regardless of the circumstances– Grade 2: Difficult to observe at a walk or when

trotting on straight line but consistently apparent under certain circumstances

– Grade 3: Consistently observable at a trot under all circumstances

– Grade 4: Obvious at a walk– Grade 5: minimal weight bearing in motion or at

rest/complete inability to move


Other scales

• 1 to 8 (UK)

• 1 to 10 (F)

– Matter of subjectivity

– « Arts » of practice

>>> variability and disagreement => risk of multi-consultations


Other classic complains aroundlocomotor system

• Poor lateral translations

• Poor extensions

• Cross galloping

• Bunny hoping / poor dissociation at the gallop


Typical stages of a lamenessexamination

• Is the horse actually lame?

• From which leg(s) is the horse lame?

• Which segment of the localized leg(s) is the source of lameness?

• What is the nature of the lesion of the particularregion of the lame leg(s)?

• What is the treatment?

• What is the prognosis?

• What are the costs?


Classic assessment

• Observation with naked eye


Classic assessment


• Qualitative


Classic assessment


• Qualitative

• Semi-quantitative (scales)


Classic assessment


• Qualitative

• Semi-quantitative (scales)

• At a trot (most of the time)


Why examining horses at a trot?

• Only symmetric natural gait of the horse

– Two symmetric impact « times » with an intermediate gliding (suspension) time

Lameness is by definition asymmetry


Limitations of this classic approach

• Naked eye have a reduced sampling capacity– about 10 samples/seconds vs min.200 s/s for

videocamera recorder

• Multiple lamenesses– Primary and secundary lameness– Primary and compensatory lameness

• Hind limb lameness is always more difficult to assess

• What about gaited horses?• What about axial skelettal (« back ») injuries?


Limitations of « naked eye » exam

• Need of objective gait / lameness evaluationmodalities

– No or less bias

– More sensitive : higher data sampling capacity

– Repeatable

– Quantitative


Objective evaluation of lameness types

• Kinetic technique: study of the forces thatproduces or are produced by the movement

• Kinematic : descriptive analysis and quantification of the movement

• Electromyography: mesurement of the muscular activity during movement

UC Davis, Ca



• Kinetic technique: – Stationary force plate: measures vertical, horizontal

and transverse forces

Lameness generally => decrease in vertical forces

UC Davis, Ca



• Kinetic technique alternatives:

– Pressure mats and « in-shoe » systems

• Not durable not as repeatable as force plate

– Force measuring horse shoes

• None commercially available

– Force measuring treadmill

• One-of-a-kind U. Zurich


Kinematic

Eadwaerd Muybridge 18th century


Eadwaerd Muybridge Sally Gardner at at Gallop 1878


Modern motion capture systems

Qualisys AB, Göteborg Sweden


Combination of kinetic and kinematic


Body-mounted inertial sensors

• Giroscopic sensors (1 – 3 – 8 – 18) attached to the horse’s body and wireless transmittingdatas to evaluator

• Multiple systems on the market allowing use in natural environment


Equimetrix®


Equusys®


Equinosys® Lameness Locator®


Lameness Locator®


Clinical case

• 10 years old riding poney mare

• Pleasure riding

• Was operated 1 year before for OC RF fetlock

• Lost of condition

• Locking movement right hind downhill


Clinical case


Flexion test


Local anaesthesia DBLPN LH


Local anaesthesia DBLPN RH


Conclusion

• Subtle lameness evaluation can be very tricky

• Subjective qualitative evaluation alone is toolimited

• Objective kinematic systems commerciallyavailable BUT have also some limits

– They can not substitute practitionner

– Bilateral symmetric lameness

– Back and neck problems

the less than obvious lameness and the horse that travel unevenly dr. olivier simon, dmv diplomate...

Education