Alternative Trimming Methods. Caldwell & Paricio

Transcription

1 Alternative Trimming Methods Caldwell & Paricio

2 Trimming and Shoeing the Equine Hoof a Challenge

3 Aim link foot trimming to anatomy & bio-mechanical function Courtesy of Mike Savoldi

4 Aim link external points of reference to internal anatomy VERTICLE DEPTH HEEL TOE RATIO 3;1 FD 10 13mm Insertion CDET Force vector HWD 15-17mm COP Centre of Pressure COR Insertion DDFT Point of Frog Centre of Rotation CD 15-17mm Longitudinal force HEEL TOE RATIO 3;1 CD Illustrations; M. Taylor CJF

5 Aim The importance to farriers of accurate in the field anatomical referencing Trimming Accurate & shoe Shoe placement Selection Guide Shoe selection fabrication & based application anatomical orientation

6 Learning outcomes - How to trim a horse? Dynamic-functional references Individual-natural references Static geometric references

7 Learning outcomes - How to trim a horse? Hoof geometry as a predictive indicator of pathology Bio mechanics of the hoof under load Basic foot trimming techniques for dynamic balance and performance horse shoeing.

8 How to trim a horse? Considerations Anatomical Biomechanical Body And Limb Conformation + Axial Alterations The Hoof Capsule Shape, Proportion, Marks Initial Contact + Landing Load During The Mid-stance Phase Lever Arm + Dorsal Breakover Devices And Provocation Tests Diagnosis Symptoms

9 Anatomical Considerations P1 CHL DHW EP P2 CB P3 DL DS SOLEAR ARCH HB / DC Illustrations; M. Taylor CJF

10 Anatomical Considerations Illustrations; M. Taylor; A. Parks

11 Anatomical Considerations Illustrations; M. Taylor CJF

12 Anatomical Considerations Illustrations; M. Taylor; C. PolIitt; J. Rooney; R. Bowker

13 Anatomical Considerations Illustrations; M. Taylor; C. Pollitt

14 Biomechanical Considerations The Hoof Is An Inverted Cone

15 Hoof Mechanism Biomechanical Considerations

16 Biomechanical Considerations Mechanical Properties of Horn Courtesy of J. Reilly Courtesy of A. Parks Adapted from Kasapi

17 Biomechanical Considerations Mechanical Properties of Horn Courtesy of J. Reilly

18 Biomechanical Considerations Spatial dimension Geometry describes every point in threedimensional space with three axis & six coordinates. Each axis is perpendicular to the other two They are usually labelled x, y, and z Newton's law of motion Force is subject to a reaction equal in magnitude and direction

19 Biomechanical Considerations Force = Mass x Acceleration (9.8 metre per second) C.O.M Centre of mass Action force Remote Action force CoM Action force Remote Action force CoM Lever Arm = torque Lever Arm = torque Action force through bone to bone contact Remote action force (gravitational pull at CoM)

20 Trimming and Shoeing the Equine Hoof a Challenge

21 Static Geometric References How to trim a horse? Dynamic Functional References Individual Natural References Zehenlänge = 7,6 8,9 cm Vorder-:Trachtenwand = 3 (2) : 1 parallel Huf passend zum Fesselstand Hoof Pastern Axis Theory Theory of the Heel Length Relation T-Square Method Strasser Method Footing Theory dorsal Breakover Dorsal, palmar, mediolateral Lever Arm 4-Point Trim Natural Balance Trim/ Natural Hoof Care Universal Sole Thickness Savoldi F-Balance Method Methode of the DHG

22 How to trim a horse? Dynamic-functional References Individual-natural References Static geometric References

23 How to trim a horse? Static References

24 How to trim a horse? Static References Toe Axis Theory Straight Toe Axis From The Frontal And The Side = Optimal Load Of The Coffin -, Pastern- And Fetlock Joint = Plane Footing And Ideal Gait Pattern Pastern Axis Theory 3 Reference Lines - Pastern Line (= Frontal) - Toe Line (= From The Side) - Metacarpal Line (= From The Back) = No Relationship With The Footing Vertical Axis Parallel To The Body Axis Parallel Coronary Band And Weight Bearing Margin + Perpendicular To The Axis

25 How to trim a horse? Static References Mechanical Implications High Correlation between the hoof angle and the palmar angle

26 How to trim a horse? Static References Mechanical Implications Increasing Lever Arms Decreasing Loaded Area Palmar Shift Of The CoP?

27 Biomechanical Effects of Toe Conformation

28 Impact Of Biomechanical Load

29 Is There A Model

30 Is There A Model - Traditional Farriery Teaching Static-geometric Model The Hoof Capsule Shape, Proportions and Marks The Hoof In Numbers And Angles

31 Traditional Farriery Teaching Static-geometric Model Balch Et Al. 1997: Guidelines For Hoof Length Based On The Weight Of The Horse Horse Weight Toe Length Horse Size Kg Cm Small Medium Large Dorsal Toe Length = 7,6 8,9 Cm Heels: Dorsal Toe = 3 (2) : 1 + Parallel

32 Is There A Model - Geometric Proportions Model (Duckett 1989) Duckett s Dot & Bridge (1989) Courtesy of Dave Duckett FWCF Key words; Proportions & Joint Congruency

33 Is There A Model - Geometric Proportions Model (Duckett 1989) Equivalence of Hoof Proportions Duckett (1990)

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35 Is There A Model Feral Horse Model (Jackson 1991)

36 Is There A Model Natural Balance Model (Jackson 91. Ovnicek 93, 95, 2003)

37 Is There A Model Natural Balance Proportions Model (Ovnicek 1993)

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39 Is There A Model Peer Reviewed Evidence (Hampson et al 2011, 2013) Hampson et al 2010; 2011 &2013 the influence of environment Study:- The left forefeet collected from 100 adult feral horses from five geographicallyseparated populations selected on the basis of substrate hardness under foot

40 Is There A Model Peer Reviewed Evidence (Hampson et al 2011, 2013) Conclusion:- No Single Feral Horse Foot Model Exists Evidence feral horses were subject similar pathologies as domestic horses No clear evidence to suggest that the feral horse foot model would offer any advantage

41 Kummer et al 2006 Study: The influence of farriery on the Perfect Hoof model Front hooves of 40 Warmblood horses were radiographed at eight weeks pre and post trimming. 22 lateromedial and 16 parameters on the dorsopalmar view were measured and the effect of hoof trimming calculated. Conclusion trimming affects the orientation of P3 within the hoof capsule

42 Kummer et al 2007 Study: The influence of farriery on the Perfect Hoof model Study: 6 different farriers trimmed 40 Warm blood on 6 occasions Courtesy of Mark Aitkens & the Flying Anvil Foundation Results: significant differences between farriers significant difference between each repetition of the same farrier

43 A test of the universal applicability of a commonly used principle of hoof balance Mark N. Caldwell a, b, Lorraine A. Allan a, Gina L. Pinchbeck c, Peter D. Clegg b, Katherine E. Kissick a and Peter I. Milner b* We Investigated The Use Of A Standardised Method Of Hoof Trimming Using A Mapping Protocol To Locate The Vertical Position Of The Centre Of Rotation Of The Distal Interphalangeal Joint and the dorsodistal tip of P3.

44 A test of the universal applicability of a commonly used principle of hoof balance Aim;- to assess the accuracy of pre- and post-trimmed hoof proportions for foot balance indicators, advocated by others

45 A test of the universal applicability of a commonly used principle of hoof balance A standardised trimming technique, Digital photography & foot mapping Pre-post trim data collection (external markers)

46 A test of the universal applicability of a commonly used principle of hoof balance The standardised Horizontal Hoof Plane trimming protocol allows the consistent reproduction of proportional measurement data

47 A test of the universal applicability of a commonly used principle of hoof balance Hoof Mapping Briefly, this is a grid or a series of lines that can be drawn on the shod or unshod foot. 1. The point through the middle of the horizontal line at the toe will correspond to the dorsodistal margin of the distal phalanx 2. The point where the diagonal lines meet will correspond to the COR. Holes drilled through these points in a cadaver Dr. S. O Grady foot 2014 and then dissected will confirm.

48 A test of the universal applicability of a commonly used principle of hoof balance Radiographic validation of hoof balance indicators Purpose built leg press (pneumatic) up to 120psi 90 intersection marked on floor X-ray head and stand. Head was fixed in position once set and the stand was rotated through 90

49 post trim validation measure / post trim SL percentage of sagittal length ф heel bulb A test of the universal applicability of a commonly used principle of hoof balance Results Trimming Validation Measures pre & post trim proportions of sagittal length cor / sl cop / sl fra / sl bo / sl dhwl / bbl external anatomical reference point post trim pre trim post trim cadaver foot 1-49 cor / sl cop / sl fra / sl bo / sl 86% 72% 64% 50%

50 DHWL adjusted A test of the universal applicability of a commonly used principle of hoof balance Results Duckett s Dot & Centre of Rotation Regression 95% CI S R-Sq 86.7% R-Sq(adj) 85.3% COR-DIPJ

51 A test of the universal applicability of a commonly used principle of hoof balance Results Duckett s Dot & Centre of Rotation Comparisons (post trim) Adjusted Difference Significance P value CoR 1.67± 2.02 P=0.12 Duckett s Dot -6.44± 6.80 P<0.01 Courtesy M. Savoldi & M. Craig

52 Hoof Trimming - Dynamic Approaches Plane Footing = Equal Distribution Of The Forces Effecting The Hoof During The Landing (Footing) (Emery Et. Al. 1977) All Parts Of The Weight Bearing Margin Shell Contact The Ground At The Same Time Minimize The Negativ Impact Effect During The Landing Phase Part Of The Wall With First Contact = To Long Shorten (Mostly The Steeper Wall) Part Of The Wall With The First Contact = To Short Shorten Of The Opposit Side (Stashak 1989) Load During The Main Stance Phase???

53 Influence of Trimming on Dynamics

54 Hoof Trimming - Dynamic Approaches Lever Arm And Dorsal Breakover +

55 Dorsopalmar Pressure Distribution - Dynamics Stance Walk Trott

56 Hoof Trimming - Dynamic Approaches Time / energy

57 Trimming Protocol: Object weight bearing concentric to the DIPJ

58 Questions +