Please cite any peer-reviewed source that suggests "poor hoof form" causes poor (impaired?) circulation within the hoof capsule (i.e., from PDA to PDV).
EQUINE DIGITAL VENOGRAM IN RELATION TO THE BIOMECHANICS
OF THE FOOT
Lorenzo D’Arpe Med Vet*, Luigi Michele Coppola Med Vet *, Prof. Daniele Bernardini*,
Stefano Masiero Med Vet#.
* Dipartimento di Scienze Cliniche Veterinarie, Università di Padova (Italia)
# Libero professionista, Vicenza.
Introduction. There are many existing scientific studies on centre of pressure or mass in the equine
foot; many techniques and instruments have been used in these studies (Xu H et al. 1999, Arabian
AK et al. 2001 and Leveillard D. 2005) and this has helped to understand biomechanics and dynamic
effects on gait analysis related to trim and shoeing (Willemen et al. 1996, Wilson AM et al.
1998, Xu H et al. 1999, Van Heel MC et al. 2004, Van Heel MC et al. 2005).
Many studies have been oriented to evaluate the relationship between the body weight load and
anatomical changes of the foot (Crevier-Denoix N et al. 2001, Hobbs SJ et al. 2004, Burn JF et al.
2001, Colles CM et al. 1989 and Redden RF. 2003).
Olivier A et al. (1989) underlined the effect of weight loading on the coronary band and interstitial
fluid pressure in horses.
Pietra M et al. (2004) highlighted the influence of weight bearing on Doppler evaluation of lateral
palmar digital arteries in healthy horses.
The aim of this research is the visualization of fine detailed variations of vascular bed utilizing digital
venography and the relationship to the biomechanical effects of changing the Palmar Angle (PA)
to the ground line and weight-bearing position.
Materials and methods. The X-ray examinations were performed at Veterinary Clinical Sciences
Dep. of Padua, on thoroughly cleaned unshod feet of six horses not referred for foot problems, 3
chronic sub-clinical laminitis and 3 sound, the horses were aged between 5 and 14 years, body
weight between 400 and 550 kg.
We used a wood-iron podoblock specially designed and realized with Moreau X. (height 8,9 cm,
length 16,4 cm, with 16,4 cm, able to change PA between –15° and +15° with a step every 5°), it
was placed under the weight bearing frontfoot and radiographed with principal tubulus corneus
(Caudron I. et al 1997) along dynamic podoblock’s sagittal axis, the neck of the horse was maintained
along body sagittal axis at same level of withers during the x-ray examination, in order to
equally distribute horses weight.
Static Centre of Pressure (SCP) was identified following the technique described by Leveillard D.
(2005) with the horse standing squarely on 4 feet (4SCP) and on 3 feet (3SCP). We positioned the
4SCP or 3SCP, the weight force application point, under the center of the dynamic podoblock.
In order to evaluate the difference of weight force in different postures we calculated the load on
each front foot in both postures with a digital scale.
The foot was placed medially in contact with X-ray cassette in order to reduce magnification phenomenon
as much as possible. Konica x-ray films and radiological apparatus (Pollux 700 “Odel
srl”) were used. X-ray beam was oriented in the middle of solar aspect of PIII perpendicular to cassette.
X-ray images were taken in latero-medial projection at a distance of 80 cm (D’Arpe L. et al.
2006).
Seven x-ray images were performed moving dynamic podoblock’s angle of 5° every 30 sec. and
without moving X-ray machine from the ground. Two venography examinations were performed on
each foot in order to relatively reduce the importance of perivascular diffusion and blood dynamic
effects correlated with venography technique (D’Arpe 2004). First venography exam was performed
by injecting contrast liquid (Iopamidolo 150 mg)** at –15°, progressively modified to +15°. Sec-
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360
ond, exam (one week later), vice versa injecting at +15° progressively modified to –15°.
Results
After injecting at –15° and +15°
-15° Absent vascularization of coronary bend and dorsal laminar vessels
-10° Poor vascularization of coronary bend and dorsal laminar vessels
-5° Still poor but improved
0° Close to normal
+5° Still poor but improved
+10° Poor vascularization of bulbar vessels
+15° Absent vascularization of bulbar vessels
Discussion. We have not noticed any significant variation in examinations injected at –15° and
+15°.
According to Pietra M. et al. (2004) we noticed a considerable difference between tripodal and
quadripodal posture. We have correlated this to weight load variation between 4SCP and 3SCP;
each front foot was charged of 115-155 kg in 4SCP and 220-310 kg in 3SCP.
We observed, according to previous observations of Thompson KN et al. (1993), Crevier-Denoix N
(2001) and Redden RF. (2003), that Deep Digital Flexor Tendon (DDFT) tension played an important
role for the vascular bed to fill with the contrast liquid.
The results obtained, relative to vascular changes correlated to PA and consequently DDFT tension
changes, showed that a negative PA induced compression of coronary band and dorsal laminar vessels;
and a positive PA induced the compression of bulbar vessels.
Conclusion. This study permitted us to visualize how vascular foot bed can be modified by little
changes of PA correlated to DDFT tension and weight-load force differences in standing posture.
We conclude that manipulating PA is important to mechanically improve the vascularization of the
foot.
**Iopamiro 300, fl 50 ml (Bracco SpA Milano)
Bibliografia disponibile presso gli autori
Indirizzo per la corrispondenza/Address for correspondence:
Lorenzo D’Arpe
Dipartimento di Scienze Cliniche Veterinarie, Università di Padova, V.le dell’università 16,
Legnaro di Padova, Italia. e-mail:
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Proceedings of the European Equine Meeting of the Year 2008 - XIV SIVE - FEEVA Congress, Venice, Italy
__________________
The above study
suggests to me that changing angles of the hoof, whether by wedging or leaving heels or toes too high would create disruptions in the blood supply to either toe or heel
Please cite any peer-reviewed source that suggests "poor hoof form" is a cause of a poor (impaired?) immune response.
Isn't it obvious if blood circulation is hampered to any area you will get an impaired repair mechanism?