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because of the potential detrimental effects of the excessive heat.
For carpal valgus, the composite extension is placed on
Fig 9: Grade 3 carpal valgus in a 2-month-old foal. [Colour figure can be viewed at
wileyonlinelibrary.com]
2017; O’Grady 2017). Various clinicians have described trimming the lateral side of the foot aggressively when there is a valgus deformity in an attempt to increase the ground surface on this side of the foot (Greet and Curtis 2003). However, it is this authors’ opinion that the foal does not grow sufficient horn at this age to make an appreciable difference and changing the medial to lateral orientation of the foot may have detrimental effects on the immature hoof capsule as well as the physis. Using some form of extension to increase the ground surface of the foot and change the forces on the physis seems to be more beneficial (Cheramie and O’Grady 2003; Greet and Curtis 2003; O’Grady 2017). Periosteal elevation is a controversial surgery that is
routinely performed on foals with mild to moderate angular limb deformities (Garcia-Lopez 2017). However, the author has not referred a foal for this surgery in 20 years as the author saw no difference when compared with foals that
had controlled exercise (brief turnout in a small paddock with firm footing) and the application of a hoof extension (O’Grady unpublished data, 2014). If stall confinement is used initially, the mare and foal should be bedded on firm footing (such as a thin layer of sawdust) for the foot extensions to be effective. Initially, the author prefers using some form of extension to increase the ground surface area of the foot on a given side and change the forces on the affected joint. Some type of composite applied to the hoof wall is preferred rather than a cuffed shoe that is attached with glue as this type of shoe appears to restrict movement of the hoof capsule and contracts the foot especially the heels. As noted previously in Footcare in foals: A review part 1, the author will not apply a composite to a foal’s foot before 3 weeks of age
the medial side of the hoof and toward the heels which appears to redirect the forces on the physis on the overloaded side of the limb by moving the axis of weight bearing towards the centre of the limb (Fig 10). The extension also appears to promote centreline breakover. The extension is made from an acrylic composite mixed with fibreglass strands or a urethane composite applied directly to the foot and shaped to the desired width. Properly applied for maximum results, the extension should begin at the contact point of the heel and feather up most of the length of the wall. It should not extend dorsally beyond the junction of the quarter and toe to be of any benefit. Also, it should not be built up on the sole but only tapered along the sole toward the frog. The extension should be no wider than a vertical line drawn from the coronet to the ground. If the extension is too wide, it applies leverage on the attached side that will invariably distort the hoof capsule. The extension should be removed every 2–3 weeks for 1–2 days to allow the hoof wall to dry out and not break up. Also, with chronic use, there may be a restriction of hoof wall growth which may contribute to long-term distortion of the wall. Strict controlled exercise as described above is essential for this conservative approach to be successful. In severe cases of carpal valgus or cases that have not responded to conservative therapy, surgery such as a transphyseal screw or staple or a wire transphyseal bridge placed across the distal radial physis may be necessary (Garcia-Lopez 2017; McCarrel 2017). The author likes to combine a medial extension with the surgery, however, it may affect the clinician’s ability to assess the limb to accurately determine the time for implant removal (A. Parks, personal communication, 2012). In many cases, a surgical procedure may be performed too early before conservative therapy has allowed sufficient time to correct
Fig 10: Urethane extension placed on medial side of hoof on foal in Figure 9. [Colour figure can be viewed at
wileyonlinelibrary.com]
© 2019 EVJ Ltd
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