PMC9020972_01
The lateral view image demonstrates a normal hoof-pastern axis in the right foreleg but broken back conformation in the left foreleg. The growth rings were also exhibited in the right hoof wall's medial side (white head of yellow arrows).
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fig1
However, growth rings appeared in the hoof wall's medial aspect (Figure 1).
Radiographic images of the (a-c) left and (d-f) right front hooves of a show jumping pony. Both front hooves demonstrated a positive hoof angle, denoted by the angle between red lines at the ventral aspect of the coffin bone and ground contact surface (a, d), with a greater degree in the right front hoof (d). The left front hoof also showed a negative hoof-pastern axis (a). The hoof wall height between the medial and lateral sides of each hoof was equal, indicating no shear heels were observed in both front hooves (b, e). A slight irregularity of the navicular bone's ventral border was concomitantly detected in both front hooves (c, f).
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fig2
Radiographic projections of lateromedial, dorsopalmar, and 65  dorsopalmar positions showed minor irregularity of the navicular bone's distal border in both front hooves (Figure 2).
The application of the z-bar shoe on the affected right front hoof. The hoof was trimmed and rasped before fitting with the z-bar shoe (a, b). A non-weight-bearing portion was created on the medial side of the shoe base on the local anaesthesia area (yellow arrow) (c, d). Hoof conformation was adjusted bilaterally to increase the hoof angle and improve the hoof-pastern axis position (d).
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fig3
A non-weight-bearing portion of the z-bar shoe was designed to eliminate loading on the medial palmar region (Figures 3(a)-3(c)). Despite a slight asymmetry during trotting at 12-20 weeks of shoeing, the trotting symmetry was restored following strategic adjustment of the hoof conformation at 24 weeks of shoeing (Figure 3(d)) (Supplemental File 16).
The mean lameness score on the right forelimb following the hard surface lunging in the clockwise and counterclockwise directions. Gait analysis was performed before shoeing, immediately postshoeing, and 12 weeks and 24 weeks postshoeing.
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The lameness score improvement remained until the end of observation at 24 weeks postshoeing (Supplemental Files 12 and 13) (Figure 4).
Radiographic images of the (a-c) left and (d-f) right front hooves of a show jumping pony at 30 weeks of shoeing management. The left front hoof demonstrated an improvement in the hoof-pastern axis after a given period of management (a), while a positive hoof angle was still observed in the right front hoof but displayed a lower degree than before shoeing management (d). Hoof's balance was also corrected in both front hooves (b, e). A slight irregularity of the navicular bone's ventral border was still marked in both front hooves (c, f).
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fig5
The radiographic images, taken at 30 weeks of the management period, also showed an improvement of hoof balance in both front hooves (Figure 5).