This experimental study examined the effects of dorso-palmar and medio-lateral hoof imbalance on intra-articular pressure and fluid distribution in the coffin joint. Cadaver limbs were loaded in a hydraulic press to simulate vertical forces generated by standing and walking. Intra-articular coffin joint pressures were measured with the hoof in a neutral position and after a 5-degree wedge was added under the heel, toe, medial and lateral sides before and after 5 milliliters of fluid were injected into the joint. Silicone was injected into the coffin joints and the limbs were loaded for 3 hours with toe, heel and lateral wedges.
Heel wedges increased intra-articular joint pressure from negative to positive in normal joints. With increased intra-articular pressure, the heel wedge further increased joint pressure while the toe wedge reduced joint pressure. Medial and lateral wedges had little effect on joint pressure. Articular contact was localized dorsally with the heel wedge in a palmar direction with the toe wedge and toward the lateral side with the lateral wedge. The authors concluded a neutral “balanced” hoof is ideal and elevated heels may be detrimental to the coffin joint.
Anecdotally, flare ups of chronic laminitis have been linked to antigen challenges such as vaccines or environmental allergens. Intradermal skin testing was performed on seven horses with chronic laminitis and seven control horses without hoof disease to test the hypothesis that horses with chronic laminitis are hyper-reactive when exposed to common antigens.