Clodronate improves lameness in horses without changing bone turnover markers.

Abstract

BACKGROUND: Clodronate is prescribed to performance horses with lameness. Despite its clinical popularity, little research has been done to understand the effects of clodronate in the horse. OBJECTIVES: Our objective was to determine if a single treatment with clodronate at the clinically approved dose altered bone remodelling, bone cell recruitment or lameness in the horse. STUDY DESIGN: Twelve university-owned equestrian team competition horses with a history of forelimb lameness due to navicular syndrome were randomised to receive either 1.4 mg/kg clodronate (CLOD n = 6) or an equivalent volume of LRS (CONT; n = 6) in a blinded manner. METHODS: Blood was evaluated weekly for 8 weeks before and after drug administration (clodronate or placebo) for bone turnover markers CTX-I and osteocalcin. Lameness evaluations were performed to assess for change in lameness 1 week before and 1, 2, 3 and 8 weeks after drug administration. Coach questionnaires were performed to assess for change in ridden performance 1, 2, 3 and 8 weeks after drug administration. Bone cell recruitment was evaluated in vitro 2 weeks before and after drug administration. RESULTS: There were no differences in in vitro bone cell recruitment from whole bone marrow or in bone turnover markers CTX-I or osteocalcin. A small but significant decrease in forelimb lameness was detected in CLOD treated horses 1 week after treatment (P = 0.005). There were no significant differences in hindlimb lameness. Coaches identified an improvement in performance significantly more often in CLOD vs. CONT (P = 0.01) at week 8. MAIN LIMITATIONS: Two CONT horses received intra-articular anti-inflammatory medication after treatment, which may have altered lameness results. CONCLUSIONS: A single dose of clodronate appears to reduce lameness without producing detectable effects on bone turnover markers. Due to the long half-life of a bisphosphonate drug, the effect of multiple doses on bone remodelling and lameness should be investigated. The Summary is available in Portuguese - see Supporting Information.