Clodronate Improves Lameness in Horses Independent of Anti-Resorptive Effects In Vivo

Introduction: Clodronate has become a popular choice for veterinarians treating chronic lameness issues in the horse. Despite its clinical popularity, little research has been done to understand the effects of clodronate in the horse.

Materials and Methods: Our objective was to determine if clodronate at the clinically approved dose altered bone remodelling or bone cell recruitment and lameness. Twelve university-owned horses randomly received either 1.4 mg/kg clodronate (CLOD, n = 6) or an equivalent volume of LRS (CONT, n = 6) as treatment in a blinded manner. Blood was evaluated weekly for 16 weeks around treatment for bone turnover markers. Lameness evaluations and coach questionnaires were performed to assess for change in lameness or performance. Bone cell recruitment was evaluated in vitro 2 weeks before and after treatment.

Results: There was no difference in in vitro bone cell recruitment from whole bone marrow. There were no differences in markers of bone turnover, osteocalcin or CTX-I. There was a significant difference (reduced lameness) of both forelimb and hindlimb lameness in CLOD horses versus CONT. Coaches identified an improvement in performance significantly more often in CLOD versus CONT.

Discussion/Conclusion: Clodronate appears to reduce lameness with minimal effects on bone turnover.

Acknowledgement: This project was supported by a Department grant and a College endowment for equine research.

No conflict of interest has been declared by the author(s).