Investigation of the immediate analgesic effects of extracorporeal shock wave therapy for treatment of navicular disease in horses

Objectives-To measure the acute analgesic properties of extracorporeal shock wave therapy (ESWT) in horses with navicular disease using objective ground reaction forces (GRF). Study Design-Prospective study. Animals-Nine client-owned horses with unilateral forelimb lameness caused by navicular disease. Methods-Horses were trotted at 3 m/s over a force plate to record pre-treatment GRF of the lame and contra-lateral forelimbs. After ESWT of the lame limb, applied with a radial unit to each of the frog and heel bulb areas with 1500 pulses at 4 bar and 10 Hz, GRF measurements were repeated at 15 minutes and 24-hour intervals for 7 days. From the 5 trials recorded at each time, peak vertical force (PVF) was calculated and averaged. Data were compared between limbs and over time using a 2-way repeated-measures ANOVA. Results-Mean (+/- SD) PVF was significantly different between lame (day 1; 4339 +/- 626 N) and contra-lateral (day 1; 5236 +/- 515 N) limbs pre-treatment (P <.05). After ESWT treatment, this difference remained unchanged at 15 minutes and from days 1 to 7. To confirm navicular disease, palmar digital analgesia significantly reduced the lameness (lame 5144 +/- 430 N; contralateral 5082 +/- 586 N; P >.05). Conclusions-Single ESWT treatment applied in this manner does not influence lameness in horses with navicular disease. Clinical Relevance-Although many equine regulatory commissions currently ban the use of ESWT before competition, our results suggest that such regulations may be unfounded. Further research is required to determine the long-term analgesic properties of this frequently used treatment modality in equine athletes. (c) Copyright 2005 by The American College of Veterinary Surgeons