Histomorphologic evaluation of extracorporeal shock wave therapy of the fourth metatarsal bone and the origin of the suspensory ligament in horses without lameness.

This research article seeks to understand the impact of extracorporeal shock wave therapy (ESWT) on the bone and bone-ligament interface in healthy horses. The study found that ESWT significantly increased osteoblast numbers without causing any damage to associated soft tissue structures or inducing cortical microfractures.

Research Methodology

• Six horses with no signs of lameness were chosen for this study.
• The origins of the suspensory ligament at the metacarpus (with a 35 mm probe depth) and fourth metatarsal bone (5 mm probe depth) were subjected to the ESWT twice – on days 0 and 16.
• The therapy was delivered using a shock count of 2000, maintaining an energy flux density of 0.15 mJ/mm2.
• One forelimb and one hindlimb were randomly selected to be treated, while the contralateral limbs served as the non-treated controls.
• Scans of the bone were performed on days -1 (or before the ESWT was conducted), 3, 16, and 19.
• Histomorphological analysis of both the treated and untreated tissues was performed on day 30.

Research Findings

• The ESWT therapy showed a significant increase in the number of osteoblast cells, which aid in bone formation, but did not damage any soft tissue or lead to any cortical microfracture.
• There was a marked positive correlation between the increase in osteoblast numbers and the radiopharmaceutical uptake observed on lateral views of the hind limb on day 3 and 16, and on caudal views of the forelimb on day 3.

Conclusions

• The therapy demonstrated potential to increase osteoblast numbers in horses.
• The connections between increased osteoblast count and radio-pharmaceutical consumption imply that stimulation of bone formation took place soon after ESWT.
• No damage to the bone or the bone-ligament structure was observed given the therapy settings used in this study, indicating that ESWT can be safely administered to horses.