Effects of extracorporeal shock wave therapy on desmitis of the accessory ligament of the deep digital flexor tendon in the horse.
Authors: Waguespack R Wayne, Burba Daniel J, Hubert Jeremy D, Vidal Martin A, Lomax Larry G, Chirgwin Sharon R, Lopez Mandi J
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Extracorporeal Shock Wave Therapy for Accessory Ligament Desmitis Injury to the accessory ligament of the deep digital flexor tendon (ALDDFT) remains a challenging condition in equine practice, prompting investigation into whether extracorporeal shock wave therapy (ESWT)—a treatment already used for other soft tissue injuries—might accelerate healing of collagenase-induced lesions in this structure. Waguespack et al. employed a rigorous paired, blinded controlled design in eight Thoroughbreds, deliberately creating standardised ALDDFT lesions through collagenase injection, then treating one ligament per horse with ESWT (1000 shocks at 0.15 mJ/mm²) whilst leaving the contralateral ligament as a control, with serial ultrasonographic assessment and tissue analysis at 15 weeks post-injury. Although ESWT-treated ligaments showed significantly elevated type I collagen mRNA expression compared to controls at the final timepoint, no meaningful differences emerged between treated and untreated ligaments regarding lesion size, echogenicity, fibre alignment, microstructural organisation, or overall collagen and glycosaminoglycan content. These findings suggest that whilst ESWT may stimulate collagen gene expression, this molecular response does not translate into demonstrable structural or compositional advantages in naturally healing ALDDFT desmitis, indicating that current evidence does not support routine ESWT application for this specific injury in clinical practice.
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Practical Takeaways
- •ESWT does not appear to provide additional benefit over natural healing for ALDDFT lesions in this controlled model, despite increasing collagen I gene expression
- •Lesions in this structure show natural improvement over 12 weeks regardless of ESWT treatment, so baseline expectations for healing timeline should not change based on this therapy
- •While ESWT increased collagen I mRNA, this did not translate to structural or compositional improvements, suggesting potential disconnect between gene expression and functional healing
Key Findings
- •No significant differences in lesion size, echogenicity, or fiber alignment between ESWT-treated and control ligaments at any evaluation timepoint
- •Both ESWT-treated and control ligaments showed significant improvement in fiber alignment by 9-12 weeks post-injury
- •ESWT-treated ligaments showed significantly higher collagen type I mRNA levels at 15 weeks, but no differences in microstructure or composition
- •Lesion size and echogenicity increased at 6 weeks then decreased by 12 weeks in both groups, suggesting natural healing progression