Suspensory ligament size does not change after plantar fasciotomy and neurectomy of the deep branch of the lateral plantar nerve by ultrasonographic assessment.
Authors: Scharf Alexandra, de Solis Cristobal Navas, Sampson Sarah N, Glass Kati, Watts Ashlee E
Journal: Veterinary surgery : VS
Summary
# Editorial Summary Plantar fasciotomy combined with neurectomy of the deep branch of the lateral plantar nerve (PFN) is an established surgical treatment for chronic proximal suspensory desmopathy in horses, yet little is known about its biomechanical effects on the ligament itself. Scharf and colleagues examined 21 horses with hindlimb proximal suspensory ligament (PSL) disease using serial ultrasonographic measurements before surgery and at various postoperative intervals, validating their measurements against high-field MRI in a subset of 19 animals. Across both imaging planes, PSL cross-sectional area remained statistically unchanged from preoperative to postoperative assessment (median values approximately 2.1–2.3 cm², with no significant difference detected), despite the fact that 80% of owners reported functional improvement and 75% of horses returned to work at or above preoperative levels by 12-month follow-up. These findings suggest that PFN provides clinical and functional benefit through neurological mechanisms (pain relief via denervation) rather than through structural healing or remodelling of the PSL itself, fundamentally altering how we should counsel clients about recovery and progression of rehabilitation. Consequently, ultrasonographic or MRI monitoring of ligament size cannot be reliably used as an objective marker to guide return-to-work decisions in PFN cases; instead, clinical assessment and gradual ridden exercise progression remain the appropriate framework for managing these patients postoperatively.
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Practical Takeaways
- •Ultrasonography is a reliable tool for measuring suspensory ligament size and can be used confidently for serial monitoring, though agreement with MRI should be considered for complex cases
- •Improvement in clinical function and return to work after plantar fasciotomy and neurectomy occurs without measurable changes in ligament cross-sectional area, suggesting structural remodeling may not be the primary mechanism of pain relief
- •Do not use PSL-CSA measurements alone to guide return-to-work decisions; clinical assessment and functional recovery should take precedence over imaging findings
Key Findings
- •Ultrasonographic measurement of proximal suspensory ligament cross-sectional area (PSL-CSA) showed excellent intraobserver reliability and good agreement with MRI assessment
- •PSL-CSA did not change significantly between preoperative and postoperative measurements following plantar fasciotomy and neurectomy
- •80% of owners reported horses were 'better' at median 12-month follow-up and 75% returned to or exceeded preoperative exercise levels despite no measurable change in ligament size