Mineralization of the Equine Palmar/Plantar Annular Ligament Treated by Surgical Resection.
Authors: Garvican Elaine R, Wylie Claire E, Payne Richard J, Smith Roger K W, Head Marcus J
Journal: Veterinary surgery : VS
Summary
Mineralization of the palmar/plantar annular ligament (PAL) represents an uncommon but potentially debilitating condition in horses and ponies, characterised by abnormal bone and cartilage formation within ligamentous tissue—a process termed metaplasia—that causes focal pain and progressive lameness ranging from subtle gait changes to severe weight-bearing dysfunction. Garvican and colleagues reviewed surgical cases from two referral hospitals, identifying seven ponies with PAL mineralization that had been lame for between five weeks and six months before referral; lameness severity varied considerably among individuals, though three cases demonstrated pronounced pain on direct palpation over the affected ligament. Surgical resection of the mineralized tissue proved effective in six of the seven cases (86% success rate), with histological analysis of four resected samples confirming the presence of fibrocartilaginous and/or osseous metaplasia rather than simple calcification. The practical significance for practitioners lies in recognising PAL mineralization as a potential diagnosis in cases of chronic palmar/plantar heel pain unresponsive to conventional farriery and conservative management, and understanding that surgical intervention offers good functional outcomes without serious post-operative complications. Whilst this remains a limited case series, the findings justify consideration of definitive surgical treatment when diagnostic imaging reveals ligamentous mineralisation and conservative approaches—including therapeutic shoeing modifications and rest protocols—have failed to resolve lameness.
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Practical Takeaways
- •Consider PAL mineralization as a differential diagnosis in cases of chronic lameness localized to the palmar/plantar aspect, especially when conservative treatment has failed
- •Surgical resection of mineralized PAL tissue has a good success rate (86%) for restoring soundness in affected ponies
- •Pain response to direct pressure over the PAL area may help identify this condition clinically before advanced imaging
Key Findings
- •Lameness duration before referral ranged from 5 weeks to 6 months with severity grades 1-5/10
- •Histological examination of resected tissue revealed fibrocartilaginous and/or osseous metaplasia in 4 cases
- •6 of 7 ponies (86%) became sound following surgical resection of mineralized PAL tissue
- •Surgical treatment offered favorable outcomes where conservative methods had failed