Texas Equine Veterinary Association

www.texasequineva.com • 14 Management Strategies One of the most important aspects of management is corrective trimming and shoeing. The goals of trimming and shoeing are to maintain or restore appropriate medial to lateral hoof balance, ease break-over, and support/elevate the heels. Injection of the coffin joint, navicular bursa, and/or digital flexor tendon sheath with corticosteroids and hyaluronic acid can provide substantial, but frequently temporary, anti-inflammatory effects and pain relief. Ultrasound and radiographic-guided lateral approaches to injection of the navicular bursa have been described (Nottrott 2017; Daniel 2016). The benefit is that injection avoids penetration of the DDFT. A recent report evaluated response to navicular bursa injections in horses with signs of navicular syndrome on MRI. Efficacy of navicular bursa injections and the decision to inject the digital flexor tendon sheath was highly dependent on the disease process identified on MRI (Marsh 2012). A period of rest with controlled exercise is frequently recommended, depending on the known or suspected degree of soft tissue injury. Another report compares management of horses with DDFT injuries with rest and intra-synovial injection of corticosteroids and hyaluronic acid compared to injections without rest. Horses receiving rest in conjunction with corticosteroid injection returned to use for a significantly longer duration than horses with rest alone (Lutter 2015). Surgical management of navicular syndrome is dependent on the type and severity of lesion. Navicular bursoscopy is most beneficial when lesions within the navicular bursa, adhesions, or DDFT dorsal border lesions are present. Palmar digital neurectomy may be indicated in horses with chronic heel pain that is unresponsive to medical management and does not include a significant DDFT lesion, as the duration of efficacy of neurectomy is shortened in cases of core or linear DDFT lesions. These horses are at risk of progressive damage to the DDFT once they return to athletic activity after surgery (Gutierrez-Nibeyro 2015). Furthermore, neurectomy may be contraindicated in horses with DDFT lesions, as the risk of complete rupture of the DDFT is increased. In summary, while the complex interaction of structures within the navicular apparatus is not well understood, the use of complementary imaging modalities can aid in identification of multiple lesions, selection of appropriate management protocols, and improve determination of prognosis. The importance of soft tissue injuries in conjunction with bony abnormalities should not be minimized, as these lesions also dictate management strategies and prognosis. References: 1. Baxter, GM and Adams OR. Adams and Stashak's Lameness in Horses. 6th ed. Wiley-Blackwell, 2011. 2. Nagy A, Bodo G, Dyson SJ, et al. Diffusion of contrast medium after perineural injection of the palmar nerves: An in vivo and in vitro study. Equine Vet J. 2009; 41(4): 379-383. 3. Biavaschi Silva G, De La Corte FD, Brass KE, et al. Duration and efficacy of different local anesthetics on the palmar digital nerve block in horses. J Equine Vet Sci. 2015; 35: 749-755. 4. Rabba S, Bolen G, Verwilghen D, et al. Ultrasonographic findings in horses with foot pain but without radiographically detectable osseous abnormalities. Vet Radiol Ultrasound. 2011; 52(1): 95-102. 5. Sampson SN, Schneider RK, Gavin PR, et al. Magnetic resonance imaging findings in horses with recent onset navicular syndrome but without radiographic abnormalities. Vet Radiol Ultrasound. 2009; 50(4): 339-346. 6. Lutter JD, Schneider RK, Sampson SN, et al. Medical treatment of horses with deep digital flexor tendon injuries diagnosed with high-field- strength magnetic resonance imaging: 188 cases (2000-2010). J Am Vet Med Assoc. 2015; 247(11): 1309-1318. 7. Nottrott K, De Guio C, Khairoun A, Schramme M. An ultrasound-guided, tendon-sparing, lateral approach to injection of the navicular bursa. Equine Vet J. 2017; 49(5): 655-661. 8. Daniel AJ, Goodrich LR, Barrett MF, et al. An optimised injection technique for the navicular bursa that avoids the deep digital flexor tendon. Equine Vet J. 2016; 48(2): 159-164 9. Marsh CA, Schneider RK, Sampson SN, Roberts GD. Response to injection of the navicular bursa with corticosteroid and hyaluronan following high-field magnetic resonance imaging in horses with signs of navicular syndrome: 101 cases (2000-2008). J Am Vet Med Assoc. 2012; 241(10): 1353-1364. 10. Gutierrez-Nibeyro SD, Werpy NM, White NA, et al. Outcome of palmar/plantar digital neurectomy in horses with foot pain evaluated with magnetic resonance imaging: 50 cases (2005-2011). Equine Vet J. 2015; 47: 160-164. Transverse MRI of the foot at the level of the collateral sesamoidean ligament of the navicular bone demonstrating enlargement of the lateral lobe of the deep digital flexor tendon with a hyperintense core lesion.

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