Laminitis in the pony: conservative treatment vs dorsal hoof wall resection

Laminitic pain: parallels with pain states in humans and other species

Laminitis poses a threat to all horses, and is widely considered as being one of the most important diseases of horses and a global equine welfare problem. The effects of laminitis lead to debilitation, development of pronounced digital pain, and great suffering in the afflicted animal. The precise pathophysiological processes that result in laminitic pain are poorly defined, and hence the delivery of effective palliative care is clinically challenging. Knowledge and understanding of pain states in other animal species may further aid the elucidation of equine laminitic pain mechanisms, guide the search for treatable causes of this multifactorial problem, and thereby help achieve enhanced therapeutic and palliative care. However, parallels drawn from pain states in other animals must consider species differences in both anatomy and physiology, and the specific nature of the laminitic disease process.

Clinical presentation, diagnosis, and prognosis of chronic laminitis in Europe

The terminology relating to laminitis is confusing. This article describes how equine veterinarians, by using their eyes and fingers alone, can diagnose and evaluate a case of chronic laminitis. This evaluation will enable veterinarians to give a statistically significant prognosis that can be further refined by measurements taken from plain, weight-bearing lateromedial radiographs of the affected hooves. Should invasive techniques such as digital venography also be used, the results of both techniques are complementary.

Chronic laminitis: strategic hoof wall resection

In the chronic-laminitic foot, severe soft-tissue compression and compromised circulation can result in osteitis and sepsis at the margin of the distal phalanx. Resultant inflammation and sepsis may cause the coronary corium to swell, drain, or separate from the hoof capsule, usually within 8 weeks of laminitis onset. Slow-onset cases of soft-tissue impingement can develop secondary to distal phalanx displacement due to lack of wall attachment. With either presentation, partial upper wall resection is required to reverse compression and vascular impingement by the hoof capsule. If the pathology is not overwhelming, the area reepithelializes and grows attached tubular horn. Firm bandaging and restricted exercise until tubular horn has regrown enhances recovery and the return of a strong hoof.

Laminitis in the horse: a review

Laminitis has been a recognized disease since early Greek and Roman times, but it is still bothering both practitioners and scientists. In the last decade a lot of new fundamental research has been done to elucidate the pathogenesis of laminitis. New insights into the pathogenesis, the predisposing factors (including nutritional overload, endotoxaemia, shock, management, etcetera), clinical and radiological signs, differential diagnosis, therapy, and prognosis of the disease are described. The data, however, are not always in agreement with each other, giving further proof of the complexity of the syndrome.

Factors involved in the prognosis of equine laminitis in the UK

The significance of clinical and radiological parameters as prognostic indicators for laminitis, 'founder' and 'sinking syndrome' was studied using case records of 216 horses and ponies. Five animals were destroyed without treatment and were not included in the results of the study. One hundred and sixty-two (77%) animals returned to athletic soundness; 7 animals (3%) did not regain full athletic function, 42 animals (20%) died or were destroyed. Cases were assigned to 4 groups on the basis of initial clinical examination alone. These groups were laminitis, acute founder, 'sinker' and chronic founder. This grouping was found in itself to be the most important prognostic parameter which was studied. Stepwise regression analysis of the data from animals by group indicated that the radiological measurement of founder distance, was the most significant radiological prognostic measurement for acute founder cases. Less significant prognostic parameters were the severity of lameness, rotation angles, the presence of solar prolapse, and the number of feet affected. The height of the animal at the withers was not significantly related to outcome. The prognosis for horses was not significantly different from that for ponies.

Digital perfusion, evaluated scintigraphically, and hoof wall growth in horses with chronic laminitis treated with egg bar-heart bar shoeing and coronary grooving

Nuclear scintigraphy was used to assess digital perfusion before and after treatment in 10 horses with clinical and radiographic evidence of chronic laminitis. Horses were evaluated for lameness, degree of distal phalanx rotation, and heel-toe hoof wall growth ratio, and randomly divided into two treatment groups. Group 1 horses received only egg bar-heart bar shoeing; Group 2 underwent egg bar-heart bar shoeing and coronary grooving. Horses were re-evaluated for digital perfusion, lameness, degree of distal phalanx rotation, and hoof wall growth at 6 week intervals over the 18 week follow-up period. Prior to treatment, relative scintigraphic activity at the dorsal laminar area was decreased and relative scintigraphic activity at the toe and adjacent solar area was increased. Egg bar-heart bar shoeing was associated with significantly increased dorsal laminar scintigraphic activity and significantly decreased solar scintigraphic activity over the 18 week period. Coronary grooving, in combination with egg bar-heart bar shoeing, resulted in a significantly lower heel-toe hoof wall growth ratio but did not enhance digital perfusion. Seven of 10 (70%) horses were responsive to treatment, defined as an improvement in lameness by at least one grade. Horses that were refractory to treatment had significantly lower dorsal laminar scintigraphic activity and higher palmar coronary scintigraphic activity prior to treatment than horses that responded to treatment. Our results are the first to demonstrate that egg bar-heart bar shoeing is associated with improved dorsal laminar perfusion, and support the use of this technique. In addition, we found that pre-treatment nuclear scintigraphy was predictive of clinical outcome in horses with chronic laminitis treated with corrective shoeing.

A retrospective evaluation of laminitis in horses

Case records of 202 horses treated for laminitis were reviewed with the intent of determining the long-term outcome and correlating this with digital radiographic findings and with the degree of pain associated with the laminitis. At long-term follow-up 57 horses had returned to athletic soundness (Group 1), 20 horses were intermittently lame (Group 2), 19 horses had permanent severe lameness (Group 3), 97 were dead (Group 4), and 9 were lost to follow up. Using simple regression analysis, functional outcome did not correlate with the degree of rotation (R2 = 0.004) or the presence of distal displacement (R2 = 0.139). Functional outcome did correlate with the clinical grade of laminitis (R2 = 0.504). Horses in Group 1 had significantly less distal phalangeal rotation (5.89 +/- 6.48 degrees) than did horses in Group 2 (11.10 +/- 8.19) and Group 3 (14.50 +/- 10.80), but were not significantly different from Group 4 horses (7.49 +/- 6.57). Of 96 surviving horses, 23 had evidence of distal displacement compared with 54 of 97 non-survivors. Based on these results, horses that develop distal displacement of the distal phalanx are more likely to die than are horses without distal displacement; however, the presence or absence of distal phalangeal displacement and the degree of distal phalangeal rotation cannot be used to predict the outcome of a horse with laminitis. Clinical assessment is a more reliable means of determining the final outcome and should be given precedence over radiographic findings.