radiography

Background

Laminitis is a painful disease of equines. Radiographic and post-mortem evaluations of feet are often an important part of welfare investigations, and professional opinions by veterinarians are necessary in resulting legal cases. Any difference in measurements between the two modalities can cause uncertainty, potentially affecting the legal decision.

Objectives

To quantify the difference between radiographic and postmortem pre-mortem vs. post-mortem effects.

Study design

Case series.

Methods

Seven donkeys with laminitis confirmed via standard workup, euthanased for reasons unrelated to the study, were selected. Weight-bearing and non-weight-bearing lateral radiographs were taken of both front feet within 24 h pre-mortem. Feet were removed and sagitally sectioned between 48 and 72 h post-mortem. Lateral radiographs were taken of the feet immediately following sectioning. Founder distance and rotation were evaluated at each time point and compared using paired t-tests (P < 0.05).

Results

Compared with pre-mortem weight-bearing radiographs, nonweight-bearing feet had a decreased founder distance and decreased rotation. Compared with pre-mortem non-weight- bearing radiographs, post-mortem feet had increased rotation and no change in founder distance. There were no significant differences between post-mortem direct measurements and post- mortem radiographs. Compared with standard weight-bearing radiographs, post-mortem measurements had a decreased founder distance and increased rotation.

Main limitations

Small sample size. Further samples are needed to confirm these initial conclusions.

Conclusions

Measurements of post-mortem feet have a decreased founder distance and an increased rotation compared with standard radiographic images. Changes in founder distance are seen due to changes in weight-bearing. Changes in rotation are seen post-mortem, and can be explained by autolysis of the laminae and/or rigor mortis causing tendon contracture. Most studies have focused on indications and severity of laminitis in living animals using radiographs: postmortem measurements should therefore be interpreted with caution.

Competing interests

None declared.

Ethical animal research

Approved by The Donkey Sanctuary. Donkeys were owned by The Donkey Sanctuary and were used with consent.

Sources of funding

The Donkey Sanctuary.

Objective

To establish and validate an objective method of radiographic diagnosis of anatomic changes in laminitic forefeet of donkeys on the basis of data from a comprehensive series of radiographic measurements.

Animals

85 donkeys with and 85 without forelimb laminitis for baseline data determination; a cohort of 44 donkeys with and 18 without forelimb laminitis was used for validation analyses.

Procedures

For each donkey, lateromedial radiographic views of 1 weight-bearing forelimb were obtained; images from 11 laminitic and 2 nonlaminitic donkeys were excluded (motion artifact) from baseline data determination. Data from an a priori selection of 19 measurements of anatomic features of laminitic and nonlaminitic donkey feet were analyzed by use of a novel application of multivariate statistical techniques. The resultant diagnostic models were validated in a blinded manner with data from the separate cohort of laminitic and nonlaminitic donkeys.

Results

Data were modeled, and robust statistical rules were established for the diagnosis of anatomic changes within laminitic donkey forefeet. Component 1 scores ≤ −3.5 were indicative of extreme anatomic change, and scores from −2.0 to 0.0 denoted modest change. Nonlaminitic donkeys with a score from 0.5 to 1.0 should be considered as at risk for laminitis.

Conclusions and clinical relevance

Results indicated that the radiographic procedures evaluated can be used for the identification, assessment, and monitoring of anatomic changes associated with laminitis. Screening assessments by use of this method may enable early detection of mild anatomic change and identification of at-risk donkeys.