The wooden shoe as an option for treating chronic laminitis

Various farriery methods have been described for treating chronic laminitis, yet no particular method has become the preferred choice. The wooden shoe may possess certain advantages such as redistributing load evenly over the palmar/plantar section of the foot due to its flat solid construction and the mechanics (bevelled perimeter, breakover and heel elevation) that can be incorporated directly into the fabrication of the shoe. It should be apparent that the advantages of this farriery option will also be limited unless strict attention is paid to the details involving radiology, foot preparation and alignment of the distal phalanx within the hoof capsule.     

Evaluation using hoof wall strain gauges of a therapeutic shoe and a hoof cast with a heel wedge as potential supportive therapy for horses with laminitis

OBJECTIVE: To evaluate using strain gauges, a hoof cast with heel wedge, and a therapeutic shoe with unsupported toe for their effectiveness in redistribution of load from the dorsal hoof wall. STUDY DESIGN: In vitro biomechanical study. SAMPLE POPULATION: Twenty forelimb specimens. METHODS: Rosette strain gauges were placed on the dorsal and lateral hoof wall of 20 normal shaped hooves. Limbs were loaded vertically using a tensile testing machine with a 1 Hz sinusoidally cycling load up to 3000 N during 15 seconds. Mean values of principal strain and direction at 2500 N load were calculated for 3 experimental conditions (unshod, therapeutic shoe with unsupported toe, and hoof cast with heel elevation) and tested by ANOVA (P<.05). RESULTS: Vertical limb loading in an unshod hoof leads to a biaxial compression of the dorsal wall with high longitudinal compression (epsilon2 = -1515 microm/m). Principal strain at the dorsal wall (epsilon2) was decreased by 23% with the therapeutic shoe and by 59% with the hoof cast. On the lateral hoof wall principal strain was unchanged with the shoe, but increased by 34% with the cast. CONCLUSIONS: Strain measurements indicate unloading of the dorsal hoof wall by both methods with the cast being more effective than the shoe. CLINICAL RELEVANCE: The hoof cast with wedge offers substantial unloading of the dorsal wall, but increases load on the quarter. Therefore a hoof cast would likely be most helpful in acute laminitis when palmar structures can still bear load. The therapeutic shoe offers rehabilitation and regrowth of the dorsal wall without increased load on the quarter wall.     

An investigation of the shape of the hoof capsule in hindlimbs,its relationship with the orientation of the distal phalanx and comparison with forelimb hoof capsule conformation

There is limited information documenting hind foot conformation. The objectives of the study were to describe the shape of the hoof capsule of hindlimbs from the lateral aspect in horses of variable breeds, and, within horses, to compare the conformation of the hoof capsule of forelimbs and hindlimbs and determine the orientation of the distal phalanx within the hoof capsule in hindlimbs. Lateral photographs of the fore and hind feet (n = 225) and lateromedial radiographs of the hind feet (n = 29) were obtained. Differences among breed and shoeing status groups were assessed using multivariable mixed-effects linear regression models. Angular parameters and ratios of linear measurements were compared between fore and hind feet; angular radiological variables and photographic parameters of the hind feet were compared. The mean dorsal hoof wall angle for hind feet (50.9°±3.7°) was smaller than forefeet (51.8°±3.9°) (P = 0.04). The mean heel angles for hind feet (36.4°±9.6°) were smaller than forefeet (40.1°±9.3°; P < 0.001). Dorsal hoof wall (P < 0.001) and heel (P = 0.002) angles were larger in unshod than shod feet. In the hind feet, the dorsal hoof wall was parallel to the dorsal aspect of the distal phalanx. The median angle of the distal phalanx to the horizontal (angle S) was 0.6° (interquartile range: −1.4, 2.3°). There was a positive relationship between angle S and the hoof wall angle (W); each 1° increase in angle S was associated with 0.6° increase in angle W (P < 0.001). Angle S was also positively associated with photographic heel angle; each degree increase in the angle S was associated with 1.8° increase in the heel angle (P < 0.001). It was concluded that the angle of the distal phalanx to the horizontal in hindlimbs is smaller than published values for forelimbs. The orientation of the distal phalanx in hindlimbs is correlated with external characteristics of the hoof capsule.     

A fresh look at white line disease

White line disease occurs secondary to a hoof wall separation. Clinical signs may vary from not being lame to severe lameness with rotation of the distal phalanx depending on the extent of the disease affecting the inner hoof wall. The author has found that removal of the hoof wall overlying the diseased area combined with the appropriate farriery is the most important aspect of therapy.     

White line disease: A review (1998–2018)

White line disease (WLD) is a significant pathological condition that affects the equine hoof. White line disease continues to frustrate veterinarians and farriers due to the diversity regarding the aetiology, diagnosis and especially treatment. Furthermore, WLD lacks a definitive definition as the disease becomes apparent only when the hoof wall is compromised with an extensive separation, a hoof capsule distortion is present or when lameness exists. Clinical signs can range from a minor hoof wall separation to an extensive disruption of the external laminar bond resulting in displacement of the distal phalanx within the hoof capsule. There has been a myriad of treatments and topical preparations proposed for treating WLD, but most remain controversial with few having any scientific documentation or evidence of efficacy. This review of WLD is based on the sparse information available in the veterinary literature, the large number of WLD cases treated successfully in the authors’ combined practices using conventional farriery and the relevant questions that hopefully can be answered in the future.     

Farriery for the foal: A review part 2: Therapeutic farriery

The extensive nature of this topic warrants this review paper to be divided into two parts: ‘Basic trimming in foals’ and ‘Therapeutic farriery in foals’. Management of the feet and limbs during this juvenile period will often dictate the success of the foal as a sales yearling or mature sound athlete. Overall hoof care in the foal is often a joint venture between the veterinarian and the farrier. The orthopaedic disorders discussed in this paper that require input from the two professions are flexural limb deformities (FLD) and angular limb deformities (ALD). The concept of protecting the foot from the deleterious effects of mal-loading created by many FLDs and ALDs is just as important as using the symptomatology as an instrument to correct the deformity. This paper presents a review of the current information regarding the farriery for these two limb deformities while dispelling some of the anecdotal methodology, such as the use of toe extensions to treat flexural deformities, that presently exists. Considering the deficiency of information in the literature, segments of this text will be based on the author's extensive clinical practice, comprehensive clinical records and comparisons of case outcomes.     

Sheared heels and the correlation to spontaneous quarter cracks

The strong association between sheared heels and a spontaneous quarter crack is hard to ignore. Although inappropriate farriery may play a role, limb conformation and the landing pattern of the horse appear to be the dominant factors causing this type of hoof capsule deformation. The importance of determining the underlying cause and implementing the appropriate farriery cannot be over emphasised when managing a quarter crack associated with a sheared heel. The repair of spontaneous quarter cracks will be of little value, and the defect will have a tendency to recur, unless the cause is identified and rectified.     

Various aspects of barefoot methodology relevant to farriery in equine veterinary practice

The structures of the equine foot have the unique ability to adapt, change shape and restore. There are multiple benefits in shod vs. barefoot or in allowing the horse to be without shoes for a given time period to improve the palmar section of the foot. However, it requires a transition period, a change in the manner in which the foot is trimmed, a commitment from the owner/trainer and, in the case of leaving the horse without shoes permanently, it depends whether the horse can perform the desired function without shoes.     

Supracoronary approach for keratoma removal in horses: Two cases

Two competitive horses were presented for examination of chronic lameness; one associated with a hoof‐wall deformity, the other with a firm mass over the dorsal pastern region. Radiographs revealed moderately radiopaque masses associated with both deformities. The lesions were characterised ultrasonographically as noninvasive, well‐circumscribed heterogeneous masses. Computed tomographic examination of the second case revealed a well‐defined, partially mineralised, bi‐lobed mass with associated bony resorption of the underlying middle phalanx. Both patients were anaesthetised and the keratomas surgically removed via approaches 1–2 cm proximal to the coronary bands. Both horses were stall‐sound 2 days after surgery and returned successfully to an equal level of competition by 8 months. A supracoronary approach is a viable alternative to partial or complete hoof wall resection for the removal of nonsolar keratomas from the foot of a horse.     

Quantitative assessment of increased sensitivity of chronic laminitic horses to hoof tester evoked pain

Reasons for performing study: To evaluate quantitative sensory testing (QST) of the feet of laminitic horses using a power‐assisted hoof tester. Hypothesis: Hoof Compression Thresholds (HCTs) can be measured reliably and are consistently lower in horses with chronic laminitis than in normal horses. Methods: HCTs of chronic laminitic (n = 7) and normal horses (n = 7) were repeatedly measured using a hydraulically powered and feedback controlled hoof tester. Data from 2 tests, at 3 sites in both forefeet, during 3 sessions were collected and statistically analysed using linear mixed models. Results: The mean ± s.e. HCT for the laminitic horses was 29.6 ± 3.5 kg/cm² and for horses in the normal group was 59.8 ± 4.3 kg/cm². Residual variance was the largest of the error components and was greater (P<0.001) for the normal horses; none of the other components significantly differed between the 2 groups. Averaging of HCTs from each foot could produce a test with intraclass correlation coefficients of 0.83 for the normal group and 0.87 for the laminitic group, with an estimated sensitivity of 0.94 and a specificity of 0.93. This test would permit detection with 80% power and 95% confidence of a reduction of over 40% in the difference in mean HCTs between laminitic and normal horses following effective treatment provided that the experimental groups are of 9 or more horses. Conclusions: HCTs can be safely and reliably measured experimentally using this hoof tester. The level of variability found indicates that, under these conditions, treatments may need to produce at least a 40% improvement to be detected. Simplification of the hoof tester, training of the horse and repeated testing may permit the method to be used clinically to detect changes in the HCTs of individual laminitic horses but these potential improvements will require further investigation. Potential relevance: Measurement of HCTs can provide an additional means for assessing the effectiveness of treatments for alleviation of chronic equine laminitis.     

Radiographic and radiological assessment of laminitis

Radiographic studies are an essential component in evaluation of horses with laminitis. The standard radiographs that should be obtained to aid assessment of horses with laminitis are the lateromedial, horizontal dorsopalmar and dorsal 45° proximal palmarodistal oblique views. This article will summarise the assessment of these 3 projections in the laminitic horse as well as discuss the prognostic significance of common radiological abnormalities in horses with laminitis.     

Farriery for the foal: A review part 1: Basic trimming

The extensive nature of this topic warrants this review paper to be divided into two parts: ‘Routine basic trimming in foals’ and ‘Therapeutic farriery in foals’. Hoof care in the first few months of life is serious business and should never be taken lightly. Good farriery is vital for the development of the hoof capsule and the conformation of the limb. Management of the feet and limbs during the juvenile period will often dictate the success of the foal as a sales yearling or mature sound athlete. Overall hoof care of a foal is often a joint venture between the veterinarian and the farrier. Part 1 of this paper will outline the concept of a footcare programme, examination of the foal's feet and limbs along with what constitutes good basic farriery to properly apply the trim. It will also emphasise the importance of maintaining a good veterinarian-farrier relationship - the farrier being responsible for basic trimming with veterinary oversight when necessary, and if orthopaedic disorders develop, the farrier will have significant input with therapeutic farriery.     

An investigation of the relationships between angles and shapes of the hoof capsule and the distal phalanx

Reasons for performing study: There is little scientific evidence to support the premise that poor foot conformation predisposes to foot pain and lameness. Objectives: To determine relationships between external characteristics of the hoof capsule and angles of the distal phalanx; to determine variability in shape of the distal phalanx; and to investigate association between distal phalanx angles and the injury causing lameness. Materials and methods: Feet were documented photographically and radiographically. Linear and angle measurements were obtained for the hoof capsule and distal phalanx and compared statistically. Horses were categorised according to injury group, and angles and linear ratios were compared between groups. Results: There was modest correlation between hoof wall and heel angles and angles of the distal phalanx. There was variation in shape of the distal phalanx. There was no significant association between injury type and angles of the distal phalanx, although there was a trend for the angle of the dorsal aspect of the distal phalanx with the horizontal to be smaller in horses with injuries of the podotrochlear apparatus or deep digital flexor tendon compared with other groups. Conclusions: There are variations in shape of the distal phalanx largely due to differences in orientation of the concave solar border and the solar border to the horizontal. Variations in shape of the distal phalanx were not accurately correlated with external characteristics of the hoof capsule. There were weak associations between injury groups and angles of the distal phalanx. Clinical relevance: Further work is required to elucidate risk factors for foot‐related lameness.     

Radiographic assessment of cattle hoofs (ungulae) of the Nellore breed: Reference standards

The purpose of this work was to determine a radiographic standard of normality for lateral and medial ungulae in 3‐year‐old bovine females of the Nellore breed. Twenty‐six cows underwent radiographic exposure of the medial and lateral ungulae of the hindlimbs and forelimbs; abaxioaxial projections were used. The images were analyzed; distances were measured between the dorsal surface of the distal phalanx and the surface of the hoof capsule. The two angles formed, i.e., an angle between the dorsal surface of the distal phalanx and a line parallel to the sole (inner), and an angle between the dorsal surface of the hoof and a line parallel to the sole (outer), were also recorded. The results suggested a standard of normality for the proximal, middle and distal distances of the ungulae of the forelimbs: 0.96 ± 0.12 cm. For the measurement of hindlimbs, except for the distal distances of the side ungulae, the suggested value was 1.02 ± 0.14 cm; for the distal measurement of the lateral ungulae of the hindlimbs, the value was 1.09 ± 0.12 cm. For inner and outer angles, the values were 36.45° ± 4.4° for the medial ungulae of the forelimbs and 42.50° ± 3.8° for other ungulae of the forelimbs and hindlimbs (standard deviations of the values suggested for the angles should be used as variations between different animals, limbs and ungulae; they should not be used between angles of the same ungula).     

A Photometric Method for Recording Hoof Diseases in Cattle,with Special Reference to Haemorrhages of the Sole

Bergsten, C: A photometric method for recording hoof diseases in cattle, with special reference to haemorrhages of the sole. Acta vet. scand. 1993,34,281-286.– After cleaning and trimming, the sole surface and interdigital space of the hooves of cows are photographed in a standardized way. The colour slides are projected on to a screen and the haemorrhages of the sole (reflecting Pododermatitis aseptica diffusa) and the lesions of Dermatitis interdigitalis and Erosio ungulae are scored according to their severity and extent by 2 people who do not know the identity of the cows. In a repeatability test the correlation coefficients between 2 assessments of the haemorrhages in the sole ranged between 0.78 and 0.88 for assessments of the front hooves, the hind hooves and all the hooves together.     

Equine laminitis model: Cryotherapy reduces the severity of lesions evaluated seven days after induction with oligofructose

Reasons for performing study: A previous preliminary study demonstrated the potential of distal limb cryotherapy (DLC) for preventing laminitis. Clinically, DLC must be effective for periods longer than 48 h and the preventive effect must extend beyond its discontinuation. Objectives: To evaluate the effect of DLC, applied during the developmental phase of induced laminitis, on the severity of clinical laminitis and lamellar histopathology 7 days after dosing. Methods: Eighteen normal Standardbred horses were divided into 3 groups of 6. Continuous cryotherapy was applied for 72 h to the distal limbs of the first group. The second and third groups were administered laminitis inducing doses of oligofructose and 72 h of cryotherapy applied (immediately after dosing) to the second group. After clinical assessment all horses were subjected to euthanasia 7 days after dosing and hoof lamellar tissues were harvested and analysed. Results: In the laminitis induced horses clinical lameness and laminitis histopathology was significantly reduced in horses that underwent 72 h of DLC compared with untreated controls. Cryotherapy alone produced no significant lameness or other ill effect. Conclusions: Continuous, medium‐ to long‐term (72 h) cryotherapy applied to the distal limbs of horses safely and effectively ameliorates the clinical signs and pathology of acute laminitis. Potential relevance: Pre‐emptive distal limb cryotherapy is a practical method of ameliorating laminitis in ill horses at risk of developing the disease.