Laminitis in a horse!!

 The following radiographs are from a gelding that has been lame for nearly 1 year. The gelding has been treated for laminitis/founder and despite efforts by the farrier and veterinarian, the gelding's conditions has worsened. He is non-weight bearing on one forelimb at the time of my exam. The right front foot is imaged in Figure 1 and the left front foot in Figure 2. In Figures 3 and 4 the palmar angle (angle "A") is measured in both front feet. The palmar angle corresponds to the angle that the bottom or palmar surface of the coffin bone makes with the horizon. In both front feet, the palmar angle measures approximate +23-25 degrees. Normally, the palmar angle may range between zero to +5 degrees. Abnormal palmar angles may be negative or greater than +7-8 degrees. However, even though the right and left front feet share the same palmar angle, it is for two very different reasons!

Figure 1 (Right front)

Figure 2 (Left front)

Figure 3 (Right front)

Figure 4 (Right front)

The most likely causes for an increased palmar angle include coffin bone rotation and coffin joint contracture. The difference between these two conditions is key to making the correct diagnosis. In the case of laminitis, the coffin bone rotates under the influence of the deep digital flexor tendon and due to a lack of attachment between the coffin bone and the lamina (i.e. laminitis). In Figure 5, the degree of coffin bone "rotation" is estimated based on the difference between angles "A" and "B". Normally, the hoof wall (red line over "A")  is parallel with the coffin bone (red line over "B"). When these two lines are parallel, the angles equal each other and there is zero degrees of coffin bone rotation. Therefore, the problem with the left front limb in Figure 5 is laminitis and secondary coffin bone rotation.

Figure 5 (Left front)

The right front foot has zero degrees of coffin bone rotation however the palmar angle is the same as in the left front foot. This due to coffin joint contracture and is the definition of a "Club foot". In Figure 6, the lines corresponding to the hoof wall and coffin bone are parallel and as such angle  "A" equals angle "B". Figure 7 diagrams the concept of coffin joint contracture that results in an angle of contracture (angle "A"). Typically, a club foot or coffin joint contracture does not result in non-weight bearing lameness but rather a life long commitment to proper shoeing and trimming. In this case, first glance of the radiographs might be deceiving because both front feet have an abnormal palmar angle, but it is the left front foot with the coffin bone rotation and life threatening laminitis! The deep digital flexor tendon was transected in the left front limb and follow-up radiographs will follow!
To be continued......

Figure 6 (Right front)

Figure 7 (Right front)

Club foot!!

The radiograph below is from a weanling colt with a severe case of a "club foot". Figure 1 is the affected foot and figure 2 is the normal foot. X-ray vision was not necessary in this case to confirm the diagnosis due to the classic distortion of the hoof capsule. Club feet in foals develop from tendon contracture or secondary to accelerated skeleton growth. As the leg bones grow in length the soft tissue structures (tendons and ligaments) cannot keep up with the rate of growth resulting in contracture of the joint spaces. In the case of a "club foot" it is the coffin joint or DIP joint that is contracted and results in abnormal hoof growth.

Figure 1

Figure 2

The yellow line below corresponds to the alignment of the short pastern bone and the coffin bone. In Figure 3, the alignment is normal. However in Figure 4 the dorsal surface of the coffin bone is not aligned with the short pastern bone. The letter "A" in figure 4 corresponds to the angle of contracture. The contracture occurs in part due to the strong pull of the deep digital flexor tendon that attaches to the bottom of the coffin bone. As the leg bones lengthen and the flexor tendons do not keep up with the growth rate, the coffin bone is pulled resulting in contracture of the joint.

Figure 3

Figure 4

Treatment of this condition in young horses varies and includes early weaning, reduced caloric intake,  repeated injections of oxytetracycline to relax the tendons, corrective trimming/shoeing, and surgical transection of the distal check ligament. In my clinical experience, many foals with mild contracture respond well to the oxytetracycline and corrective trimming protocol. However, more advanced cases such as this colt require surgical intervention. The distal check ligament attaches to the deep digital flexor tendon and essentially keeps it in "check". By cutting the ligament, there is some release of the pull by the deep digital flexor tendon on the coffin bone. This surgical procedure can be performed in a stall-side setting, in a standing patient. Once it is determined that surgery is indicated, the sooner the better!  The colt in this case was treated with oxytetracycline and corrective trimming for 2 months with minimal improvement. When he was 6 months old, the distal check ligament of the affected limb was transected. Figure 5 is the "club foot" 45 days post surgery, note the corrected alignment of the pastern and coffin bones. The colt's lameness resolved.  This case highlights the importance of early documentation with radiographs and early intervention to correct the "club foot".

Figure 5