Plantar Annular Ligament Desmitis in a Horse

A 10 year old gelding presented for bilateral rear-limb lameness associated with excessive "wind puff" formation. The gelding typically had some wind puff formation above the rear fetlock joints but it had suddenly increased and subsequently the lameness was noted. Physical exam noted moderate to severe fluid accumulation within the distal flexor tendon sheaths, otherwise known as wind puffs (Figures 1-2). The fluid within the flexor tendon sheath tends to accumulate at the top of the sheath due to a very thin band of connective tissue that spans the back or plantar/palmar aspect of the fetlock. This tissue is called the plantar/palmar annular ligament (PAL) of the fetlock (Figure 2 (blue circle))

Figure 1

When fluid begins to accumulate within the tendon sheath due to simple tenosynovitis of the sheath or a tendon/ligament injury, the PAL becomes restrictive resulting in a "wind puff" (Figure 2, red circle), which consists of a pocket of fluid noted just above the fetlock joint. As the fluid increases in volume the PAL is stretched and inflammation develops within the ligament. Once inflammation develops within the PAL, lameness in that limb is common.

Figure 2

 Diagnosis is confirmed via ultrasonic exam. In Figures 3-4, the flexor tendons within the sheath are imaged and include the superficial flexor (SDF: blue) and deep digital flexor tendon (DDF: green). In addition, the PAL is visualized directly above the SDF tendon. Normally, the PAL is very thin and only measures 2-4mm in thickness. In this horse, the PAL measured nearly 10mm in thickness (blue arrows) and there were pockets of edema (black areas) along with poor fiber alignment! Chronic thickening of the PAL ligament may result in the inflammation within the SDF tendon which will significantly worsen the prognosis and lameness!  For this reason, careful examination via ultrasound is key.

 (Figure 3

 In this particular horse there does not appear to be involvement of the SDF or DDF tendons. The PAL appears very thick and inflamed. In Figure 4, the same area is imaged in a cross sectional view (left image) and a transverse view (right image). The significant amount of edema and disrupted fiber pattern within the PAL is quite evident in the both views!! Management of this condition involves corrective shoeing, topical anti-inflammatory application, and in my opinion surgical intervention. Once the PAL is grossly thickened, it is my experience that only surgical transection of the PAL ligament will provide a long term solution for the horse. It is very important to thoroughly ultrasound the limb through the pastern area to ensure that no ligaments or tendons are involved!! Finally, wind puffs are a common occurrence in many sport horses and usually indicate that the horse is in steady work. However, asymmetric wind puffs or a sudden increase in size is not normal and merits examination by your veterinarian!!

Figure 4

Thin Soles in a Horse!!

The radiographs below in Figures 1-3 belong to a middle-aged QH gelding that presented for severe lameness. The gelding was recently trimmed by the farrier and had a history of mild to moderate foot pain.
On presentation, the gelding was very sore when asked to walk on a firm surface and was not willing to walk in a tight circle! There were NO pounding digital pulses however firm pressure, via my finger tips, over the sole region resulted in a strong pain reaction by the gelding. Radiographs were taken and severely thin soles were diagnosed in both front feet (Figure 1 and 2). The actual thickness of the sole was difficult to measure due to the thinness but was approximated at 2-3mm (Figure 3). Less than 5mm of thickness essentially corresponds to 1 swipe with the hoof knife!!

Figure 1

Figure 2

Figure 3

In Figure 4, there is a radiograph of a normal horse's foot. The sole depth at the toe region is approximately 15-20mm. In my experience, when the sole thickness is less than 10mm, there is increased likelihood of foot pain from concussion with the ground. Thin soled horses are at high risk for sole bruising and sub-solar abscess development. Unfortunately, some horses are "naturally" thin soled due to poor genetics and MUST be managed with shoes. The corrective shoeing is simple and may include a rim pad, leather pad , or soft pour-in pad. I strongly recommend radiographic evaluation PRIOR to any foot trimming to determine the sole thickness of horses that have a history of chronic foot pain!

Figure 4

Sand Impaction in a Horse

A six year old gelding presented for recurrent low grade fever and intermittent diarrhea. At the time of the initial exam the gelding was alert and showing no signs of discomfort. Vitals were normal and body temperature was 100.5 degrees.  A blood sample was collected for complete blood count (CBC) analysis and a rectal exam was performed. A large, firm structure was palpated along the left flank of the horse which was consistent with an impaction of the "pelvic flexure".  The fecal material removed from the rectum was partially formed and had a grainy feel to it. Several hand fulls of manure were placed in a rectal sleeve and the sleeve was filled with water (Figure 1).  A significant amount of sand was identified in the sleeve filled with water!

Figure 1

 The gelding was treated aggressively with water and mineral oil via a naso-gastric tube however; his condition worsened and he was referred to a surgical facility. Despite knowing that the gelding had a pelvic flexure impaction which is usually managed medically, the gelding was taken to surgery due to refractory pain. Abdominal exploration revealed an extremely large, firm impaction of the left colon which "bottle necked" at the pelvic flexure (blue arrow in Figure 2).  Discovery of such an impaction during surgery typically results in making a small opening in the colon wall and resolving the impaction. However, a small tear was discovered along the edge of the impaction which had resulted in fecal contamination of the abdomen. Prognosis was poor and the owners opted for humane euthanasia.

Figure 2

This case of sand impaction in a horse is sadly NOT uncommon in the state of Florida! The accumulation of sand within the colon of a horse is typically a result of poor pasture conditions and can develop very quickly. There are several "hair-pin" turns within the large colon of horses which create ideal conditions for the accumulation of sand and other debris. The pelvic flexure is one of those "hair-pin" turns and is one of the most common locations for colon impactions in horses. Unfortunately, once the sand impaction develops it is very difficult to resolve by providing oral medication such as psyllium (Figure 3)  and mineral oil (Figure 4).

Figure 3

Figure 4

The clinical indicators of sand accumulation in horses include intermittent diarrhea, low white blood cell count, fever and plus/minus colic. The sand is abrasive to the lining of the colon which results in diarrhea and sequestration of white blood cells in the colon wall. Horses with sand accumulation within their colons often have a week or month-long history of diarrhea! This is the time to treat the horse with sand clearing products. Once the horse becomes completely obstructed, surgery may be the only option to resolve the impaction. There are several products available to treat horses on a monthly basis as "sand clearing" products however once sand has accumulated within the colon, these products are not effective. They are more effective if used as products to prevent sand accumulation in combination with good pasture management! This condition is treatable but MUST be addressed when clinical signs first develop!!

Sub-solar Abscess in a Horse!!

Figure 1

The radiograph in Figure 1 is of a horse's hind foot. This gelding has been suffering from chronic laminitis/founder for over 1 year. When I first examined this horse, there was nearly zero sole depth between the coffin bone and the bottom of the foot. In addition, the coffin bone was reduced in size due to gradual degradation (pedal osteitis) of the coffin bone. The pedal osteitis developed due to the chronic pedal bone rotation that is evident in Figure 2 (non-parallel red lines). It was decided that a deep digital flexor tenotomy combined with appropriate shoeing may help stabilize the foot and promote sole growth. Over 4-6 months after the surgery, the gelding's sole depth increased significantly, indicating normal hoof growth and he was more comfortable on this limb.

Figure 2

Recently, the gelding's lameness worsened and he was non-weight bearing when examined. A lateral radiograph was performed (Figure 1-3). A large, radiolucent area (red circle) was noted in the toe region of the foot with a track that appeared to be traveling toward the coronary band (Figure 3). These findings are consistent with a large, sub-solar abscess! 

Figure 3

The shoe was removed and a large "hole" was noted at the apex of the frog that extended into a cavity with the circumference of a golf ball! The abscess appeared to be draining however it involved a significant amount of space between the bottom of the sole and the coffin bone. After removing the shoe, the foot was soaked in a warm epsom salt solution and then was "packed" with a strong disinfectant. The gelding's lameness improved within 24 hrs however he remains lame at the walk. His return to soundness will take some time and most likely require a specialized shoe known as a hospital plate. Recurrent foot abscess formation is a common problem among chronically foundered horses and highlights the importance of regular trimming/shoeing plus radiographic examination!

Figure 4