Incomplete rupture of the gastrocnemius and superficial digital flexor muscles in a Quarter Horse stallion.

The paper is about the treatment of a Quarter Horse stallion with a rare muscle injury in its hind limb, resulting in severe lameness and further complications, which were successfully managed conservatively.

Introduction and Examination

• The research begins with a description of the unusual case of a 16-year-old Quarter Horse stallion, weighing 500 kg. The horse was displaying acute severe lameness in its left hind limb and was initially examined.
• Upon checking, signs of failure in the caudal component of the reciprocal apparatus were observed. In simpler terms, the horse’s tarsus (equivalent to the human ankle) flexed concurrently with an extension of the stifle joint (equivalent to the human knee), indicating a likely muscle injury.
• To confirm the cause, radiographic evaluations were conducted which ruled out fractures or joint injuries as reasons for the lameness.

Deterioration and Initial Management

• Despite ruling out fractures, the horse’s condition worsened over the following two days, leading to the horse becoming non-weight bearing on the wounded limb. This demanded immediate medical attention.
• The treatment started by wearing a full-limb splint over a Robert-Jones bandage on the plantar aspect (the back-side) of the limb for a period of 30 days.
• On the 34th day post the initial injury, the horse showed weak function of the reciprocal apparatus, with a limited ability to bear weight.

Complications and Further Treatment

• Six days after the removal of the splint, the horse developed laminitis, a painful and potentially crippling condition affecting the hoof, in the opposite hind limb.
• In response, the horse was managed with a sling for 5 weeks which unfortunately led to another complication – contracture of the deep digital flexor tendon. This is essentially a shortening or hardening of the muscles, tendons or tissue which restricts normal movement.
• But eleven weeks after the initial injury, the stallion was discharged from the hospital walking comfortably with a 1-cm-high block placed under the heel of the left hind foot as assistance.

Conclusion

• The paper concludes that the horse’s injury was likely due to a forced extension of the muscle while it was in contraction, possibly resulting from a fall with the hind limb extended under the body.
• Despite complications, such an unusual injury in a heavily muscled adult horse was successfully managed through conservative treatment methods.