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Clinical Case Challenge: More than right craniodorsal hip luxation?
History An eight-month-old male German shepherd puppy escaped from his owner’s yard and was found several days later with obvious lameness in the right rear ...
May 6, 2019

History

An eight-month-old male German shepherd puppy escaped from his owner’s yard and was found several days later with obvious lameness in the right rear leg and a large area of full-thickness skin loss extending from the mid-portion of the right inner thigh to the opposite side of the prepuce.  The local veterinarian obtained radiographs of the pelvis, which showed a right craniodorsal hip luxation with no evidence of fractures in the area.  The veterinarian cleaned and debrided the thigh wound, covered it with a tie-over bandage, and referred the patient to Foster Hospital for Small Animals at Cummings Veterinary Medical Center.

What’s Your Diagnosis?

Question 1 – What are the options for managing the hip luxation in this case, and the pros and cons of each?

Answer

If DV radiographs do not demonstrate avulsion of the fovea capitus, closed reduction of hip luxation under general anesthesia can be attempted.  This was not considered in this case because it would require placement of an Ehmer sling directly over the open wound.  Instead, options for open reduction and surgical stabilization of the joint were considered.  Stabilization options include direct suturing of the joint capsule, creation of a prosthetic joint capsule, and the toggle pin technique.  Of these, the toggle pin technique provides the most support to the joint and allows early use of the operated hip.  It was chosen in this case to simplify management of the open wound.  The technique involves drilling a hole through the femoral neck and acetabulum. A toggle pin with heavy non-absorbable suture attached to it is passed through the acetabular hole.  The sutures are then passed down the hole in the femoral neck and secured.  The sutures replace the torn round ligament, which normally holds the femoral head in the acetabulum (Figure 1).

Question 2 – What are the options for managing the open wound, and the pros and cons of each?

Answer

Options for early open wound management are a conventional wet-to-dry tie-over bandage and application of a vacuum-assisted closure (VAC) system (KCI Inc., San Antonio, TX).  While the conventional technique is effective, it requires daily sedated bandage changes, is unreliable in preventing infection, and does not encourage the formation of granulation tissue.    In vacuum-assisted closure systems, a fitted porous polyurethane sponge is placed directly in the wound and covered with a sterile adhesive plastic drape that is glued to the patient’s skin surrounding the wound.  Continuous negative pressure is delivered to the wound and sponge via a tube connected to a small vacuum device and canister that sit beside the patient (Figure 2).  The system draws exudate away from the wound, draws the edges of the wound inward, and markedly increases the speed of granulation tissue formation.  The toggle pin and VAC system were placed in a single anesthetic episode in this case and allowed the puppy to walk and rest while the wound granulated, without the need for daily bandage changes (Figure 3).   The VAC system was removed and the granulated wound was closed five days later.

Postoperative radiograph showing the toggle pin positioned medial to the acetabulum

Postoperative radiograph showing the toggle pin positioned medial to the acetabulum. The holes drilled in the femoral neck and acetabulum can be faintly visualized.

The VAC system following application to the right thigh wound

The VAC system following application to the right thigh wound. The wound is filled by the black polyurethane sponge and covered by an adhesive plastic drape. The tube runs to the vacuum device, which is applying continuous negative pressure to the wound and sponge.

German Shepherd following repair of the hip luxation

The patient following repair of the hip luxation and application of the VAC system.