Abstract
A distal physeal metatarsal fracture (Salter IV) in a 15-month-old female reticulated giraffe (Giraffa camelopardalis) was successfully managed by external coaptation using fiberglass walking casts and barn confinement. The animal was immobilized using xylazine and etorphine on four occasions over 20 weeks for three cast applications and the final cast removal. It was maintained in barn confinement during this time and for an additional 2 months because of joint laxity in the affected fetlock after removal of the final cast. Return of the animal to the herd was uneventful although full resolution of soft tissue swelling and laxity in the affected joint required several months.
Case Report
A 15-month-old female giraffe presented with an acute weight bearing lameness of the right hind limb associated with significant lateral deviation of the extremity distal to the fetlock. The fetlock area was swollen and the degree of misalignment was such that a fracture or luxation was apparent, yet the animal bore considerable weight on the injured limb. It was separated in a stall for immobilization and evaluation the following day. The stall had a quarter circle configuration and a swing gate designed for crowding a giraffe to restrict space during immobilization.
The animal was estimated to weigh 400 kg. It was darted with 25 mg xylazine (Xyla-Ject, Phoenix Pharmaceuticals, Inc., St. Joseph, MO, USA) combined with 10 mg atropine (Atropine Sulfate L.A., Phoenix Pharmaceuticals, Inc., St. Joseph, MO, USA). The squeeze was gradually closed to restrict movement until the animal was confined in a space in which it was unable to turn around. Twenty minutes after the initial injection, 2 mg etorphine (M-99, Lemon Co., currently available from Wildlife Pharmaceuticals, Inc., Fort Collins, CO, USA) combined with 75 mg hyaluronidase (Wydase, Wyeth Laboratories, Inc., Philadelphia, PA, USA) was given by pole syringe. The squeeze gate prevented the animal from falling over backward and recumbency was complete in 9 minutes. The gate was then opened, the animal was laid in lateral recumbency with the head and neck elevated. Oxygen was administered by nasal catheter and the tongue was extended to prevent it from impeding respiration.
Radiographs revealed a distal physeal fracture of the metatarsal bone and a fracture of the corner of the distal lateral metatarsus (Salter IV) with 10–15% lateral displacement at the physis. Traction was applied to the injured limb for approximately 15 minutes by means of a rope tied around the base of the foot and attached to a cable ratchet device (“come-along”). The animal was prevented from sliding when traction was applied by securing another set of thick cotton ropes through the groin, around the limb and up over the hip to tie against a back wall. Intravenous ketamine (Ketaset, Fort Dodge Laboratories, Inc., Fort Dodge, IA, USA) was given to deepen anesthesia during traction. This effort was unsuccessful and an equine-type walking cast was applied to a level just below the hock without further attempts to reduce the fracture. This was done using fiberglass cast material over custom foam support and stockinette (Orthopedic Products Division/3M, St. Paul, MN, USA).
Total work time required to accomplish the procedures was 132 minutes. Four supplemental doses of 200 mg ketamine IV and two doses of 0.5 mg IV etorphine were given during the procedure. The last dose of etorphine was given to position the animal in sternal recumbency for closure of the crowding gate prior to recovery. Reversal was accomplished with tolazoline (Priscoline, Ciba-Geigy Corp., Pharmaceuticals Div., Summit, NJ, USA) 100 mg IV and diprenorphine (M50-50, Lemon Co.) 6 mg IV. The animal stood 9 minutes after reversal, but fell back down to a sternal position until successfully standing at 15 minutes. The crowding gate prevented it from falling on its side.
The giraffe was confined in two adjoining barn stalls measuring 8.6 m × 6 m, and 8 m × 5 m. It was not bearing weight on the affected limb for several days and was given phenylbutazone (Equi-Phar Butazolidin, Vedco, Inc., St. Joseph, MO, USA) 2 g/day on the feed during this time. During a second immobilization 2 weeks later, the cast was removed and radiographs were taken which showed the fracture to be stable with possible early callus formation. Swelling of the fetlock was reduced and the fracture site was stable by palpation. A second cast was applied as before with extra reinforcement of the toe to compensate for excessive wear from dragging the cast. The heel area was built up to help promote weight bearing. The time required to complete the procedures was 86 minutes and additional doses of etorphine and ketamine were necessary as before. The animal stood up successfully on the first attempt 5 minutes after reversal using 300 mg tolazoline IV and 6 mg diprenorphine IV. The giraffe was walking with improved use of the limb 3 days after the second cast was applied and was fully weight bearing in about 3 weeks. By this time, it trotted around the barn stalls showing excellent adaptation to the cast.
The second cast was removed in 8 weeks. Radiographs showed solid callus formation with bone remodeling and beginning resorption of the fragment. A third cast was applied since it was judged that at least 16 weeks of cast immobilization would be required for complete healing, as is recommended in the equine for this type of fracture. At the time of this procedure, the animal’s body weight was estimated at 450 kg. For the third immobilization, 50 mg xylazine and 3 mg etorphine were given, which provided excellent induction with 42 minutes of work time. However, respirations were irregular and shallow with breath holding. This was improved by giving doxapram (Dopram-V, Fort Dodge Laboratories, Inc., Fort Dodge, IA, USA) 20 mg IV, after which respirations were regular at 24/minutes. The animal stood up with good control 2 minutes after reversal using 400 mg tolazoline (½ IV and ½ IM) and 6 mg diprenorphine IV.
The giraffe was immobilized a fourth time at 20 weeks post fracture to remove the final cast and radiograph the limb. Immobilization and reversal doses were the same as for the previous procedure and provided a smooth induction and recovery (28 minutes of work time) with doxapram given as before to stimulate respiration. Radiographs showed complete calcification and remodeling of the fracture site with slight lateral angulation distal to the fracture. There was significant concern about instability of the fetlock because of marked flexor tendon laxity in the unsupported joint after 20 weeks in a cast. The animal was confined in the immobilization stall with the crowding gate positioned to restrict space (21 m2) for 2 weeks to allow the supporting tendons and ligaments to strengthen and tighten while avoiding a destabilizing force from overexertion. The animal remained calm and compliant while in this confinement. Phenylbutazone was given for 3 weeks and access to additional space was gradually permitted.
The giraffe was released from the barn into the exhibit 6.5 months after the injury. It bolted out of the barn and galloped around the exhibit for about 15 minutes without resting. There were no signs of lameness or favoring of the injured limb although there was still a slightly perceptible lateral deviation of the extremity distal to the fracture. The laxity of the fetlock gradually reduced over the next several months and there have been no further complications in the 2 years since the original injury.
This injury almost certainly resulted from the animal wedging its foot under a gap beneath a gate while it was recumbent with its limbs extended posteriorly. It then stood up before retracting the limb. All gates and barriers were carefully inspected to identify and eliminate such gaps.
The successful management of this fracture was based on several factors, but among the most important were:
1. Having a tractable patient
2. Having an adequate immobilization stall with a crowding gate to allow for controlled induction and recovery with reduced risk of injury to the unstable fracture site or to the animal
3. Having spacious barn facilities for separation of the patient on a clean dry substrate for several months
4. Allowing adequate time for healing prior to return of the animal to the exhibit and to other herd members
Literature Cited
1. Bush M, Ensley PK, Mehren K, Rapley W. Immobilization of giraffes with xylazine and etorphine hydrochloride. J Am Vet Med Assoc. 1976;169:884–885.