R. Cook1; C. Thacher2; P. Calle1; B.
Raphael1; A. Kapatkin2; M. Stetter1
A 1.5 year old male polar bear (Ursus maritimus) presented non-weight bearing on the left hindlimb. The animal had been housed with his mother, an 8.5 y.o. female which had successfully reared previous offspring. The facilities included a naturalistic exhibit with a fresh water pool and an off exhibit holding area with a fresh water pool. The animals were fed a balanced ration which included an omnivore biscuit (Animal Spectrum, Inc. Lincoln, Nebraska 685060307), mackerel, herring, chicken with supplemental vitamin E and thiamin. The offspring was observed eating solid foods as well as nursing from the mother during the days prior to presentation.
The 148.6 kg animal was anesthetized with Teletamine:Zolazepam (Telazol(r) A.H. Robins Company, Richmond, VA 23220) at an initial combined dose rate of 1.7 mg/kg with supplements of teletamine:Zolazepam and ketamine Hcl (Ketaset(r) Aveco Co., Inc. Fort Dodge, Iowa 50501). In later procedures an initial combined dose rate of 3 to 3.3mg/kg of telazol was used which provided approximately 30 minutes sedation during which time the animal was moved to surgery, intubated and transferred to inhalant anesthesia with isoflurane at the Wildlife Health Center on the grounds of the Wildlife Conservation Park/Bronx Zoo. Physical exam and radiographic findings revealed a left supracondylar femoral fracture and fractures of the left metatarsals 1 through 5. A lateral patellar surgical approach was utilized for initial femoral fracture repair which included two intramedullary 5/16 pins to stabilize the fracture followed by four cross pins (two 3/30 and two 5/16): two intramedullary and two transcortical. The metatarsal fractures were stabilized with fiberglass casting tape (Delta-Lite "S" R, Johnson & Johnson, Raynham, MA 02767) extending from the toes to the hock. Five days post operatively a pin was protruding from the femoral fracture site and radiographs confirmed destabilization of the reduction and movement of the pins. The fracture site was again exposed using a lateral patellar approach. The previously inserted pins were removed and the fracture again stabilized using four 3/16" intramedullary pins in a cross pin fashion (2 lateral and two medial transcortical). A 6 hole broad 4.5 mm dynamic compression plate was applied to the lateral aspect of the femur using 3 cortical screws in holes 1-3 and 3 cancellous screws in holes 4-6.
Over the 10 week clinical course the animal underwent 8 anesthetic events which included the initial 2 surgeries, root canal surgery to repair a fractured right lower canine tooth repeat radiographs and cast changes. At 10 weeks the animal was released from the WHC to its enclosure. Initially the animal noticeably favored the left rear leg. Over the ensuing months there was a marked improvement in ambulation. At 6 months post-operatively there is little to no discernable gait abnormality. Medications used during the course of the disease included Enrofloxacin (Baytril(r), Miles Inc. Shawnee Mission, Kansas 66201) at approximately 2.5 mq/kg BID either P.O. Or I.M. x 30 days and flunixine meglumine (BanamineR, Schering-Plough Animal Health Corp., Kenilworth, New Jersey 07033) 0.8 to 1.0 mg/kg BID either P.O. or I.M. x 10 days.