Ibandronate for prevention of femoral head deformity after ischemic necrosis of the capital femoral epiphysis in immature pigs.
BACKGROUND
Femoral head deformity is the most serious sequela of ischemic necrosis of the immature femoral head. The purpose of this study was to determine if a highly potent antiresorptive agent, ibandronate, can inhibit bone resorption during the repair of the infarcted femoral head and thus alter the repair process. We hypothesized that preservation of the trabecular framework by inhibiting osteoclastic bone resorption would minimize the development of deformity in a piglet model of ischemic necrosis. The effect of ibandronate on long-bone growth was also assessed.


METHODS
Ischemic necrosis of the right femoral head was produced in twenty-four piglets by placing a ligature tightly around the femoral neck. The animals were divided into three groups according to whether they received saline solution, prophylactic treatment, or post-ischemia treatment. The contralateral, untreated femoral heads from the animals that had received saline solution served as the normal control group. At eight weeks, the femoral heads were assessed for deformity with radiography and for trabecular bone indices with histomorphometry. Also, the length of femur from the untreated side was measured on the radiographs and compared among the groups.


RESULTS
Radiographic assessment showed that the epiphyseal quotient, determined by dividing the maximum height of the osseous epiphysis by the maximum diameter, was better preserved in the prophylactic (p < 0.001) and post-ischemia (p = 0.02) treatment groups than in the group treated with saline solution. Histomorphometric assessment also showed that the trabecular bone indices were better preserved in the prophylactic and the post-ischemia treatment groups than in the group treated with saline solution (p < 0.01). The mean femoral length on the untreated side of the animals treated with ibandronate was reduced compared with the length on the untreated side of the animals that had received saline solution (p </= 0.01).


CONCLUSIONS
Ibandronate preserves the trabecular structure of the osseous epiphysis and prevents femoral head deformity during the early phase of repair of ischemic necrosis in the piglet model.
Kim
Harry K W
HK
Shriners Hospitals for Children, 12502 Pine Drive, Tampa, FL 33612, USA. hkim@shrinenet.org
Randall
Timothy S
TS
Bian
Haikuo
H
Jenkins
Joe
J
Garces
Amanda
A
Bauss
Frieder
F
D000818:Animals; D001862:Bone Resorption / Q000517:prevention & control*; D004164:Diphosphonates / Q000627:therapeutic use*; D004838:Epiphyses / Q000098:blood supply*; D005270:Femur Head / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology*; D005271:Femur Head Necrosis / Q000473:pathology*; D000077557:Ibandronic Acid; D007238:Infarction / Q000150:complications; D007511:Ischemia; D008297:Male; D010014:Osteolysis / Q000517:prevention & control; D011859:Radiography; D013552:Swine
D004164:Diphosphonates; D000077557:Ibandronic Acid