Effect of risedronate on bone resorption during consolidation phase of distraction osteogenesis: a rabbit model.
OBJECTIVE
To evaluate the effects of continuous local injection of risedronate in the prevention of bone resorption in a lengthened segment.


METHODS
11 male rabbits underwent subperiosteal osteotomy of the left tibia and an external fixator was applied anteromedially. After a lag phase of one week, a 2-week distraction phase and a 5-week consolidation phase followed. Risedronate was continuously injected into the centre of the distracted segment at a rate of 10 micro g/kg/day during the first 14 days of consolidation by a subcutaneously implanted osmotic pump. A control group received purified buffer solution (PBS) using the same protocol. The lengthened bone segments were evaluated using radiography, quantitative computed tomography, and 3-point bending mechanical test.


RESULTS
Risedronate injection prevented osteopenia as compared to PBS injection. The mean bone mineral content, volumetric density and cross-sectional area of the lengthened segments were significantly higher in the risedronate group than in controls (as much as 65%, 30%, and 25%, respectively). There was no significant difference between the 2 groups regarding the ultimate load to failure.


CONCLUSIONS
Continuous local injection of risedronate into the lengthened segment can prevent osteopenia during distraction osteogenesis but fails to enhance mechanical strength of newly distracted segments.
Heidari
Pedram
P
Department of Orthopedic Surgery, Imam Khomeni Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
Abbaspour
Aziz
A
Baghdadi
Taghi
T
Espandar
Ramin
R
Farzan
Mahmoud
M
Amanpour
Saeid
S
Rasouli
Mohammad Reza
MR
Mohagheghi
Mohammad Ali
MA
Amiri
Hamid Reza
HR
Yasui
Natsuo
N
D000818:Animals; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001861:Bone Regeneration / Q000187:drug effects*; D001862:Bone Resorption / Q000209:etiology / Q000517:prevention & control*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D012968:Etidronic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005500:Follow-Up Studies; D015552:Injections, Intralesional; D007430:Intraoperative Care / Q000379:methods*; D008297:Male; D019857:Osteogenesis, Distraction / Q000009:adverse effects* / Q000379:methods; D011817:Rabbits; D011859:Radiography; D012189:Retrospective Studies; D000068296:Risedronic Acid; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome
D050071:Bone Density Conservation Agents; D000068296:Risedronic Acid; D012968:Etidronic Acid