Application of calcium phosphates and fibronectin as complementary treatment for osteoporotic bone fractures.
BACKGROUND
The gradual aging of the population results in increased incidence of osteoporotic bone fractures. In a good quality bone, the fixation with the usual methods is adequate, but not in osteoporotic bone, in which consolidation delays and other complications are common, with failure rates for screws up to 25%.


OBJECTIVE
To test fibronectin loaded hydroxyapatite as a complementary treatment for osteoporotic fractures.


METHODS
This study was performed in a vivo model; 42 female osteoporotic adult rabbits 4-5kg (White New Zealand) were used. Two groups (hydroxyapatite and fibronectin loaded hydroxyapatite) and a control group were tested. 3 time points 24h, 48h and 5days were studied. Defects were created in both femurs, in one of them, a cannulated screw (4mm) and a biocompatible material were placed; in the other femur a screw was inserted without supplemented material forming the control group. Osteoporosis was induced from models already known throughout administration of steroids. Samples were analyzed histologically and through imaging (micro Ct).


RESULTS
Basal levels of BMD are observed below to normal when compared to other studies (0.25/0.3 instead of 0.4). Global and dependent of time analysis of samples, show no significant differences for samples analyzed. However, an important trend was noted for variables that define the trabecular bone microarchitecture. Indices that define trabecular microarchitecture in the comparative analysis found to have statistical differences (p<0.01).


CONCLUSIONS
Osteosynthesis in an osteoporotic bone is a challenge for the surgeon, due to a reduced bone mineral density and different bone architecture. The main finding was the verification of the hypothesis that the trabecular bone parameters increases with our augmentation material in weak rabbit bone quality. Also, the histological analyses of samples show an increase of non inflammatory cells in protein samples (OHAp-Fn) from the first 24hours.


CONCLUSIONS
An early response of rabbit osteroporotic bone to a complementary treatment with fibronectin loaded hydroxyapatite has been observed. This response is reflected in greater values for indices that define the trabecular bone microarchitecture, thickness and separation, a greater non-inflammatory cellularity after only 24hours and an increased amount of connective tissue observed at 48hours.
Hospital 12 de Octubre, Madrid, Spain. Electronic address: jvrquintanaplaza@gmail.com.
Javier Quintana
JQ
Plaza
Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain.
Lorena Benito
LB
Garzón
Hospital 12 de Octubre, Madrid, Spain.
Beatriz Bravo
BB
Gimenez
Biomaterials group, ICTP-CSIC, Madrid, Spain.
Belén Fernández-Montes
BF
Moraleda
Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain.
Francisco
F
Collía
Biomaterials group, ICTP-CSIC, Madrid, Spain; Polymeric Biomaterials Group, CIBER-BBN, Madrid, Spain.
Luis M
LM
Rodríguez-Lorenzo
D000818:Animals; D001843:Bone Cements / Q000494:pharmacology; D015519:Bone Density; D001863:Bone Screws; D002130:Calcium Phosphates / Q000494:pharmacology / Q000627:therapeutic use*; D004195:Disease Models, Animal; D017886:Durapatite / Q000494:pharmacology; D005260:Female; D005264:Femoral Fractures / Q000188:drug therapy / Q000473:pathology / Q000601:surgery; D005353:Fibronectins / Q000494:pharmacology / Q000627:therapeutic use*; D010024:Osteoporosis / Q000473:pathology* / Q000628:therapy; D058866:Osteoporotic Fractures / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery*; D011817:Rabbits
D001843:Bone Cements; D002130:Calcium Phosphates; D005353:Fibronectins; D017886:Durapatite
Fibronectin; Hydroxyapatite; Osteoporotic; Osteosynthesis