Shear-load carrying capacity of cancellous bone after implantation of self-reinforced polyglycolic acid and poly-L-lactic acid pins: experimental study on rats.
Both distal femora of 40 rats were implanted with a self-reinforced polyglycolic acid (SR-PGA) pin in the right femur and with a self-reinforced poly-L-lactic acid (SR-PLLA) pin in the left femur. The intact femora of 20 rats served as controls. The follow-up times were 1, 3, 6, 12, 24, 36, 48, and 52 weeks. After killing all operated and control femora were examined macroscopically and radiographically. The shear-load carrying capacities of all the femurs were investigated, and the SR-PGA and SR-PLLA fixed specimens were compared with each other and with the control specimens. The shear-load carrying capacities reached their highest values at 36 weeks in the SR-PGA and SR-PLLA fixed and control specimens. Thereafter they gradually decreased. At 52 weeks both the SR-PGA fixed specimens and the control specimens had statistically significantly (p < 0.001) higher values than the SR-PLLA fixed specimens, when the influence of the pins had ceased. Otherwise, the shear-load capacities showed higher values in the SR-PLLA fixed specimens, as the pins carried the load. During the whole follow-up period the mean shear-load carrying capacity of the SR-PGA fixed specimens was 171.2 N and that of the SR-PLLA fixed specimens 180.9 N, the corresponding value of the control specimens was 148.2 N.
Nordström
P
P
Department of Orthopaedics and Traumatology, Helsinki University Central Hospital, Finland. pia.nordstrom@hus.fi
Pohjonen
T
T
Törmälä
P
P
Rokkanen
P
P
D000818:Animals; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D001858:Bone Nails; D005269:Femur / Q000601:surgery; D019344:Lactic Acid; D008422:Materials Testing; D011091:Polyesters; D011100:Polyglycolic Acid; D011108:Polymers; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide)