Subject-specific planning of femoroplasty: An experimental verification study

Abstract

The risk of osteoporotic hip fractures may be reduced by augmenting susceptible femora with acrylic polymethylmethacrylate (PMMA) bone cement. Grossly filling the proximal femur with PMMA has shown promise, but the augmented bones can suffer from thermal necrosis or cement leakage, among other side effects. We hypothesized that, using subject-specific planning and computer-assisted augmentation, we can minimize cement volume while increasing bone strength and reducing the risk of fracture. We mechanically tested eight pairs of osteoporotic femora, after augmenting one from each pair following patient-specific planning reported earlier, which optimized cement distribution and strength increase. An average of 9.5(±1.7)ml of cement was injected in the augmented set. Augmentation significantly (P<0.05) increased the yield load by 33%, maximum load by 30%, yield energy by 118%, and maximum energy by 94% relative to the non-augmented controls. Also predicted yield loads correlated well (R2=0.74) with the experiments and, for augmented specimens, cement profiles were predicted with an average surface error of <2mm, further validating our simulation techniques. Results of the current study suggest that subject-specific planning of femoroplasty reduces the risk of hip fracture while minimizing the amount of cement required.

Can be the cement augmentation na improvement method of preventing hip fractures in osteoporotic patients?

“…Augmentation significantly increased the yield load by 33%, maximum load by 30%, yield energy by 118%, and maximum energy by 94% relative to the non-augmented controls. Basafa et al, 19 …”

“…The materials used in all experimental studies were cadaveric femurs with mineral density compatible with osteoporotic bones, and the augments were of many types: PMMA (seven studies), [10][11][12][13][14][15][16] CPC (two studies), 17,18 elastomers (four studies), [19][20][21][22] metal implants (two studies). 23,24 The metal implants were of two types, a titanium screw and a steel spiral shaped implant.…”

“…As the thought of the thermal injury occurring to the bone tissue in the indurating process, it was found that the optimization of the amount of volume of PMMA could reduce the rise of temperature and consequently shorten the possibility of a thermal lesion. [17][18][19][20] One of them even described the optimized volume, 6 mL, and the best positioning for the finite element use for the optimal mechanical result. 14 The studies using elastomers showed an enhancement of the bone strength against the fracture occurrence.…”

“…As negative possible outcomes, most of them described the possibility of thermal injury, a more difficult surgery for treatment in case of fracture occurrence and a chance of happening different patterns, more complex or unusual, of fracture due to the local density change. [15][16][17][18][19][20] The results of studies using the CPC showed an increase in the peak loading to fracture occurrence in values ranging from 21 to 43%, but the augmentation volumes used of such substance weren't described, but observing the radiography images of their articles we noted that the one with best results showed a complete filling of the proximal femur, a questionable fact for its application in vivo. There was no significant rise of temperature during polymerization of this product, as it was not observed description of optimization reFerences in their positioning.…”

“…8,9 In consideration to the importance of this subject, the authors present a literature review related to prevention of the fractures of the hip, presenting data in order to encourage the possibility of better results with this scientific development and ensuring this big step in the change of the evolution of fractures of the proximal femur in elderly patients.…”