In:
PLOS ONE, Public Library of Science (PLoS), Vol. 18, No. 9 ( 2023-9-14), p. e0291599-
Abstract:
Despite the success of primary total hip arthroplasty, the number of revisions remains high. Infection, aseptic loosening, periprosthetic fractures and dislocations are the leading causes of hip revision. Current revision stem designs feature a tapered body with circumferential placed longitudinal thin metal splines that cut into the femoral cortex of the diaphysis to provide axial and rotational stability. Modifications to the spline design may help improve primary stability in various bone qualities. The purpose of this study was to evaluate whether the rotational stability of a revision hip stem can be improved by an additional set of less prominent, wider splines in addition to the existing set of splines. It is hypothesized that the additional splines will result in greater cortical contact, thereby improving torsional strength. Methods and findings The ultimate torsional strength of an established modular revision stem (Reclaim ® , DePuy Synthes) was compared to a Prototype stem design with two sets of splines, differing in prominence by 0.25 mm. Five pairs of fresh-frozen human femurs (n = 10) were harvested and an extended trochanteric osteotomy was performed to obtain common bone defects in revision. Stems were implanted using successive droptower impacts to omit variability caused by mallet blows. The applied energy was increased from 2 J in 1 J increments until the planned implantation depth was reached or seating was less than 0.5 mm at 5 J impact. The ultimate torsional strength of the bone-to-implant interface was determined immediately after implantation. Image superposition was used to analyze and quantify the contact situation between bone and implant within the femoral canal. Cortical contact was larger for the Prototype design with the additional set of splines compared to the Reclaim stem (p = 0.046), associated with a higher torsional stability (35.2 ± 6.0 Nm vs. 28.2 ± 3.5 Nm, p = 0.039). Conclusions A second set of splines with reduced prominence could be shown to improve primary stability of a revision stem in the femoral diaphysis in the presence of significant proximal bone loss. The beneficial effect of varying spline size and number has the potential to further improve the longevity of revision hip stems.
Type of Medium:
Online Resource
ISSN:
1932-6203
DOI:
10.1371/journal.pone.0291599
DOI:
10.1371/journal.pone.0291599.g001
DOI:
10.1371/journal.pone.0291599.g002
DOI:
10.1371/journal.pone.0291599.g003
DOI:
10.1371/journal.pone.0291599.g004
DOI:
10.1371/journal.pone.0291599.g005
DOI:
10.1371/journal.pone.0291599.g006
DOI:
10.1371/journal.pone.0291599.g007
DOI:
10.1371/journal.pone.0291599.g008
DOI:
10.1371/journal.pone.0291599.g009
DOI:
10.1371/journal.pone.0291599.g010
DOI:
10.1371/journal.pone.0291599.s001
DOI:
10.1371/journal.pone.0291599.s002
DOI:
10.1371/journal.pone.0291599.s003
DOI:
10.1371/journal.pone.0291599.r001
DOI:
10.1371/journal.pone.0291599.r002
DOI:
10.1371/journal.pone.0291599.r003
DOI:
10.1371/journal.pone.0291599.r004
Language:
English
Publisher:
Public Library of Science (PLoS)
Publication Date:
2023
detail.hit.zdb_id:
2267670-3
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