lnfluence of stem design on Total Hip Arthroplasty. Clinical and radiological assessment based on randomized controlled trials and register data
Abstract
Since the 1960s, total hip arthroplasty has revolutionized the care of patients
with end-stage osteoarthritis. Results after surgery using contemporary
implants are usually good. Nevertheless, new implants are constantly being
developed and introduced to the market. In recent years, there has been a
trend towards shorter femoral implants, to save proximal bone and thereby
facilitate any future revision surgery.
This thesis aimed to evaluate three different stem design, comparing them
with a reference stem (Papers I–III). In Paper IV, register data were used to
study and compare survival rates and first-time revisions of short stems
versus stems of standard length.
Small differences in outcome were found between implants as regards
patient-reported outcome measures and migration as seen through
radiostereometric analysis. In contrast to the aim of the design, two of the
studied implants had more pronounced loss of proximal bone stock. In Paper
IV, the short stems showed survival rates equalling those of standard stems.
In first-time revisions, short stems were, more frequently than standard
stems, exchanged with stems of standard length as opposed to longer
revision stems.
In conclusion, there were small differences in outcome between the implant
designs studied and reference stems. Two of the studied stems were
associated with increased loss of proximal bone density, this stands in
contrast to the aim of the design. However, if revision becomes necessary, a
short stem seems to allow for replacement with a stem of standard length,
which may be advantageous in younger patients with risk of repeated revision
surgery.
Parts of work
I. Rilby, K., Nauclér E., Mohaddes, M., Kärrholm J., Similar
outcome with a new anteverted or a straight standard stem:
a randomized study of 72 total hip arthroplasties evaluated
with clinical variables, radiostereometry, and DXA up to 2
years. Acta Orthopaedica. 2022; 93: 59-67. https://doi.org/10.1080/17453674.2021.1993606 II. Rilby, K., Nauclér E., Mohaddes, M., Kärrholm J., No difference
in outcome or migration but greater loss of bone mineral
density with the Collum Femoris Preserving stem compared
with the Corail stem: a randomized controlled trial with five year follow-up. The Bone & Joint Journal. 2022; 104-B(5):
581-588. https://doi.org/10.1302/0301-620X.104B5.BJJ-2021-1539.R1 III. Rilby, K., Mohaddes, M., Kärrholm J., Similar results
after five years with the use of the Fitmore or the CLS femoral
components. The Bone & Joint Journal Open. 2023; 4(5): 306-
314 https://doi.org/10.1302/2633-1462.45.BJO-2023-0007.R1 IV. Rilby, K., van Veghel M., Mohaddes M., van Steenbergen L., Lewis P., Kärrholm J., SchreursW., Hannink G. Does choice of primary stem influence choice of revision stem? Evaluation of 591 first time femoral stem revisions in 16,258 primary short-stem Total Hip Arthroplasties (THA) and 32,515 matched standard-stem THAs from the Australian, Dutch and Swedish Arthroplasty Registers. In manuscript.
Degree
Doctor of Philosophy (Medicine)
University
University of Gothenburg. Sahlgrenska Academy
Institution
Institute of Clinical Sciences. Department of Orthopaedics
Disputation
Fredagen 3 maj 2024, kl 9.00, R-Aulan, R-huset, Mölndals sjukhus, Göteborgsvägen 31, Mölndal
Date of defence
2024-05-03
karin.rilby@vgregion.se
Date
2024-04-09Author
Rilby, Karin
Keywords
total hip arthroplasty
radiostereometric analysis
patient-reported outcomes
bone mineral density loss
Revision
Publication type
Doctoral thesis
ISBN
978-91-8069-689-0 Tryck
978-91-8069-690-6 pdf
Language
eng