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· DOS Abstracts
High incidence of periprostetic lucency in CCI
Evolution ankle implants, measured by CT and X-ray
Sanja Somodi, Jeannette Østergaard Penny, Kim Hegnet Andersen, Lars Bo
Ebskov, Peter Bro Rasmusen, Omar Muharemovic
Dep. of Radiology, Hvidovre Hospital; Dep. of Orthopaedics, Hvidovre Hospital;
Dep. of Orthopaedics, Hvidovre Hospital; Dep. of Orthopaedics, Hvidovre
Hospital; Dep. of Orthopaedics, Hvidovre Hospital; Dep. of Radiology,
Background:
A mobile bearing ankle prosthesis used at Hvidovre Hospital
2010-2013, was abandoned due to failures and findings of bone loss at revi-
sion.
Purpose / Aim of Study:
The aim of this study was to a) Determine our true
revision rate, b) Investigate prevalence, size and location of periprosthetic bone
cysts through X-ray and CT and c) Relate these findings patient reported out-
come measurements (PROMs).
Materials and Methods:
51 primary surgeries were performed, prior to this
study 8 had been revised. Out of 43 un-revised patients, 36 were enrolled and
underwent evaluation with metal artefact reduction CT-scans and conventional
X-ray. They filled out 3 PROMs; SEFAS, SF-12, EQ-5D. Cyst volume larger than
0.1 ml was measured using VITREA volume tools for CT-scans and calculation
of spherical volume for X- rays; using AP- and lateral projections. PROMs as-
sociation to osteolytic volume was analyzed by linear- and logistic regression.
Findings / Results:
Finding large osteolytic lesions caused 4 additional patients
to undergo revision and 7 are being monitored due to high risk of failure. Of
the original 51 implants 14 have been revised, primarily because of osteolytic
lesions and non-union (8 true revisions/implant exchange or bone transplant),
periprosthetic fractures (3 cases, of which 2 were non-traumatic fractures) and
3 cases due to exostosis. The 3- and 5 year revision rate was 14% and 16% for
revision and 17% and 27% overall. Cystic lesions were found in 81% of par-
ticipants. Total cystic volume was not significantly related to PROM-scores (P
0.16-0.5).
Conclusions:
The implant investigated performs below standard, compared to
public registries* that report overall 5 year revision rates at 5 - 6.5% in compa-
rable implants. Cysts were common, large and not related to PROMs. *Swedish
National Foot Registry Ann. Report 2013. New Zealand 15 Year Report 2014.
No conflicts of interest reported
61.