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DOS Kongressen 2016 ·
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Good 2 year results with the new conical press-fit
cup design and dual-mobility articulation in total
trapeziometacarpal arthroplasty
Maiken Stilling, Lone Kirkeby, Lene Dremstrup, Torben Bæk-Hansen
Department of Orthopaedics, University Clinic of Hand, Hip and Knee Surgery,
Hospital Unit West
Background:
Cup failure is a recognized problem in total trapeziometacarpal
(TM) joint prosthesis, which may be related to cup design and bone quality.
Purpose / Aim of Study:
To evaluate cup migration and clinical outcome with a
new large conical press-fit TM cup design with dual- mobility articulation.
Materials and Methods:
Case-study of the first 50 patients (50 hands, 43
females) with Eaton stage 2-4 osteoarthritis of the TM joint scheduled for sur-
gery with the Moovis Elektra press-fit dual-mobility TM cup (June 2013 thru
June 2014). Bone Mineral Density (BMD) was measured pre-operative in the
trapezium. Cup migration (model-based RSA), DASH score and function were
measured at baseline, 3 months, 1 and 2 years. Total Translation (TT) of the cup
was calculated as square root (x^2+y^2+z^2).
Findings / Results:
Patients were mean 56 years (range 43-69). Only 44 out
of planned 50 Moovis cups were inserted because 3 trapeziums were too small,
2 trapeziums fractured and 1 was too soft. Pre-operative BMD was mean 0.67
(range 0.42 – 1.04) g/cm2. TT cup migration at 2 years followup was mean
0.39 (sd 0.6) mm, and there was no increase in migration from 3 months to 2
years (p>0.20). At 2 years followup 2 Moovis cups (6%) had progressive mi-
gration above 1mm and might be loose, but no cups dislocated or were revised
by 2 years followup. There was no correlation between pre- operative BMD and
cup migration (p>0.43). DASH score improved a mean 22 (sd 24) to 1 year
(p=0.000).
Conclusions:
Moovis Elektra cup fixation was acceptable for most implants
(94%) up to 2 years, no implants dislocated or were revised, and the functional
results improved up to 1 year. The cup was too large to fit the trapezium in 3
patients, but instead a smaller cup design (Electra Bimetal) could be utilized.
3 patients had intraoperative trapezium fracture, which may be related to the
large cup size.
No conflicts of interest reported
118.