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· DOS Abstracts
Survival of hip resurfacing arthroplasty and the Mitch
proximal epiphyseal replacement - Results from the
Danish Hip Arthroplasty Registry
Maja Tang Jensen, Per Kjærsgaard-Andersen, Søren Overgaard, Claus Varnum
Department of Orthopaedic Surgery, Department of Clinical Research, , Vejle
Hospital, University of Southern Denmark,; Department of Orthopaedic Sur-
gery, Vejle Hospital; Department of Clinical Research, Department of Ortho-
paedic Surgery and Traumatology, University of Southern Denmark, Odense
University Hospital.; Department of Orthopaedic Surgery, Vejle Hospital
Background:
The Mitch proximal epiphyseal replacement (PER) was developed
to preserve proximal femoral bone and minimize femoral neck fracture associ-
ated with hip resurfacing arthroplasty (HRA). There are no mid-term results on
HRA from Denmark and to our knowledge, there are no studies on the Mitch
PER.
Purpose / Aim of Study:
1) To study survival and risk of revision for HRAs
compared to cementless metal-on-polyethylene total hip arthroplasty (MoP
THA). 2) To study the survival and risk of revision for the Mitch proximal epiphy-
seal replacement (PER) compared to MoP THA.
Materials and Methods:
Using propensity score, we matched 1) 1.057 HRA
to 1.057 cementless MoP THA and 2) 202 Mitch PER to 1010 cementless MoP
THA from the Danish Hip Arthroplasty Register. To estimate the relative risk (RR)
of revision, we used regression with the pseudo-value approach and treated
death as a competing risk. 95% confidence intervals were estimated.
Findings / Results:
1) Median follow-up was 7.7 (interquartile range (IQR):
6.4-8.4) years for HRA and 7.5 (IQR: 6.2-9.1) for MoP THA. The cumulative
incidence for any revision of HRA at 10 years follow-up was 11.0% (CI: 8.5-
12.3) and 6.3% (CI: 5.6-6.4) for MoP THA. The RR of revision was 1.57 (CI:
1.16-2.12) for HRAs at 10 years follow-up. By excluding the ASR components,
the RR of revision at 10 years was 1.26 (CI: 0.90-1.78). 2) Median follow-up
was 6.6 (IQR: 5.8-7.5) years for Mitch PER and 6.6 (IQR: 5.7-7.3) years for
MoP THA. The cumulative incidence of revision was 9.6% (CI: 4.2-17.7) for
Mitch PER and 5.4% (CI: 5.1-5.7) for THA MoP at 8 years. The RR of revision
was 2.08 (CI: 0.97-4.48) for Mitch PER at 8-years of follow-up.
Conclusions:
Both HRA and Mitch PER had increased risk of revision compared
to the cementless MoP THA. When excluding ASR, the HRA group had similar
risk of revision compared to MoP THA.
No conflicts of interest reported
70.