DOS Kongressen 2014 ·
197
Acetabular dysplasia increases risk for
malpositioning of the acetabular component
in Total Hip Arthroplasty (THA)
Kirill Gromov, Meridith Greene, Christopher Barr, Peter Gebuhr, Henrik Malchau,
Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital
Hvidovre; Harris Orthopaedic Laboratory, Massachusetts General Hospital
Background:
Persistent acetabular dysplasia (AD) following periacetabular os-
teotomy (PAO) has been hypothesized to increase the risk for malpositioning of
the acetabular component that may subsequently lead to higher rates of wear,
dislocation and impingement.
Purpose / Aim of Study:
The purpose of this study was to investigate wheth-
er AD is an independent risk factor for cup malpositioning.
Materials and Methods:
839 primary THA patients, with pre and postopera-
tive pelvic radiographs, from 16 centers in the USA and Europe are enrolled
into a prospective 10year outcome study. All patients were operated using an
uncemented Biomet® cup and a Biomet® stem of surgeons’ choice. Patient de-
mographics and surgical parameters were recorded. AD was assessed by mea-
suring lateral center edge (LCE) angle and defined as LCE<25°. Cup positioning
was determined on postoperative AP pelvic images using Martell Hip Analysis
Suite. Acceptable ranges were defined as 30-45° abduction and 5-25°version.
Multivariate logistic regression analysis was performed to calculate adjusted risk
for cup malpositioning.
Findings / Results:
504 (60%) acetabular cups were within the abduction
range, 608 (73%) were within the anteversion range, and 377 (45%) were
within the range of both. Surgical approach, presence of AD, and JSW>0 inde-
pendently predictedmalposition of the acetabular component. Surgical approach
(direct lateral vs posterolateral), JSW>0, and AD resulted in a 2.00 (1.24-3.22),
1.51 (1.09-2.01) and 1.49 (1.11-1.99) increase in risk for malposition of the
acetabular component, respectively.
Conclusions:
Presence of AD, defined as an LCE angle <25°, is an independent
risk factor for malposition of the acetabular component during primary THA.
Skin approach and radiological grade of OA were also independently correlated
with malpositioned cups.
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