6.
Does previous periacetabular osteotomy compromise optimal cup
positioning and clinical outcome of total hip replacement?
Charlotte Hartig-Andreasen, Maiken Stilling, Kjeld Søballe, Theis Muncholm
Thillemann, Anders Troelsen
Dept. of Orthopedic Research Aarhus University Hospital; Dept. of Orthopedic
Research, Aarhus University Hospital; Dept. of Orthopedics, Aarhus
University Hospital; Dept. of Orthopedics, Horsens Hospital; Dept. of
Orthopedics, Hvidovre Hospital
Background:
Although periacetabular osteotomy (PAO) is a success, some
dysplastic hips develop osteoarthritis following PAO. Typically these hips are
extreme cases with severe dysplasia before PAO. The conversion of PAO to
THR may therefore be associated with technical challenges that could
compromise good cup positioning and clinical outcome.
Purpose / Aim of Study:
To evaluate radiographic, clinical and patient
reported outcome of THR in hips with previous PAO.
Materials and Methods:
38
hips (34 patients) treated with THR after previous
PAO were included in the study at routine follow-up. The mean age at THA
was 40.5 years. The follow-up included standardized AP pelvic and lateral hip
radiographs that were analyzed for acetabular cup position, 2D linear wear
(
Polywear), heterotopic calcification, osteolysis or loosing. A clinical hip
examination was performed, and alongside, Harris Hip score (HHS), SF36 and
WOMAC questionnaires were collected. Any complications and revisions
were noted.
Findings / Results:
16
patients had remaining dysplasia (CE<25o, range -5o-
24
o) after PAO. At a mean follow-up of 6.4 years (4.2- 10.1) after THR the
cup abduction angle was 43o (range 28o-65o; n=1>60o), cup anteversion was
22
o (range 7o-43o; n=2>40o) and polyethylene wear rate (MoM and CoC
excluded) was 0.15 mm/year (range 0.05-0.27). There were no component
revisions or dislocations. Patients reported VAS satisfaction of 10 (10 the
best), a total WOMAC score of 78 (100 the best), and a HHS of 89 (100 the
best), all median values. Leg-length discrepancy after THR was confined
within 1 cm in 33 hips and within 2 cm in the remaining hips.
Conclusions:
In general THR after previous PAO can be performed with
optimal cup position, high patient satisfaction, good patient reported outcome
and few complications. However, cup positioning following PAO may be a
technical challenge.
