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· DOS Abstracts
Hip arthroplasty with the Primoris® stem –
Bone remodelling around a short femoral neck
stem
Janus Duus Christiansen, Lauersen Mogens Berg, Gordon Blunn,
Poul Torben Nielsen
Northern Ortopaedic Division, Aalborg University Hospital; , University College
London, RNOHT, Stanmore, United Kingdom
Background:
Total hip arthroplasty gives immediate pain relief and restoration
of mobility in patients with end stage osteoarthritis. If the patient returns for
revision and after two or three revisions bone stock left for reimplantation will
be compromised. The Primoris ® stem is a development of earlier conceived
bone-saving prosthesis in order to preserve bone stock.
Purpose / Aim of Study:
This study includes postoperative changes in BMD in
the proximal femur and evaluation of bone stock preservation at 1 year follow
up (FU) in patients with the Primoris ® stem.
Materials and Methods:
: A prospective cohort study of 52 patients sched-
uled for surgery with the femoral neck-preserving Primoris ® stem was car-
ried out. Patients were studied with DEXA-scans, RSA- analysis, Harris hip
score, UCLA activity score, WOMAC, EQ5D health questionnaire and Oxford
Hip scores. Results from DEXA-scanner were measured in 3 specific regions of
interest (ROI) - the regions of calcar (ROC), trochanter minor (ROT) and a dia-
physial reference (ROD). Postoperative BMD results from day one, 6 months
and 12 months were analysed.
Findings / Results:
3 patients were excluded, leaving 49 patients for BMD-
analysis. A slightly significant decrease was found at 6 months FU compared to
day one in ROC and ROT. There was no significant difference at 12 months FU
compared to day one. A non significant gain of BMD was found at 12 months FU
compared to 6 months FU.
Conclusions:
As to bone preservation the results are encouraging. Later fol-
low up will be performed to evaluate if the bone stock remains. If the proximal
femoral bone stock is preserved and diaphysis is not compromised then the po-
tential for successful future revision is maximized.
147.
