Bone loss seen in medium-term with both customized femoral and uncemented anatomical stem .
OrthoEvidence Journal (OE Journal) - ACE Report
OE Journal. 2013;1(2):20 Acta Orthop. 2011 Aug;82(4):410-6. Epub 2011 Jun 1487 patients were randomized to undergo hip arthroplasty with an uncemented customized unique femoral stem or a uncemented ABG-I anatomical stem. The primary outcome examined was periprosthetic bone loss (change in bone mineral density), measured by Dual-energy X-ray absorptiometry (DXA) from baseline to the follow-up. The results indicated loss in bone mineral density for both customized femoral and uncemented anatomical stem at the 5-year (medium-term) follow-up.
Was the allocation sequence adequately generated?
Was allocation adequately concealed?
Blinding Treatment Providers: Was knowledge of the allocated interventions adequately prevented?
Blinding Outcome Assessors: Was knowledge of the allocated interventions adequately prevented?
Blinding Patients: Was knowledge of the allocated interventions adequately prevented?
Was loss to follow-up (missing outcome data) infrequent?
Are reports of the study free of suggestion of selective outcome reporting?
Were outcomes objective, patient-important and assessed in a manner to limit bias (ie. duplicate assessors, Independent assessors)?
Was the sample size sufficiently large to assure a balance of prognosis and sufficiently large number of outcome events?
Was investigator expertise/experience with both treatment and control techniques likely the same (ie.were criteria for surgeon participation/expertise provided)?
Yes = 1
Uncertain = 0.5
Not Relevant = 0
No = 0
The Reporting Criteria Assessment evaluates the transparency with which authors report the methodological and trial characteristics of the trial within the publication. The assessment is divided into five categories which are presented below.
4/4
Randomization
3/4
Outcome Measurements
4/4
Inclusion / Exclusion
4/4
Therapy Description
3/4
Statistics
Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65
The Fragility Index is a tool that aids in the interpretation of significant findings, providing a measure of strength for a result. The Fragility Index represents the number of consecutive events that need to be added to a dichotomous outcome to make the finding no longer significant. A small number represents a weaker finding and a large number represents a stronger finding.
Why was this study needed now?
Implantation of a prosthesis can change the load distribution of the host bone. Customized femoral stems are, therefore, specifically designed to provide optimal physiological load transfer and minimize stress shielding. This study examines the outcomes in periprosthetic bone loss using DXA in hip arthroplasties implementing an uncemented customized femoral stem and an uncemented anatomical stem.
What was the principal research question?
What are the outcomes in periprosthetic bone loss (change in bone density),when undergoing hip arthroplasty with an uncemented customized unique femoral stem, compared to an uncemented anatomical ABG-I stem in patients with primary or secondary osteoarthritis at 5 years?
- The proximal Gruen zones showed the greatest degree of bone loss in both the anatomical ABG-I stem group and the customized Unique stem group.
- There was a statistically significant difference in bone mineral density (BMD) reduction at Gruen zone 4 between the two groups. The ABG-I group had at 1.6% reduction in BMD compared to a 9.7% reduction in the Unique group (p=0.003)
- The ABG-I group had at 15% reduction in BMD at zone 1, compared to a 14% reduction in the Unique group. At zone 7, the ABG-I group had at 28% reduction reduction in BMD compared to a 27% reduction in the Unique group.
- The Unique group showed significant differences in BMD in Gruen zones 1, 2, 3, 4, and 7 when compared to baseline (p<0.001). The ABG-I group showed significant differences in BMD in Gruen zones 1, 2, 6, and 7 when compared to baseline (p<0.001).
- No patients required hip revision surgery at the 5-year follow-up, but 5 patients reported complications. The ABG-I group had 2 patients with an early dislocation, 1 patient developed a deep venous thrombosis, and 1 patient had an episode of subluxation. 1 patient from the Unique group had an intraoperative injury of the common peroneal nerve.
What should I remember most?
Both the anatomical and customized stems had proximal bone loss at the 5-year follow-up - this was unavoidable due to stress-shielding.
How will this affect the care of my patients?
There is still uncertainty regarding the clinical consequences of proximal bone loss around uncemented stems in the medium- and long-term . Further research is needed to better define the effects of proximal bone loss following total hip arthroplasty.
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