Total hip replacement vs. hip resurfacing for patients with degenerative hip joint disease .
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OrthoEvidence Journal (OE Journal) - ACE Report
OE Journal. 2014;2(4):4 Bone Joint J. 2013 Nov 1;95-B(11):1464-73Exclusive Author Interview
Dr. Vendittoli discusses total hip replacement versus hip resurfacing for the treatment of degenerative hip joint disease.
219 hips in 192 patients diagnosed with degenerative hip joint disease, were randomly assigned to treatment with either metal-on-metal hip resurfacing or total hip replacement. The purpose was to compare to two in terms of clinical benefits, metal ion levels, and radiographic outcomes over 8 years after treatment. The results of the study indicated that for young patients suffering from hip joint degeneration, both total hip replacement and hip resurfacing result in similar, improving clinical outcomes and revision rates approximately 8 years postoperatively. Osteolysis was observed more frequently with THR, while higher titanium levels were found in patients who received HR.
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
2/4
Outcome Measurements
4/4
Inclusion / Exclusion
2/4
Therapy Description
4/4
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?
While total hip replacement (THR) has proven its effectiveness in elderly patients, its overall efficacy in young, active patients is still in question. The amount of patients undergoing THR has rapidly increased over the past decade, with a significant amount of this increase originating from younger male patients. Durability of THRs in younger patients has come into question in recent years, causing a shift in popularity back to metal-on-metal (MoM) hip resurfacing (HR). While there are a wide variety of benefits to HR, such as preservation of femoral neck, avoidance of femoral canal violation, and improvement of future revision surgery outcomes, the comparative efficacy of HR to THA in younger patients remains unknown.
What was the principal research question?
How does metal-on-metal hip resurfacing compare to total hip replacement in terms of clinical benefits, metal ion levels, and radiographic outcomes approximately 8 years after treatment in patients with degenerative hip joint disease?
- At a mean follow up of 8 years, 4% (4 patients) of THR and 6% (6 patients) of HR were revised (p=0.569). Five patients in the hip resurfacing group experienced a collapse of the femoral head, while the 6th patient underwent revision due to early component migration. Of the 4 patients in the THR group, one revision was due to recurrent dislocation, two due to infection, and one due to traumatic peri-prosthetic femoral fracture (at 6 years).
- No significant differences were found between the two groups regarding pain/discomfort at any of the measured sites (hip, groin, greater trochanter area, thigh, and buttocks; all p>0.05) for any follow-up . Six resurfacing patients compared to zero in the THR group complained of significant groin pain that lead to investigation or treatment (p=0.015). Two were for femoroacetabular impingement related pain, while the other four were for Brooker's grade 3 heterotopic ossification.
- Squeaking was reported in two patients who received THR and none in the hip resurfacing group. Three hip resurfacing patients and five THR patients underwent re-operation without implant revision, which was not statistically different between the groups (p=0.428).
- At final follow-up, mean UCLA score was significantly better in the hip resurfacing group (p=0.035). However, the proportion of patients performing high impact activity (UCLA activity score of 10) was similar (13.8% vs. 19.6% in the THR and hip resurfacing groups, respectively; p=0.301). Hop and step tests showed a trend that favoured hip resurfacing by final follow-up, but these findings did not reach statistical significance (p=0.055 and 0.066, respectively).
- No difference in WOMAC or PMA scores were found at final-follow up between the groups (p=0.675 and 0.866 respectively), and no significant improvements were observed in either group from 2 years to final follow-up in either group for these outcomes.
- By 5 year follow-up, Ti level was significant higher in the resurfacing group (2.4 ug/L in the hip resurfacing group vs. 1.6 ug/L in the THR group; p=0.006). No significant difference in Cr (2.1 vs. 1.4 ug/L; p=0.180), or Co levels (0.8 vs. 0.8 ug/L; p=0.614) were found between the groups.
- At final follow-up, no loose acetabular components were found in either group. Two femoral resurfacing heads, when analyzed at final follow-up, were considered to be loose, and one case femoral neck narrowing > 10% was found. Progressive osteolysis occurred in 30 of 81 THRs (37%) and 2 of 83 hip resurfacings (2.4%) (p<0.001). Impingement between the femoral neck and metallic liner was observed in 5 patients in the THR group.
What should I remember most?
At the average final follow-up of 8 years, no significant difference in revision rates or reoperations without revisions were found between the two groups. Mean UCLA scores were significantly higher in the hip resurfacing group, but similar WOMAC and PMA scores were found between the two by final follow-up. Osteolysis occurred significantly more often the total hip arthroplasty. At 5 year follow-up, mean cobalt and chromium levels were comparable between the groups, and titanium levels were significantly higher with hip resurfacing.
How will this affect the care of my patients?
The results of this study indicate that in young patients suffering from hip joint degeneration, both total hip replacement and hip resurfacing result in similarly good clinical outcomes and revision rates approximately 8 years after treatment. Future survival analyses should be conducted if bone preservation in hip resurfacing translates to any favourable outcome over longer follow-up.
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