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| General |
| Study Status |
Completed |
| 522 Number / Requirement Number |
PS110029 / PSS001 |
| Date Original Plan Accepted |
10/15/2012
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| Date Current Plan Accepted |
12/04/2015
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| Study Name |
Clinical Study
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| Device Name |
Encore clp offset total hip system, metal/metal hip system,fmp metal/metal acetabular insert, revelation stem,djo surgical revision femoral i-lip system, metal backed acetabular component,
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| Root Document Number |
K083651
K092331
K063414
K052320
K040354
K070221
K950542
K003250
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| General Study Protocol Parameters |
| Study Design |
Cross-Sectional Study
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| Data Source |
New Data Collection
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| Comparison Group |
Concurrent Control
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| Analysis Type |
Analytical
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| Study Population |
Transit. Adolescent B (as adults) : 18-21 yrs,
Adult: >21
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| Detailed Study Protocol Parameters |
| Study Objectives |
This study has a hybrid cross-sectional design based on new enrollment and its main objective is to examine the long term safety and effectiveness of the FMP metal-on-metal (MoM) Acetabular Hip System. The study is aimed to examine devices retrieved after revision and to assess adverse events associated with DJO MoM hip devices. The chromium and cobalt ion levels in whole blood and serum samples from implanted subjects will be prospectively determined at different post-implant time points. Secondary objectives of the study include: (1) evaluation of the overall success of the device over time, (2) the effect of nutritional status on metal ion concentrations and 3) the effect of demographic factors on device outcomes. The primary null hypothesis is that there will be no change in chromium or cobalt ion concentrations at a specified post-implant time point compared to baseline. The hypothesis will be tested for the metal ion concentrations in both whole blood (erythrocytes) and serum at multiple time points. However, multiple comparison corrections will not be used for two metal ion types, repeated tests (Year 1, 2, etc.), or for two sample types (blood or serum). Sample size calculations and subsequent statistical tests will use a 5% type 1 error rate for two-sided tests.
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| Study Population |
The main study population will consist of consented subjects (>18 year-old) who are scheduled for hip replacement surgery; the study population will include baseline (pre-implantation) subjects with similar indications as a candidate for MoM hip replacement. General exclusion criteria are metal allergies and renal dysfunction.
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| Sample Size |
With a total proposed sample size of 340 subjects (one visit per subject), the two cohorts will be as follows: Cohort B (N=315): Subjects who qualify for the study, including subjects who have not been implanted with any hip implant and are seen only at baseline (N = 75) and subjects who have a DJO MoM implant, have not had a revision, and are seen at a single cross-sectional post-op time point between Year 1 and Year 8 (N = 240, i.e., 30 at each time point). Cohort C, sample size 25: Subjects who have received a DJO MoM implant that will be revised in the near future. These subjects will provide data at one time point, the time of revision.
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| Key Study Endpoints |
The chromium and cobalt ion concentrations will be determined in all subjects in both Cohorts B and C. Serum cobalt concentration [Co-S], serum chromium concentration [Cr-S] and blood chromium concentration [Cr-B] will be measured using inductively coupled mass spectroscopy. Metal ion measurements will be examined with regards to time after surgery, adverse local tissue reactions, revision rates and physical exam findings.
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| Follow-up Visits and Length of Follow-up |
Not applicable; All patients will be assessed in a single visit (i.e., a total of 340 subject-visits with no plans to assess the same patient at more than one time point).
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| Interim or Final Data Summary |
| Actual Number of Patients Enrolled |
128
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| Actual Number of Sites Enrolled |
8
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| Patient Followup Rate |
Not applicable as this was a cohort study
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| Final Safety Findings |
Mean metal ion levels did not show notable increases over post-implantation time. There were
no statistically significant trends between adverse events and metal ions, apart from pain (there
was negative correlation between ion levels and pain score).
Post-hoc analysis suggested that a metal ion threshold of >2.5ppb has a higher sensitivity for
detecting ALTR; however, even this threshold showed a sensitivity of less than 50% suggesting
that patient and surgical factors were as important in assessing adverse events and ALTR as
metal ion levels. Related to patient factors, there were nominally significant findings for levels
related to diet and geographic location; however, these were not determined to be consistent, or
clinically interpretable.
None of the reported adverse events were unexpected for total hip arthroplasty.
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| Final Effectiveness Findings |
The mean Harris Hip Score, a recognized patient reported outcome to assess clinical success showed an average of 84.5, which is considered to the in the “good” range.
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| Study Strengths and Weaknesses |
Assessment of metal ion levels, imaging and clinical outcomes at various timepoints in unilateral and bilateral patients can help with optimizing management of patients with MoM total hip arthroplasty. However, study limitations such as cross-sectional design with single metal ion
measurements, small cohort sizes, and the lack of pre-specified hypotheses restricted possibilities for more detailed assessment of putative correlations between metal ion levels and clinically/radiographically-manifested adverse outcomes.
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| Recommendations for Labeling Changes |
No labeling change is being recommended because DJO MoM THA devices are no longer marketed.
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