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| General |
| Study Status |
Completed |
| 522 Number / Requirement Number |
PS110070 / PSS002 |
| Date Original Plan Accepted |
01/30/2017
|
| Date Current Plan Accepted |
03/09/2021
|
| Study Name |
Metal Ion Levels Microport
|
| Device Name |
Metal transcend articulation system
|
| Root Document Number |
K004043
K021349
K031963
K041425
K042530
K043073
K043099
K041586
K041114
K051348
K051995
K052915
K053588
K060356
K060358
K061844
K070785
K080663
K082924
K091423
K081090
K110029
|
| General Study Protocol Parameters |
| Study Design |
Cross-Sectional Study
|
| Data Source |
New Data Collection
|
| Comparison Group |
Concurrent Control
|
| Analysis Type |
Descriptive
|
| Study Population |
Adult: >21
|
| Detailed Study Protocol Parameters |
| Study Objectives |
The study design is multi-center, cross-sectional, new enrollment. The primary objective of the study is to determine the prevalence of adverse local issue reactions (ALTR) in subjects implanted with the WMT MoM THA System overall and for each defined cross-section interval. Secondary objectives include the determination of whole blood and serum cobalt and chromium metal levels for subjects implanted with the WMT MoM THA System overall and for each defined cross-sectional interval and the estimation of baseline whole blood and serum cobalt and chromium ion levels in subjects not implanted with any metal implant.
|
| Study Population |
The study population is comprised of patients who received WMT metal-on-metal hip implants. The control group is comprised of patients without metallic implants, with the exception of dental implants.
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| Sample Size |
The sample size for Group 1 is 155 subjects who must have been implanted between 4 and 8 years prior to the study start date. The sample size for Group 2, the control group, is 100 patients.
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| Key Study Endpoints |
Study endpoints include Adverse Local Tissue Reaction (ALTR), serum and whole blood cobalt and chromium metal ions, and HOOS (Hip disability and Osteoarthritis Outcome Score, ) and the comparison of functional outcomes in subjects with and without confirmed ALTR.
|
| Follow-up Visits and Length of Follow-up |
Attempts will be made to enroll all eligible patients at participating clinical sites. Patients who present with ALTR will be followed for 1 year
or until revision, whichever occurs first.
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| Interim or Final Data Summary |
| Actual Number of Patients Enrolled |
173 hips including 86 metal-on-metal hips (in 75 patients) and 87 controls (87 subjects). All metal -on- metal hips were CONSERVE brand
devices.
|
| Actual Number of Sites Enrolled |
Data was supplied only from 3 sites as 1 site was closed due to inability to provide source documentation
|
| Patient Followup Rate |
44% (4 patients out of 9 patients with ALTR returned for their second visit after initial visit and diagnosis
|
| Final Safety Findings |
Metal ion levels (chromium whole blood ion levels, chromium serum ion levels, cobalt whole blood ion levels, cobalt serum ion levels) were
significantly higher in subjects with a CONSERVE acetabular device compared to the control subjects. In patients with metal-on-metal hip systems, there was no statistically significant difference in metal ion levels between patients with ALTR and patients without ALTR. Chrome metal ion levels in both whole blood and serum were generally higher in ALTR patients compared to patients without ALTR, however these levels did
not show a statistically significant difference. The maximum metal ion levels were observed in patients with no ALTR diagnosis. Maximum levels of metal ions were Chromium whole blood 15.8 ug/L, Cobalt whole blood 26 ug/L, Chromium serum 26 ug/L, and Cobalt serum 33.4 ug/L.
When evaluating only hips with solely Wright Medical Technology (WMT) systems (i.e., those hips with stems, heads and acetabular components labeled for use together) there were 17 hips (33%, 95% CI: 20.8%, 47.9%) out of 51 WMT Group 1 hips with MRI data that had determination of “Abnormal - Suggestive of ALTR” from third-party MRI radiologists. When study investigators considered all clinical factors (MRI results, metal
ion levels and symptoms/function) ALTR was diagnosed in 11 hips out of 73 hips (15%, 95% CI: 7.9%, 25.7%). A total 8 of 73 hips (11%) diagnosed with ALTR underwent revision within one year.
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| Final Effectiveness Findings |
The majority of metal-on-metal hip patients in the study had Hip Disability and Osteoarthritis Outcome Scores (HOOS scores), a recognized measure of device effectiveness, in the good to excellent range regardless of ALTR diagnosis. Therefore, pain and functional outcomes are not sufficient alone to diagnose ALTR.
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| Study Strengths and Weaknesses |
Strengths: There is a comparator group (patients without orthopedic implants), and the study uses MRI examination, the gold standard,
to detect adverse local tissue reaction (ALTR).
Weaknesses: The study is cross -sectional in nature with the absence of long-term follow-up of individual patients. The sample size of patients with metal-on-metal hip implants (73) is small and there is a lack of representativeness of the general patient population (95% Caucasian). The approved metal ion protocol did not address all 522 order questions (e.g., Do these average levels increase over a minimum of the first six years post-implant?) due to the limitation of the cross-sectional study design and because metal ion level measurement was not historically part of the standard of care, therefore the baseline metal ion level was not available for comparison
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| Recommendations for Labeling Changes |
No labeling change is recommended since the devices are no longer marketed in the US
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