|
|
| General |
| Study Status |
Completed |
| 522 Number / Requirement Number |
PS110093 / PSS003 |
| Date Original Plan Accepted |
12/07/2012
|
| Date Current Plan Accepted |
12/07/2012
|
| Study Name |
Explant Analysis
|
| Device Name |
Zweymueller-sl hip prosthesis stem
|
| Root Document Number |
K871453
K032348
K033634
K033943
K974728
K003758
K053536
K071723
K091003
K091973
K063251
K071856
K073499
K081007
|
| General Study Protocol Parameters |
| Study Design |
Other Study Design
|
| Data Source |
New Data Collection
|
| Comparison Group |
Concurrent Control
|
| Analysis Type |
Analytical
|
| Study Population |
Transit. Adolescent B (as adults) : 18-21 yrs,
Adult: >21
|
| Detailed Study Protocol Parameters |
| Study Objectives |
This will be an analysis of explanted devices.
|
| Study Population |
Patients who undergo metal-on-metal hip implant revision
|
| Sample Size |
100 patients, 12 sites
|
| Key Study Endpoints |
Explant analysis to yield failure modes
|
| Follow-up Visits and Length of Follow-up |
Not applicable. This is an analysis of explanted devices.
|
| Interim or Final Data Summary |
| Actual Number of Patients Enrolled |
113
|
| Actual Number of Sites Enrolled |
6
|
| Final Safety Findings |
The majority of failures occurred between 1 to 5 years. The main causes for revision surgery listed are: (i) pain (92%), (ii) loosening (79%), (iii) elevated cobalt and chromium ion levels in the blood (10%), (iv) presence or suspected pseudotumor (4%), and (v) osteolysis (3%).
Pronounced articular damage (scratching, pitting or bashing) was observed on 16 of 113 cups (14%) and 23 of 113 heads (20%). In 6 instances, cups and heads with pronounced articular damage were paired together. Articular discoloration/sta ining was observed on 59 of 113 cups (52%) and 90 of 113 heads (80%). In terms of impingement, there were 11 stem necks available for observation. Some form of circumferential marking was present on 6 of the stem necks (55%). Some form of rim marking was noted on 27 of 113 cups (24%). In three cases, both the cup and stem showed marking. A wear scar extending through the rim of the cup was observed in 10 of the 113 cases (9%) analyzed.
Total taper wear varied from 0.1 to 24mm3, with an average taper wear of 2.5 mm3. All taper wear greater than 10mm3 occurred past 3 years. Goldberg scores >2 were observed on 8 of 113 head tapers (7.1%), 7 of 113 taper adapter outer surfaces (6.2%) and 83 of 113 taper adapter inner surfaces (73%).
|
| Final Effectiveness Findings |
Not applicable, explant analysis study focused on safety.
|
| Study Strengths and Weaknesses |
A prominent strength of the study is its adequate sample size. A weakness of the study is the absence of complete clinical data in all cases.
|
| Recommendations for Labeling Changes |
No labeling changes are recommended because the device is no longer marketed.
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