Devices › Prosthesis, hip, semi-constrained (metal uncemented acetabular component)
Device brand name · Prosthesis hip
Unk Stem: medical device reports filed with FDA
285 reports name it, 2014–2026. Manufacturer given most often on reports: Zimmer Biomet. Product code KWA.
- 285
- device reports naming the brand
- 0% of all MAUDE reports · about 23 a year
- 101
- reports, 12 months to August 2026
- 70 in the 12 months before
- 2.1%
- classified as malfunction
- 3.4% across the product code
- 0.7%
- classified as death, as reported
- 2 reports · not verified by FDA
FDA's MAUDE database holds 285 reports that name the brand "Unk Stem" (prosthesis hip), received between January 2014 and August 2026; the manufacturer given most often on reports is Zimmer Biomet. Spellings of one product vary from report to report.
101 reports arrived in the 12 months to August 2026, up 44% from 70 in the 12 months before. FDA releases MAUDE data monthly; reports can arrive months after an event, so the newest months grow in later releases. The event types recorded are injury (97.2%), malfunction (2.1%) and death (0.7%); across all prosthesis, hip, semi-constrained (metal uncemented acetabular component) reports (product code KWA) death is recorded in 0.3% and malfunction in 3.4%. Event type is the reporter's classification of the report, not a verified outcome.
The device problems coded most often are insufficient device problem information (9.8%), material erosion (7%) and loosening of implant not related to bone-ingrowth (6.3%). The patient problems coded most often are pain, periprosthetic fracture and bone fracture(s). FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data."
Reports by month, five years
Reports by the month FDA received them. FDA releases MAUDE data monthly; reports can arrive months after an event, so the newest months grow in later releases.
By year received
Event type and report source
Event type, as classified on the report
Who filed the report
Grey bar: all 138,213 reports carrying product code KWA. Event type is the filer's classification and is not verified by FDA.
Device problems coded
| Device problem (FDA code) | Reports | Share | Share across product code |
|---|---|---|---|
| Insufficient device problem information | 28 | 9.8% | 52% |
| Material erosion | 20 | 7% | 1.3% |
| Loosening of implant not related to bone-ingrowth | 18 | 6.3% | 0.2% |
| Corrodedthe device corroded | 9 | 3.2% | 2% |
| Implant subsidence | 6 | 2.1% | 0% |
| Migrationthe device moved from where it was placed | 6 | 2.1% | 0.4% |
| Detachment of device or device componentpart of the device came off | 5 | 1.8% | 0.1% |
| Fracturea broken bone | 3 | 1.1% | 1.3% |
| Device dislodged or dislocated | 2 | 0.7% | 5.2% |
| Unstable | 2 | 0.7% | 0.3% |
| Difficult to insertthe device was hard to insert | 1 | 0.4% | 0.1% |
| Failure to osseointegrate | 1 | 0.4% | 0.1% |
| Inadequacy of device shape and/or size | 1 | 0.4% | 0.2% |
| Loss of or failure to bond | 1 | 0.4% | 1.2% |
| Migration or expulsion of device | 1 | 0.4% | 1% |
| Patient device interaction problem | 1 | 0.4% | 0.1% |
| Separation failure | 1 | 0.4% | 0.1% |
FDA's device problem codes as entered on the report; one report can carry several. Generic codes such as "no apparent adverse event" are left out.
Patient problems coded
| Patient problem (FDA code) | Reports | Share |
|---|---|---|
| Painpain, site not specified | 37 | 13% |
| Periprosthetic fracture | 27 | 9.5% |
| Bone fracture(s) | 24 | 8.4% |
| Metal related pathology | 24 | 8.4% |
| Failure of implant | 18 | 6.3% |
| Medical device site infectioninfection at the device site | 16 | 5.6% |
| Joint dislocationa dislocated joint | 13 | 4.6% |
| Ambulation or postural difficulties | 10 | 3.5% |
| Aseptic loosening | 10 | 3.5% |
| Osteolysis | 10 | 3.5% |
| High metal ion levels | 9 | 3.2% |
| Joint laxity | 7 | 2.5% |
| Bursitis | 4 | 1.4% |
| Embolism | 4 | 1.4% |
| Extraskeletal ossification | 4 | 1.4% |
Patient problem codes are present mainly in reports filed since 2019 and are often blank.
In context
| Measure | Unk Stem | Product code KWA | All MAUDE reports |
|---|---|---|---|
| Reports | 285 | 138,213 | 26,136,888 |
| Share of that pool | — | 0.2% | 0% |
| Classified as death, per 1,000 reports | 7 | 3 | 9 |
| Classified as injury | 97.2% | 94.3% | 36.2% |
| Classified as malfunction | 2.1% | 3.4% | 62.3% |
| Filed by the manufacturer | 100% | 99.2% | 94.9% |
Shares are of reports, not of devices in use. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data."
Other brands with product code KWA
| Brand | Reports | Latest 12 months | Classified as death |
|---|---|---|---|
| Pinnacle Mtl Ins Neut36idx52od | 3,720 | 13 | 0.1% |
| Pinnacle Mtl Ins Neut36idx54od | 2,874 | 11 | 0.1% |
| Asr Acetabular Cups 52 | 2,428 | 2 | 0.1% |
| Asr Uni Femoral Impl Size 46 | 2,500 | 2 | 0.1% |
| Asr Acetabular Cups 54 | 2,350 | 0 | 0.4% |
| Asr Uni Femoral Impl Size 47 | 2,423 | 0 | 0.4% |
| Asr Acetabular Cups 56 | 2,206 | 0 | 0.4% |
| Asr Uni Femoral Impl Size 49 | 2,278 | 0 | 0.4% |
| Asr Acetabular Cups 50 | 2,056 | 0 | 0.1% |
| Asr Uni Femoral Impl Size 45 | 2,119 | 0 | 0.1% |
| Pinnacle Mtl Ins Neut36idx50od | 2,066 | 9 | 0% |
| Unknown Hip Acetabular Liners | 4,814 | 260 | 0.2% |
| Durom Acetabular Component | 2,071 | 0 | 0.1% |
| Unknown Hip Acetabular Cup | 3,215 | 106 | 0.4% |
| Unknown Depuy Asr Acetabular Cup | 1,933 | 0 | 0.2% |
Ordered by report count for navigation only. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data." FDA also states that "common products may have a higher number of adverse events due to the higher total number of people using the product."
Questions about Unk Stem reports
How many FDA reports name Unk Stem?
285 medical device reports in the openFDA MAUDE release of 28 Sep 2026, covering reports received through August 2026; 101 in the latest 12 months.
What kinds of events are reported?
injury (97.2%), malfunction (2.1%) and death (0.7%). "Event type" is how the report was classified when filed: death, injury, malfunction or other.
What device problems are coded?
insufficient device problem information (9.8%), material erosion (7%), loosening of implant not related to bone-ingrowth (6.3%), corroded (3.2%) and implant subsidence (2.1%). These are FDA's device problem codes as entered on the report.
Who files these reports?
manufacturer reports (100%). Manufacturers and user facilities are required to report; voluntary reports come from health professionals and the public.
Do these reports show that Unk Stem was at fault?
No. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data." FDA adds that "a causal relationship cannot be established between product and reactions listed in a report."
How do I report a problem with a medical device?
Through FDA MedWatch (Form FDA 3500 for health professionals and consumers), or to the manufacturer. See the guide on how to report.
Where this comes from. Counts are built from the openFDA Device Adverse Event (MAUDE) bulk export released 28 Sep 2026, which holds reports FDA received through 31 Aug 2026. Brand, generic and manufacturer names are as written on the reports; product code names come from FDA's device classification. A report counts here when any device it lists carries this brand name after punctuation and capitalisation are normalised. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.
Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.