Devices › Prosthesis, knee, patellofemorotibial, semi-constrained, cemented, polymer/metal/polymer
Device brand name · Prosthesis knee
Unknown Bearing: medical device reports filed with FDA
317 reports name it, 2013–2026. Manufacturer given most often on reports: Zimmer Biomet. Product code JWH.
- 317
- device reports naming the brand
- 0% of all MAUDE reports · about 24 a year
- 84
- reports, 12 months to August 2026
- 20 in the 12 months before
- 2.2%
- classified as malfunction
- 14.7% across the product code
- 0.3%
- classified as death, as reported
- 1 reports · not verified by FDA
317 medical device reports received by FDA name the brand "Unknown Bearing" (prosthesis knee); the manufacturer given most often on reports is Zimmer Biomet; received from May 2013 to August 2026. Brand names are as the reporter or manufacturer wrote them, so one product can appear under several spellings.
84 reports arrived in the 12 months to August 2026, up 320% from 20 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 (97.5%), malfunction (2.2%) and death (0.3%); across all prosthesis, knee, patellofemorotibial, semi-constrained, cemented, polymer/metal/polymer reports (product code JWH) death is recorded in 0.2% and malfunction in 14.7%. 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 (23.7%), device dislodged or dislocated (9.5%) and naturally worn (9.5%). The patient problems coded most often are pain, joint dislocation and loss of range of motion. 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 158,133 reports carrying product code JWH. 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 | 75 | 23.7% | 18.1% |
| Device dislodged or dislocated | 30 | 9.5% | 1.7% |
| Naturally worn | 30 | 9.5% | 6.8% |
| Unstable | 29 | 9.1% | 4.3% |
| Fracturea broken bone | 6 | 1.9% | 7.3% |
| Noise, audible | 6 | 1.9% | 1% |
| Migration or expulsion of device | 4 | 1.3% | 1.5% |
| Loosening of implant not related to bone-ingrowth | 3 | 0.9% | 4% |
| Material erosion | 3 | 0.9% | 0.2% |
| Positioning failure | 3 | 0.9% | 0.2% |
| Detachment of device or device componentpart of the device came off | 2 | 0.6% | 1.2% |
| Mechanical problema mechanical problem | 2 | 0.6% | 0.5% |
| Patient device interaction problem | 2 | 0.6% | 0.5% |
| Compatibility problem | 1 | 0.3% | 0% |
| Device appears to trigger rejection | 1 | 0.3% | 0.5% |
| Difficult to insertthe device was hard to insert | 1 | 0.3% | 0.8% |
| Inadequacy of device shape and/or size | 1 | 0.3% | 0.5% |
| Malposition of device | 1 | 0.3% | 0.9% |
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 | 69 | 21.8% |
| Joint dislocationa dislocated joint | 30 | 9.5% |
| Loss of range of motion | 19 | 6% |
| Arthrofibrosis | 12 | 3.8% |
| Joint laxity | 11 | 3.5% |
| Swellingswelling | 11 | 3.5% |
| Failure of implant | 9 | 2.8% |
| Joint impingement | 8 | 2.5% |
| Medical device site infectioninfection at the device site | 8 | 2.5% |
| Extraskeletal ossification | 7 | 2.2% |
| Fluid discharge | 6 | 1.9% |
| Limited mobility of the implanted joint | 6 | 1.9% |
| Ambulation or postural difficulties | 5 | 1.6% |
| Impaired healingslow healing | 5 | 1.6% |
| Swelling/ edema | 4 | 1.3% |
Patient problem codes are present mainly in reports filed since 2019 and are often blank.
In context
| Measure | Unknown Bearing | Product code JWH | All MAUDE reports |
|---|---|---|---|
| Reports | 317 | 158,133 | 26,136,888 |
| Share of that pool | — | 0.2% | 0% |
| Classified as death, per 1,000 reports | 3 | 2 | 9 |
| Classified as injury | 97.5% | 84.1% | 36.2% |
| Classified as malfunction | 2.2% | 14.7% | 62.3% |
| Filed by the manufacturer | 100% | 98.4% | 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 JWH
| Brand | Reports | Latest 12 months | Classified as death |
|---|---|---|---|
| Unknown Knee Tibial Insert | 2,247 | 130 | 0.2% |
| Unknown Knee Femoral | 1,897 | 65 | 0.2% |
| Unknown Knee Tibial Tray | 1,958 | 57 | 0.2% |
| Persona Tibial Articular Surface Provisional | 1,584 | 0 | 0% |
| Itotal G2 | 1,250 | 0 | 0% |
| Specific Device Not Reported | 1,462 | 20 | 0.2% |
| Apex Knee System | 1,001 | 49 | 0% |
| Djo Surgical | 4,713 | 2,448 | 0% |
| Unknown Knee | 1,847 | 18 | 1.5% |
| Attune Fb Tib Base Sz 5 Cem | 863 | 18 | 0% |
| Attune Fb Tib Base Sz 4 Cem | 797 | 14 | 0% |
| Pfc Sigma/Ov/Dome Pat 3peg 38 | 806 | 3 | 0.4% |
| Unknown Knee Patella | 791 | 26 | 0.4% |
| Unknown Reconstructive Product | 2,579 | 0 | 0.4% |
| UNK Attune Knee Tibial Insert | 895 | 102 | 0.1% |
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 Unknown Bearing reports
How many FDA reports name Unknown Bearing?
317 medical device reports in the openFDA MAUDE release of 28 Sep 2026, covering reports received through August 2026; 84 in the latest 12 months.
What kinds of events are reported?
injury (97.5%), malfunction (2.2%) and death (0.3%). "Event type" is how the report was classified when filed: death, injury, malfunction or other.
What device problems are coded?
insufficient device problem information (23.7%), device dislodged or dislocated (9.5%), naturally worn (9.5%), unstable (9.1%) and fracture (1.9%). 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 Unknown Bearing 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.