Devices › Prosthesis, knee, patellofemorotibial, semi-constrained, cemented, polymer/metal/polymer
Device brand name · Prosthesis knee
Unknown Patella: medical device reports filed with FDA
280 reports name it, 2011–2026. Manufacturer given most often on reports: Zimmer Biomet. Product code JWH.
- 280
- device reports naming the brand
- 0% of all MAUDE reports · about 18 a year
- 13
- reports, 12 months to August 2026
- 10 in the 12 months before
- 0%
- classified as malfunction
- 14.7% across the product code
- 1.1%
- classified as death, as reported
- 3 reports · not verified by FDA
FDA's MAUDE database holds 280 reports that name the brand "Unknown Patella" (prosthesis knee), received between February 2011 and July 2026; the manufacturer given most often on reports is Zimmer Biomet. Spellings of one product vary from report to report.
13 reports arrived in the 12 months to August 2026, up 30% from 10 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 (98.9%) and death (1.1%); 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 (33.9%), naturally worn (6.1%) and migration or expulsion of device (3.6%). The patient problems coded most often are pain, loss of range of motion and failure of implant. 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 | 95 | 33.9% | 18.1% |
| Naturally worn | 17 | 6.1% | 6.8% |
| Migration or expulsion of device | 10 | 3.6% | 1.5% |
| Unstable | 10 | 3.6% | 4.3% |
| Device dislodged or dislocated | 8 | 2.9% | 1.7% |
| Fracturea broken bone | 7 | 2.5% | 7.3% |
| Loosening of implant not related to bone-ingrowth | 5 | 1.8% | 4% |
| Noise, audible | 5 | 1.8% | 1% |
| Inadequacy of device shape and/or size | 3 | 1.1% | 0.5% |
| Malposition of device | 3 | 1.1% | 0.9% |
| Material erosion | 3 | 1.1% | 0.2% |
| Migrationthe device moved from where it was placed | 3 | 1.1% | 0.8% |
| Degraded | 2 | 0.7% | 0.2% |
| Loss of osseointegration | 2 | 0.7% | 0.9% |
| Unintended movement | 2 | 0.7% | 0.3% |
| Breakthe device broke | 1 | 0.4% | 3.9% |
| Corrodedthe device corroded | 1 | 0.4% | 0.1% |
| Device damaged by another device | 1 | 0.4% | 0% |
| Device operates differently than expectedthe device behaved unexpectedly | 1 | 0.4% | 0.8% |
| Improper or incorrect procedure or method | 1 | 0.4% | 0.2% |
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 | 52 | 18.6% |
| Loss of range of motion | 15 | 5.4% |
| Failure of implant | 13 | 4.6% |
| Injurya physical injury | 10 | 3.6% |
| Swelling/ edema | 10 | 3.6% |
| Bone fracture(s) | 7 | 2.5% |
| Falla fall | 7 | 2.5% |
| Inflammationinflammation | 7 | 2.5% |
| Joint dislocationa dislocated joint | 7 | 2.5% |
| Swellingswelling | 7 | 2.5% |
| Cellulitisa skin infection | 6 | 2.1% |
| Limited mobility of the implanted joint | 6 | 2.1% |
| Ambulation or postural difficulties | 5 | 1.8% |
| Bacterial infectiona bacterial infection | 5 | 1.8% |
| Cyst(s) | 5 | 1.8% |
Patient problem codes are present mainly in reports filed since 2019 and are often blank.
In context
| Measure | Unknown Patella | Product code JWH | All MAUDE reports |
|---|---|---|---|
| Reports | 280 | 158,133 | 26,136,888 |
| Share of that pool | — | 0.2% | 0% |
| Classified as death, per 1,000 reports | 11 | 2 | 9 |
| Classified as injury | 98.9% | 84.1% | 36.2% |
| Classified as malfunction | 0% | 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 Patella reports
How many FDA reports name Unknown Patella?
280 medical device reports in the openFDA MAUDE release of 28 Sep 2026, covering reports received through August 2026; 13 in the latest 12 months.
What kinds of events are reported?
injury (98.9%) and death (1.1%). "Event type" is how the report was classified when filed: death, injury, malfunction or other.
What device problems are coded?
insufficient device problem information (33.9%), naturally worn (6.1%), migration or expulsion of device (3.6%), unstable (3.6%) and device dislodged or dislocated (2.9%). 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 Patella 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.