Prosthesis, knee, femorotibial, unicompartmental, semi-constrained, metal/polymer, mobile bearing: medical device reports filed with FDA

5,163 reports carry this product code, 2007–2026; 12 brands with a page.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "Although MDRs are a valuable source of information, this passive surveillance system has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data. In addition, the incidence or prevalence of an event cannot be determined from this reporting system alone due to potential under-reporting of events and lack of information about frequency of device use." And: "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."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

5,163
reports with this product code: 0% of all MAUDE reports; 309
reports, 12 months to August 2026: 362 in the 12 months before; 3.8%
classified as malfunction: 62.3% across all reports; 1.1%
classified as death, as reported: 0.9% across all reports

Product code NRA is FDA's classification for "Prosthesis, knee, femorotibial, unicompartmental, semi-constrained, metal/polymer, mobile bearing" (unknown panel), a class 3 device. 5,163 medical device reports carry this product code, 0% of the MAUDE database, from May 2007 to August 2026.

309 reports arrived in the 12 months to August 2026, down 15% from 362 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 (94.9%), malfunction (3.8%) and death (1.1%). 12 brand names with a page on this site carry this code; the brands table is 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."

Brands with this product code

Brand	Reports	Latest 12 months	Classified as death	Classified as malfunction
Unknown Knee	515	18	1.5%	0.3%
Unknown Oxford Bearing	258	42	0.4%	0.2%
Unknown Oxford Knee	226	0	3.3%	2.2%
Unknown Oxford Tibial Component	192	32	0%	1.7%
Unknown Oxford Femoral Component	173	30	0.3%	0%
Unknown Tibial Component	9	200	0%	0.5%
Unknown Bearing	7	84	0.3%	2.2%
Unknown Femoral Component	5	90	0.3%	1.6%
Unknown Articular Surface	1	78	0%	1.1%
Unknown Femoral	1	27	0%	0%
Unknown NexGen Articular Surface	1	26	0%	0.8%
Unknown Tibial Tray	1	25	0.2%	3%

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."

Manufacturers named

Manufacturer (as written on reports)	Reports	Share
Biomet UK	4,234	82%
Biomet Orthopedics	412	8%
Zimmer Biomet	293	5.7%
Biomet	15	0.3%
Biomet France R L	2	0%

Reports by month, five years

FDA releases MAUDE data monthly; reports can arrive months after an event, so the newest months grow in later releases.

Event type and report source

Event type

Death1.1%58

Injury94.9%4,902

Malfunction3.8%196

Other0.1%3

Not given0.1%4

Who filed

Manufacturer report99.6%5,142

Voluntary report0.3%14

User facility report0%0

Distributor report0%0

Not given0.1%7

Grey bar: all 26,136,888 MAUDE reports.

Device problems coded

Device problem (FDA code)	Reports	Share
Insufficient device problem information	1,462	28.3%
Device dislodged or dislocated	574	11.1%
Fracturea broken bone	310	6%
Loose or intermittent connection	225	4.4%
Migration or expulsion of device	215	4.2%
Loosening of implant not related to bone-ingrowth	172	3.3%
Device slipped	168	3.3%
Patient device interaction problem	150	2.9%
Unstable	138	2.7%
Naturally worn	106	2.1%
Breakthe device broke	69	1.3%
Mechanical problema mechanical problem	61	1.2%
Malposition of device	53	1%
Material integrity problema problem with the device material	53	1%
Device operates differently than expectedthe device behaved unexpectedly	43	0.8%
Noise, audible	38	0.7%
Migrationthe device moved from where it was placed	37	0.7%
Unintended movement	33	0.6%
Loss of or failure to bond	31	0.6%
Implant, removal of	22	0.4%

Questions about prosthesis, knee, femorotibial, unicompartmental, semi-constrained, metal/polymer, mobile bearing reports

What is product code NRA?

FDA's classification code for "Prosthesis, knee, femorotibial, unicompartmental, semi-constrained, metal/polymer, mobile bearing", class 3, reviewed by the unknown panel. Every device report carries the product code of the device involved.

How many reports carry this code?

5,163 reports through August 2026, 309 of them in the latest 12 months.

Which brands appear most often?

Unknown Knee (515), Unknown Oxford Bearing (258), Unknown Oxford Knee (226), Unknown Oxford Tibial Component (192) and Unknown Oxford Femoral Component (173). Widely used products collect more reports because more people use them.

Can the brands table be used to rank the devices?

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." Brands differ in how many are in use, how long they have been sold and how reports are collected.

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. 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.