Devices › Prosthesis, knee, patellofemorotibial, semi-constrained, cemented, polymer/metal/polymer
Device brand name · Knee tibial insert
GMK Sphere Total Knee System: medical device reports filed with FDA
673 reports name it, 2024–2026. Manufacturer given most often on reports: Medacta International. Product code JWH.
- 673
- device reports naming the brand
- 0% of all MAUDE reports · about 270 a year
- 356
- reports, 12 months to August 2026
- 315 in the 12 months before
- 2.1%
- classified as malfunction
- 14.7% across the product code
- 0%
- classified as death, as reported
- 0 reports · not verified by FDA
FDA's MAUDE database holds 673 reports that name the brand "GMK Sphere Total Knee System" (knee tibial insert), received between January 2024 and August 2026; the manufacturer given most often on reports is Medacta International. Spellings of one product vary from report to report.
356 reports arrived in the 12 months to August 2026, up 13% from 315 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 (97.9%) and malfunction (2.1%); 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 device appears to trigger rejection (45.6%), loosening of implant not related to bone-ingrowth (3%) and device dislodged or dislocated (2.8%). The patient problems coded most often are medical device site infection, joint laxity and implant pain. 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 |
|---|---|---|---|
| Device appears to trigger rejection | 307 | 45.6% | 0.5% |
| Loosening of implant not related to bone-ingrowth | 20 | 3% | 4% |
| Device dislodged or dislocated | 19 | 2.8% | 1.7% |
| Malposition of device | 6 | 0.9% | 0.9% |
| Migrationthe device moved from where it was placed | 5 | 0.7% | 0.8% |
| Osseointegration problem | 4 | 0.6% | 0.3% |
| Naturally worn | 3 | 0.4% | 6.8% |
| Difficult to insertthe device was hard to insert | 2 | 0.3% | 0.8% |
| Implant subsidence | 2 | 0.3% | 0% |
| Positioning failure | 2 | 0.3% | 0.2% |
| Insufficient device problem information | 1 | 0.1% | 18.1% |
| Manufacturing, packaging or shipping problem | 1 | 0.1% | 0.1% |
| Misassembly by users | 1 | 0.1% | 0% |
| Positioning problem | 1 | 0.1% | 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 |
|---|---|---|
| Medical device site infectioninfection at the device site | 279 | 41.5% |
| Joint laxity | 262 | 38.9% |
| Implant pain | 59 | 8.8% |
| Loss of range of motion | 32 | 4.8% |
| Appropriate clinical signs, symptoms and conditions term/code not available | 17 | 2.5% |
| Joint dislocationa dislocated joint | 17 | 2.5% |
| Painpain, site not specified | 12 | 1.8% |
| Aseptic loosening | 8 | 1.2% |
| Damage to ligament(s) | 8 | 1.2% |
| Hypersensitivity/allergic reaction | 5 | 0.7% |
| Inadequate osseointegration | 5 | 0.7% |
| Metal related pathology | 4 | 0.6% |
| Fibrosis | 1 | 0.1% |
| Hematomaa collection of blood under the skin or in tissue | 1 | 0.1% |
| Osteolysis | 1 | 0.1% |
Patient problem codes are present mainly in reports filed since 2019 and are often blank.
In context
| Measure | GMK Sphere Total Knee System | Product code JWH | All MAUDE reports |
|---|---|---|---|
| Reports | 673 | 158,133 | 26,136,888 |
| Share of that pool | — | 0.4% | 0% |
| Classified as death, per 1,000 reports | 0 | 2 | 9 |
| Classified as injury | 97.9% | 84.1% | 36.2% |
| Classified as malfunction | 2.1% | 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 GMK Sphere Total Knee System reports
How many FDA reports name GMK Sphere Total Knee System?
673 medical device reports in the openFDA MAUDE release of 28 Sep 2026, covering reports received through August 2026; 356 in the latest 12 months.
What kinds of events are reported?
injury (97.9%) and malfunction (2.1%). "Event type" is how the report was classified when filed: death, injury, malfunction or other.
What device problems are coded?
device appears to trigger rejection (45.6%), loosening of implant not related to bone-ingrowth (3%), device dislodged or dislocated (2.8%), malposition of device (0.9%) and migration (0.7%). 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 GMK Sphere Total Knee System 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.