FDA product code KRO: Prosthesis, Knee, Femorotibial, Constrained, Cemented, Metal/Polymer
KRO is the FDA product code for prosthesis, knee, femorotibial, constrained, cemented, metal/polymer. It is a Class II device, regulated under 21 CFR 888.3510 and reviewed by the Orthopedic panel. FDA has cleared 87 510(k) submissions under KRO, 12 in the last five years, from 41 different applicants. The average 510(k) review took 120 days (median 88); 67 days on average over the last three years. FDA has posted 124 recalls for KRO devices, 57 initiated in the last five years.
Classification
| Field | Value |
|---|---|
| Device name | Prosthesis, Knee, Femorotibial, Constrained, Cemented, Metal/Polymer |
| Device class | Class II |
| Regulation | 21 CFR 888.3510 |
| Review panel | OR — Orthopedic |
| Medical specialty | Orthopedic |
| Premarket route | 510(k) |
| Implant | Yes |
510(k) clearances per year for KRO
| Year | Clearances | Avg. review days |
|---|---|---|
| 2017 | 1 | 90 |
| 2019 | 3 | 203 |
| 2020 | 1 | 437 |
| 2021 | 3 | 45 |
| 2022 | 1 | 60 |
| 2023 | 4 | 141 |
| 2024 | 3 | 80 |
| 2025 | 3 | 60 |
| 2026 | 1 | 62 |
Compare with all 510(k) review times · Search every KRO clearance
Top KRO applicants
| Applicant | Clearances | Latest |
|---|---|---|
| Howmedica Osteonics Corp. | 9 | 2013-02-22 |
| Biomet, Inc. | 9 | 2008-06-11 |
| Zimmer, Inc. | 6 | 2020-12-10 |
| Waldemar Link GmbH & Co. KG | 5 | 2022-05-03 |
| Stanmore Implants Worldwide , Ltd. | 5 | 2015-01-20 |
36 more applicants have KRO clearances. See the full list in Caduvo.
Most recent KRO clearances
| 510(k) | Applicant | Device | Decision date | Review days |
|---|---|---|---|---|
| K261898 | Howmedica Osteonics Corp. dba Stryker Orthopaedics | Triathlon® Knee System; Triathlon® Hinge Knee System; Scorpio® Total Knee System | 2026-08-06 | 62 |
| K252898 | Howmedica Osteonics Corp., Dba Stryker Orthopaedics | Triathlon® Tritanium® Asymmetric Patella; Triathlon® Tritanium® Symmetric Patella; Triathlon® Symmetric Patella; Triathlon® Asymmetric Patella; Scorpio® Universal Dome Patella; Triathlon® Hinge Bumper | 2025-12-15 | 95 |
| K252303 | United Orthopedic Corporation | Stem Extension Line (USTAR II System) | 2025-08-22 | 29 |
| K251665 | Howmedica Osteonics Corp., Dba Stryker Orthopaedics | Triathlon® Hinge Knee System | 2025-07-25 | 56 |
| K242871 | Depuy Ireland UC | ATTUNE Revision Hinge Knee | 2024-11-21 | 59 |
Recalls for KRO devices
124 product recalls in 43 recall events; 57 initiated in the last five years and 61 still open. Most recent: 2026-07-30.
| Year | Recalls |
|---|---|
| 2017 | 19 |
| 2018 | 2 |
| 2021 | 5 |
| 2023 | 25 |
| 2024 | 4 |
| 2025 | 1 |
| 2026 | 27 |
Frequently asked questions
What is FDA product code KRO?
KRO is the FDA product code for prosthesis, knee, femorotibial, constrained, cemented, metal/polymer. It is a Class II device, regulated under 21 CFR 888.3510 and reviewed by the Orthopedic panel.
What device class is KRO?
Class II, regulation 21 CFR 888.3510. Typical premarket route: 510(k).
How long does a 510(k) take for product code KRO?
Across 87 cleared submissions the average was 120 days from receipt to decision (median 88).
Which companies have the most KRO clearances?
Howmedica Osteonics Corp. (9); Biomet, Inc. (9); Zimmer, Inc. (6); Waldemar Link GmbH & Co. KG (5); Stanmore Implants Worldwide , Ltd. (5).
Have KRO devices been recalled?
Yes: 124 product recalls across 43 recall events; the most recent began 2026-07-30.
Next steps
- Run an FDA pathway report with predicate devices for product code KRO
- Run a recall and safety report across every KRO manufacturer
- Watch product code KRO for new clearances and recalls
Source: openFDA device classification, 510(k), PMA, De Novo and recall data (public domain). Review days run from FDA receipt to decision. Not regulatory advice.
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