510(k) · Cleared
ClearedUnited Stem, Psa Type
Data to Oct 25, 2026 (FDA decisions) Oct 12, 2026 (recalls) Sep 30, 2026 (MAUDE) refreshed weekly
United Orthopedic Corp. · JWH Prosthesis, Knee, Patellofemorotibial, Semi-Constrained, Cemented, Polymer/Metal/Polymer
Cleared on Jun 14, 2010 as substantially equivalent to K082424 (United Orthopedic Corp., 2008) and 2 other predicates after a 66-day review. Its family tree reaches back 3 generations to 1996. 3 later devices descend from it.
- Decided
- Jun 14, 2010
- Review
- 66 days
- Class
- Class II
- Product code
- JWH
- Recalls
- None
- Predicates
- 3
Its longest line of descent runs back 3 generations to K962137 (1996). 10 ancestors in all, the oldest K864671 (1987). 3 later devices descend from it, 1 citing it directly.
- Root · 3 generations backK962137 Genesis II Constrained SystemSmith & Nephew Richards, Inc. · 1996 · Recalled
- 2 generations backK041106 Revision Knee SystemSmith & Nephew, Inc. · 2004 · Recalled
- 1 generation backK043440 Smith & Nephew, Inc. Revision Knee SystemSmith & Nephew, Inc. · 2005 · Recalled
- This deviceK100981 United Stem, Psa TypeUnited Orthopedic Corp. · 2010
- Descendant · cites it directly · 2 of its ownK190100 USTAR II SystemUnited Orthopedic Corporation · 2019 · Recalled
- Descendant · 2 generations on · 0 of its ownK252303 Stem Extension Line (USTAR II System)United Orthopedic Corporation · 2025
- Descendant · 2 generations on · 0 of its ownK243656 U2 Total Knee System – PF+ Patella; USTAR II System– PF+ PatellaUnited Orthopedic Corporation · 2025
Most influential descendants
Showing 3 of 3 · See all- K190100USTAR II SystemUnited Orthopedic Corporation · 2019 · cites it directly2descendants
- K252303Stem Extension Line (USTAR II System)United Orthopedic Corporation · 2025 · 2 generations on0descendants
- K243656U2 Total Knee System – PF+ Patella; USTAR II System– PF+ PatellaUnited Orthopedic Corporation · 2025 · 2 generations on0descendants
View FIG. 1 as a table
Line of descent and top descendants
| Generation | Number | Device | Applicant | Decided | Recalls |
|---|---|---|---|---|---|
| −3 | K962137 | Genesis II Constrained System | Smith & Nephew Richards, Inc. | 1996 | 1 |
| −2 | K041106 | Revision Knee System | Smith & Nephew, Inc. | 2004 | 1 |
| −1 | K043440 | Smith & Nephew, Inc. Revision Knee System | Smith & Nephew, Inc. | 2005 | 7 |
| 0 (this device) | K100981 | United Stem, Psa Type | United Orthopedic Corp. | 2010 | — |
| +1 | K190100 | USTAR II System | United Orthopedic Corporation | 2019 | 5 |
| +2 | K252303 | Stem Extension Line (USTAR II System) | United Orthopedic Corporation | 2025 | — |
| +2 | K243656 | U2 Total Knee System – PF+ Patella; USTAR II System– PF+ Patella | United Orthopedic Corporation | 2025 | — |
Other ancestors by year cleared
| Year cleared | Devices | With a Class I recall |
|---|---|---|
| 1987 | 1 | 0 |
| 1995 | 1 | 0 |
| 1996 | 2 | 0 |
| 2002 | 1 | 0 |
| 2006 | 1 | 0 |
| 2008 | 1 | 0 |
Descendants by year cleared
| Year cleared | Devices | With a Class I recall |
|---|---|---|
| 2019 | 1 | 0 |
| 2025 | 2 | 0 |
Sources: FDA 510(k) database (decision fields), the FDA summary (predicates and indications), FDA recall and enforcement reports, and MAUDE; processed by 510(k) Report. Verify on FDA.gov · Methodology and accuracy.
Planning a device in JWH? A 510(k) Report weighs predicate choices, recall history and review times for a new device like this one.
Top candidate predicates for a new JWH device
- #1 K221479 Persona Personalized Knee Systemscore 22.4 · 11 generations · no Class I recall
- #2 Held for the reportin the report
- #3 Held for the reportin the report
What was it cleared against? (3)
Devices the submitter claimed this one is substantially equivalent to (*), and reference devices cited for a specific test or feature (†), as written in the FDA summary.
| Type | Number | Device | Decided |
|---|---|---|---|
| * | K082424 | United U2 Total Knee SystemSummary page 1…ed prosthesis per 2 1 CFR 888.3560. This falls under the Orthopedics panel. Predicate Device: I. "UNITED" U2 Total Knee system -PSA Type (K082424) 2. "DEPUY" Anatomic Modular Knee (AMK) System (K864671)… | 2008 |
| * | K864671 | Anatomic Modular Knee (Amk) SystemSummary page 1…vice: I. "UNITED" U2 Total Knee system -PSA Type (K082424) 2. "DEPUY" Anatomic Modular Knee (AMK) System (K864671) 3. "SMITH & NEPHEW" LEGION Revision Knee System (K043440) Device Desc… | 1987 |
| * | K043440 | Smith & Nephew, Inc. Revision Knee SystemSummary page 1…Modular Knee (AMK) System (K864671) 3. "SMITH & NEPHEW" LEGION Revision Knee System (K043440) Device Description: "UNITED Stem-PSA Type is an additional size extension of stem to the existing, previously cleare… | 2005 |
What descends from it? (3)
1 later device cites it directly; ranked here by how many devices descend from each in turn.
| Number | Device | Decided | Descendants |
|---|---|---|---|
| K190100 | USTAR II System | 2019 | 2 |
Has anything in its family been recalled? (0 Class I)
No FDA recall names this device.
No ancestor or descendant has a Class I recall.
What does this lineage say?
- The line of descent spans 14 years and passes through 3 companies; a new generation was cleared every 5.3 years on median.
- 7 of the 10 ancestors have a recall of any class.
- Of its descendants, K190100 (United Orthopedic Corporation, 2019) has gone furthest, with 2 descendants of its own.
- 8 other devices also cite its predicate K082424.
How does its category compare?
All JWH devicesJWH Prosthesis, Knee, Patellofemorotibial, Semi-Constrained, Cemented, Polymer/Metal/Polymer: FDA decisions, review times, recalls and adverse event reports over 20 years. 2010, this device’s year, is highlighted.
FDA decisions per year · JWH
20in 2025
2026 to Oct 25, outlined.
Median 510(k) review, days · JWH
55in 2025
Receipt to decision; years with fewer than 3 clearances left blank.
Recalls per year · JWH
2in 2025
Class I (0 since 2007) Class II/III not classified
Adverse event reports per year · JWH
9,306in 2025
MAUDE reports naming product code JWH, not matched to any one device; reports are not rates.
View these four charts as a table
| Year | Decisions | Median 510(k) review, days | Recalls (Class I) | MAUDE reports |
|---|---|---|---|---|
| 2007 | 18 | 74 | 14 | 1,305 |
| 2008 | 17 | 81 | 10 | 1,483 |
| 2009 | 11 | 168 | 109 | 1,870 |
| 2010 | 19 | 85 | 32 | 3,286 |
| 2011 | 25 | 87 | 27 | 5,133 |
| 2012 | 33 | 85 | 85 | 5,203 |
| 2013 | 31 | 128 | 31 | 6,135 |
| 2014 | 33 | 98 | 13 | 6,722 |
| 2015 | 27 | 87 | 11 | 6,881 |
| 2016 | 18 | 88 | 17 | 7,586 |
| 2017 | 25 | 118 | 61 | 12,263 |
| 2018 | 25 | 90 | 14 | 14,071 |
| 2019 | 28 | 133 | 5 | 14,987 |
| 2020 | 22 | 59 | 2 | 12,592 |
| 2021 | 24 | 61 | 8 | 9,408 |
| 2022 | 17 | 56 | 12 | 8,364 |
| 2023 | 20 | 57 | 67 | 8,947 |
| 2024 | 19 | 89 | 7 | 10,828 |
| 2025 | 20 | 55 | 2 | 9,306 |
| 2026 | 12 | 63 | 4 | — |
What is it indicated for?
Stem - PSA Type is included in U2 Total Knee System-PSA type. U2 Total Knee System-PSA type is indicated for use in skeletally mature patients with severe knee pain and disability undergoing surgery for knee arthroplasty due to rheumatoid arthritis, osteoarthritis, primary and secondary traumatic arthritis, polyarthritis, collagen disorddrs, avascular necrosis of the femoral condyle or pseudogout, posttraumnatic loss of joint configuration, particularly…
Read the full statement (119 words)
Stem - PSA Type is included in U2 Total Knee System-PSA type. U2 Total Knee System-PSA type is indicated for use in skeletally mature patients with severe knee pain and disability undergoing surgery for knee arthroplasty due to rheumatoid arthritis, osteoarthritis, primary and secondary traumatic arthritis, polyarthritis, collagen disorddrs, avascular necrosis of the femoral condyle or pseudogout, posttraumnatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior pateltectomy, moderate valgus, varus, or flexion contraction. This device is intended for use in patients who require augmentation and/or stem extensions due to inadequate bone stock and/or require constrained stabilization for tibiofemoral joint due to soft tissue imbalance. U2 Total Knee System-PSA type isdesigned for cemented use only.
Indications for use as stated in the FDA summary.
https://510kreport.com/device/K100981 · printed Nov 4, 2026
Cite this page
510(k) Report. “K100981: United Stem, Psa Type.” Lineage record from FDA 510(k) data and the FDA summary. Updated Nov 3, 2026. Accessed Nov 4, 2026. https://510kreport.com/device/K100981
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Record history
- FDA decision record loaded May 2, 2026
- Summary read Oct 13, 2026 (extraction version 9eaa42aa01ed)
- Lineage and recalls computed Nov 3, 2026
- Page last updated Nov 3, 2026