510(k) · Cleared
ClearedU2 Total Knee System – PF+ Patella; USTAR II System– PF+ Patella
Data to Oct 25, 2026 (FDA decisions) Oct 12, 2026 (recalls) Sep 30, 2026 (MAUDE) refreshed weekly
United Orthopedic Corporation · MBH Prosthesis, Knee, Patello/Femorotibial, Semi-Constrained, Uncemented, Porous, Coated, Polymer/Metal/Polymer
Cleared on Jul 31, 2025 as substantially equivalent to K212941 (Encore Medical, L.P. Dba Djo Surgical, 2022) and 3 other predicates after a 247-day review. Its family tree reaches back 8 generations to 1994.
- Decided
- Jul 31, 2025
- Review
- 247 days
- Class
- Class II
- Product code
- MBH
- Recalls
- None
- Predicates
- 4
Its longest line of descent runs back 8 generations to K921308 (1994). 75 ancestors in all, the oldest K864671 (1987). No later device cites it as a predicate yet.
- Root · 8 generations backK921308 HG Multilock Hip Prosthesis W/ TI-NidiumZimmer, Inc. · 1994 · Recalled
- 7 generations backK972893 Partnership Revision Femoral StemsHowmedica Corp. · 1997
- 6 generations backK983404 Type 3 Femoral ComponentsHowmedica Corp. · 1998 · Recalled
- 5 generations backK013106 2 Piece Modular Hip StemHowmedica Osteonics Corp. · 2002 · Recalled
- 4 generations backK022549 Restoration Modular SystemHowmedica Osteonics Corp. · 2002 · Recalled
- 3 generations backK090757 Biomet Modular Femoral Revision SystemBiomet, Inc. · 2009 · Recalled
- 2 generations backK130063 Arcos Trochanter ButtonBiomet, Inc. · 2013
- 1 generation backK190100 USTAR II SystemUnited Orthopedic Corporation · 2019 · Recalled
- This deviceK243656 U2 Total Knee System – PF+ Patella; USTAR II System– PF+ PatellaUnited Orthopedic Corporation · 2025
View FIG. 1 as a table
Line of descent and top descendants
| Generation | Number | Device | Applicant | Decided | Recalls |
|---|---|---|---|---|---|
| −8 | K921308 | HG Multilock Hip Prosthesis W/ TI-Nidium | Zimmer, Inc. | 1994 | 1 |
| −7 | K972893 | Partnership Revision Femoral Stems | Howmedica Corp. | 1997 | — |
| −6 | K983404 | Type 3 Femoral Components | Howmedica Corp. | 1998 | 1 |
| −5 | K013106 | 2 Piece Modular Hip Stem | Howmedica Osteonics Corp. | 2002 | 37 |
| −4 | K022549 | Restoration Modular System | Howmedica Osteonics Corp. | 2002 | 3 |
| −3 | K090757 | Biomet Modular Femoral Revision System | Biomet, Inc. | 2009 | 18 |
| −2 | K130063 | Arcos Trochanter Button | Biomet, Inc. | 2013 | — |
| −1 | K190100 | USTAR II System | United Orthopedic Corporation | 2019 | 5 |
| 0 (this device) | 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 |
| 1992 | 1 | 0 |
| 1994 | 2 | 0 |
| 1995 | 8 | 0 |
| 1996 | 7 | 0 |
| 1997 | 2 | 0 |
| 1999 | 2 | 0 |
| 2000 | 6 | 0 |
| 2001 | 1 | 0 |
| 2002 | 4 | 0 |
| 2003 | 7 | 0 |
| 2004 | 2 | 0 |
| 2005 | 8 | 0 |
| 2006 | 2 | 0 |
| 2007 | 2 | 0 |
| 2008 | 1 | 0 |
| 2010 | 3 | 0 |
| 2011 | 1 | 0 |
| 2013 | 3 | 0 |
| 2014 | 1 | 0 |
| 2015 | 1 | 0 |
| 2022 | 1 | 0 |
| 2023 | 1 | 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 MBH? 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 MBH device
- #1 K241597 Freedom® Total Knee System - Porous Tibial…score 19.9 · 8 generations · no Class I recall
- #2 Held for the reportin the report
- #3 Held for the reportin the report
What was it cleared against? (4)
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 |
|---|---|---|---|
| * | K212941 | Porous PatellaSummary page 6…roduct Codes MBH, JWH, KRO Predicate Device Information 510(k) Number Predicate Trade Name Product Code Primary Predicate K212941 Porous Patella e+™ MBH, JWH Secondary Predicate Devices K132624 Triathlon… | 2022 |
| * | K132624 | Triathlon Tritanium Metal-Backed PatellaSummary page 6…e Trade Name Product Code Primary Predicate K212941 Porous Patella e+™ MBH, JWH Secondary Predicate Devices K132624 Triathlon® Tritanium® Metal- MBH, JWH Backed Patella K221705… | 2013 |
| * | K221705 | U2 Total Knee System-PF+Summary page 6…MBH, JWH Secondary Predicate Devices K132624 Triathlon® Tritanium® Metal- MBH, JWH Backed Patella K221705 U2 Total Knee System-PF+ MBH, JWH Page 1 of 4… | 2023 |
| * | K190100 | USTAR II SystemSummary page 7…4 Traditional 510(k) U2 Total Knee System – PF+ Patella; USTAR II System – PF+ Patella 510(k) Number Predicate Trade Name Product Code K190100 USTAR II System – USTAR II Knee KRO, KWL, LPH, LWJ System Device Descripti… | 2019 |
What descends from it?
No later submission names this one as a predicate yet.
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 31 years and passes through 5 companies; a new generation was cleared every 3.7 years on median.
- 47 of the 75 ancestors have a recall of any class.
How does its category compare?
All MBH devicesMBH Prosthesis, Knee, Patello/Femorotibial, Semi-Constrained, Uncemented, Porous, Coated, Polymer/Metal/Polymer: FDA decisions, review times, recalls and adverse event reports over 20 years. 2025, this device’s year, is highlighted.
FDA decisions per year · MBH
8in 2025
2026 to Oct 25, outlined.
Median 510(k) review, days · MBH
98in 2025
Receipt to decision; years with fewer than 3 clearances left blank.
Recalls per year · MBH
1in 2024
Class I (5 since 2007) Class II/III not classified
Adverse event reports per year · MBH
1,561in 2025
MAUDE reports naming product code MBH, 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 | 10 | 59 | 0 | 27 |
| 2008 | 3 | 70 | 0 | 21 |
| 2009 | 3 | 209 | 2 | 89 |
| 2010 | 4 | 84 | 0 | 121 |
| 2011 | 5 | 84 | 15 | 247 |
| 2012 | 5 | 90 | 1 (1) | 370 |
| 2013 | 6 | 138 | 4 (4) | 308 |
| 2014 | 9 | 114 | 0 | 385 |
| 2015 | 8 | 100 | 0 | 955 |
| 2016 | 4 | 74 | 1 | 1,034 |
| 2017 | 4 | 115 | 9 | 1,007 |
| 2018 | 6 | 89 | 1 | 1,191 |
| 2019 | 1 | — | 1 | 1,394 |
| 2020 | 7 | 112 | 2 | 1,089 |
| 2021 | 6 | 48 | 0 | 1,539 |
| 2022 | 7 | 57 | 0 | 1,261 |
| 2023 | 6 | 94 | 2 | 1,263 |
| 2024 | 10 | 84 | 1 | 1,497 |
| 2025 | 8 | 98 | 0 | 1,561 |
| 2026 | 7 | 153 | 4 | — |
What is it indicated for?
U2 Total Knee System - PF+ is indicated in knee arthroplasty for reduction or relief of pain and/or improved knee function in skeletally mature patients with severe knee pain and disability due to rheumatoid arthritis, osteoarthritis, primary and secondary traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis of the femoral condyle or pseudogout, posttraumatic loss of joint configuration, particularly when there is patellofemoral…
Read the full statement (277 words)
U2 Total Knee System - PF+ is indicated in knee arthroplasty for reduction or relief of pain and/or improved knee function in skeletally mature patients with severe knee pain and disability due to rheumatoid arthritis, osteoarthritis, primary and secondary traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis of the femoral condyle or pseudogout, posttraumatic loss of joint configuration, particularly when there is patellofemoral joint surface erosion, dysfunction or prior patellectomy, moderate valgus, varus, or flexion deformities. This device may also be indicated in the salvage or previously failed surgical attempts or for knee in which satisfactory stability in flexion cannot be obtained at the time of surgery. Femoral Component, PF+, Tibial Baseplate, PF+, Tibial Extension Stem, Patella, Onset, E-XPE, PF+, and Patella, Asymmetric Onset, E-XPE, PF+ are indicated for both cemented and cementless use.
USTAR II Total Knee System
1. Metastatic tumor (i.e. osteosarcoma, chondrosarcoma, giant cell tumor or osteoma) where massive resection and transplantation are needed.
2. Severe knee joint damage resulting from trauma where massive resection and transplantation are needed.
3. Non-inflammatory degenerative joint disease such as avascular necrosis, osteoarthritis, or traumatic arthritis.
4. Revision of previously failed total joint arthroplasty, osteotomy, or arthrodesis.
5. Joint instability resulting from excessive bone resection.
For Femoral component, Hinged/ Tibial baseplate, Hinged/ Cemented tibial stem/ Cemented Straight stem, RHS, non coated/ Cemented Curved stem, RHS, non coated/ Cemented Straight stem, RHS/ Cemented Curved stem, RHS/ Tibial Augment: These devices are single use implant and intended for cemented use only.
For Distal Femoral Component, RHS/ Proximal Tibial Component, RHS/ Tibial stem/ Segment Part, RHS/ Segment Part, RHS, Bridge: These devices are single use implant and intended for cementless use only.
Indications for use read by OCR from a scanned FDA summary, so letters may be misread. Check the PDF before quoting it.
https://510kreport.com/device/K243656 · printed Nov 6, 2026
Cite this page
510(k) Report. “K243656: U2 Total Knee System – PF+ Patella; USTAR II System– PF+ Patella.” Lineage record from FDA 510(k) data and the FDA summary. Updated Nov 3, 2026. Accessed Nov 6, 2026. https://510kreport.com/device/K243656
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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