# K252725: Stem Extension Line (U2 Total Knee System—PSA Type)

- Pathway: 510(k) (Special)
- Applicant: United Orthopedic Corporation
- Decided: Sep 25, 2025 after 28 days
- Product code: JWH (Prosthesis, Knee, Patellofemorotibial, Semi-Constrained, Cemented, Polymer/Metal/Polymer)
- Device class: 2
- Regulation: 21 CFR 888.3560
- Recalls of this device: none
- Data: FDA decisions to Oct 25, 2026; recalls to Oct 12, 2026

## Lineage
Longest line of descent: 3 generations back to K021657 (2002). 4 ancestors in all.
No later device cites it as a predicate yet.
0 of 5 devices in its family (counting itself) have a Class I recall.

## Predicates on the family tree (from the FDA summary)
- K082424: United U2 Total Knee System, United Orthopedic Corp. (2008) Summary page 5.

## Indications for use
This device is indicated in knee arthroplasty 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 contraction. This device is intended for use in patients who require augmentation and/or stem extensions due to inadequate bone stock and/or require increased stabilization for tibiofemoral joint due to soft tissue imbalance. The femoral and tibial augments are to be attached to their respective components with a fixation screw or screws. Note: In the US, this device is for cemented use only.

Source page: https://510kreport.com/device/K252725
Methodology: https://510kreport.com/methodology