knee

A Move Forward in Mobile Bearing Design

The Zimmer NexGen LPS-Flex Mobile and LPS-Mobile Bearing Knees provide an anteriorly positioned pivot near the entry point of the anterior cruciate ligament (ACL).

• An anterior pivot at the ACL site replicates the anatomic center of rotation^1,2
• Anterior pivot design leads to lower patellofemoral forces that lead to anterior knee pain, patellar subluxation and dislocation, component wear, damage, and loosening^3,4
• An anterior stop on the tibial plate prevents bearing spin-out and allows 25 degrees of unimpeded internal/external rotation

The LPS-Flex Mobile Bearing Knee Femoral Component has an enhanced cam/spine mechanism that is designed to provide stability at up to 155 degrees of active flexion.

• Deepened patellar groove delivers smooth patellar tracking, relieves pressure on the patella, and reduces forces that may cause patella clunk, pain, and premature wear
• Subluxation resistance increases at deep flexion angles as the cam moves down the spine
• Extended posterior flanges safely accommodate tibio-femoral contact during deep flexion

Wear

• Increased contact area/lower contact stresses
• Frontal plane conformity ratio

• Sagittal plane conformity ratio at extension and low angles of flexion⁵

• Femoral radii are matched to size-specific articular surfaces
• Allowing only unidirectional rotational motion potentially reduces cross-shear and consequent wear⁶

Refer to the package insert for indications, contraindications, warnings, precautions and adverse effects.

*P.F.C^® is a trademark of Johnson & Johnson Corporation

The LPS-Flex Mobile Bearing Knee is supported by both clinical history and published study results.

• Ten years of successful clinical history in the European Union and Japan
• A study published in The Journal of Arthroplasty in 2010 reports a higher degree of postoperative flexion with the LPS-Flex Mobile Bearing Knee than with comparable mobile bearing designs reported in the literature⁷
• A study published in Clinical Orthopaedics and Related Research in 2004 reports patients with LPS-Flex Mobile Bearing Knee had similar kinematics patterns to the control patients with a healthy knee⁸
• A study published in the Journal of Biomechanics in 2005 reports implanted patella experienced similar kinematics to the non-implanted healthy knee⁹  

NexGen LPS-Flex Mobile and LPS Mobile Bearing Knee (US Only)

1. Argenson JN, Scuderi GR, Komistek RD, Scott WN, Kelly MA, Aubaniac JM. In vivo kinematic evaluation and design considerations related to high flexion in total knee arthroplasty. J Biomech. 2005;38(2):277-284.
2. Hollister AM, Jatana S, Singh AK, Sullivan WW, Lupichuk AG. The axes of rotation of the knee. Clin Orthop Relat Res. 1993;290:259-268.
3. Smith AJ, Lloyd DG, Wood DJ. Pre-surgery knee joint loading patterns during walking predict the presence and severity of anterior knee pain after total knee arthroplasty. J Orthop Res. 2004;22(2):260-266.
4. Browne C, Hermida JC, Bergula A, Colwell CW Jr, D'Lima DD. Patellofemoral forces after total knee arthroplasty: effect of extensor moment arm. Knee. 2005;12(2):81-88.
5. Gsell R, Yao JQ, Laurent MP, Crowninshield RD: Improved oxidation resistance of highly crosslinked UHMWPE for total knee arthroplasty. Society for Biomaterials 28th Annual Meeting Transactions, 542, 2002.
6. ZRR_WA_1577_06
7. Jones, V.C. et al. An experimental model of tibial counterface polyethylene wear in mobile bearing knees: The influence of design and kinematics. Bio-medical Materials & Related Research, 1999;9:189-196.
8. Tarabichi, S. et al. Achieving Deep Flexion After Primary Total Knee Arthroplasty. Journal of Arthroplasty. 2010; Vol.25,No.2,219-224.
9. Scuderi G.R. et al. In vivo kinematic evaluation and design considerations related to high flexion in total knee arthroplasty. Journal of Biomechanics. Number 38, pp 277-284. 2005.
10. Ranawat, C.S. "Design features of mobile-bearing knee implants", Orthopedics Today, Technical Monograph to the Dec. 2000 issue, 10-122, 2000

Indications: The NexGen® LPS-Flex/LPS-Mobile Bearing Knees are posterior-stabilized, cemented, knee prostheses indicated for patients with severe knee pain and disability due to osteoarthritis, traumatic arthritis, femoral avascular necrosis and moderate valgus, varus, or flexion deformities.

Contraindications: The device is contraindicated in patients with affected joint or systemic infection, insufficient bone stock, osteoporosis, skeletal immaturity or severe instability of the joint.

Warnings: Do not reuse (single patient use only). All 17 and 20mm articular surfaces require a locking screw. Use only NexGen all-polyethylene patellas with these mobile knees. Do not use; any damaged component, components from other knee systems, CR, CRA, CR-Flex or any porous components.

Precautions: Use sizing charts to correctly match components. Safety and effectiveness of this device has not been established in patients with rheumatoid arthritis, collagen disorders, polyarthritis, or pseudogout; or in patients who need a revision total knee replacement.

Adverse Effects: Implant loosening due to osteolysis, tibiofemoral subluxation or bearing disassembly, dislocation, joint instability or knee stiffness.

Refer to the package insert for indications, contraindications, warnings, precautions and adverse effects.