CR Flex GSF Porous Femoral LPS Flex GSF Porous Femoral LPS Flex Porous Femoral prosthesis, knee, patello/femorotibial, semi-constrained, uncemented, porous, coated, polymer/metal/polymer various sizes This device is indicated for patients with severe knee pain and disability due to: Rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis. Collagen disorders, and/or avascular necrosis of the femoral condyle. Post-traumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy. Moderate valgus, varus, or flexion deformities. The salvage of previously failed surgical attempts or for a knee in which satisfactory stability in flexion cannot be obtained at the time of surgery. " The CR-Flex GSF and LPS-Flex GSF uncoated (Option) and precoat styles are intended for cemented use only. " The CR-Flex GSF and LPS-Flex GSF porous coated femoral components may be used cemented or uncemented (biological fixation). " Specific uses with CR-Flex GSF or LPS-Flex GSF femorals: Provides increased flexion capability for patients who have both the flexibility and desire to increase their flexion range. The CR-Flex GSF femoral, when used with 90-prefix NexGen CR articular surfaces, 00-prefix 10, 12 or 14 mm or 90-prefix 17 or 20 mm Prolong¿ Highly Crosslinked Polyethylene CR articular surfaces, or with Gender Solutions Natural-Knee Flex Congruent articular surfaces, is designed for use with a functional posterior cruciate ligament and when load bearing range of motion (ROM) is expected to be less than or equal to 155 degrees. The LPS-Flex GSF femoral, when used with LPS-Flex articular surfaces, is designed for use with both cruciate ligaments excised and when load bearing ROM is expected to be less than or equal to 155 degrees."