Two-Year Results of the PHANTOM High Flex Trial: A Single-Arm Study on the Atlas Unicompartmental Knee System Load Absorber in Patients With Medial Compartment Osteoarthritis of the Knee

The Atlas Knee System was designed to fill the gap between no longer effective conservative treatments and more invasive surgery for young patients with medial knee osteoarthritis (OA). This article reports on the 2-year results of a single-arm study of 26 subjects who previously reported favorable clinical outcomes 1 year post implantation. Western Ontario and McMaster Universities Osteoarthritis Index pain and function scores improved by a clinically meaningful amount relative to baseline, and subjects had a return to normal range of motion. This study confirmed that the benefit of a joint unloading device in the management of young patients with medial knee OA is maintained over 2 years. This trial was registered with ClinicalTrials.gov (NCT02711254).