Multi-centre, non-randomized, observational cohort study at four sites in the US. Eligible participants were females with knee pain, a body mass index (BMI)>or =25 kg/m(2), symptomatic radiographic evidence of medial TF OA, and varus mal-alignment. The 29 participants had a mean age of 62 years, mean BMI of 36 kg/m(2), with eight index knees graded as Kellgren-Lawrence (K&L)=2 and 21 as K&L=3