“…There were some promising results in the 1980s with the McKeever metallic hemiarthroplasty which was roughly shaped like the tibial plateau (Emerson and Potter, 1985;Scott et al, 1985;Springer et al, 2006). However, in studies with this device, as well as clinical studies with the UniSpacer TM implant, degeneration of the opposing femoral cartilage and onset of osteoarthritis in other compartments were the most common causes of failure (Emerson and Potter, 1985;Scott et al, 1985;Springer et al, 2006;Amstutz et al, 1994;D'Arcy and Devas, 1976;Hallock and Fell, 2003;Sisto and Mitchell, 2005;Bailie et al, 2008).…”