Various studies have compared cost-effectiveness of UKA and TKA. In 2006, Soohoo et al. (2006) analysed cost-effectiveness using a decision model. The study supported UKA as a cost-effective alternative for the treatment of unicompartmental arthritis when the durability and function of a UKA are assumed to be similar to those of a primary TKA. Using non-matched data from the NJR, Willis-Owen et al. (2009), at a three year follow up, reported cost savings of £1761 (about $2650) per knee treated with UKA compared to TKA, data which is supported by other observational studies (Shakespeare & Jeffcote, 2003; Xie et al, 2010). Longer term assessment has been provided by Slover et al. (2006) who, focusing on the elderly low demand population and using the Norwegian Arthroplasty Register, demonstrated that UKA had a lower mean cost and higher mean number of quality adjusted life years gained compared to TKA. Conversely, Koskinen et al. (2008), using the Finnish Arthroplasty Register, report that in the short term UKA was associated with lower costs, but in the long term, due to the higher revision rate, TKR was the more cost effective.
In 2007, Confalonieri et al. (2007) in a study involving 64 patients, compared the mid-term outcome and cost-effectiveness of UKA with minimally invasive computer assisted TKA in patients matched for age, gender, time to follow up, pre-operative arthritis and range of movement. The authors concluded that UKA cost at least 3100 Euros (approximately US $4100) less than computer assisted TKA due to shorter surgical time and shorter in-patient stay. In 2015, Ghomrawi et al. (2015) assessed the effect of age on cost-effectiveness of UKA vs TKA using a Markov decision analytic model. They considered lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) from a societal perspective for patients undergoing surgery at 45, 55, 65, 75 or 85 years of age. Transition probabilities were estimated from the literature; survival, from the Swedish Knee Arthroplasty Register; and costs, from the literature and the Healthcare Cost and Utilization Project (HCUP) database. The authors concluded that, for patients sixty-five years of age and older, UKA was more cost-effective with lower lifetime costs and higher QALYs. In the 45 year group, UKA became cost-effective when its 20-year revision rate dropped from 28% to 26% and in the 55 year old group when it changed from 28% to 27%. The OUKA implanted by experienced surgeons would therefore be cost effective in all age groups as the 20-year survival would be expected to be better than 75% even in the young (see Chapter 5).
