Background: At present there is no evidence to support the use of the Oxford PROM scores to set pre-operative thresholds for referral for hip and knee replacement surgery. Despite this the practice has been widespread in the NHS. Objectives/Research Questions: Can the Oxford Hip/Knee scores (OKS/OHS) be used to set referral thresholds for hip/knee replacement surgery? Does the choice of threshold affect the cost effectiveness of the procedure? Methods: Thresholds for the Oxford scores were calculated, based on a capacity to benefit model linking pre-operative OKS/OHS to the probability of a good outcome – creating an online ACHE tool. Markov models were constructed to assess how the cost-effectiveness of TKA and THA compared with no arthroplasty varies with pre-operative OKS/OHS over a 10-year time horizon from a UK NHS perspective. Results: The absolute threshold for the OHS was 41 and 42 for the OKS. A model was created that used preoperative Oxford scores to estimate the probability of a good outcome allowed – e.g. an OHS of 35 or an OKS of 30 offers a patient a 70% probability of achieving a good outcome. The economic evaluation demonstrated that TKA and THA cost < £20,000 per quality adjusted life-year (QALY) gained for >99.9% of patients who currently undergo surgery. It is cost-effective to conduct TKA on patients with OKS of 43 (95% credible interval, CrI: 43,44) or less and on patients with THA of 45 or less (95% CrI: 44, 45). Conclusion: Using the ACHE tool the Oxford Hip/Knee Scores can be used to assess an individual patients suitability for hip or knee replacement surgery. On a population level both interventions are highly cost-effective right up to the absolute threshold for intervention. The ACHE tool appears to be a useful evidence based clinical tool to aid referral from primary to secondary care.
Price, AndrewCook, JonathanDakin, HelenSmith, JamesKang, SujinBeard, David
Faculty of Health and Life Sciences
Year of publication: 2017Date of RADAR deposit: 2018-04-16