Risk-benefit and costs of unicompartmental (compared to total) knee replacement for patients with multiple co-morbidities: a non-randomised study, and different novel approaches to minimize confounding (UTMOST)

Study type

• Study type:
  Non-interventional study
• Scope of the study:
  Assessment of risk minimisation measure implementation or effectiveness

  Effectiveness study (incl. comparative)

  Other
• If ‘other’, further details on the scope of the study:
  Methodology, Health Economics

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Medical condition to be studied:
  Knee arthroplasty

  Knee operation

Population studied

• Age groups:
  Adults (18 to < 46 years)

  Adults (46 to < 65 years)

  Adults (65 to < 75 years)

  Adults (75 to < 85 years)

  Adults (85 years and over)
• Estimated number of subjects:
  380000

Study design details

• Main study objective:
  Our overarching aims are:1. To study the validity of different epidemiology analytical methods -used in drug and vaccine studies to minimise confounding- for the assessment of alternative surgical procedures. 2. To apply the identified methods to the analysis of risks, benefits, costs and cost-effectiveness of surgical alternatives for knee replacement for patients with multiple comorbidities.
• Outcomes:
  Post-operative Oxford Knee Score (PROMs). One and 5-year risks (revision surgery, systemic infection, wound infection, cardiovascular disease, and venous thromboembolism), mortality, health-related quality of life (EQ-5D), NHS hospital costs (as identified in HES).
• Data analysis plan:
  In the first stage, different methods will be tested to evaluate the association between knee replacement type and both primary and secondary outcomes in the comparison cohort: 1.Propensity score (PS) methods, 2.High-dimensional PS, and 3.Instrumental variable analyses. A chi square test for heterogeneity will be used to formally test for differences between the estimates obtained in TOPKAT compared to the different observational analyses. In a second stage, those methods able to obtain results equivalent (i.e. not significantly different) to the TOPKAT post-operative PROMs findings will be applied to the analysis of the association between UKR (compared to TKR) and all study outcomes (risk/s, revision, benefits, mortality, costs and cost-effectiveness) in the co-morbidity cohort.