Cost-effectiveness analysis of two rehabilitation plans after primary total knee arthroplasty of individuals aged 65 and over: an economic evaluation

Introduction – Knee arthroplasty is one of the most frequent surgical procedures worldwide. Physiotherapy is widely recommended following surgery. Health systems are facing enormous financial constraints – in Portugal, for example, health expenditure has been steadily increasing and accounted for 11.2% of the Gross Domestic Product (GDP) in 2021 – so it is essential to conduct economic evaluation for resource allocation1-3. Objective – To compare two different rehabilitation plans in individuals aged ≥65 following primary Total Knee Arthroplasty (TKA). Methods – A single-centre experimental study with pre-post intervention assessment of a consecutive sample of two randomized groups: Group 1 (n=15) received face-to-face physiotherapy twice per week, supplemented by a home exercise program, and Group 2 (n=9) received face-to-face physiotherapy three times per week without additional exercises. Both groups received treatment for five weeks. The effectiveness was measured through individual subcomponents. Pain and function were evaluated by the Oxford Knee Score (scale 12-60 points). Active range of motion (AROM) for knee flexion and extension was measured in degrees with a goniometer. Lower limb muscle strength was measured by counting the number of stands in accordance with the 30s Chair Stand Test. Comparison of effectiveness between the two groups was conducted using parametric and non-parametric tests. The cost of each plan was calculated using the Portuguese Complementary Diagnostic and Therapeutic Means (MCDT) price list. Economic comparison was made by calculating the incremental cost-effectiveness ratio (ICER). Results – Both groups achieved improvements in all effectiveness indicators, with Group 1 showing better outcomes (overall average Group 1=88% versus Group 2=44%). The resulting ICER of € -38.82/effectiveness unit was favourable to Group 1. Conclusion – The Group 1 rehabilitation plan was the cost-effective alternative over the comparator, highlighting a potential way to optimize health resources in the hospital department where the study was conducted.