# Evidence-based informed consent forms for total knee arthroplasty and anaesthesia: development and pilot study

## TL;DR

This paper describes the development and testing of evidence-based informed consent forms for knee replacement surgery and anesthesia, aiming to improve patient understanding and decision-making.

## Contribution

The study introduces evidence-based, legally compliant informed consent forms for TKA and anesthesia, validated through patient feedback and iterative improvements.

## Key findings

- The forms were rated as understandable and helpful by patients, though individual information needs varied.
- The multiple-choice test and e-learning program were revised based on feedback to improve clarity and usability.
- The study highlights the need for personalized counseling and structural changes in clinical practice to maximize the forms' potential.

## Abstract

Informed consent is a legal and ethical prerequisite for elective procedures such as total knee arthroplasty (TKA). However, standard informed consent forms often lack evidence-based content and do not adequately support informed decision-making. The aim was to develop and pilot test an evidence-based informed consent form for TKA.

We conducted a two-phase study. In Phase 1, we developed an extended, evidence-based informed consent form for TKA, as well as a corresponding form for anaesthesia, based on systematic evidence syntheses, expert reviews, and standards outlined in the Guideline Evidence-based Health Information. We also developed an e-learning program to train clinicians in the appropriate use of informed consent forms. In addition, we developed a multiple-choice test to assess patients’ knowledge and risk perception. In Phase 2, we piloted the informed consent forms with potential patients through think-aloud interviews and focus groups, assessing their acceptability, usability and comprehensibility with iterative revisions. The multiple-choice test was also piloted and revised. Qualitative data were analysed using qualitative content analysis.

We developed evidence-based informed consent forms for TKA and anaesthesia. Content and risk communication follow the Guideline Evidence-based Health Information and meet legal requirements under German law. Benefits and complications were presented using natural frequencies and visualised with bar charts. The forms were piloted in six think-aloud and three focus group interviews with 17 participants. Feedback from participants and experts highlighted the need for revisions in the presentation of numerical data, terminology, structure and layout, which were addressed iteratively. Overall, the forms were rated as understandable, relevant and helpful, though individual information needs varied. The 12-item multiple-choice knowledge test was revised to improve clarity and was perceived as comprehensible and applicable. The e-learning programme includes videos, texts and interactive elements, and is designed for flexible use over 90 to 180 min.

The informed consent forms are now available. Evidence-based informed consent forms are feasible and perceived by patients as helpful and understandable. The variety of patients’ information needs underlines the need for personalised counselling and structural adjustments in clinical practice so that the potential of evidence-based informed consent forms can be exploited.

The online version contains supplementary material available at 10.1186/s13018-026-06729-z.