Purpose

The purpose of the study was to assess how context influences range of motion measurements in hand surgery.

Methods

One hundred seventy-five consecutive patients presenting to a hand surgery clinic were evaluated over 7 sessions. Passive and active motion were measured with a goniometer and by visual estimation. The affected joint was measured by 3 different examiners-one hand surgeon and 2 research assistants (RAs). Measurements by the RAs were performed under the pretense of imaginary project titles and purposes.

Results

Range of motion measurements were easily influenced. As the invented project's purpose became more specific and dependent on physician intervention, the bias became more pronounced. Measurements performed under construed project titles that promoted surgical intervention garnered outcomes that supported surgery (P < 0.01). Conversely, when the manufactured study's intent was to find support in conservative treatment, this outcome could also be generated (P < 0.01).

Discussion

Range of motion measurements can easily be influenced by the context of the study, even in seemingly blinded examiners. Reliable range of motion measurements can only be made when the examiner has no knowledge of the study's intent.