Abstract

In retrospective studies the range of motion of the knee is gathered from existing clinical notes or databases. This study aims to assess the validity of this retrospective data. The range of motion of 48 patients was assessed using a goniometer and compared to that entered in the patient notes by the examiner during a routine clinical examination, without the examiner being aware. The range of motion of a further 20 patients was subsequently assessed and compared to the findings of the same clinical examiners but this time with the examiner being aware. When the examiner was unaware of the study, the accuracy of the measured range of motion was clinically unacceptable. When the examiner was aware of this study, the accuracy of the measure was much improved. The patient's body mass index can affect the accuracy of visual estimation. Visual estimation of range of motion can be accurate and correlates well to that measured by a goniometer if the examiner attempts to be accurate. However range of motion that is routinely measured in a clinical setting and entered into the patient notes is not accurate and should not be relied on in future research.