Analysis of subjective knee complaints using visual analog scales

A questionnaire using a system of visual analog scales was developed for analyzing subjective knee complaints. This system was tested on 117 consecutive patients who had undergone knee surgery and 65 patients at their initial office evaluation of a knee disorder. The validity of and patient affinity for this type of questionnaire was compared with that of three other established subjective evaluation methods. The visual analog scale system was shown to be valid and comparable to other methods while offering several advantages. It brought greater sensitivity and greater statistical power to data collection and analysis by allowing a broader range of responses than did traditional categorical responses. It removed bias that was introduced by examiner questioning, and it allowed graphic temporal comparisons. Most importantly, patient affinity was higher for this type of subjective evaluation than for other methods.