Visual estimation of finger angles: do we need goniometers?

Seventy-one plastic surgeons and therapists, of varying levels of seniority and experience, were asked to examine a resin cast of an adult male hand and use estimation to measure the angles of the metacarpophalangeal and interphalangeal joints of each digit. Visual estimation by all subjects was inaccurate by a mean of approximately 25% (median percentage error 22, range 1-100). Consultants were the most accurate, whilst physiotherapists were the least. Regular goniometer users were no more accurate. However, hand surgery experience correlated with accuracy, as did a stated interest in hand surgery. Although visual accuracy improves with experience, it is still an inaccurate technique. We, therefore, recommend that goniometers should be used for measuring angles in hand surgery patients.