Visual estimation of angles by orthopedic surgeons.

A literature review indicates that the exactness of visual estimation of angles has not adequately been addressed. This study used a series of angles to examine how accurately and consistently practicing orthopedic surgeons were able to visually estimate angles. The data indicate that orthopedic surgeons were able to visually estimate angles to within 10 degrees 93.1% of the time and to within 5 degrees 64.6% of the time. Repeat measurements 6 weeks later were within 5 degrees of the initial responses 82.2% of the time and within 10 degrees of the initial responses 94.5% of the time. The number of years in practice or in training was irrelevant to the validity and reliability of the estimates. Acute angles of 31 degrees or less were consistently overestimated.