How Does Level and Type of Experience Affect Measurement of Joint Range of Motion?

Comparison of range of motion measurements by 3 types of investigators with different levels and types of training using three different measurement techniques. The study hypothesis was that the accuracy and precision of range of motion measurements would vary based on (1) the level and type of experience of the investigator and (2) the measurement technique used.

Descriptive laboratory study.

Ten fresh frozen cadavers (20 upper and 20 lower extremities).

Shoulder, elbow, hip, and knee motion were measured using 3 different measurement techniques (digital photography, goniometry, and visual estimation) by 3 groups of investigators (attending orthopedic surgeons, physical therapists, and residents). Accuracy was defined by the difference from the reference standard (motion capture analysis), whereas precision was defined by the proportion of measurements within either 5° or 10° of the reference standard. Analysis of variance, t-tests, and chi-squared tests were used.

Statistically significant (p < 0.05) differences in accuracy were found for hip flexion, abduction, internal rotation, external rotation, and knee flexion. However, none of these differences met the authors' defined clinical significance (maximum difference 3°). Precision was significantly (p < 0.05) different for elbow extension, hip flexion, abduction, internal rotation, external rotation, and knee flexion.

This study found that clinically accurate measurements of shoulder, elbow, hip, and knee motion are obtained regardless of technique used or the investigators' level and type of experience. Precision was equivalent for all shoulder motions, elbow flexion, and knee extension, but varied by as much as 7% to 28% between groups for all other motions.