Interexaminer reliability of a leg length analysis procedure among novice and experienced practitioners

The purpose of this study was to evaluate the interexaminer reliability of a leg length analysis protocol between an experienced chiropractor and an inexperienced chiropractic student who has undergone an intensive training program.

Fifty participants, aged from 18 to 55 years, were recruited from the New Zealand College of Chiropractic teaching clinic. An experienced chiropractor and a final-year chiropractic student were the examiners. Participants were examined for leg length inequality in the prone straight leg and flexed knee positions by each of the examiners. The examiners were asked to record which leg appeared shorter in each position. Examiners were blinded to each other's findings. kappa statistics and percent agreement between examiners were used to assess interexaminer reliability.

kappa analysis revealed substantial interexaminer reliability in both leg positions and also substantial agreement when straight and flexed knee results were combined for each participant. kappa scores ranged from 0.61, with 72% agreement, for the combined positions to 0.70, with 87% agreement, for the extended knee position. All of the kappa statistics analyzed surpassed the minimal acceptable standard of 0.40 for a reliability trial such as this.

This study revealed good interexaminer reliability of all aspects of the leg length analysis protocol used in this study.