Reactivity of leg alignment to articular pressure testing: evaluation of a diagnostic test using a randomized crossover clinical trial approach.

OBJECTIVE

A study was undertaken to assess the reliability of detecting leg alignment changes (reactivity) and to determine if the observed leg alignment reactivity can be attributed to a rotatory articular pressure challenge.

DESIGN

Prospective double-blind crossover trial of a diagnostic test.

SETTING

Laboratory: Center for Technique Research.

PARTICIPANTS

Forty-two chiropractic college students, faculty and staff.

INTERVENTIONS

A standardized force of 2 or 3 kg was applied with a 1 cm2 rubber-tipped pressure algometer on the lateral aspect of the T3-T7 spinous processes and the posterior aspect of the lateral masses of C1.

MAIN OUTCOME MEASURES

Leg alignment reactivity: an increase in leg alignment discrepancy (yes or no) following a diagnostic intervention.

RESULTS

The reliability for detecting leg alignment reactivity was poor: on average, Kappa = 0.05 in the thoracics and 0.06 at C1. On average, the attributable risk of leg alignment reactivity (pressure test risk--sham test risk) was less than 4%. In many cases, the sham rate was greater than the pressure test rate.

CONCLUSIONS

For the population investigated, leg alignment reactivity to rotatory pressure testing can, in the majority of cases, be attributable to background noise. This procedure was not found to be viable for identifying vertebrae for adjustment. Further research with different subject populations, regions of investigation, leg alignment measurement techniques and vertebral challenge techniques are indicated.