J Manipulative Physiol Ther. 2002 Sep; 25(7): 465-70.

Immediate changes in the quadriceps femoris angle after insertion of an orthotic device.

Kuhn DR, Yochum TR, Cherry AR, Rodgers SS.

Clinical Science and Chiropractic Divisions, Postgraduate Faculty, Radiology Consultants/Midwest, Logan College of Chiropractic, Chesterfield, Mo 63006, USA.

OBJECTIVE: To measure changes in the quadriceps femoris angle (Q-angle) after the insertion of full-length flexible orthotics. SETTING: Outpatient health center of Logan College of Chiropractic. SUBJECTS: A total of 40 male subjects were included in the study population. The selected population all demonstrated bilateral pes planus or hyperpronation syndrome. DESIGN: Before-after trial. METHOD: A cohort demonstrating bilateral hyperpronation was recruited. The subjects were cast according to standard protocols provided by the manufacturer. Subject right and left Q-angles were measured with and without the orthotic in place. The landmarks used were marked with a permanent marker, and great care was taken to accurately assess the angles formed. The evaluator was not told whether the measure was before or after orthotic insertion. A modified quailcraft goniometer was used. DATA ANALYSIS: The data set was collected and assessed by the t test. RESULTS: Thirty-nine of 40 test subjects showed reduced Q-angle, which was in the direction of correction. A 2-tailed matched sample showed statistically significant mean reduction in Q-angle measures. There was a minority of patients who showed asymmetrical Q-angle measures. Within this group there was greater symmetry of Q-angle measures after placement of the orthotic. CONCLUSION: Insertion of full-length, flexible orthotic devices significantly improves the Q-angle in hyperpronating male subjects. If the literature accurately links an increase in the Q-angle with a predisposition for knee injury, then the possibility of long-term benefits following the use of flexible orthotics exists. More research is required to determine whether these biomechanical changes are maintained after use of these orthotics.