Immediate Changes in the Quadriceps Femoris Angle After Insertion of an Orthotic Device
D. Robert Kuhn, DC,a Terry R. Yochum, DC,b Anton R. Cherry,c and Sean S. Rodgersc
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. (J Manipulative Physiol Ther 2002;25:465-70)