The Clinical Significance Of Q-angle Measurement Of Knee Joint For The Diagnosis Of Recurrent Patellar Dislocation

Objective Explore the clinical significance for diagnosis of recurrent patellar dislocation by measuring the Q Angle changes when extrapolate patella knee.Methods Between August2012and March2014,32female patients (33knees) confirmed with recurrent patellar dislocation by arthoscopy were collected as trial group, which average age was17.4years old (range from16to24years).20female patients (20knees) confirmed with simple meniscus injury were collected as control group at the same time, which average age was19.4years old (range from11to25years). Q-angle of the trial group’s was measured when the knee was at the extension position,30°flexion,30°flexion with correcting patella and the last position as patellar dislocation was corrected in surgical operation. Q-angle of the control group was measured only at the extension position and30°flexion. Then we calculated the changed degree of Q-angle in two groups when the knee was measured at the extension position and30°flexion. Independent sample T-test was used to analyze Q-angle degrees at the extension position,30°flexion and the changed degrees of two groups. The Q-angle, at30°flexion with correcting patella and in surgical operation, of the trial group was analyzed by paired T-test. Results Q-angle in the control group is14.25°±2.62°at the extension position,7.08°±2.45°at the extreme extrapolation, the average change angle is7.13°±2.23°.while that in the control group is16.30°±3.35°at the extension position,7.15°±2.67°at the extreme extrapolation, the average change angle was9.15°±2.55°. Q-angle in the trail group was16.30°±3.35°at the extension position,7.15°±2.67°at the extreme extrapolation, the average change angle was9.15°±2.55°. comparing Q-angle between the two groups at extension position was that t=-2.94, P=0.004<0.05.Comparing the average change angle between the two groups was that t=-3.62, P=0.001<0.05. Q-angle in the control group is16.18°±2.48°at the30°lexion position,7.55°±2.44°at the extreme extrapolation, the average change angle was8.53±2.20°.while that in the trail group is18.97°±3.59°t the30°flexion position,7.67°±2.75°at the extreme extrapolation, the average change angle was11.09°±2.57°. comparing Q-angle between the two groups at the30°flexion position was that t=-3.92, P=0.0001<0.05. Comparing the average change angle between the two groups was that t=-4.60, P=0.0001<0.05。Conclusions1.For women with recurrent patellar dislocation, the Q-angle of the trail group was higher than the control group no matter in which position.2.By measuring the Q-angle of patient who was highly suspected with patellar dislocation under the different between the straight and the buckling30°with the extrapolating patella conditions,it’s should be considered that the patient suffering recurrent patellar dislocation if the average change angle of the Q Angle at the extension position and at the30°flexion position was great.