Research Of The Matching Degree Of The Patellofemoral Joint In The Patients And The Normal Volunteers-a MRI Study

Objective 1. Gain the percentage of the knees with the patella and the femoral trochlear contacting at time of full knee extension through the research.2. Comparison of the imaging parameters of the patients with patellofemoral instability and normal control group, gain the value of these imaging parameters for these diagnosis of patellofemoral instability.Methods 1. Selected male patients 21 cases (total 25 knees) with complete medical history and MRI data, which have been all diagnosed as patellofemoral joint instability.2. All patients have underwent the MRI examination at the time of the knee complete extension, and only sevral patients (6 cases 7 knees) were endured at the knee 30°lexed. Thus the measurement results were recorded in two groups:P0, P30.3. Endured physical examination to the male volunteers without the symtoms of the patellofemoral instability, and did the MRI examination for the normal ones in total knee extension and with the knee flexed 30°positions. Then measured their FTA, CA and PTA in the MRI imagings, excluded the abnormal ones. Finally the total numbers were 14 cases (25 knees). Then mearsured the other parameters of the imaging, divided the measurement results into two groups:No and N30.4. Obtained the percent-age of the patella and femoral trochlea contacting of the total knees through observation and measurement when the knee complete extension.5. Analysized the results of the measurement with the statistical software SPSSV13.0, compared the differences between the group Po and group No, group P30 and group N3o, and calculated the sensitivity, specificity and accuracy of each parameters in the diagnosis of patellofemoral instability.Results 1. Normal volunteers'knee at full extension the patella in the middle of all the cross-sectional and sagittal plane have come into contact with the femoral trochlea.2. When the knee extended completely, the differences of the parameters between the patient group and the normal volunteer group were statistically significant expected APF, c,d and PS.3. When the knee at the position of the 30°flexed, MLCR, c, d have no statistically significant difference, the remaining parameters are statistically significant.4. The parameters PTCR, PTSR, a, b, e, B have the diagnostic value for the patellofemoral instability.Conclusion 1. In our research, normal volunteers'knee at full extension the patella in the middle of all the cross-sectional and sagittal plane have come into contact with the femoral trochlea.2. When the knee was full extended and at the position of the 30°flexed, the parameters reflecting the trochlear dysplasia and the matching level of the patellofemoral joint are statistically significant differed between the two groups, and the the parameters reflecting the patellar dysplasia have no statistically significant between them.3. When PTCR<0.13, PTSR<0.14, a<7.6, b<0.1, e<20, B<3.4, it has the diagnostic value for the patellofemoral instability. PTCR and a among them have the higher sensitivity, specificity and accuracy, thus they have the higher diagnostic value.