Patellofemoral Joint Instability In X-ray Changes

Objective:Patellofemoral joint instability is one of the reason of knee pain,patellofemoral joint cartilage degeneration and knee joint dysfunction.Therefore,it often lead to anterior knee pain and recurrent dislocation of the patellofemoral joint.Articular cartilage are most vulnerable to injury because of abnormal patellar track.In severe cases,articular cartilage will become to be bare due to excessive wear of articular cartilage.It will appear uncomfortable in knee flexion,extension or walking process.Patients with knee dislocation often become nervous and afraid of the use of the knee.Therefore,the diagnosis and treatment of patellofemoral joint instability is very important in clinical work.The data was measured in lateral and axial knee X-ray film.The evidence of diagnosis of instability for the patellofemoral joint can be early provided.Methods:46 patients with patellofemoral joint instability was researched total of 58 knee.We measured 30°lateral flexion and 45°axial X-ray of patella.Lateral projection in the knee,the patient side to check the table.l Knee examined was in latera and 30°flexion location.The centerline of the inner side of the knee point to vertical side and the cephalic angle was 5°～7°.Merchant in the patella when the axial projection,the patient supine on the examination bed and the knee flexion at the bedside of about 45°.A device was used to maintain the knee at the point of view and hold Adapter,Side of the centerline was pointed to adequate.Vertical lines as opposed to angled 60°through the patella.Insall index,index of patella,femur trochlear concave depth,lateral patellofemoral angle,patellar coordination angle(matching angle),patello-femoral index,wae measured and compared with control group with 20 patients.All data are measured by ulnar joint activities.The parameters was measured by three doctors repeatly and the averages wae taken.Result:The measurement of Insall index,lateral patellofemoral angle,the patella index, patellofemoral coordination angle(matching angle),femur trochlear concave depth,patello-femoral index average value between two groups are significant difference.Conclusion:The greater value shows that the the medial articular surface was more narrow and it trend to be WibergⅢorⅣpatella.And typeⅢand typeⅣpatella was poor stability. Patellofemoral coordination angle(matching angle) shows that the patella and femoral trochlear groove of the relationship of spaces.It is the standards of determining the central patellar subluxation.Lateral patellofemoral angle as the standard of abnormal patellar tilt,femur trochlear concave depth shallow easily lead to instability in the patellofemoral joint and the patella easily to be dislocation.Patello-femoral index indicate the ratio of medial and lateral patellofemoral joint.The value being greater than 1 shows that the lateral gap becomed narrowing and the patella relocated.Patellofemoral instability influences alignment,paraposition and stability of the patella,patellar moving trajectory.Therefore the lateral \and the axial X-ray has great significance for diagnosis of patellofemoral joint instability.