Application of patella tilting angle on X-ray image in diagnosis of patellofemoral arthropathy

Objective To observe the diagnostic significance of range of the patella tilting angle in patients with patellofemoral disease. Methods In the orthopedic department of the First Hospital of Harbin, 214 cases of 214 knees diagnosed as patellofemoral joint disease with knee pain and limited flexion activities were enrolled to the experimental group , among whom rheumatoid arthritis, joint infection or joint injury was excluded. The age of experimental group was from 27 to 65 years, with an average age of (50±4)years. The control group enrolled 60 cases of 60 knees without knee joint diseases or pain. The age of control group was 28 to 77 years, (51±3) years on average. X-ray image of knee-patella at 30 ° knee-flexion axial position was used to measuring the size of the patella tilting angle. Results The patella tilting angle of the experimental group was between 18.5 ° and 35.2 °; the patella tilting angle increased at 30 ° knee-flexion axial position in X-ray image. The patella tilting angle of the control group was between 7.7 ° and 18.7 °, which was in the normal range. Conclusion Patella tilting angle measurement has important significance for patellofemoral joint disease diagnosis; when it increases at 30 ° knee-flexion axial position in X-ray with joint pain, the patient may be diagnosed joint disease and arthroscopic treatment can be performed. Key words: Patella; Patellofemoral joint; Joint diseases; X-rays