Assessment of patellar maltracking using combined static and dynamic MRI

Abstract

Between January 1995 and Jul 1997, 474 patients with anterior knee pain resistant to conservative treatment were referred for MR of the knee. The MR examination consisted of routine sequences with an additional patellofemoral dynamic examination using a technique that has been developed at this institution. The dynamic study examines both knees simultaneously, with the patient supine and the quadriceps loaded. No gating or restraint apparatus is needed. Patellar subluxation or tilt was present in 188(40%) of cases, bilateral in 104 and unilateral in 84 cases (right 39, left 45). It was classified as mild in 51%, moderate in 39% and severe in 10%. Subluxation was more prevalent in females than males (42% vs. 37%) and this was most obvious in the severe group where 68% were female. In 90 knees selected at random, four measurements of patellofemoral morphology were obtained using reconstructed images from a volume gradient echo sequence. These measurements were correlated with the degree of subluxation or tilt. A tibial tubercle distance greater than 20 mm, a femoral sulcus angle greater than 150 degrees, sulcus depth less than 4 mm were specific for subluxation but no measurement proved to be sufficiently sensitive to preclude a tracking study. MRI can be used to define more precisely the anatomy of the extensor mechanism and its relationship to the femur and tibia, in both a static and dynamic setting. In this way, patients with anterior knee pain can be classified more accurately and the outcomes of treatment more reliably assessed.

In Vivo Noninvasive Evaluation of Abnormal Patellar Tracking During Squatting in Patients with Patellofemoral Pain

“…Numerous reports have been published on patellar tracking patterns in vitro 7,[11][12][13][14][15] , in healthy subjects 2,[16][17][18][19][20][21][22][23][24][25][26] , and in subjects with patellofemoral pain [27][28][29][30][31][32][33] . In agreement with previous studies 15,30 , our investigation found that healthy subjects exhibited minimal medial patellar spin as the knee flexed from full extension to 90°.…”

“…Current literature has suggested that the etiology of patellofemoral pain is multifactorial 3,6,7 and may be associated with static patellar malalignment and abnormal patellar tracking [5][6][7][8][9][10] . Numerous studies have investigated patellofemoral kinematics 2,7,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] ; however, few have investigated the specific role that static malalignment and patellar maltracking play in patellofemoral pain [27][28][29][30][31][32][33] . In vitro experiments 7,[11][12][13][14][15] are unlikely to represent dynamic patellar kinematics accurately because of the lack of in vivo forces or the pathological changes associated with patellofemoral pain syndrome.…”

“…In vitro experiments 7,[11][12][13][14][15] are unlikely to represent dynamic patellar kinematics accurately because of the lack of in vivo forces or the pathological changes associated with patellofemoral pain syndrome. A number of in vivo studies have been conducted with use of imaging techniques such as biplane fluoroscopy 26 and both dynamic [17][18][19][27][28][29] and static magnetic resonance imaging 20,21,30 . Because the use of biplane fluoroscopy involves exposure to ionizing radiation, it is not ideal for clinical assessment.…”

The role of magnetic resonance imaging in the evaluation of patellofemoral joint diseases

“…Şunu unutmamak gerekir ki efüzyon varlığı da patellar yarı çıkığa neden olur ya da belirginleştirir. [15] 3. Anormal patellar eğimin (tilt) değerlendi-rilmesi: Lateralde patellofemoral açının değerlendirilmesidir.…”

“…[16] Patellar eğimi ölçmek için birçok yöntem vardır. [14][15][16] En kolay olan ölçüm, patella orta kesiminden geçen aksiyel görüntüde lateral patellar faset yüzüne paralel ve anteriyor femoral kondillere teğet çizilen çizgiler arasında yapılan patellofemoral açı ölçümüdür. Genel olarak, patellofemoral açı 8 dereceden fazladır ve lateralde açıktır.…”