title: Injury patterns of medial patellofemoral ligament and correlation analysis with articular cartilage lesions of the lateral femoral condyle after acute lateral patellar dislocation in adults: An MRI evaluation.
abstract: OBJECTIVE
  The purpose of this study was to investigate the injury characteristics of medial patellofemoral ligament (MPFL), and to analyse the correlations between the injury patterns of MPFL and articular cartilage lesions of the lateral femoral condyle in adults with acute lateral patellar dislocation (LPD).
  
  
  METHODS
  Magnetic resonance (MR) images were prospectively obtained in 121 consecutive adults with acute LPD. Images were acquired using standardised protocols and these were independently evaluated by two radiologists.
  
  
  RESULTS
  Forty-eight cases of partial MPFL tear and 71 cases of complete MPFL tear were identified. Injuries occurred at an isolated femoral attachment (FEM) in 48 cases, an isolated patellar insertion (PAT) in 36 cases and an isolated mid-substance (MID) in five cases. More than one site of injury to the MPFL (COM) was identified in 30 cases. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 4.2% (2/48) and 6.3% (3/48) in the FEM subgroup, 19.4% (7/36) and 22.2% (8/36) in the PAT subgroup and 6.7% (2/30) and 13.3% (4/30) in the COM subgroup, respectively. The PAT subgroup showed significantly higher prevalence rate of chondral and osteochondral lesions in the lateral femoral condyle when compared with the FEM subgroup. The prevalence rate of chondral and osteochondral lesions of the lateral femoral condyle were 8.5% (6/71) and 19.7% (14/71) in the complete MPFL tear subgroup and 10.4% (5/48) and 4.2% (2/58) in the partial MPFL tear subgroup, respectively. The subgroup of the complete MPFL tear showed significantly higher prevalence rate of osteochondral lesions in the lateral femoral condyle when compared with the subgroup of the partial MPFL tear.
  
  
  CONCLUSIONS
  Firstly, the MPFL is most easily injured at the FEM, and secondly at the PAT in adults after acute LPD. The complete MPFL tear is more often concomitant with osteochondral lesions of the lateral femoral condyle than the partial MPFL tear. The isolated patellar-sided MPFL tear is more easily concomitant with chondral lesions and osteochondral lesions of the lateral femoral condyle than the isolated femoral-sided MPFL tear.
authors.affiliation: Department of Ultrasonography, Shandong Provincial Qianfoshan Hospital of Shandong University, Jinan 250014, China.
authors.forename: Guang-ying
authors.initials: GY
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Shandong Provincial Corps Hospital of Chinese People's Armed Police Force, Jinan 250014, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Department of Radiology, Affiliated Hospital of Binzhou Medical College, Binzhou 256603, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Radiology, Shandong Provincial Qianfoshan Hospital of Shandong University, Jinan 250014, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Shi
authors.affiliation: Department of Ultrasonography, Shandong Provincial Qianfoshan Hospital of Shandong University, Jinan 250014, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Radiology, Shandong Provincial Corps Hospital of Chinese People's Armed Police Force, Jinan 250014, China.
authors.forename: Bing-jun
authors.initials: BJ
authors.lastname: Ji
authors.affiliation: Department of Radiology, Shandong Provincial Corps Hospital of Chinese People's Armed Police Force, Jinan 250014, China.
authors.forename: Bai-sheng
authors.initials: BS
authors.lastname: Sun
authors.affiliation: Department of Ultrasonography, Shandong Provincial Qianfoshan Hospital of Shandong University, Jinan 250014, China. Electronic address: qydinghy@163.com.
authors.forename: Hong-yu
authors.initials: HY
authors.lastname: Ding
mesh_terms: D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000293:injuries / Q000473:pathology; D005260:Female; D006801:Humans; D007593:Joint Instability; D007718:Knee Injuries / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D008023:Ligaments, Articular / Q000000981:diagnostic imaging* / Q000293:injuries / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010329:Patella / Q000000981:diagnostic imaging* / Q000293:injuries / Q000473:pathology; D031222:Patellar Dislocation / Q000175:diagnosis / Q000000981:diagnostic imaging*; D015995:Prevalence; D011446:Prospective Studies; D015203:Reproducibility of Results
keywords: Articular cartilage; Knee; Lateral patellar dislocation; Magnetic resonance imaging; Medial patellofemoral ligament