title: Morphological analysis of the knee joint in patients with hip dysplasia.
abstract: OBJECTIVE
  The purpose of this study was to investigate the morphological changes of the knee in patients with untreated developmental dysplasia of the hip.
  
  
  METHODS
  Morphological analysis of 150 knee joints in 75 patients with developmental dysplasia of the hip was performed by examining computed tomographic (CT) images. Of these patients, 36 had unilateral developmental dysplasia of the hip and 39 had bilateral developmental dysplasia of the hip. Therefore, 36 hips were normal, and 114 hips were dislocated. CT images ranged from the iliac crest to 2 cm inferior to the tibial tuberosity.
  
  
  RESULTS
  Compared with the knees in patients with normal hips, the femoral condyles in patients with dislocated hips were smaller and exhibited greater medial and lateral condylar asymmetry. The anterior femoral condylar angle of the femur was increased, as was the groove angle, while the trochlear groove was shallower in patients with dislocated hips. Furthermore, the lateral patella shift was reduced and the patellar tilt angle was increased in patients with dislocated hips compared with patients with normal hips. The extent of changes in these variables differed with the degree of dislocation. However, the posterior condylar angle of the femur was not affected by the degree of dislocation.
  
  
  CONCLUSIONS
  These findings suggest that developmental dysplasia of the hip is associated with morphological changes in the knee joint. These changes should be considered during hip and knee surgery.
  
  
  METHODS
  Prospective study, level II.
authors.affiliation: Department of Orthopaedics, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 639 Zhizaoju Road, Shanghai, 200011, People's Republic of China.
authors.forename: Huiwu
authors.initials: H
authors.lastname: Li
authors.forename: Xinhua
authors.initials: X
authors.lastname: Qu
authors.forename: You
authors.initials: Y
authors.lastname: Wang
authors.forename: Kerong
authors.initials: K
authors.lastname: Dai
authors.forename: Zhenan
authors.initials: Z
authors.lastname: Zhu
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005269:Femur / Q000473:pathology; D006617:Hip Dislocation / Q000473:pathology*; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010329:Patella / Q000473:pathology; D057071:Patellofemoral Joint / Q000473:pathology; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult