title: Comparison of Radiological Parameters between Normal and Patellar Dislocation Groups in Korean Population: A Rotational Profile CT-Based Study.
abstract: OBJECTIVE
  Patellofemoral instability is a common cause of anterior knee pain in adolescents and young adults. Most normal and pathological values for diagnosing patellofemoral instability are based on Western literature. We conducted this radiological study to determine normal values for different patellofemoral parameters in a Korean population and to evaluate their usefulness in diagnosis.
  
  
  METHODS
  We retrospectively reviewed the rotational profile computerized tomography (CT) scans of the patellar dislocation and control groups. Trochlear, patellar, rotational profile, and trochleo-patellar alignment parameters were compared between the groups. Receiver operating characteristic curves were drawn for significant parameters, and sensitivity and specificity were calculated for the cut-off values.
  
  
  RESULTS
  There were 48 patients in the patellar dislocation group and 87 patients in the control group. In the control group and patellar dislocation group, the mean sulcus angle was 132.5° and 143.3°, respectively, trochlear depth was 6.04 mm and 3.6 mm, bisect offset was 56.4% and 99.9%, lateral patellar tilting was 9.8° and 19.2°, patellar facet asymmetry was 63.5% and 45.16%, and the tibial tuberosity-trochlear groove (TT-TG) distance was 10.91 mm and 27.16 mm, respectively.
  
  
  CONCLUSIONS
  The trochlear depth, bisect offset, patella tilting, and TT-TG distance were parameters that significantly contributed to patellar instability. Rotational profile CT can be considered a good diagnostic tool to assess all these parameters that help to identify anatomical aberration resulting in patellofemoral instability, thereby helping in formulating the most effective treatment plan.
authors.affiliation: Department of Orthopedic Surgery, Lady Hardinge Medical College University of Delhi, New Delhi, India.
authors.forename: Jatin
authors.initials: J
authors.lastname: Prakash
authors.affiliation: Department of Orthopaedic Surgery, Chonnam National University Bitgoeul Hospital, Gwangju, Korea.
authors.forename: Jong-Keun
authors.initials: JK
authors.lastname: Seon
authors.affiliation: Department of Orthopaedic Surgery, Chonnam National University Bitgoeul Hospital, Gwangju, Korea.
authors.forename: Seong-Hwan
authors.initials: SH
authors.lastname: Woo
authors.affiliation: Department of Orthopedic Surgery, Chinese People's Armed Police Force, Zhejiang Corps Hospital, Jiaxing, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Jin
authors.affiliation: Department of Orthopaedic Surgery, Chonnam National University Bitgoeul Hospital, Gwangju, Korea.
authors.forename: Eun-Kyoo
authors.initials: EK
authors.lastname: Song
keywords: Computerized tomography; Dislocation; Parameter; Patella; Radiologic