title: Patellar instability in Indian population: relevance of tibial tuberosity and trochlear groove distance.
abstract: BACKGROUND
  The tibial tuberosity to trochlear groove (TTTG) distance in the western population is extensively studied through various modalities such as X-rays, computerised tomography and magnetic resonance imaging. However, to our knowledge there is very little or no literature support to indicate that TTTG distance has been studied in the Indian population.
  
  
  METHODS
  We therefore undertook a study to measure the TTTG distance in 100 MRI scans of normal Indian knees. Patients with the following co-morbidities were excluded from the study; ligamentous laxity, patellofemoral instability, mal-alignment and osteoarthritis. We measured TTTG distance on the axial MRI slices using OsiriX software.
  
  
  RESULTS
  The mean value for females was found to be 14.07 mm and that for male was found to be 13.34 mm. Our study indicates that the TTTG distance, using MRI scans as measurement modality, in the Indian population is significantly different when compared to the published western data.
  
  
  CONCLUSIONS
  We believe that this study can form the basis for future studies on the relationship between TTTG distance and patellar instability in Indian population.
authors.affiliation: Hiranandani Orthopaedic Medical Education (HOME), Dr L. H. Hiranandani Hospital, Hillside Avenue, Hiranandani Gardens, Powai, Mumbai 400076, India.
authors.forename: Sourabh
authors.initials: S
authors.lastname: Kulkarni
authors.affiliation: Hiranandani Orthopaedic Medical Education (HOME), Dr L. H. Hiranandani Hospital, Hillside Avenue, Hiranandani Gardens, Powai, Mumbai 400076, India.
authors.forename: Amith P
authors.initials: AP
authors.lastname: Shetty
authors.affiliation: Hiranandani Orthopaedic Medical Education (HOME), Dr L. H. Hiranandani Hospital, Hillside Avenue, Hiranandani Gardens, Powai, Mumbai 400076, India.
authors.forename: Karan K
authors.initials: KK
authors.lastname: Alva
authors.affiliation: Hiranandani Orthopaedic Medical Education (HOME), Dr L. H. Hiranandani Hospital, Hillside Avenue, Hiranandani Gardens, Powai, Mumbai 400076, India.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Talekar
authors.affiliation: Hiranandani Orthopaedic Medical Education (HOME), Dr L. H. Hiranandani Hospital, Hillside Avenue, Hiranandani Gardens, Powai, Mumbai 400076, India.
authors.forename: Vijay D
authors.initials: VD
authors.lastname: Shetty
keywords: Patellar dislocation; Patellar instability; TTTG distance