title: Position of the patella in adults in central India: evaluation of the Insall-Salvati ratio.
abstract: OBJECTIVE
  To assess the Insall-Salvati ratio in normal Indian adults to determine its applicability and the incidence of patella alta and baja in Indian populations.
  
  
  METHODS
  800 knees in 200 men and 200 women aged 18 to 50 (mean, 30) years were evaluated using lateral radiographs. The knee was set in semi-flexion (30º) to enable good visualisation of the patellar tendon and its insertion into the tibia on radiographs. The length of the patellar tendon (LT) over the length of the patella (LP)-the Insall-Salvati ratio-was measured, using a vernier caliper.
  
  
  RESULTS
  The mean LT/LP ratio was 1.14 (standard deviation, 0.18). Based on the 95% confidence interval, the ratio was considered normal if within ±40%. The LT/LP ratio was significantly higher in females than males (1.17 vs. 1.12, p<0.01). The cut-off point of patella alta was significantly greater in our Indian subjects than in western subjects (>1.5 vs. >1.2, p<0.0001). In the present cohort, the frequencies of patella alta (ratio, >1.5) and patella baja (ratio, <0.7) were 2.8% and 1%, respectively.
  
  
  CONCLUSIONS
  The use of the Insall-Salvati ratio to determine the patellar position is less applicable to Indian populations in which squatting, sitting cross-legged, and kneeling are customs. We propose that the normal range of the ratio for squatters among Indian populations be 0.7 to 1.5.
authors: Department of Orthopaedics, Netaji Subhas Chandra Bose Medical College Jabalpur, (MP), India. drsachinupadhyay@gmail.com
authors: Sachin
authors: S
authors: Upadhyay
authors: H K T
authors: HK
authors: Raza
authors: Pranay
authors: P
authors: Srivastava
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D010329:Patella / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D011859:Radiography; D055815:Young Adult
keywords: patella; patellar ligament