title: A comparison between the dimensions of positive transtibial residual limb molds prepared by air pressure casting and weight-bearing casting methods.
abstract: BACKGROUND
  Creating a socket with proper fit is an important factor to ensure the comfort and control of prosthetic devices. Several techniques are commonly used to cast transtibial stumps but their effect on stump shape deformation is not well understood. This study compares the dimensions, circumferences and volumes of the positive casts and also the socket comfort between two casting methods. Our hypothesis was that the casts prepared by air pressure method have less volume and are more comfortable than those prepared by weight bearing method.
  
  
  METHODS
  Fifteen transtibial unilateral amputees participated in the study. Two weight bearing and air pressure casting methods were utilized for their residual limbs. The diameters and circumferences of various areas of the residual limbs and positive casts were compared. The volumes of two types of casts were measured by a volumeter and compared. Visual Analogue Scale (VAS) was used to measure the sockets fit comfort.
  
  
  RESULTS
  Circumferences at 10 and 15 cm below the patella on the casts were significantly smaller in air pressure casting method compared to the weight bearing method (p=0.00 and 0.01 respectively). The volume of the cast in air pressure method was lower than that of the weight bearing method (p=0.006). The amputees found the fit of the sockets prepared by air pressure method more comfortable than the weight bearing sockets (p=0.015).
  
  
  CONCLUSIONS
  The air pressure casting reduced the circumferences of the distal portion of residual limbs which has more soft tissue and because of its snug fit it provided more comfort for amputees, according to the VAS measurements.
authors.affiliation: PhD candidate in Orthotics and Prosthetics, Department of Orthotics and Prosthetics, Faculty of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. bhajiaghaei@yahoo.com.
authors.forename: Behnam
authors.initials: B
authors.lastname: Hajiaghaei
authors.affiliation: PhD, Professor of Physiotherapy, Department of Physiotherapy, Iran University of Medical Sciences, Tehran, Iran. ebrahimi.e@iums.ac.ir.
authors.forename: Ismail
authors.initials: I
authors.lastname: Ebrahimi
authors.affiliation: PhD, Assistant Professor of Orthotics and Prosthetics, Department of Orthotics and Prosthetics, Faculty of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. mojtaba.kamyab@gmail.com.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Kamyab
authors.affiliation: PhD, Assistant Professor of Orthotics and Prosthetics, Department of Orthotics and Prosthetics, Faculty of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. hassan_saeedi2@yahoo.co.uk.
authors.forename: Hassan
authors.initials: H
authors.lastname: Saeedi
authors.affiliation: PhD, Assistant Professor of Orthotics and Prosthetics, Department of Orthotics and Prosthetics, Faculty of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. marjalali@gmail.com.
authors.forename: Maryam
authors.initials: M
authors.lastname: Jalali
keywords: Air pressure; Cast; Transtibial prosthesis; Weight bearing