Prediction of Skeletal Medial-Lateral for transfemoral ischial containment sockets

Abstract

Abstract-Accurate measurement of the pelvis is critical for well-fitting and comfortable ischial containment sockets. The "Skeletal Medial-Lateral (ML)" is intrusive and unreliable to measure in vivo. This study aimed to determine how accurately the Skeletal ML could be predicted and to identify which measurements were significant predictors. Computed tomography scans were randomly sampled from a cadaveric database (n = 200). Inclusion criteria were age > 20 yr; lower-limb alignment that replicated the anatomical position; and no evidence of osteological trauma, implants, or bony growths. Multivariate linear regression models were developed to predict the Skeletal ML based on a suite of independent variables, including sex, body mass, and distance between pelvic landmarks. The regression model explained 76% of the variance in the Skeletal ML (p < 0.001). Variables that contributed significantly to the prediction of the Skeletal ML (p < 0.05) included body mass, sex, inter-greater trochanter distance, pelvic depth, and age. Significant predictors of the Skeletal ML dimension characterize variation in subcutaneous adipose tissue thickness and pelvic morphology. The Skeletal ML could be predicted with relatively small errors (standard error of estimate = 7 mm) that could be easily and reliably adjusted during socket fitting. Further research is needed to test the predictive tool in a real-world setting.

Prediction of ischial ramal angle for transfemoral ischial containment sockets

“…The methodology of this study has been described in detail previously 5 and as such, a summary has been reported here. Australia.…”

“…hip abduction). 5 Apparatus. CT scans were measured using Vitrea, version 3.1 (Vital Images Inc; Minnetonka, MN, USA).…”

“…The database included all persons whose death was reported to the Coroner within the state of Victoria, Australia; hence, it was believed to be representative of the Australian population. 5 Cases were randomly sampled and subsequently vetted against the following exclusion criteria until 200 cases – sufficient to meet the minimum sample size requirement 5 – were obtained. Cases were excluded if: younger than 20 years of age, mass or stature outside of Australian population norms, 6 evidence of osteological trauma, orthopaedic implants, body growths (e.g.…”

“…The author (MQ) was trained to use Vitrea, and reliability of the measurement protocol was demonstrated prior to the commencement of the study. 5…”

“…With these landmarks and planes identified, the Vitrea angle tool was used to measure the IR angle (Figure 4 solid line) as illustrated in the transverse plane ( Figure 5). Similarly detailed descriptions have been reported previously 5 describing how each of the independent variables were measured from the CT scans.…”