Prediction of the skeletal medio-lateral dimension using non-invasive anthropometric measurements for the provision of ischial containment sockets

Abstract

The regression model is not sufficiently accurate to predict skeletal medio-lateral for clinical purposes. Accuracy of the prediction could be improved with more accurate input data from computed tomography scans and use of other independent variables that explain the unique variance not already described by the participants' sex. Clinical relevance This pilot study demonstrates potential for the skeletal medio-lateral to be predicted using non-invasive anthropometric measurements. Given this proof of concept, future investigators should use more accurate input data from computed tomography scans and identify alternative independent variables that explain the variance in the skeletal medio-lateral not attributable to sex.

Prediction of Skeletal Medial-Lateral for transfemoral ischial containment sockets

“…While the regression model was able to explain 59 percent of the variance in the Skeletal ML, only sex contributed significantly to the prediction [4]. The standard error associated with the prediction was 9 mm [4].…”

“…One of the most important measurements is the "Skeletal Medial-Lateral (ML)" because it defines the ML dimension of the socket brim that intimately encapsulates the pelvis and provides the necessary coronal plane stability to the remnant femur and pelvis that enables comfortable and effective gait [4][5][6][7][8]. Specifically, the Skeletal ML describes the coronal plane distance Abbreviations: ASIS = anterior superior iliac spine, BMI = body mass index, CT = computed tomography, GT = greater trochanter, ICC = intraclass correlation coefficient, ML = mediallateral, PSIS = posterior superior iliac spine, SEE = standard error of estimate, TEM = technical error of measurement.…”

“…between the medial aspect of the ischium and lateral shaft of the femur immediately inferior to the greater trochanter (GT) and includes the subcutaneous adipose tissue and skin [4][5][6]. Measurement of the Skeletal ML is difficult to obtain in vivo because of the need to accurately palpate anatomical features of the medial ischium and simultaneously locate a caliper in the intergluteal cleft.…”

“…Given an understanding of how the Skeletal ML is measured, it is not surprising that the technique is considered intrusive and that large variations in measurements are common [4]. We are not aware of any studies that have established the accuracy or reliability of the Skeletal ML measurement in vivo.…”

“…A pilot study on living subjects sought to determine the accuracy with which the Skeletal ML could be predicted using noninvasive measurements typically recorded by prosthetists during their everyday clinical practice, including sex, stature, anterior-posterior dimension (i.e., distance between the adductor longus tendon near its origin and the ischial tuberosity in sitting), and iliofemoral angle (i.e., soft tissue angle in the coronal plane between the lateral femoral shaft and gluteus medius in standing) [4]. While the regression model was able to explain 59 percent of the variance in the Skeletal ML, only sex contributed significantly to the prediction [4].…”