Background
Prior studies have identified age as a factor in determining an individual’s likelihood of receiving a prosthesis following a lower limb amputation. These studies are limited to specific subsets of the general population and are unable to account for pre-amputation characteristics within their study populations. Our study seeks to determine the effect of pre-amputation characteristics on the probability of receiving a prosthesis for the general population in the United States.
Objective
Identify pre-amputation characteristics that predict of the likelihood of receiving a prosthesis following an above-knee amputation (AKA).
Design
A retrospective, population-based cohort study.
Setting
Olmsted County, Minnesota (2010 population: 144,248)
Participants
Individuals (n=93) over the age of 18 years who underwent an AKA i.e. knee disarticulation or trans-femoral amputation while residing in Olmsted County, MN between 1987 and 2013.
Methods
Characteristics affecting the receipt of a prosthesis were analyzed using a logistic regression and a random forest algorithm for classification trees. Pre-amputation characteristics include age, sex, amputation etiology, year of amputation, mobility, cognitive ability, comorbidities, and time between surgery and the prosthesis decision.
Main Outcome Measures
The association of pre-amputation characteristics with the receipt of a prosthesis following an AKA.
Results
Twenty Four of the participants received a prosthesis. The odds of receiving a prosthesis were almost 30 times higher in those able to walk independently prior to an amputation relative to those who could not walk independently. A 10-year increase in age was associated with a 53.8% decrease in the likelihood of being fit for a prosthesis (odds ratio=0.462, p-value =.030). Time elapsed between surgery and the prosthesis decision was associated with a rise in probability of receiving a prosthesis for the first three months in the random forest algorithm. No other observed characteristics were associated with receipt of a prosthesis.
Conclusions
The association of pre-amputation mobility and age with the likelihood of being fit for a prosthesis is well-understood. The effect of age, after controlling for confounders, still persists and is associated with the likelihood of being fit for a prosthesis.