Predictors of Receiving a Prosthesis for Adults With Above-Knee Amputations in a Well-Defined Population

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 preamputation characteristics within their study populations. Our study seeks to determine the effect of preamputation characteristics on the probability of receiving a prosthesis for the general population in the United States. Objective To identify preamputation characteristics that predict of the likelihood of receiving a prosthesis following an above-knee amputation. 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 above-knee amputation, that is, knee disarticulation or transfemoral 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. Preamputation characteristics included age, gender, amputation etiology, year of amputation, mobility, cognitive ability, comorbidities, and time between surgery and the prosthesis decision. Main Outcome Measures The association of preamputation characteristics with the receipt of a prosthesis following an above-knee amputation. 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 =.030). Time elapsed between surgery and the prosthesis decision was associated with a rise in probability of receiving a prosthesis for the first 3 months in the random forest algorithm. No other observed characteristics were associated with receipt of a prosthesis. Conclusions The association of preamputation 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.