Surgical and rehabilitation outcomes of patients undergoing through knee amputation compared with above knee amputation

Abstract

Background: Through knee amputation (TKA) may offer benefits over above knee amputation (AKA) in patients unsuitable for below knee amputation. This retrospective analysis compared surgical and rehabilitation outcomes post TKA and AKA. Methods: All TKA and AKA procedures recorded in the Scottish Physiotherapy Amputee Research Group dataset from January 2007 to December 2017 were included for analysis. All aetiologies, re-amputations and bilateral procedures were included. Demographic information, surgical outcomes (ie, further surgery, survival, and length of stay) and rehabilitation outcomes (ie, limb fitting, early rehabilitation, and mobility scores) were compared using descriptive and inferential statistics, including Kaplan–Meier, log-rank statistics and multivariate logistic regression. Results: In total, 4,197 procedures were included for analysis (3,471 initial AKA, 146 initial TKA, 580 initial below-knee or other level). Survival (p=0.809) and length of stay (p=0.696) were similar between groups, but TKA had significantly higher rates of further surgery (p<0.001). Multivariable analysis showed that patients who undergo TKA at centres which perform small numbers of TKA are significantly more likely to need further surgery (p=0.048). A significantly larger proportion of these patients had a limb fitted (25%) compared with only 12% of those from centres performing larger numbers of TKA (p=0.041). Overall, 31% (n=23) of those with TKA and 30% (n=725) of those with AKA had a limb fitted (p=0.854). All other rehabilitation outcomes were similar between groups. Conclusion: High volume centres have better surgical outcomes but appear to select patients not likely to limb fit. Despite this, similar proportions of patients did subsequently limb fit between groups, which may suggest superior rehabilitation potential for TKA compared with AKA, although the numbers performed in Scotland are very small. Prospective randomised studies are urgently needed to inform clinical practice.