BMI as A Risk Factor
Strong evidence supports that obese patients have less improvement in outcomes with total knee arthroplasty (TKA).

There were four high quality papers extracted that addressed complication rates after total knee arthroplasty for obese patients. Two (Bordini 2009, Judge 2012) demonstrated no higher complication rates in obese patients, whereas the other two (Jamsen, 2013, Amin,2006) did show higher rates of  complications.  The conflicting high quality papers negate each other and did not allow for a recommendation regarding complications. There were two high quality papers that demonstrated less improvement in functional outcomes in obese patients after total knee arthroplasty (Judge 2012, Amin 2006).  As such the recommendation was made that strong evidence supports the risk for less good outcomes after total knee arthroplasty.