The effect of varus and valgus deformity on results of cementless mobile bearing TKA.

We aimed to determine whether preoperative angular deformity affects survivorship or postoperative alignment after cementless mobile bearing total knee arthroplasty. Nine hundred seventeen knees were grouped according to preoperative mechanical alignment: normal, 0-5 degrees ; abnormal, 6-10 degrees ; severely abnormal, >10 degrees. Ten-year survival estimates were 89.7% for the severely abnormal alignment group, 95.5% for the abnormal alignment group, and 94.9% for the normal alignment group. Postoperatively, normal alignment was restored in 95.6% of knees in the severely abnormal group and 94.5% of knees in the abnormal group. For the normal alignment group, 99.2% of knees remained normally aligned after TKA. These differences in postoperative alignment may explain the severely abnormal alignment group's inferior survivorship outcome. This study shows that cementless mobile bearing implants can be successfully used in a wide range of angulated deformed knees, although preoperatively deformed knees did not do as well as preoperatively undeformed knees.