Randomized controlled trial comparing the radiologic outcomes of conventional and minimally invasive techniques for total knee arthroplasty

The objective of this study was to compare the radiologic outcomes of total knee arthroplasty using the conventional technique with those using minimally invasive surgery (MIS) techniques. Ninety patients were randomized to undergo conventional (control), MIS mini-incision mid-vastus (mini), or MIS side-cutting (side cut) techniques for their total knee arthroplasty. Long-leg radiographs were assessed postoperatively. The mean overall limb varus alignments were 1.03 degrees (SD, 2.58 degrees) for the control group, 0.87 degrees (SD, 2.96 degrees) for the mini group, and 0.37 degrees (SD 4.27 degrees) for the side cut group. The mean overall limb alignments within +/- 3.0 degrees varus/ valgus were 83.3%, 83.3%, and 56.7%, respectively. Femoral implant placement (P = .028) and overall limb alignment (P = .024) in the side cut group were significantly poorer as compared with those in the control group. The side cut group also had more outliers in the coronal plane. Results were comparable between the mini and control groups. The side cut technique appears to affect the accuracy of implant placement.