Improved Accuracy of Acetabular Component Position and Leg Lengths with the Two-Incision Total Hip Replacement Technique

We sought to determine whether a non-originating surgeon early in his experience with the MIS two-incision technique for THA could place components with appropriate accuracy. Thirty five consecutive hip replacements performed between July of 2003 and March of 2004 using the two-incision technique were closely matched by height and weight with an equal number of control small incision arthroplasties. The two-incision surgeries were performed after the surgeon's twentieth case and prior to the surgeon's fifty sixth two-incision case. We assessed immediate postoperative films for leg length discrepancy and acetabular position, and compared the two groups by chi squared analysis. Both leg length accuracy and abduction angle were significantly superior with the two-incision technique. No arthroplasty performed with the two-incision technique had a leg length discrepancy of more than 10 mm, versus five in the control group (p<0.025). The abduction of one cup fell outside the 35–49° range in the two-incision group, while ten did so in the control group (p<0.01). With this study, we have shown that a non-originating surgeon early in his experience with the MIS two-incision technique can place acetabular components and equalise leg lengths with superior precision. We believe the fluoroscopic control and supine position greatly enhance the surgeon's accuracy, and more than compensate for the potentially decreased direct vision with this technique.