The incorporation of computer navigation in total hip arthroplasty (THA) has been much slower than for total knee arthroplasty (TKA). One reason for this is that a majority of THAs are performed with the patient in the lateral position through a posterior or lateral approach, making the tracker placement and the registration process cumbersome. In the direct anterior approach, the patient is in the supine position, which accommodates pelvic tracker placement and markedly facilitates the registration process. At our institution, we use the direct anterior approach and computer navigation on all of our primary THAs. We hypothesized that computer navigation improves cup placement without increasing operative time.
Materials and methods: This was a retrospective study comparing a consecutive series of 150 computer navigated THAs to a consecutive series of 150 non-navigated hips. The two groups were similarly matched by age, gender, and body mass index. Postoperative anteroposterior pelvic radiographs and operative times were analyzed.
Results: The navigation group mean cup inclination was 41° (range, 32° to 54°), compared to 36° (range, 19° to 52°) for the non-navigated group. The mean surgical time for the navigation group was 56 minutes (range, 34 to 91 minutes) and 61 minutes (range, 33 to 119 minutes) for the non-navigated group.
Conclusion: The results suggest that computer navigation is easy to incorporate when utilizing a direct anterior approach and in our series shortens the operative time. The accuracy and precision of cup angle placement is comparable to our non-navigated method but appears to be slightly improved with computer navigation. Although more work is needed for progress with this promising technology, we believe that incorporating computer navigation for hip arthroplasties in the supine position is straightforward and of great value.