The Role of Imageless Computer-Assisted Navigation During Total Knee Arthroplasty on Femoral Component Sagittal Alignment and Outcomes.

BACKGROUND

While total knee arthroplasty (TKA) is highly successful, 15%-20% of patients are not satisfied postoperatively, which may be due to alignment of the TKA components. Imageless computer navigation was developed to increase implant alignment accuracy and precision, but controversy surrounds the patient benefit of this technology. The target of femoral sagittal alignment and its role in patient-reported outcomes (PROMs) after TKA using assistive technology has not been well-defined.

METHODS

Femoral sagittal alignment, 30-day complications, and PROMs through 1 year were collected retrospectively from unilateral elective TKA patients who underwent surgery between July 2020 and February 2023. Two surgeons equally versed in conventional and imageless navigation techniques participated in patient record identification. Students -tests and chi-square tests of proportion were used to compare outcomes, 30-day complications, and alignment.

RESULTS

Completed PROMs were available for 387 patients; 181 in the computer navigation group and 206 in the conventional arthroplasty group. PROMs were statistically significantly different between groups, favoring computer navigation ( = .014 at 12 months). Lateral femoral angle measurements were greater in females who underwent TKA with computer navigation ( < .001). Of note, 14 patients in the conventional technique group returned to the emergency department within 30 days, as compared to 4 in the navigation group ( = .033).

CONCLUSIONS

PROMs are improved in the navigation group compared to the conventional technique group. Fewer patients in the navigation group returned to the emergency department. Navigation appeared to provide a small benefit compared to conventional techniques, though final lateral femoral angle was not predictive of outcomes. Additional surgical characteristics may need to be examined to determine the reasons for the differences in outcomes between these techniques.