Correlations between Navigation and Radiographic Measures of Alignment

Area of Science:

• Orthopedic surgery
• Biomechanical analysis
• Surgical navigation technologies

Background:

• Accurate limb alignment is crucial for successful total knee arthroplasty (TKA) and open wedge high tibial osteotomy (HTO).
• Intraoperative navigation systems aim to improve surgical accuracy, but their correlation with radiographic alignment requires evaluation in different orthopedic procedures.
• Discrepancies between navigation and radiographic measurements can impact clinical outcomes and necessitate careful assessment.

Purpose of the Study:

• To compare the correlation between intraoperative navigation and radiographic alignment in patients undergoing TKA versus HTO.
• To assess the reliability of navigation and radiographic alignment measurements before and after surgery in both procedures.
• To identify differences in the accuracy and discrepancies of coronal alignment between TKA and HTO using these two methods.

Main Methods:

• Prospective enrollment of 91 knees for TKA and 82 patients for open wedge HTO.
• Comparison of the absolute difference in mechanical axis (MA) between navigation and radiography, both preoperatively and postoperatively.
• Analysis of the percentage of outliers (defined as >3 degrees difference) between navigation and radiographic MA for both groups.

Main Results:

• Preoperatively, TKA showed a significantly greater absolute difference (2.6 vs. 1.5 degrees) and a higher percentage of outliers (37% vs. 10%) between navigation and radiography compared to HTO.
• Postoperatively, HTO demonstrated a significantly greater absolute difference (2.4 vs. 1.4 degrees) and a higher percentage of outliers (28% vs. 10%) between the two measurement methods.
• The discrepancy in coronal alignment measurements was significantly higher preoperatively in TKA and postoperatively in HTO.

Conclusions:

• The reliability of intraoperative navigation versus radiographic alignment differs between total knee arthroplasty and open wedge high tibial osteotomy.
• Preoperative alignment assessment shows greater variability with navigation in TKA, whereas postoperative assessment reveals greater variability in HTO.
• These findings highlight the need for procedure-specific considerations when utilizing navigation and radiographic alignment in knee reconstruction surgeries.