Soft tissue balancing in total knee arthroplasty using sensor-guided assessment: is there a learning curve?

Sensor-guided assessment for soft tissue balance in total knee arthroplasty (TKA) has been reported to improve patient satisfaction and self-reported outcome scores. As more surgeons adopt this technology in TKA, we performed this study to identify if there is a learning curve with its use.

Analysis of a total of 90 consecutive cases was performed in this study. Initial and final intercompartmental pressure differences were recorded before and after knee ligament balancing. The first 45 patients (group 1) were compared to the last 45 patients (group 2) in terms of operative time and the final state of knee balance. A balanced knee was defined as pressure difference between medial and lateral compartments of ≤15 pounds.

Group 1 had 10 unbalanced knees in the final pressure difference assessment, while all cases in group 2 were balanced (P < 0.001). There was no statistically significant difference in mean operative time between the two groups. A scatter plot of intercompartmental pressure difference identified that after 30 cases, the capacity to achieve knee ligament balance improved.

This study suggests that there is a learning curve with the use of sensor-guided assessment in TKA in achieving knee balance; however, the differences noted between initial and final groups were small and may not be of clinical significance.