Does the Use of Intraoperative Pressure Sensors for Knee Balancing in Total Knee Arthroplasty Improve Clinical Outcomes? A Comparative Study With a Minimum Two-Year Follow-Up.

ABSTRACT

BACKGROUND: It is undetermined whether using sensors for knee balancing in total knee arthroplasty (TKA) improves patient outcomes. The purpose of this study was to compare clinical outcomes of sensor balance (SB) with manual balance (MB) TKA with a minimum two-year follow-up. METHODS: A consecutive series of 207 MB TKAs was compared with 222 SB TKAs between April 2014 and April 2017. A single surgeon performed all surgeries, using the same prosthesis. The primary end point was the aggregated mean change in four subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS4) between preoperative and two-year time points. Secondary outcomes included mean differences between groups in all five KOOS subscales, proportions of knee balancing procedures, and rates of reoperations including revisions and manipulations for stiffness. RESULTS: The mean changes in the KOOS4 aggregated means for MB TKA (42.4; standard deviation, 29.1) and SB TKA (41.5; standard deviation, 25.0) were not significantly different (mean difference, 0.9; 95% confidence interval -2.6 to 4.4, P = .62). There were significantly more balancing procedures in the SB group (55.9% versus 16.9%; P < .01). There were no significant differences in the number of reoperations (1.4% SB versus 1.4% MB; P = .71) or manipulations for stiffness (3.7% SB versus 4.4% MB; P = .69). CONCLUSION: The use of sensors in TKA to achieve knee balance did not result in improved clinical outcomes, despite significantly increasing the number of surgical interventions required to achieve a balanced knee. Sensors did not alter the rates of revision surgery or requirements for manipulation. It remains to be determined whether precise soft-tissue balancing improves prosthetic survivorship and joint biomechanics.