Total Knee Arthroplasty and Intra-Articular Pressure Sensors: Can They Assist Surgeons with Intra-Operative Decisions?

Abstract

Purpose of Review Soft tissue imbalance, presenting as instability or stiffness, is an important cause of revision total knee arthroplasty (TKA). Traditional methods of determining soft tissue balance of the knee lack precision and are not reliable between operators. Use of intra-operative pressure sensors offers the potential to identify and avoid soft tissue imbalance following TKA. This review aims to summarise the literature supporting the clinical indication for the use of intra-articular pressure sensors during TKA. Recent Findings Analytical validation studies suggest that intra-operative pressure sensors demonstrate ‘moderate’ to ‘good’ intra-observer reliability and ‘good’ to ‘excellent’ interobserver reliability throughout the flexion arc. However, there are important errors associated with measurements when devices are used out-with the stated guidelines and clinicians should be aware of the limitations of these devices in isolation. Current evidence regarding patient benefit is conflicting. Despite positive early results, several prospective studies have subsequently failed to demonstrate significant differences in overall survival, satisfaction, and patient-reported outcome measures within 1 year of surgery. Summary Surgeon-defined soft tissue stability appears to be significantly different from the absolute pressures measured by the intra-operative sensor. Whilst it could be argued that this confirms the need for intra-articular sensor guidance in TKA; the optimal ‘target’ balance remains unclear and the relationship with outcome in patients is not determined. Future research should (1) identify a suitable reference standard for comparison; (2) improve the accuracy of the sensor outputs; and (3) demonstrate that sensor-assisted TKA leads to patient benefit in patient-reported outcome measures and/or enhanced implant survival.

Robotic Arm-assisted versus Manual (ROAM) total knee arthroplasty: a randomized controlled trial

“…robotic-assisted TKA (rTKA) to align the implants within 1°, 7 and offers protection of the periarticular soft-tissues; 8 in addition, intraoperative pressure sensors can be used to objectively balance the knee joint. 9 Robotic-assisted knee surgery has evolved over the last decade, with increasing evidence of improved component alignment and patient outcomes when compared to manually performed knee surgery. 7 Currently the most commonly employed rTKA is the MAKO (Stryker, USA) system, which is robotic arm-assisted and aids protection of the soft-tissue structures around the knee using a 3D boundary determined by haptic rendering.…”

“…6 Advances in technology have enabled robotic-assisted TKA (rTKA) to align the implants within 1°, 7 and offers protection of the periarticular soft-tissues; 8 in addition, intraoperative pressure sensors can be used to objectively balance the knee joint. 9…”