Reproducibility of an Intraoperative Pressure Sensor in Total Knee Replacement.

Camdon Fary,Richard De Steiger,Dean Mckenzie

doi:10.3390/s21227679

Abstract

Appropriate soft tissue tension in total knee replacement (TKR) is an important factor for a successful outcome. The purpose of our study was to assess both the reproducibility of a modern intraoperative pressure sensor (IOP) and if a surgeon could unconsciously influence measurement. A consecutive series of 80 TKRs were assessed with an IOP between January 2018 and December 2020. In the first scenario, two blinded sequential measurements in 48 patients were taken; in a second scenario, an initial blinded measurement and a subsequent unblinded measurement in 32 patients were taken while looking at the sensor monitor screen. Reproducibility was assessed by intraclass correlation coefficients (ICCs). In the first scenario, the ICC ranged from 0.83 to 0.90, and in the second scenario it ranged from 0.80 to 0.90. All ICCs were 0.80 or higher, indicating reproducibility using a IOP and that a surgeon may not unconsciously influence the measurement. The use of a modern IOP to measure soft tissue tension in TKRs is a reproducible technique. A surgeon observing the measurements while performing IOP may not significantly influence the result. An IOP gives additional information that the surgeon can use to optimize outcomes in TKR.

Highlights

For many years, intraoperative pressure (IOP) sensors have been incorporated in total knee replacement (TKR) surgery to measure compartmental tissue tension [1]
Insufficient tension leading to instability, subluxation, or even dislocation of the TKR is clinically readily identified intraoperatively compared to over-tension or stiffness
Surgery was performed by fellowship-trained knee arthroplasty surgeons who had been in specialist practice for over 12 years

Summary

Introduction

Intraoperative pressure (IOP) sensors have been incorporated in total knee replacement (TKR) surgery to measure compartmental tissue tension [1]. Sensors quantify medial and lateral compartment pressures and can define the contact points between the femoral component and tibial insert through the trial joint’s range of motion [4]. This enables the surgeon to adjust soft tissue tension while receiving dynamic visual feedback that is specific to both the TKR design and the patient’s soft tissue envelope. Surgeons have been shown to be poor predictors of the true state of balance and over-tensioning of soft tissue is believed to be a significant cause of worse outcomes in TKR [7,8]. This could be a reflection of a low reproducibility of the use of an IOP, which was not assessed

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Discussion

Conclusion