Accuracy of soft tissue balancing in TKA: comparison between navigation-assisted gap balancing and conventional measured resection

Soft tissue releases are often required to correct deformity and achieve balance in total knee arthroplasty (TKA). However, releasing soft tissues can be subjective, highly variable and is perceived as an ‘art’ in TKA. The objective of this study was to compare the rate of soft tissue release required to achieve a balanced knee in tibial-first gap- balancing versus conventional, measured resection TKA, and its effect on outcomes.Soft tissue releases were documented and reviewed in 1256 robotic-assisted gap- balancing and 85 robotic-assisted measured-resection TKAs. Knees were stratified by coronal deformity (varus: >2° varus; valgus: >2° valgus). Rates of releases were compared between the two groups and literature. A subset of these patients were also enrolled in a prospective study. KOOS outcomes were captured pre-operatively and at 6M post TKA.The frequency of soft tissue release was significantly lower in the robotic gap- balancing group, with 21% of knees requiring release versus 40% (p=0.001) in the robotic measured resection group and 67% (p<0.001) for conventional measured resection. Pre-operative KOOS scores were similar between groups, however 6M scores showed a significant improvement in QOL, Sports and Symptoms scores in knees not released.Robotic assisted TKA with predictive gap balancing was found to reduce the number of releases across all coronal angles compared to conventional instruments. Furthermore, performing a soft tissue release rather than bone resection to achieve balance, correlated with worse outcomes. Further research is required to understand when imbalance should be corrected with bone resection adjustment versus soft tissue release.

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Accuracy of Soft Tissue Balancing in Robotic-Assisted Measured-Resection TKA Using a Robotic Distraction Tool

10.29007/h8kn ◽

2019 ◽

Author(s):

Jan Koenig ◽

Sami Shalhoub ◽

Eric Chen ◽

Christopher Plaskos

Keyword(s):

Soft Tissue ◽

Range Of Motion ◽

Measurement Data ◽

Soft Tissue Balance ◽

Maximum Difference ◽

Robotic Assisted ◽

Soft Tissue Balancing ◽

Gap Measurement ◽

Measured Resection ◽

Patient Reported

Achieving proper soft tissue balance during total knee arthroplasty (TKA) can reduce post- operative instability and stiffness as well as improve patient reported outcomes. The objective of this study was to compare final intra-operative coronal balance throughout the knee range of motion in navigated robotic-assisted TKA when performed with quantifiable feedback from a robotic ligament tensioning tool versus with standard trials and navigation measurements alone.The study included a prospective cohort of 52 patients undergoing robotic-assisted TKA using a measured resection technique. The cohort was divided into two sequential groups: a non-sensor-assisted group (n=25) and a subsequent sensor-assisted group (n=27). Once bony cuts and soft tissue balancing was performed in the non-sensor cohort, the final tibiofemoral gaps were measured throughout the knee range of motion using a robotic-assisted tensioner with the surgeon blinded to the measurements. For the sensor cohort, the surgeon preformed soft-tissue releases or re-cuts in order to balance the knee using the gap measurement data from the robotic tensioner. The robotic-assisted tensioner was then used to measure the final medial and lateral gap measurements.The average mediolateral gap difference throughout the range of flexion was 1.9 ± 0.7 mm with maximum difference of 7.8 mm for the non-sensor cohort. The sensor cohort had an average mediolateral difference of 1.5 ± 0.6 mm and a maximum difference of 3.8 mm. The difference between the two groups was statistically significant from 60 to 90 degrees of flexion. 38-41% of knees were balanced to within 1 mm mediolaterally in the non-sensor group compared to 48-70% for the sensor group when measured at various flexion angles. 65-76% of knees were balanced to within 2 mm for the non-sensor group compared to 78-86% for the sensor-assisted group. The number of knees requiring subsequent soft tissue releases was similar in each group. Soft tissue balancing with the aid of a robotic tensioning tool resulted in significantly more accurate soft tissue balance than when using navigation measurements and standard trials alone in this single surgeon study.

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Soft-tissue balancing in total knee arthroplasty: cruciate-retaining versus posterior-stabilised, and measured-resection versus gap technique

International Orthopaedics ◽

10.1007/s00264-013-2133-9 ◽

2013 ◽

Vol 38 (3) ◽

pp. 531-537 ◽

Cited By ~ 39

Author(s):

Tomoyuki Matsumoto ◽

Hirotsugu Muratsu ◽

Yohei Kawakami ◽

Koji Takayama ◽

Kazunari Ishida ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Soft Tissue ◽

Knee Arthroplasty ◽

Cruciate Retaining ◽

Soft Tissue Balancing ◽

Gap Technique ◽

Measured Resection ◽

Total Knee

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Accuracy of soft tissue balancing in total knee arthroplasty using surgeon-defined assessment versus a gap-balancer or electronic sensor

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02439-w ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Ran Zhao ◽

Yanqing Liu ◽

Hua Tian

Keyword(s):

Total Knee Arthroplasty ◽

Soft Tissue ◽

Knee Arthroplasty ◽

Sensor Data ◽

Soft Tissue Balancing ◽

Electronic Sensor ◽

Prior Performance ◽

Cumulative Summation ◽

Total Knee ◽

Sensitivity Specificity

Abstract Background Soft tissue balancing is essential for the success of total knee arthroplasty (TKA) and is mainly dependent on surgeon-defined assessment (SDA) or a gap-balancer (GB). However, an electronic sensor has been developed to objectively measure the gap pressure. This study aimed to evaluate the accuracy of soft tissue balancing using SDA and GB compared with a sensor. Methods Forty-eight patients undergoing TKA (60 knees) were prospectively enrolled. Soft tissue balancing was sequentially performed using SDA, a GB, and an electronic sensor. We compared the SDA, GB, and sensor data to calculate the sensitivity, specificity, and accuracy at 0°, 45°, 90°, and 120° flexion. Cumulative summation (CUSUM) analysis was performed to assess the surgeon’s performance during the sensor introductory phase. Results The sensitivity of SDA was 63.3%, 68.3%, 80.0%, and 80.0% at 0°, 45°, 90°, and 120°, respectively. The accuracy of the GB compared with sensor data was 76.7% and 71.7% at 0° and 90°, respectively. Cohen’s kappa coefficient for the accuracy of the GB was 0.406 at 0° (moderate agreement) and 0.227 at 90° (fair agreement). The CUSUM 0° line achieved good prior performance at case 45, CUSUM 90° and 120° showed a trend toward good prior performance, while CUSUM 45° reached poor prior performance at case 8. Conclusion SDA was a poor predictor of knee balance. GB improved the accuracy of soft tissue balancing, but was still less accurate than the sensor, particularly for unbalanced knees. SDA improved with ongoing use of the sensor, except at 45° flexion.

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