Sensor Assessment of Gap Balance in Mobile-Bearing Unicompartmental Knee Arthroplasty
Summary
Here, we present a protocol to measure the gap contact force and gap balance in mobile-bearing unicompartmental knee arthroplasty (UKA). Along with the clinical and radiographic data, we hope to determine the normal range of the contact force and set up the threshold of the gap balance.
Abstract
The most important procedure of mobile-bearing unicompartmental knee arthroplasty (UKA) is to balance the knee flexion and extension gap. Conventionally, the balance was determined by the subjective assessment of plugging out the feeling gauge. Since it mainly depended on the surgeons’ experience, the accuracy was always in doubt. In the past 10 years, pressure sensors have been introduced to guide the gap balance in total knee arthroplasty (TKA). However, the sensor technique was introduced to UKA very recently. Herein is our sensor assessment of the gap balance in 20 cases UKA by one experienced surgeon. The sensor was a custom-designed force sensor matrix according to the shape of the tibial trial of mobile-bearing UKA. The postoperative clinical outcomes and radiographic results were recorded for future comparison. We aim to use this method to assess more than 200 cases of UKA by various surgeons to ultimately standardize the gap-balance result.
Introduction
The mobile-bearing UKA is currently one of the most successful treating methods for anteromedial osteoarthritis (AMOA) of the knee1. The balance of the flexion and extension gap during the operation is the key to a successful UKA2,3. The gap overload might aggravate the wear of the mobile bearing. Moreover, the elevated gap contact force might lead to postoperative valgus deformity and degeneration of the lateral compartment4. Therefore, achieving an optimal gap tightness as well as an acceptable gap balance in UKA is an important part of the learning curve5. According to the mobile-bearing UKA manual of surgical technique6, the surgeon must use the feeling gauge to insert and plug out of the joint gap to "feel" the contact force. By evaluating the force required to insert and remove the insert, the surgeon could estimate whether the gap balance is acceptable. Therefore, the judgment depended mainly on the surgeon's experience.
In recent years, digital measurement of intraoperative gap balance of medial and lateral gap had been widely reported in total knee arthroplasty (TKA)7,8,9. Recommendations for the threshold of the gap balance had also been set7. However, the sensor technique was introduced to UKA very recently without a well-recognized gap-balancing goal.
Last year, a force sensor specially designed to measure joint gap contact force during mobile-bearing UKA was introduced5. In the present research protocol, the sensor-guided gap force measurement method is demonstrated. In addition, a case series of 20 patients who had undertaken mobile-bearing UKA is included to assess the gap contact force and the gap balance. The final goal of this protocol is to determine the normal range of contact force and set up the threshold of gap balance in mobile-bearing UKA.
Protocol
Representative Results
Discussion
This study provided a detailed protocol of sensor technology in assessing the joint gap contact force and balance in mobile-bearing UKA. We hope to set up a goal of standard contact force as well as gap-balancing difference, which would allow the orthopedic surgeons to determine the bearing thickness and gap-balancing more easily in the future.
The overload of the joint gap may lead to postoperative valgus deformity of the limb, future degeneration of the lateral compartment, and even OA progr…
Disclosures
The authors have nothing to disclose.
Acknowledgements
This work was supported by the Capital Health Research and Development of Special (grant number 2020-2-4067), Beijing Natural Science Foundation (grant number 7202183); National Natural Science Foundation of China (grant numbers 81972130, 81902203, and 82072494), and Elite Medical Professionals project of China-Japan Friendship Hospital (NO.ZRJY2021-GG08). Since the computer program and the digital table equations are protected by the patent law, authors could be contacted for this information.
Materials
| Oxford UKA | Zimmer/Biomet | For the catalog numbers refer to Oxford Partial Knee Microplasty Instrumentation (femoral component, tibial component, meniscus bearing) | |
| Teflon Tape | 3M | Abrasion resistant adhesive tape widely used in biomechanical experiments | |
| Verasense | OrthoSensor | Verasense | TKA sensor |
| Excel | Microsoft | digital table software | |
| STERRAD 100S sterilization system | Johnson&Johnson | STERRAD 100S | Low-temperature sterilizing with hydrogen peroxide gas plasma |
| UKA force sensor | Qingrui Boyuan | in house | Co-designed and produced by Qingrui Boyuan Technology |
| Computer program for recording raw data | Qingrui Boyuan | in house | Co-designed and produced by Qingrui Boyuan Technology |
| Protractor | Shanghai M&G Stationery Inc. | any | Sterilized in the sterilization system |
| USB line | Lenovo | any | |
| Laptop | Lenovo | any basic configuration |
References
- Mohammad, H. R., Matharu, G. S., Judge, A., Murray, D. W. New surgical instrumentation reduces the revision rate of unicompartmental knee replacement: A propensity score matched comparison of 15,906 knees from the National Joint Registry. Knee. 27 (3), 993-1002 (2020).
- Bae, J. H., et al. Epidemiology of bearing dislocations after mobile-bearing unicompartmental knee arthroplasty: Multicenter analysis of 67 bearing dislocations. Journal of Arthroplasty. 35 (1), 265-271 (2020).
- Sun, X., et al. Bearing dislocation of mobile bearing unicompartmental knee arthroplasty in East Asian countries: a systematic review with meta-analysis. Journal of Orthopaedic Surgery and Research. 16 (1), 28 (2021).
- Ro, K. H., Heo, J. W., Lee, D. H. Bearing dislocation and progression of osteoarthritis after mobile-bearing unicompartmental knee arthroplasty vary between Asian and Western patients: A meta-analysis. Clinical Orthopaedics and Related Research. 476 (5), 946-960 (2018).
- Sun, X., et al. Sensor and machine learning-based assessment of gap balancing in cadaveric unicompartmental knee arthroplasty surgical training. International Orthopaedics. 45 (11), 2843-2849 (2021).
- Oxford Partial Knee microplasty instrumentation manual of the Surgical Technique. Zimmer-Biomet Available from: https://www.zimmerbiomet.com/content/dam/zimmer-biomet/medical-professionals/000-surgical-techniques/knee/oxford-partial-knee-microplasty-instrumentation-surgical-technique.pdf (2019)
- Gustke, K. A., Golladay, G. J., Roche, M. W., Elson, L. C., Anderson, C. R. A new method for defining balance: promising short-term clinical outcomes of sensor-guided TKA. Journal of Arthroplasty. 29 (5), 955-960 (2014).
- Lakra, A., et al. The learning curve by operative time for soft tissue balancing in total knee arthroplasty using electronic sensor technology. Journal of Arthroplasty. 34 (3), 483-487 (2019).
- MacDessi, S. J., et al. Does soft tissue balancing using intraoperative pressure sensors improve clinical outcomes in total knee arthroplasty? A protocol of a multicentre randomised controlled trial. BMJ Open. 9 (5), 027812 (2019).
- Zhang, Q., et al. A novel extramedullary technique to guide femoral bone preparation in mobile unicompartmental knee arthroplasty based on tibial cut and overall alignment. Journal of Orthopaedic Surgery and Research. 15 (1), 92 (2020).
- Hurst, J. M., Berend, K. R., Adams, J. B., Lombardi, A. V. Radiographic comparison of mobile-bearing partial knee single-peg versus twin-peg design. Journal of Arthroplasty. 30 (3), 475-478 (2015).
- vander List, J. P., Zuiderbaan, H. A., Pearle, A. D. Why do medial unicompartmental knee arthroplasties fail today. Journal of Arthroplasty. 31 (5), 1016-1021 (2016).
- MacDessi, S. J., Gharaibeh, M. A., Harris, I. A. How accurately can soft tissue balance be determined in total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 34 (2), 290-294 (2019).
- Su, Z., Wang, Z., Chen, H. A force line trajectory measuring system and algorithms for unicondylar knee replacement surgery. Annual International Conference of the IEEE Engineering in Medicine and Biology Society. , 2217-2221 (2019).
- Jaeger, S., et al. The influence of the femoral force application point on tibial cementing pressure in cemented UKA: an experimental study. Archives of Orthopaedic and Trauma Surgery. 132 (11), 1589-1594 (2012).
- Ettinger, M., et al. In vitro kinematics of fixed versus mobile bearing in unicondylar knee arthroplasty. Archives of Orthopaedic and Trauma Surgery. 135 (6), 871-877 (2015).
- Brimacombe, J. M., Wilson, D. R., Hodgson, A. J., Ho, K. C., Anglin, C. Effect of calibration method on Tekscan sensor accuracy. Journal of Biomechanical Engineering. 131 (3), 034503 (2009).
- Heyse, T. J., et al. Balancing mobile-bearing unicondylar knee arthroplasty in vitro. Knee Surgery, Sports Traumatology, Arthroscopy. 25 (12), 3733-3740 (2017).
- Gustke, K. A., Golladay, G. J., Roche, M. W., Elson, L. C., Anderson, C. R. Primary TKA patients with quantifiably balanced soft-tissue achieve significant clinical gains sooner than unbalanced patients. Advances in Orthopedics. 2014, 628695 (2014).
- Nodzo, S. R., Franceschini, V., Gonzalez Della Valle, A. Intraoperative load-sensing variability during cemented, posterior-stabilized total knee arthroplasty. Journal of Arthroplasty. 32 (1), 66-70 (2017).
.