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Total knee arthroplasty (TKA) stands as a hope for individuals suffering from debilitating knee osteoarthritis. This surgical intervention not only alleviates pain but also promises improved knee function and long-term survivorship. The prevalence of knee osteoarthritis in the United States is on the rise, and projections indicate a 673% increase in demand for TKA by the year 20301.
Despite its success, a significant portion of patients — approximately 20% — remain dissatisfied post-surgery2. Residual pain, functional outcome, and preoperative expectations emerge as the primary determinants of patient satisfaction. Alarmingly, a substantial number of patients experience persistent pain during daily activities such as walking, climbing stairs, and even running post-TKA3.
Recognizing this challenge, the medical community has embarked on a journey of innovation, leveraging technology to enhance patient outcomes and satisfaction.
The TKA mechanical alignment has been commonly used and involves placing implants systematically without considering the natural anatomy of the knee. This method was once considered the best because it was simple and consistent. However, it can lead to big changes in how the knee works, such as imbalanced ligaments and less natural movement, which often leaves patients feeling dissatisfied.
Personalized joint reconstruction has been showing the potential to unlock better TKA outcomes. Medical understanding of knee anatomy and biomechanics has evolved significantly, emphasizing the importance of replicating native knee kinematics during surgery4.
Kinematic alignment strategies aim to restore the pre-arthritic native limb alignment and mitigate the need for extensive soft tissue release. Modifications such as inverse kinematic, restricted kinematic, and modified kinematic alignments have been introduced to prevent excessive alignment deviation.
Customized implants and advanced surgical techniques are pivotal in achieving this goal. While navigation systems aid in the accurate placement of cutting blocks, which is followed by freehand bone cutting, robotic systems excel in precise bone sculpting to achieve the desired implant orientation5.
Robotic-assisted surgery, with its precision tools and ability to replicate patient anatomy, facilitates exact bone resections and minimizes soft tissue damage allowing for the tailoring of TKA procedures to individual patients. The customization of the bone cuts and implants helps engineers reduce the thickness and weight of the implants and the amount of bone removed.
Moreover, personalization of TKA has profound implications for reducing the need for intra-operative adaptations. This leads to the "custom implant paradox" phenomenon, where the more personalized TKA implants become, the less reliant surgeons are on intra-operative adaptations, leading to greater standardization of surgical techniques. Therefore, the integration of custom implants enhances overall consistency and efficacy6.
The complexities of TKA surgery emphasize the importance of considering it as a holistic process rather than merely a set of implants. This process contains pre-operative imaging and planning, supply chain and hospital workflow, surgeon training and education, customized instruments and implants, as well as standardized surgical techniques and traceability.
While obstacles remain, including concerns about cost and learning curves, the potential benefits of these advancements cannot be understated.
As we strive towards the vision of a "forgotten joint" — where patients experience seamless mobility and comfort — technologies, such as robotics and customized implants, stand as indispensable allies in pursuing excellence in TKA replacement.
References
1 - Davis, K. R., & Soti, V. (2024). Effectiveness of Kinematic Alignment-Total Knee Arthroplasty in Treating Preoperative Varus and Valgus Deformities in Patients With Knee Osteoarthritis. Cureus, 16(1).
2 - Minoda, Y. (2023). Alignment techniques in total knee arthroplasty. Journal of Joint Surgery and Research, 1(1), 108-116.
3 - Sappey-Marinier, E., Tibesku, C., Selmi, T. A. S., & Bonnin, M. (2020). Custom total knee arthroplasty. Personalized hip and knee joint replacement, 255-264.
4 - Morcos, M. W., Uhuebor, D., & Vendittoli, P. A. (2023). Overview of the different personalized total knee arthroplasty with robotic assistance, how choosing?. Frontiers in Surgery, 10, 1120908.
5 - Shah, S. M. (2021). After 25 years of computer-navigated total knee arthroplasty, where do we stand today?. Arthroplasty, 3, 1-8.
6 - Saffarini, M., Hirschmann, M. T., & Bonnin, M. (2023). Personalisation and customisation in total knee arthroplasty: the paradox of custom knee implants. Knee Surgery, Sports Traumatology, Arthroscopy, 31(4), 1193-1195.
