Current Controversies in Total Knee Arthroplasty—Part 1
02 July 2019 (online)
Total knee arthroplasty (TKA) remains one of the most successful procedures in medicine today, and it has improved the quality of life for millions of people since its first introduction almost 50 years ago. Over the years, prosthetic designs and surgical techniques have evolved to the point where this has become a standard procedure performed by most orthopaedic surgeons. The projected growth of TKA over the next 10 years will make this one of the most common surgical procedures performed.
Initially, TKA was performed primarily in elderly patients with minimal functional demands and a limited life expectancy. Over the years, as the results have held up over time, the indications expanded to include younger patients and those with significant medical comorbidities. Patients can now expect upwards of 90% survivorship at 20 years with little-to-no limitations in their activity level.
While designs have become standardized to either a cruciate retaining or posterior stabilized design, a number of controversial issues still remain, and surgeons continue to push the limits of the procedure to extend outcomes and improve function. These two special issues of the Journal of Knee Surgery will examine some of the more current controversies and try to put them in perspective regarding the overall outcomes and patient expectations. We are fortunate to have leading experts in the field contributing to these special issues and the authors come from a wide range of clinical practices with a wealth of clinical experience.
In the first article of this issue, Dr. Banks et al discuss the design rationale and results of fixed bearing pivoting TKA implants with the goals being to further improve patient outcomes and decrease revision rates. These authors have more than 20 years of experience with these designs, and their data suggest that near-normal joint stability and kinematics provide a measurable benefit to patients. As Dr. Paraskevi and coauthors note that the question of fixation in TKA has gone back and forth numerous time in the over 30 years, I have been in practice. While a cemented TKA remains the gold standard, current 4th generation cementless designs may finally have overcome the fixation problems of the past and be a viable option, especially in younger patients, who are making up a greater percentage of patients undergoing TKA over time.
Initially, TKA was implanted with minimal guidance. Then in 1980, standardized instrumentation was introduced to improve the alignment and reproducibility of the procedure, with the goal being to improve patient function and outcomes. As Dr. Manrique and his colleagues point out that the use of robotics and computer navigation has become the next major advance in the surgical technique to try and improve component placement and ligament balancing, once again with the goal of improving outcomes and patient satisfaction. They provide a careful assessment for the use of robotics in TKA.
Over time, the TKA population is not only getting younger but also larger, as the obesity epidemic continues to grow in the United States and elsewhere. The percentage of obese and morbidly obese patients continues to increase, and special issues arise in this group of patients. Dr. Blake et al note that there are problems with outcomes and survivorship in this challenging cohort of patients. One technique that has gained popularity is the use of stemmed components in the morbidly obese patients to try and decrease the incidence of complications and improve outcomes, patient satisfaction, and survivorship.
Finally, Dr. Allen and colleagues discuss the controversial issue of patella resurfacing. While level 1 randomized clinical trials exist to help resolve this controversy, there still remains significant geographic variation in the incidence of patella resurfacing. They review the relevant research on this topic, provide evidence-based recommendations based on these studies and their surgical technique and criteria for nonresurfacing the patella in TKA.
I am indebted to all the authors for their hard work and efforts that went into producing this special issue. Without their commitment to excellent patient care and their interest in sharing their knowledge with orthopaedic surgeons, this would not have been possible. I believe strongly that the information presented in this special issue will provide orthopaedic surgeons with the resources necessary to improve the care of their patients, leading to better outcomes and higher patient satisfaction.