Every year, approximately 1 million new patients undergo a total knee arthroplasty in the United States1. A great majority experience pain relief, improved function, and improved quality of life, but complications occur in a fraction of patients. A complication following total knee arthroplasty can be devastating and life-changing for the patient. Furthermore, complications are extremely costly to the health-care system. Maintaining access to the surgical benefits while minimizing the number of complications is a paramount challenge.
Various studies looking at post-surgical morbidity and mortality have found that “busier is better.” In their article, Wilson et al. went beyond what had been done in prior studies by using a novel statistical approach to specify surgical-volume thresholds that correlate with increments in outcomes (complications, early reoperations, and death). Thus, the thresholds are based on actual data from the administrative database that they studied, rather than arbitrary values. As is noted in their excellent article, they answered the question of how much busier is better. This is an important advance over the prior literature on this subject.
However, there are several important questions that arise as we move forward from this point. The first question pertains to the specific results of the article itself. Are the specific thresholds defined in this article generally applicable? This is an important question, as it will be tempting for surgeons, administrators, and patients to focus on the exact thresholds reported. The only thing of which we can be certain is that the thresholds that are calculated and are reported in this work pertain specifically to the data set that was studied. It is very possible that a similar study on another data set in another location with different surgeons over a different time interval would result in different cutoff values among low, medium, high, and very high volumes with regard to surgeons and hospitals, and that the increment in risk associated with these different cutoff values will change. Before these specific cutoff values are used to inform surgeon and hospital selection or, on a larger scale, health-care policy, it will be important to validate the conclusions of this study on an entirely different data set. Indeed, as practices and procedures change over time, these cutoff values may all end up being moving targets.
Even if such information could be validated and updated on a continuing basis, a larger and more meaningful question arises. How do we use these data? The logical conclusion of this article is that all total knee arthroplasties should be done in hospitals with ≥645 cases per year by surgeons performing ≥146 cases per year. Should this become policy among payers for total knee arthroplasty? Large, integrated health-care systems have moved in this direction, routing knee replacement cases to larger specialty centers and higher-volume surgeons, and some large corporations have contracted directly with very high-volume medical centers for their employees’ joint replacement surgical procedures2. However, this approach may not be broadly applicable to the United States health-care system, at least as it is structured presently. Many parts of the United States do not have such large centers and high-volume surgeons nearby. Because many patients do not have the means or the social support to travel extended distances to specialized centers for their surgical procedures, the general implementation of such a policy could have the effect of restricting access to care.
Should patients only seek out surgeons and hospitals with volumes that rise above the highest thresholds? The authors suggest that surgeons in the lowest tier of volume consider removing total knee arthroplasty from their practice offerings to focus on other aspects of their practice, and I believe that this is a reasonable consideration. However, although multiple studies, including the present one, have found a statistical relationship between volume and reduced complication rates, not all of the highest-volume surgeons and hospitals are exceptional and have better outcomes than all surgeons and hospitals that fall below the highest tiers. We all know that there is more to being an excellent orthopaedic surgeon or an excellent hospital than simply volume. Volume is one of a number of different considerations that should be taken into account in choosing a surgeon or hospital.
Finally, is there something that can be done to alter the findings of this study and make quality of care more uniform across surgeons and centers of varying volume? It has been shown that standardization of care can improve quality3. Surgeons and hospitals can learn best practices from the best and highest-volume surgeons and hospitals and adopt these practices in lower-volume settings to improve care and outcomes.
↵* The author indicated that no external funding was received for any aspect of this work. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article.
- Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated