Copyright © 2007 by The Journal of Bone and Joint Surgery, Inc.

Commentary & Perspective

Commentary & Perspective on
"A Comparison of Total Hip and Knee Replacement in Specialty and General Hospitals"
by Peter Cram, MD, MBA, et al.

Commentary & Perspective by
William J. Maloney, MD*,
Stanford University, Stanford, California

Posted August 2007

In this investigation, the authors reviewed a cohort of Medicare beneficiaries who underwent total hip or total knee replacement in "specialty orthopaedic" or general hospitals. An orthopaedic specialty hospital was defined by the ratio of orthopaedic admissions to total admissions; a higher ratio denoted a greater level of orthopaedic specialization. From a list of 100 hospitals with a high ratio, the authors then chose thirty-eight for study by excluding hospitals in which obstetrics and gynecologic procedures were performed as well as hospitals in which pediatric care was offered. In addition, hospitals with formal medical school affiliations were also excluded from the specialty group.

The authors then used Medicare claims data to compare demographics, comorbidity, socioeconomic status, and the odds of adverse outcomes in these two different hospital settings. Outcomes of interest included sepsis, hemorrhage, pulmonary embolus, deep venous thrombosis, wound infection requiring readmission, and death. In addition, the authors evaluated length of stay and the proportion of patients who required transfer from the hospital at which they underwent the initial joint replacement to another acute-care hospital.

Their findings are interesting, but somewhat predictable. Patients who received care in specialty hospitals generally had fewer comorbidities and tended to reside in more affluent zip codes. Orthopaedic specialty hospitals had greater mean procedural volumes for hip replacement and knee replacement when compared with those in the general hospital setting. Specialty hospitals had a lower rate of adverse outcomes even when adjusted for volume and comorbidities. With use of the Medicare administrative data, the authors concluded that patient outcomes were better in specialty orthopaedic hospitals than in general hospitals.

There are several important issues that are addressed in this article, but it is important to note that this retrospective study of claims data has limitations. From the standpoint of outcomes that were measurable, the data strongly suggest that specialty hospitals did better than general hospitals. Volume has been previously shown to affect outcome in multiple studies, including hip replacement studies. The experience of the surgeon is not the only variable that matters. The entire team has an impact on outcome. This includes the operating-room team, the rehabilitation team, and the nurses on the ward. In settings in which there is high volume, it is more likely than not that standardized protocols have been established. Standardization, whether it is in manufacturing or in health care, leads to fewer errors and, I believe, more predicable outcomes.

The orthopaedic specialty hospitals tended to have patients from more affluent zip codes. This finding obviously has political implications. Specialty hospitals, whether they are orthopaedic specialty hospitals or hospitals that specialize in other areas, such as cardiovascular surgery, tend to be built in more affluent communities and tend to be somewhat more restrictive in terms of the patients that they will accept. There are concerns at the national and regional levels that this could jeopardize the financial viability of general hospitals. If the more profitable procedures are performed at specialty hospitals where patients have a higher ability to pay their health-care bills, general hospitals in those regions could be left without sufficient resources to provide a broad level of services, including services for patients who do not have the ability to pay. This issue is unlikely to go away in the near future and will be the impetus for ongoing legislation.

It is also important to point out that although the adverse outcomes that were measurable on the basis of the claims data were higher in the general hospitals, those patients also had a higher level of comorbidities. Although it is true that the study adjusted for the demographics and comorbidity with use of tools currently available to do that, there is always a question as to whether the adjustment is valid. Comorbidities tend to be more complex than can be easily measured. Issues like poor nutrition, diminished cognitive status, generalized reconditioning, and poor support systems are hard to adjust for in these types of evaluations, but they can definitely impact outcome.

The bottom line, however is that volume matters. The more we do, the better we are. Whether we are at high-volume or low-volume centers, it is important that we establish evidence-based protocols to minimize complications and optimize outcomes.

*The author did not receive any outside funding or grants in support of his research for or preparation of this work. Neither he nor a member of his immediate family received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the author, or a member of his immediate family, is affiliated or associated.