The Value of National and Hospital Registries

Following Dr. Sarmiento’s commentary, “Orthopedic Registries: Second Thoughts,” we agree that it is important and appropriate to question the value of any new additions to the orthopedic field, and registries are no exception. We thank Dr. Sarmiento for his comments on the viability of registries and the need for continued critical evaluation. Before joint registries, however, we had to rely on small-cohort analyses to assess outcomes and complications. Now, national and hospital registries, specifically joint registries, may be an invaluable source of information for orthopedic surgeons, patients, health care administrators, regulators, and implant suppliers.^1,2

Contrary to Dr. Sarmiento’s belief that registry data results are likely to have been reported in the literature, it is difficult to refute the value of recent years’ registry data in helping surgeons shape their practice. For example, according to Lewallen and Etkin,³ the National Joint Registry of England and Wales information has provided orthopedic surgeons with crucial findings regarding the outcomes of metal-on-metal hip arthroplasties. Using the England and Wales registry data from more than 400,000 primary total hip arthroplasties, Smith and colleagues⁴ noted that metal-on-metal stemmed articulations led to poor implant survival, particularly in young women with large-diameter heads, and indicated these articulations should not be used. Australian registry data on metal-on-metal devices and reports of failure rates up to 11%⁵ led one manufacturer to recall its implants.⁶ In addition, the Norwegian Arthroplasty Register evaluated survival rates and reasons for revision for 7 types of cemented primary total knee arthroplasty (TKA) between 1994 and 2009.⁷ Data on more than 17,000 primary TKAs allowed Plate and colleagues⁸ to confidently determine that aseptic loosening was related to certain TKA designs. Using registry information, they identified patients at risk for dislocation in total hip arthroplasty and concluded that large-diameter femoral head articulations could reduce dislocation rates.

Obtaining such large cohorts of patients in individual studies is not only difficult but highly unlikely. Unlike registry data, these studies are often impractical in evaluating factors of low incidence, such as revision rates, as it is often difficult to find significant differences in small populations.⁹ Furthermore, these controlled trials homogenize patients—using exclusion and inclusion criteria to eliminate potential confounders—and thus poorly represent the heterogeneity of a typical hospital’s patient population.¹⁰ Although the literature may indeed have alluded to such complications, only a database as extensive as a registry can allow us to fully comprehend the outcomes of particular implants and devices.

Dr. Sarmiento points to the AO Swiss Fracture Registry as being of little benefit and raises the concern that the American Joint Replacement Registry (AJRR) may follow with the same results. However, realizing a registry’s benefits may take time and the gradual accumulation of data. Supporting this, Hübschle and colleagues¹¹ recently used AO Swiss Fracture Registry data to validate use of balloon kyphoplasty for vertebral compression fractures and concluded that the technique is safe and effective in reducing pain—thus possibly providing the federal office with the evidence needed for reimbursement for this intervention. Therefore, this registry is now providing useful information.

We can never truly know the veracity of participating surgeons, but it is naïve to assume that this issue arises only vis-à-vis registries. If we were to debate the ethical and professional standards of colleagues in our field, such questions could extend to all studies performed, even peer-reviewed studies. Therefore, we do not think this is reason to exclude the patient data and outcomes found in registries. We must emphasize that ultimately registry data are often most useful in highlighting trends and determining triggers for further study rather than in arriving at conclusions.¹ In particular, registry data may be used in cohort studies that evaluate the risk factors for and incidence of certain outcomes. Focused higher-level interventional studies can then follow the trends observed.¹ However, registry data are also valuable on their own, when higher-level, randomized controlled trials may be impractical or unethical.¹²

Dr. Sarmiento refers to corrupt relationships between companies and orthopedists as “representing a widespread loss of professionalism in our ranks.” Despite a US Justice Department investigation into these relationships, only a few doctors were found to have had inappropriate relationships.¹³ In addition, the investigation and prosecution of companies led to an agreement requiring federal monitoring and new corporate compliance procedures, which should ensure stricter adherence to regulations.¹⁴ We do not believe this should undermine the value of registries and the work that has been contributed by thousands of surgeons hoping to improve the field of orthopedics. In addition, concerns about the influence of well-known individuals may be better directed at individual institution–based research, particularly as these specific authors also often have conflicts of interest that may skew the presentation of results. The strength of registry data is in providing collective data and large samples from a multitude of surgeons rather than from just high-volume surgeons, and therefore registry data provide a better overall picture of patients and their procedures.¹⁵ Furthermore, trends observed in national registries in countries such as New Zealand¹⁶ may aid in effectively reducing the revision rate, possibly up to 10%.¹⁷ If a US national joint registry is marginally as effective, then we may see considerable savings for our health care services.^17,18