Levels of Evidence for Primary Research Question
Grades of Recommendation for Summaries or Reviews of Orthopaedic Surgical Studies

The goal of clinical practice is that treatment for individual patients must do more good than harm and result in the greatest improvement in health compared with no treatment or alternative treatments.

In orthopaedics, major advancements over the past 30 years have included total joint replacement, internal fixation of fractures, instrumentation for the spine, and the Ponseti treatment for club foot. Based on uncontrolled case series, these treatments were obviously superior to existing options and quickly adopted. Since that time, however, relatively few comparable leaps in patient outcomes have occurred.

Evidence-based medicine has the potential to improve patient care. The term, “evidence-based medicine” was defined in 1996 by David Sackett as “the use of current best evidence, integrated with individual expertise to make the best decisions about the care of individual patients.” For evidence-based medicine to be effective, the following criteria must be met:

  • Surgeons must recognize the need for evidence.
  • Evidence must exist.
  • Surgeons must be able to find the evidence.
  • Surgeons need to use the evidence in their clinical practice.

A striking example of the power of evidence-based medicine comes from pediatric oncology. Approximately 30 years ago, pediatric oncologists had the same variability in treatment as orthopaedic surgeons do now. At that time pediatric oncologists began to enroll their patients in randomized clinical trials. Over the past 30 years, improvement in survival for childhood cancer has jumped from 10% to 70%. Upwards of 70% of children with malignancy are currently entered into clinical trials in North America. This is a powerful example of how randomized clinical trials can improve quality of care.

Promoting Levels of Evidence

Over the past 10 years, there have been significant advances in the use of evidence by journals, the promotion of evidence by professional societies, the development of specialty-based randomized trials, the increased capacity in designing and understanding trials, and the provision of evidence in an accessible form.


In 2000, the Journal of Bone and Joint Surgery (JBJS) introduced an Evidence-based Orthopaedics section. Approximately 40 journals are reviewed to identify all Level I evidence relevant to orthopaedic surgeons. On a quarterly basis, three structured abstracts are constructed and commentaries are solicited so that orthopaedic surgeons can identify the latest evidence-based treatments.

Shortly thereafter, JBJS introduced Levels of Evidence ratings for all clinical papers.3,4 Studies are divided into four types: therapeutic, prognostic, diagnostic, and economic/decision analysis. Studies are graded from Level I through Level V, with a Level of Evidence grade attached to the bottom of the abstract. Orthopaedic surgeons should look very seriously at Level I and Level II studies, as they are likely to have a significant impact on their practice.

More recently, JBJS introduced the concept called Grades of Recommendation for review articles. While each individual study has a Level of Evidence in making a treatment recommendation, Grades of Recommendation provide a summary of the totality of the literature. Grade A evidence is consistent Level I studies, Grade B evidence is consistent Level II and Level III evidence, Grade C is consistent Level IV and Level V studies, and Grade I is either insufficient or conflicting evidence, not allowing recommendation for or against intervention. A Grade is attached to treatment recommendations in review articles, thereby assisting readers in judging the importance and strength of recommendations arising from review articles.

A recent study by Hanzlik showed that randomized clinical trials with Level I evidence now comprises almost 25% of articles published in JBJS, and in the year 2005, the number of case series published in JBJS dropped below 50%. This finding demonstrates that the amount of evidence in orthopaedics is accumulating.


Professional societies have also dramatically progressed in their use of evidence. For example, the Pediatric Orthopaedic Society of North America (POSNA) requires Levels of Evidence ratings for all abstracts submitted to their annual meeting. Even more powerful have been society-wide clinical trials. For example, a POSNA-wide clinical trial published in JBJS in 2008 compared intralesional methylprednisolone with autologous bone marrow for simple bone cysts, evaluating healing, function, and pain. This multi-center trial of 28 centers involving 90 patients demonstrated that the more recent and popular treatment of injection of bone marrow had lower incidence of healing than the standard treatment of methylprednisolone for simple bone cysts.

The American Orthopaedic Association (AOA) has embarked on a process to improve the capability for designing clinical trials. Because many surgeons do not have the time to devote to a full clinical trials course (such as a Masters degree), the AOA has developed 22 modules (with 10 core modules) designed to teach the essentials of randomized clinical trials. The course, with an instructor guide, is specifically designed to be taught by non-experts. A recent JBJS publication demonstrated this course can result in significant improvement in knowledge.

More Sources

For surgeons looking to find evidence, there are several sources including MEDLINE (using Clinical Queries), the Cochrane database, or the Up-to-Date web site. In addition, recent textbooks, such as Evidence-based Orthopaedics address clinical questions based on systematic literature searches of controlled Level I to Level III studies, with Grades of Recommendations. The day is not far off when we will be able to search for evidence-based answers at the bedside using our smart phones.

In conclusion, high quality evidence in orthopaedics is increasing. The culture of orthopaedics is becoming evidence-based. High-quality evidence is available in several forms. The next challenge will be the final step of having surgeons adopt and adhere to evidence-based treatments.


  1. Sackett, D. L., W. M. Rosenberg, et al. (1996). Evidence based medicine: What it is and what it isn’t. BMJ 312(7023): 71-72.
  2. Wright, J. G. (2000). Introducing a new journal section: Evidence-based orthopaedics. J Bone Joint Surg 82: 759.
  3. Wright, J. G., M. F. Swiontkowski, et al. (2003). Introducing levels of evidence to the journal. J Bone Joint Surg Am 85-A(1): 1-3.
  4. Wright, J. G., M. Swiontkowski, et al. (2006). Levels of evidence. J Bone Joint Surg Br 88-B(9): 1264-.
  5. Wright, J. G. (2006). Revised grades of recommendation for summaries or reviews of orthopaedic surgical studies. J Bone Joint Surg Am 88-A(5): 1161-1162.
  6. Hanzlik, S., R. C. Mahabir, et al. (2009). Levels of evidence in research published in The Journal of Bone and Joint Surgery (American Volume) over the last thirty years. J Bone Joint Surg Am 91(2): 425-428.
  7. Wright, J. G., S. Yandow, et al. (2008). A Randomized Clinical Trial Comparing Intralesional Bone Marrow and Steroid Injections for Simple Bone Cysts. J Bone Joint Surg Am 90(4): 722-730.
  8. Diamond, I. R., C. Murray, et al. (2009). The American Orthopaedic Association Clinical Trials Curriculum. J Bone Joint Surg Am 91(4): 1007-1011.
  9. Wright, J. G. (2009). Evidence-Based Orthopaedics: The Best Answers to Clinical Questions, Elsevier.

Reprinted with permission from the Fall 2010 issue of COA Bulletin