Copyright © 2008 by The Journal of Bone and Joint Surgery, Inc.
Commentary & Perspective
Commentary & Perspective by
Megan E. Anderson, MD*,
Beth Israel Deaconess Medical Center, Boston, Massachusetts
Posted April 2008
This randomized study, which involved twenty-four centers across North America
and India, investigated which minimally invasive injection—methylprednisolone
acetate or bone marrow—was more effective in the treatment of simple bone cysts.
The question is cogent because simple bone cysts are common and are a frustrating
problem for patients, parents, and physicians. While they are not life or limb-threatening,
simple bone cysts do have a substantial impact on the lives of the children who
have them. Such children often must refrain from exercise and sport-related activity,
thereby missing out on health and social benefits. Instead, they may become chronic
patients, with frequent visits to the doctor's office or hospital because so
many cysts persist or recur despite multiple treatments. Many treatment options
have been proposed, but all are associated with some failure and few have been
investigated thoroughly.
The major strength of this study is its design. Randomized, blinded clinical
trials represent the highest level of evidence and can be relied on to provide
more accurate results. This study demonstrates how low the healing rates truly
are with either of these two treatments—a frustrating fact that anyone who is
involved in the care of these patients can certainly believe. Other methods of
treatment must be sought out and investigated if persistence and recurrence of
these cysts are ever to be decreased.
A second strength of the study is that it can serve as a model for other multicenter
randomized studies. This was the first trial of the Pediatric Orthopaedic Society
of North America (POSNA) Clinical Trials Network. The authors selected this research
question not only because it was an important clinical issue but also because
it was conducive to a relatively simple study that would serve as a model for
future POSNA projects. The logistics and funding issues resolved by this relatively
simple study make it possible to address more complex issues in future studies.
Multicenter randomized clinical trials are especially important for the study
of rare conditions, such as those encountered in pediatric orthopaedics and musculoskeletal
oncology. It is interesting that they are the norm for pediatric oncology in
general, where the Children's Oncology Group oversees the majority of clinical
trials in North America, and perhaps this was an example for POSNA. Trials such
as this represent a vital step toward bringing better-quality evidence-based
medicine into the realm of orthopaedics in general as a more common practice.
Multicenter randomized clinical trials, no matter how simple in design, are
still difficult to perform. The authors faced the obstacles of nonparticipation,
nonrandomization, discontinuation of protocol, and missing information, all of
which resulted in lower numbers. There was sufficient power to demonstrate that
methylprednisolone was superior to bone marrow with regard to healing rates but
not with regard to the evaluation of fracture risk in the two groups. Another
question that was not investigated was whether healing correlated with better
function or pain relief as measured with their validated instruments, the Activities
Scale for Kids and the Oucher Scale, respectively. We assume that this is the
case, but this study might have had enough power to show a definite correlation,
which would in turn have validated the modified Neer grading system for cyst
healing.
One other shortcoming was the lack of a control group. Only two interventions
were analyzed, and neither was compared with nontreatment. These decisions were
likely made in an effort to keep the study as simple as possible for the reasons
noted above and because parents might not allow their children to participate
if they knew they might be randomized to nontreatment. Perhaps with enough numbers
in a future extension of this study, a control group could be included. The authors
also point out that quantitative computed tomography1 would be a useful instrument to include
in future studies. Cysts that were predicted to put patients at lower risk for
fracture could make up the control group, with better reassurance that nonintervention
was a reasonable option for such patients.
Simple bone cysts remain a challenging problem and warrant further study.
This type of quality research is extremely valuable in the investigation of various
treatment options and as a model for multicenter cooperative randomized trials.
*The author did not receive any outside funding or grants in support of her research for or preparation of this work. Neither she nor a member of her 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 her immediate family, is affiliated or associated.
Reference
1. Snyder BD, Hauser-Kara DA, Hipp JA, Zurakowski D, Hecht AC, Gebhardt MC. Predicting fracture through benign skeletal lesions with quantitative computed tomography. J Bone Joint Surg Am. 2006;88:55-70.
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