Copyright © 2005 by The Journal of Bone and Joint Surgery, Inc.

Commentary & Perspective

Commentary & Perspective on
"Magnetic Resonance Imaging of the Knee in Children and Adolescents: Its Role in Clinical Decision-Making"
by Scott J. Luhmann, MD, et al.

Commentary & Perspective by
Lyle J. Micheli, MD*,
Children's Hospital Boston, Boston, Massachusetts

Luhmann and colleagues have performed an important study that is actually the third of a series of recent articles that attempt to determine the relative importance of clinical examination and magnetic resonance imaging in children and adolescents who sustain acute traumatic knee injuries.

In the present study, the accuracy of diagnosis obtained by an experienced pediatric sports-medicine orthopaedist who performed the clinical examination and also interpreted magnetic resonance imaging films preoperatively was compared with the accuracy of diagnosis of the same magnetic resonance imaging studies by radiologists, half of whom were not specialists in pediatric disorders. In this study, the accuracy of the surgeon's diagnosis, which was made on the basis of the preoperative clinical examination and the radiographic and magnetic resonance images (including the radiologist's interpretation), was significantly better (p < 0.05) than the diagnosis given by the radiologist with respect to anterior cruciate ligament tear, lateral meniscus tear, osteochondritis dissecans, and discoid lateral meniscus. No significant difference was found in the prediction of medial meniscal tear or osteochondral fracture.

The first such study that addressed diagnostic accuracy in this population group was published in 1998 by Stanitski1. The accuracy of the arthroscopically determined diagnosis (the gold standard) was compared with the preoperative clinical diagnosis and the preoperative radiographic diagnosis as interpreted from the preoperative magnetic resonance image. Importantly, the clinical diagnosis was that of an experienced pediatric orthopaedic sports-medicine specialist while the radiologic diagnosis was furnished by general radiologists with variable experience in interpreting musculoskeletal injuries. With these parameters, the study demonstrated a dramatically superior accuracy of the clinical diagnosis versus the magnetic resonance imaging interpretations. (It must be noted, however, that the radiographic literature was just beginning to report the specific differences in magnetic resonance imaging interpretation of the pediatric knee vs. the adult knee and in many instances, the errors in magnetic resonance imaging diagnosis could well be attributed to lack of appreciation of these differences, which are now well recognized.)

In another study, Kocher et al.2 compared the accuracy of preoperative clinical diagnoses made by an experienced pediatric orthopaedic sports-medicine specialist without the benefit of magnetic resonance imaging interpretation and compared it with the preoperative magnetic resonance imaging diagnosis made by experienced pediatric musculoskeletal radiologists. They found that clinical examination alone and selective magnetic resonance imaging had a similar overall diagnostic accuracy. Clinical examination was more sensitive for discoid lateral meniscus, while selective magnetic resonance imaging was more specific for medial meniscal tears. (It must be noted that the magnetic resonance images were ordered by the experienced examining orthopaedist after his/her initial clinical examination determined that such studies had the potential to be beneficial.)

Putting together these three similar but somewhat differently designed studies, some tentative conclusions would appear to be appropriate.

1. When evaluating acute traumatic injury of the knee in children and adolescents, magnetic resonance imaging should most appropriately be ordered by the examining orthopaedist. The magnetic resonance image is most accurately interpreted when evaluated by the examining orthopaedist who correlates them with clinical findings. We have encountered many cases in which the magnetic resonance image that was ordered by the primary care physician and interpreted by radiologists who had no specific expertise in the assessment of these pediatric disorders has been misinterpreted, resulting in a delay in diagnosis and the withholding of appropriate treatment.

2. In each of these three studies, the evaluating orthopaedic surgeon was not only trained in sports medicine but specifically in the subspecialty of pediatric orthopaedic sports medicine. Whether the same level of clinical diagnostic accuracy or magnetic resonance imaging interpretation could be attained by a general orthopaedist is not known at this time. Similarly, the accuracy of assessment of traumatic knee injuries by pediatric orthopaedists without specific training in sports medicine is also not answerable on the basis of these studies.

The results of these studies suggest that magnetic resonance images should be ordered by the examining orthopaedist. These studies would also suggest that ongoing training in pediatric orthopaedic sports medicine for both pediatric orthopaedists and general orthopaedic surgeons likely would be helpful.

We strongly agree with the author's recommendation that the magnetic resonance images must be personally evaluated by the examining orthopaedist in assessing traumatic knee disorders in children and adolescents. Whether the average orthopaedist has the same level of diagnostic accuracy as a pediatric sports-medicine subspecialist is not known at this time.

*The author did not receive grants or outside funding in support of the research or preparation of this manuscript. He did not receive 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, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.

References

1. Stanitski CL. Correlation of arthroscopic and clinical examination with magnetic resonance imaging findings of injured knees in children and adolescents. Am J Sports Med. 1998;26:2-6.
2. Kocher MS, DiCanzio J, Zurakowski D, Micheli LJ. Diagnostic performance of clinical examination and selective magnetic resonance imaging in the evaluation of intraarticular knee disorders in children and adolescents. Am J Sports Med. 2001;29:292-6.