Utility of Magnetic Resonance Imaging Obtained Before Evaluation by the Hand Surgeon Curtis M. Henn, MD, Arnold-Peter Weiss, MD, and Edward Akelman, MD The objective of this study was to assess prospectively the utility of magnetic resonance imaging (MRI) obtained before evaluation by a hand surgeon. Over a 4-week period, the hand surgeon documented the type of imaging used in each encounter, which prereferral MRIs were useful, and if he agreed with the radiologist’s interpretation. Of 396 consecutive patients, 14 (4%) presented with an MRI. Of those MRIs, 10 were found to be useful. The hand surgeons agreed with the radiologist’s interpretation on 13 of the 14. Eleven patients presented with only an MRI, and 10 of those were helpful. In contrast, none (0 of 3) of the MRIs of patients who presented with both radiographs and an MRI were useful (p D .01). These results suggest that previous retrospective studies may be confounded by recall bias. The data support the selective ordering of MRIs by referring physicians; however, ordering more than one imaging modality is less likely to be helpful. ( Journal of Surgical Orthopaedic Advances 19(3):1 – 3, 2010) Key words: hand, imaging, MRI, prereferral
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expensive, tool used in the evaluation of many musculoskeletal diseases. It is a useful adjunct in the diagnosis of soft tissue and marrow pathology in the foot and ankle(1), the identification of shoulder pathology (2), and the prevention of unnecessary knee arthroscopies (3). It is also useful in the evaluation of a wide range of hand and wrist pathology, including carpal instability, triangular fibrocartilage disorders, ulnar impaction syndrome, distal radioulnar joint instability, fracture, avascular necrosis, tendonopathy, nerve entrapment syndromes, synovial abnormalities, and soft tissue masses (4–7). Despite the utility of MRI in these fields, several studies have questioned the usefulness of MRIs (8–11). In particular, it has been opined that many of the prereferral MRIs that are obtained before an evaluation by specialists in both foot and ankle surgery and shoulder surgery are not useful to the specialist (10, 11). Overutilization of MRI may conceivably apply to hand surgery patients as well. As MRI becomes increasingly accessible, physicians are able to use this
expensive and powerful imaging modality more frequently. It is possible that physicians may be using MRI as a screening tool, rather than an advanced diagnostic tool. The primary aim of this study was to determine prospectively the usefulness of MRIs in the diagnosis and treatment of hand and wrist pathology. The secondary aim was to determine the prevalence of prereferral MRIs and radiographs. We hypothesized that many of the prereferral MRIs are ultimately not useful in the diagnosis and treatment of hand and wrist pathology.
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Magnetic resonance imaging (MRI) is a powerful, yet
From Department of Orthopaedics, Warren Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI. Address correspondence to: Curtis Henn, MD, Hospital for Special Surgery, 310 East 71st Street, Apartment 2G, New York, NY 10021; e-mail:
[email protected]. Received for publication July 7, 2009; accepted for publication July 21, 2009. For information on prices and availability of reprints call 410-4944994 X226. 1548-825X/10/1903-0000$22.00/0 Copyright 2010 by the Southern Orthopaedic Association
Materials and Methods
A fellowship-certified orthopedic hand surgeon completed a brief anonymous survey after every patient encounter. The study included all of the patients seen by either of two hand surgeons at our institution over a 4week period. The survey identified the type of imaging presented by each patient and any imaging the hand surgeon ordered. The survey indicated which MRIs were useful in the diagnosis or treatment planning and if the surgeon agreed with the radiologist’s interpretation of the MRI. This study was approved by our Institutional Review Board. The recorded results were then used to determine 1) the number of patients who presented with an MRI and/or radiographs, 2) the percentage of MRIs that were useful in the diagnosis or treatment, 3) the number of patients who had an MRI ordered by the hand surgeon, and 4) the VOLUME 19, NUMBER 3, FALL 2010
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Of the 14 MRIs that were obtained before the evaluation by the hand surgeon, 10 were deemed useful. All 10 of these MRIs were useful in the diagnosis of the patient, while 6 were useful in both diagnosis and treatment planning. Nearly all (10 of 11) of the patients who presented to the specialist with an MRI without radiographs had useful MRIs. In contrast, none (0 of 3) of the patients who presented with both an MRI and radiographs had useful MRIs. This difference was statistically significant (p D .01). The specialist agreed with the radiologist’s interpretations in 13 of the 14 prereferral MRIs. The one case in which the specialist did not agree with the radiologist was the only patient who presented with only an MRI that was then deemed not useful. Of the 396 patient encounters, 263 (66%) did not involve either radiographs or MRI, while 108 (27%) of the patient encounters involved only radiographs. A total of 58 (15%) patients presented with some form of imaging before the evaluation by the hand surgeon, with 48 (12%) presenting with radiographs, 11 (3%) presenting with MRIs, and 3 (1%) presenting with both radiographs and MRIs. Of the 382 patients who did not have an MRI before presentation to the specialist, 11 (3%) had an MRI ordered by the hand surgeon. No patient who presented with an MRI had a second MRI ordered.
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Results
20 fractures, and found that up to 87% of the prereferral MRIs were unnecessary (10). Studies in hand surgery also have questioned the clinical utility of MRI in certain subsets of patients. Sullivan and Berquist showed that in a series of 24 patients with trauma-related pain and dysfunction in the hand, wrist, or forearm, MRI altered the management of only 29% of patients (12). Furthermore, Kato et al. suggested that even high-resolution MRI is unsatisfactory in the diagnosis of tears in the triangular fibrocartilage (13). Our novel results may be secondary to two fundamental differences in study design. First, our study was prospective, while previous studies were retrospective. Recall bias may have skewed the results of earlier studies to support their hypotheses. Second, our study did not exclude subsets of patients. In particular, chronic problems may be less likely than acute problems to benefit from an MRI. Excluding acute problems, such as fractures, may effectively decrease the reported usefulness of MRIs. Every patient who presented to the specialist in our study with both an MRI and radiographs were found to have unnecessary MRIs. These cases may be more chronic than the cases that received only one type of imaging. These patients may have had particularly challenging cases that the referring physician felt required both imaging modalities, or the physician ordered radiographs and then ordered an MRI after radiographs were inconclusive. Certain referring physicians may also be ordering a battery of inappropriate imaging. Regardless of the explanation, our results indicate that more research should be directed toward the relationship between the type of imaging that a patient presents with and the subsequent usefulness of that imaging. The present study suggests that our specialists often agree with the radiologist on the interpretation of the MRI. This may be a function of highly experienced radiologists at our institution. It may also be an indication of the detail that is possible with MRI of the hand and wrist, such that radiologists are able to identify pathology that corresponds with the specialist’s interpretation. The one MRI on which the specialists disagreed with the radiologist was found to be not useful. Our study contains several inherent weaknesses. The narrow scope limits the external validity of the study, and the hand surgeons who completed the surveys were aware of the hypothesis. However, lack of blinding should skew the results to support the hypothesis that the majority of prereferral MRIs are not useful. The present study did not include the MRI findings, the final diagnoses, and the referring physician’s specialty, all of which may be related to the usefulness of the MRI. Physicians may be more likely to refer patients with positive MRIs, and the difficulty in evaluating pathology with MRI varies with
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amount of agreement between the hand surgeon and the radiologist on the interpretations of the MRIs.
Discussion
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The goals of the present study were to determine prospectively the usefulness of MRIs in the diagnosis and treatment of hand and wrist pathology and to determine the prevalence of prereferral MRIs and radiographs. Our study of 396 consecutive patients shows that while MRI usage is relatively infrequent in hand surgery, nearly 75% of MRIs that are ordered before evaluation by the hand specialist are useful in the diagnosis of the patient. These results are contrary to those of the only two previous studies, to our knowledge, that have evaluated the clinical utility of prereferral MRIs. Bradley et al. retrospectively reviewed 104 patients with chronic, atraumatic shoulder pain and found no statistically significant differences in outcomes between patients who received prereferral MRIs and patients who did not (11). Similarly, Tocci et al. retrospectively reviewed 201 consecutive patients who presented to a foot and ankle specialist, excluding 2
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References
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1. Hochman, M. G., Min, K. K., Zilberfarb, J. L. MR imaging of the symptomatic ankle and foot. Orthop. Clin. North Am. 28(4):659 – 683, 1997. 2. Iannotti, J. P., Zlatkin, M. B., Esterhai, J. L., et al. Magnetic resonance imaging of the shoulder. Sensitivity, specificity, and predictive value. J. Bone Joint Surg. 73-A(1):17 – 29, 1991. 3. Bui-Mansfield, L. T., Youngberg, R. A., Warme, W., et al. Potential cost savings of MR imaging obtained before arthroscopy of the knee: evaluation of 50 consecutive patients. Am. J. Roentgenol. 168(4):913 – 918, 1997. 4. Steinbach, L. S., Smith, D. K. MRI of the wrist. Clin. Imaging 24(5):298 – 322, 2000.
5. Potter, H. G., Asnis-Ernberg, L., Weiland, A. J., et al. The utility of high-resolution magnetic resonance imaging in the evaluation of the triangular fibrocartilage complex of the wrist. J. Bone Joint Surg. 79-A(11):1675 – 1684, 1997. 6. Zlatkin, M. B., Greenan, T. Magnetic resonance imaging of the wrist. Magn. Reson. Q. 8(2):65 – 96, 1992. 7. Zlatkin, M. B., Chao, P. C., Osterman, A. L., et al. Chronic wrist pain: evaluation with high-resolution MR imaging. Radiology 173(3):723 – 729, 1989. 8. Torstensen, E. T., Hollinshead, R. M. Comparison of magnetic resonance imaging and arthroscopy in the evaluation of shoulder pathology. J. Shoulder Elbow Surg. 8(1):42 – 45, 1999. 9. Wnorowski, D. C., Levinsohn, E. M., Chamberlain, B.C., et al. Magnetic resonance imaging assessment of the rotator cuff: is it really accurate? Arthroscopy 13(6):710 – 9, 1997. 10. Tocci, S.L., Madom, I.A., Bradley, M.P., et al. The diagnostic value of MRI in foot and ankle surgery. Foot Ankle Int. 28(2):166 – 168, 2007. 11. Bradley, M. P., Tung, G., Green, A. Overutilization of shoulder magnetic resonance imaging as a diagnostic screening tool in patients with chronic shoulder pain. J. Shoulder Elbow Surg. 14(3):233 – 237, 2005. 12. Sullivan, P. P., Berquist, T. H. Magnetic resonance imaging of the hand, wrist, and forearm: utility in patients with pain and dysfunction as a result of trauma. Mayo Clin. Proc. 66(12):1217 – 1221, 1991. 13. Kato, H., Nakamura, R., Shionoya, K., et al. Does high-resolution MR imaging have better accuracy than standard MR imaging for evaluation of the triangular fibrocartilage complex? J. Hand Surg. 25B(5):487 – 491, 2000.
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diagnosis and the joint involved. Primary care physicians and general orthopedists may have different thresholds for ordering MRIs and referring to hand surgeons. This study is the first study, to our knowledge, to evaluate prospectively the usefulness of prereferral MRIs. Contrary to the hypothesis that many prereferral MRIs are superfluous, the present study suggests that most of these MRIs are useful to the specialist. While future studies are necessary to confirm these findings, this study supports the selective ordering of MRIs by referring physicians, but ordering more than one imaging modality is less likely to be useful.
Copyright 2010 by the Southern Orthopaedic Association
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