Commentary & Perspective

Commentary & Perspective on
"Diagnostic Accuracy of a New Clinical Test (the Thessaly Test) for Early Detection of Meniscal Tears"
by Theofilos Karachalios, MD, et al.

Commentary & Perspective by
James R. Andrews, MD, and Ryan Meis, MD*,
American Sports Medicine Institute, Birmingham, Alabama

Updated February 15, 2007

Although once considered a useless remnant of a leg muscle, the meniscus is now known to play a critical role in proper knee fitness and function¹. Injury to this fibrocartilaginous structure can have deleterious effects on both the occupations and avocations of those who are affected. Although the problem is common, establishing an accurate diagnosis can occasionally be elusive. Karachalios et al. have developed a new clinical test which can potentially improve our accuracy in effectively diagnosing this injury, thereby aiding our efforts to provide our patients with appropriate information regarding treatment options.

Meniscal tears are best diagnosed clinically, through a thoughtful history and a detailed physical examination. A multitude of different tests has been described^2,3, and it is important to note that there is not one single test that can be used without fail. Instead, an accurate diagnosis is best determined after performing several tests, assembling the information from these tests, and combining the results of testing with the complete patient history. Many times, the diagnosis is confirmed with findings that have been acquired from magnetic resonance imaging, which is a point of contention raised by the authors.

The authors have abandoned the use of magnetic resonance imaging for younger patients with isolated meniscal tears, instead relying strictly on the history and the findings of physical examination when making the decision to proceed with surgery or to continue with a nonoperative treatment program. They contend that the Thessaly test alone can be utilized to diagnose meniscal tears with an accuracy that rivals that achieved with magnetic resonance imaging. While their point is well taken that all physicians must assume responsibility for cost-containment and attempt to practice medicine in a fiscally responsible manner that is consistent with appropriate patient care, magnetic resonance imaging is an outstanding tool that offers stunning, noninvasive imaging of the knee. It is extraordinarily accurate and it is not uncommon that it can add insight into other pathologic processes not appreciated during the original examination. It is difficult to believe that any one single clinical test can have equal accuracy in diagnosing meniscal tears, and I believe that we need to continue to take advantage of this technology, when appropriate.

This study has been thoughtfully structured with well-selected exclusion criteria and a good interobserver and intraobserver reliability; this demonstrates reproducibility amongst practitioners. The foundation of the Thessaly test is essentially stressing the meniscus in a manner that simulates the mechanism by which a tear is created. It seems to be relatively easy to perform and highly effective, based on the data provided by Karachalios et al. The underlying theory behind the test makes sense both biomechanically and intuitively. Again, any additional tool that can provide diagnostic information and assist in narrowing the differential diagnosis would seem to be worthwhile.

We have learned from past experience that the results of a particular physical-examination test that has been created and published by one author may not be reproducible in the hands of others. One need only to glance back at the multitude of tests for SLAP (superior labrum anterior posterior) tears to know that every test, when originally published, had outstanding sensitivity and specificity, only to be found much less reliable when tested by others⁴. This, of course, is meant as a word of caution only and is not intended to tarnish the results of this study.

The false positive rate documented for the Thessaly test is extraordinarily low in this study. One potential source of error not addressed is that of cartilaginous flaps on the femoral condyles, which often masquerade as a meniscal tear due to similar symptoms (effusion, occasional catching, and pain). The specific maneuvers required for this examination could certainly reproduce pain near the medial or lateral joint lines if an articular cartilage lesion was present. It would be interesting to see if the accuracy of the Thessaly test would hold up when challenged in this fashion. In addition, it is not inconceivable that patellofemoral symptomatology could be aggravated by this maneuver, leading to a false-positive test. Finally, I would avoid performing this test on patients with a known anterior cruciate ligament tear, as the pivoting maneuver could easily lead to a painful subluxation and creation of a new tear or extension of an existing one.

*The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They 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 authors are affiliated or associated.

References

1. Urquhart MW, O'Leary JA, Giffin JR, Fu FH. Meniscal injuries in the adult. In: DeLee JC, Drez D Jr, Miller MD, editors. Delee and Drez's orthopaedic sports medicine: principles and practice. 2nd ed. Volume 2. Philadelphia: Saunders; 2003. p 1668-86.
2. Evans PJ, Bell GD, Frank C. Prospective evaluation of the McMurray test. Am J Sports Med. 1993;21:604-8.
3. Tria AJ Jr. Clinical examination of the knee. In: Insall JN, Scott WN, editors. Surgery of the knee. 3rd ed. New York: Churchill Livingstone; 2001. p 161-74.
4. Fowler PJ, Lubliner JA. The predictive value of five clinical signs in the evaluation of meniscal pathology. Arthroscopy. 1989;5:184-6.

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