Firstly, we would like to thank Mr.White, FACS, for his comments concerning our paper. We have read his comments carefully and our detailed response is as follows:

We consider the test positive when the patient experiences either medial or lateral joint line discomfort or a sense of locking or catching. Generally speaking with this test we provoke or reproduce patient’s symptoms and, in our opinion, this is a precise end point for the test.

Due to the fact that the test is performed while keeping the foot firmly on the ground, the whole body above the knee is either externally or internally rotated (rotation of the femur and the torso in relation to the tibia). As a consequence of this, we consider that the test is performed in external rotation when the whole body moves externally and vice versa. In this respect, the figures are correct. Of course, one can argue that external or internal rotation at the knee joint refers to the rotation of the tibia in relation to the femur. We have already replied to a similar comment which Mr White has not obviously read (see our reply to Dr Harvey R. Manes’s letter to the Editor at www.jbjs.org)concerning fig. 1-E, Mr White is correct. This is an error noted by us when the proofs were corrected. However, we do not think that that this error reduces the strength of our study.

We have stated clearly in our manuscript that the reason that this test reproduces a patient’s symptoms, in our opinion, is the development of hoop stress at the intact peripheral rim of the torn meniscus (which is innervated) while loading at 20 degrees of flexion and not because of the application of direct pressure on the torn parts of the meniscus which have no nerve endings. Furthermore, when you design a study in order to evaluate the diagnostic accuracy of a method, you have to keep the diagnosis as a standard; otherwise true positive, true negative, false positive and false negative values can not be determined (Altman Practical statistics for medical research 1993). This is a basic knowledge of statistical analysis which Mr White ignores. In order to evaluate the diagnostic accuracy of the test in other possible diagnoses, such as degenerative meniscal lesions, early osteoarthritis and chondral defects, another study has been designed and is currently under way in our department. We have already informed, without being asked, the readers of the Journal about this new study in our reply to Dr Manes. We do believe that Mr White’s comments concerning our paper are unfair due to the lack of understanding of the pathomechanics of the test and due to ignorance of basic statistical principles.

Th. Karachalios, MD Associate Professor in Orthopaedics University of Thessalia, Hellenic Republic

In the paper “Diagnostic Accuracy of a New Clinical Test (The Thessaly Test) for Early Detection of Meniscal Tears” (2005;87-A:955-962), Dr. Karachalios and his colleagues illustrate a functional load bearing test for torn menisci but I have concerns about the method, the description, and the specificity of the test. The method describes a positive result as “medial or lateral joint line discomfort and a sense of locking or catching”. This is a very imprecise end point, for instance, what if a patient has a sense of discomfort but no locking or has catching but only mild or no discomfort?

Secondly, the authors in fig 1-C clearly show internal rotation of the knee and yet the caption description is of a manoeuvre involving external rotation. Similarly, in fig 1-D where the limb is clearly photographed in external rotation they describe the manoeuvre as internal rotation. This is contrary to standard practise where the direction of rotation refers to the position of the distal bone(1,2,3,4).

Confusion is reinforced by the illustration fig 1-E describing the Thessaly test at 5° of flexion. Any reader can see that the knee illustrated is in at least 15° of knee flexion.

Nor is the test convincing from a physiological stand point. The natural history of medial meniscus tearing is damage to the posterior third which comes under the highest load in weight bearing flexion. It is therefore logical to provoke pain in a medial meniscal tear with the knee in high flexion, not as the authors describe at 5 to 20° of flexion. Now, the most common alternative diagnosis to medial meniscal tearing in this age group (18 to 56 years) is medial femoral condylar damage, including osteochondritis dissecans, chondral injury, and early osteoarthritis. These conditions most commonly involve the anteromedial segment of the femur which is in contact with the tibia at 20° of weight bearing flexion, which is precisely the angle of which the Thessaly test would be expected to provoke pain in the illustration 1-A. Strangely, these diagnostic categories have been excluded from the study. Thus, the specificity referred to in table II is spurious. I wish the dance routine so beautifully illustrated was true for it would provide welcome relieve in an out-patient clinic but I think the test would shed very little light on the patient’s pathology.

References

1. Servant, C and Purkiss, S. “Examination Schemes in General Surgery and Orthopaedics”. Greenwich Medical Media Limited, Oxford University Press ISBN: 1900151 383, London, 1999, page 81.

2. Onbregt, L, Bishop, P. “Atlas of Orthopaedic Examination of the Peripheral Joints”. W B Saunders. Edinburgh. London. New York. Philadelphia. St Louis etc. 1999, page 104.

3. McRae, R. “Clinical Orthopaedic Examination”. Churchill Livingstone. Second Edition. Edinburgh, London, Melbourne & New York. 1983, page 150.

4. Solomon L, Warwick D, Nayagan S. Apley’s Concise System of Orthopaedics and Fractures. Hodder Arnold, London. Third Edition 2005, page 204.

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Firstly, we would like to thank Dr. Manes for his comments concerning our paper. We have looked carefully at the figures of the paper. Due to the fact that the test is performed while keeping the foot firmly on the ground, the whole body above the knee is either externally or internally rotated (rotation of the femur and the torso in relation to the tibia) . As a consequence of this, we consider that the test is performed in external rotation when the whole body moves externally and vice versa. In this respect the figures are correct. Of course one can argue that external or internal rotation at the knee joint refers to the rotation of the tibia in relation to the femur.

We would also like to take the opportunity to inform the readers of the Journal that we are currently evaluating the diagnostic accuracy of the Thessaly test in diagnosing degenerative meniscal lesions and the effect of chondral and patellofemoral joint disorders on its diagnostic abilities.

Th. Karachalios, M.D.

Associate Professor in Orthopaedics, University of Thessaly

To the Editor:

I especially enjoyed reading this article and will apply the Thessaly test in the examination of my knee-injured patients immediately. However there are two pictures that are improperly labelled with regard to the internal and external rotation testing for meniscal tears. Fig. 1-C depicts the tibia in internal rotation but is improperly labelled external rotation. Similarly, Fig. 1-D depicts the tibia rotated in external rotation but is labelled internal rotation. Aside from the mislabelling, the article decribes an important addition to the clinical examination of the injured knee.