Validity of the Thessaly Test in Evaluating Meniscal ...

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PJOTR GOOSSENS, PT, MT, MSc1,2 • ELLEN KEIJSERS, PT2,4 • RUTGER J.C. VAN GEENEN, MD, PhD3 • ANDRÉ ZIJTA, PT, MT, MSc1 MAARTEN VAN DEN BROEK, PT, MT, MSc1 • ARIANNE P. VERHAGEN, PT, MT, PhD2,4 • GWENDOLIJNE G.M. SCHOLTEN-PEETERS, PT, MT, PhD2,4,5

Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on August 30, 2015. For personal use only. No other uses without permission. Copyright © 2015 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.

Validity of the Thessaly Test in Evaluating Meniscal Tears Compared With Arthroscopy: A Diagnostic Accuracy Study

K

nee pathologies are highly prevalent, and there is a 45% lifetime chance of developing knee pain.12 About 50% of patients with knee pathologies in primary care consult a medical specialist or physical therapist within 1 year after the onset of their symptoms. In the Netherlands, the incidence of knee pathologies in general practice is about 13.7 per 1000 people per year, with a yearly TTSTUDY DESIGN: Diagnostic accuracy study. TTOBJECTIVE: To evaluate the diagnostic ac-

curacy of the Thessaly test compared with an arthroscopic examination in patients with suspected meniscal tears.

TTBACKGROUND: The Thessaly test was intro-

duced to improve the diagnostic accuracy of the clinical examination in detecting meniscal tears. This test appears to be a valuable alternative to other meniscal clinical tests usually performed, but additional diagnostic accuracy data are required.

TTMETHODS: Patients with suspected menis-

cal tears, referred to a hospital for arthroscopic surgery, were eligible. The Thessaly test alone and the combination of the Thessaly and McMurray tests were considered as index tests, and arthroscopy was used as the reference test. Experienced physical therapists performed the Thessaly test at 20° of flexion and the McMurray test for both knees. The physical therapist was blinded to patient information, the affected knee, and the results from possible earlier diagnostic imaging. An orthopaedic surgeon blinded to the clinical test

results from the physical therapist performed the arthroscopic examination.

TTRESULTS: A total of 593 patients were included, of whom 493 (83%) had a meniscal tear, as determined by the arthroscopic examination. The Thessaly test had a sensitivity of 64% (95% confidence interval [CI]: 60%, 68%), specificity of 53% (95% CI: 43%, 63%), positive predictive value of 87% (95% CI: 83%, 90%), negative predictive value of 23% (95% CI: 18%, 29%), and positive and negative likelihood ratios of 1.37 (95% CI: 1.10, 1.70) and 0.68 (95% CI: 0.59, 0.78), respectively. The combination of positive Thessaly and McMurray tests showed a sensitivity of 53% and specificity of 62%.

TTCONCLUSION: The results of the Thessaly test alone or combined with the McMurray test do not seem useful to determine the presence or absence of meniscal tears. TTLEVEL OF EVIDENCE: Diagnosis, level 2b.

J Orthop Sports Phys Ther 2015;45(1):18-24. Epub 24 Nov 2014. doi:10.2519/jospt.2015.5215

TTKEY WORDS: knee, McMurray, meniscus, sensitivity, specificity

prevalence of 19 per 1000 people.7 Meniscal tears are one of the most SUPPLEMENTAL common knee injuries VIDEO ONLINE in the Netherlands, and their incidence is estimated to be 3 per 1000 in men and 1 per 1000 in women.7 Approximately 25% of knee surgeries address meniscal tears.12 Meniscal tears are often seen in athletes as a result of a sports injury14 and represent about 15% of all sports injury cases.12 In addition to tears occurring in sports, osteoarthritis can also lead to a spontaneous meniscal tear through breakdown and weakening of the meniscal structure.8 In turn, meniscal tears are a risk factor for subsequent development and progression of knee osteoarthritis.8 Meniscal tears usually occur due to loaded rotational movement during knee extension. Possible risk factors for meniscal tears are sports, older age, male sex, and pre-existing pathologies such as osteoarthritis.30 Common symptoms of meniscal tears are pain (92%), discomfort (95%), swelling (56%), a clicking sound (47%), and locking of the knee (12%).11,18,31 Diagnosing meniscal tears in clinical practice requires detailed history taking and physical examination.12 Clinical tests often

Department of Physiotherapy, Amphia Hospital, Breda, the Netherlands. 2Diagnostics Research Group, Department of Physical Therapy, Avans University of Applied Sciences, Breda, the Netherlands. 3Department of Orthopaedic Surgery, Amphia Hospital, Breda, the Netherlands. 4Department of General Practice, Erasmus University Medical Center, Rotterdam, the Netherlands. 5Research Institute MOVE, Faculty of Human Movement Sciences, VU University, Amsterdam, the Netherlands. The local medical ethical committee of the Elisabeth Hospital in Tilburg, the Netherlands approved the protocol for this study. This study was funded by the Scientific College of Physiotherapy of the Royal Dutch Society for Physical Therapy. The authors certify that they have no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article. Address correspondence to Ellen Keijsers, ATTN: Gwendolijne G.M. Scholten-Peeters, PO Box 90116, 4800 RX, Breda, the Netherlands. E-mail: [email protected] t Copyright ©2014 Journal of Orthopaedic & Sports Physical Therapy® 1

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used in the diagnosis of meniscal tears include the McMurray test, the joint-line tenderness test, and the Apley test.12 The McMurray test has a reported sensitivity ranging from 16%26 to 70%12 and specificity ranging from 59%31 to 97%.21 The sensitivity of the joint-line tenderness test ranges from 55% to 85%,21 with a specificity of 15%31 to 97%.26 The Apley test, which is less often applied, has a sensitivity ranging from 13%21 to 60%12 and a specificity ranging from 70%12 to 93%.26 In all these diagnostic accuracy studies, arthroscopy was used as the reference test. Arthroscopy is considered the reference standard in diagnosing meniscal tears.9,24,29 A less-invasive diagnostic tool, magnetic resonance imaging, is also often used. A systematic review found magnetic resonance imaging to have an accuracy, sensitivity, and specificity of 86%, 91%, and 81%, respectively, for diagnosing medial meniscal tears and 89%, 76%, and 93% for diagnosing lateral tears.5 The authors5 stated that magnetic resonance imaging is the most appropriate screening tool before diagnostic arthroscopy. Based on the results of a previously published review of diagnostic test accuracy, the methodological quality of studies investigating the diagnostic accuracy of meniscal tests was poor, and the studies were highly heterogeneous.28 The authors28 also concluded that these tests were of little diagnostic value in clinical practice. However, combining the results of various tests might improve the diagnostic accuracy of physical examination in detecting a meniscal tear.2,28 A systematic review reported 77% sensitivity and 91% specificity for diagnosing meniscal tears when using a composite examination (several meniscal tests).31 This is consistent with another systematic review that found a composite examination for meniscal tears to perform much better than any clinical test used in isolation.26 In 2005, the Thessaly test was introduced as a potentially useful clinical test to detect meniscal tears.17 In contrast to all the previously used tests, the Thessaly test is performed in a loaded, weight-

bearing position with the knee at 20° of flexion. In the original study, using magnetic resonance imaging as the reference test, the Thessaly test was found to have a sensitivity of 89% for the medial meniscus and 92% for the lateral meniscus.17 More recently, Harrison et al11 found high diagnostic accuracy (sensitivity, 90.3%; specificity, 97.7%) for the Thessaly test, whereas Mirzatolooei et al23 reported more modest sensitivity (79%) and specificity (40%) values. In the latter study, the authors23 combined anterior cruciate ligament tears and meniscal tears. Both studies used arthroscopy as the reference test.11,23 Based on these data and because earlier meniscal tests have shown generally poor diagnostic accuracy values, the Thessaly test seems to be a potentially valuable clinical test to help identify meniscal tears. The high incidence of meniscal tears, the low validity of the currently used meniscal tests, and the promising (but uncertain) validity of the Thessaly test indicate the need for further study. Therefore, the aim of this study was to assess the diagnostic accuracy of the Thessaly test, alone or in combination with the McMurray test, compared with arthroscopy in patients with potential meniscal tears.

METHODS Patient Population

B

etween May 2010 and November 2012, we recruited patients (age, 18 years or older) with a knee pathology possibly due to a meniscal tear, who were referred for an arthroscopic examination at the orthopaedic surgery clinic of the Amphia Hospital in Breda and Oosterhout, the Netherlands. We excluded those who had knee surgery in the previous 3 months and patients with neurological disorders, such as multiple sclerosis, Parkinson’s disease, or a stroke. Recruitment was conducted by written and verbal invitation. The local medical ethical committee of the Elisabeth Hospital in Tilburg approved the protocol

of the study. All participants signed an informed-consent form.

Index Tests For each patient, the 2 index tests (the Thessaly test at 20° of knee flexion and the McMurray test) were performed by 1 of 7 experienced physical therapists who participated in the study, using a strict protocol (ONLINE APPENDIX, ONLINE VIDEO). Because the McMurray test may influence the performance and interpretation of the Thessaly test, the latter was performed first. Both knees were tested to blind the physical therapists to which knee was affected. Furthermore, the right knee was always tested first, irrespective of whether this was the affected knee. Only data from the affected knee were used in the data analysis. The Thessaly test was considered positive when the patient experienced discomfort/pain at the medial or lateral tibiofemoral joint line. Also, locking, catching, or a feeling of giving way experienced by the patient was considered a positive test.17 Positive test criteria for the McMurray test were pain and/or a clicking sensation.3

Reference Test Arthroscopy was used as a reference test for meniscal tears. In total, 10 experienced orthopaedic surgeons specializing in knee pathologies and working in the Amphia Hospital in Breda and Oosterhout performed the arthroscopic procedures. Unlike the clinical tests, which were performed bilaterally, surgery was only performed on the affected knee.

Test Procedure After signing an informed-consent form, patients completed a short questionnaire to report general information and kneespecific information, such as pain, swelling, locking, clicking, giving way, and any trauma or previous surgery. Completion of the questionnaire was followed by the 2 clinical tests, performed by one of the physical therapists participating in the study, then the arthroscopy. The clinical test procedure took approximately

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Patients recruited, n = 602 Patients excluded due to age less than 18 y, n = 9 Included patients, n = 593 Index test 1: Thessaly test


Positive, n = 361

Missing values, n=3 Negative, n = 228

Index test 2: McMurray test Positive, n = 398

Missing values, n=2 Negative, n = 192

Reference standard: arthroscopy

Positive, n = 493

Negative, n = 100

FIGURE. Flow diagram of patients throughout the study.

10 minutes. The time between the index tests and reference test was a maximum of 2 hours; consequently, patients received no treatment between all test procedures. Data derived from the questionnaire, the 2 index tests, and the arthroscopy were recorded on a standard data-collection form.

Blinding To minimize bias as much as possible, patients were instructed not to reveal any information to the physical therapist about the expected diagnosis, extent of the lesion, and which knee was affected. At the time of testing, the physical therapists could not be blinded to the physical appearance of the knee. However, features such as swelling, muscle atrophy, and discoloration are not unique to meniscal tears. The orthopaedic surgeon performing the arthroscopy was blinded to the results of the questionnaire and clinical tests performed by the physical therapist.

Statistical Analyses Data were analyzed using SPSS Version

20 (SPSS Inc, Chicago, IL). To calculate diagnostic accuracy, the results of the Thessaly test, the McMurray test, and both tests combined were plotted in 2-by2 tables against the results of arthroscopy. A positive score for the combination of tests was a positive result for both the Thessaly test and the McMurray test. The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio (+LR), negative likelihood ratio (–LR), diagnostic odds ratio (DOR), and overall accuracy (with 95% confidence intervals [CIs]) were calculated using the website www.vassarstats. net and SPSS Version 20. Definitions and explanations for each of these terms can be found in the literature.15

RESULTS Patient Characteristics

T

he FIGURE shows the flow of patients through the study. A total of 602 patients were recruited, of whom 9 were excluded because they were younger than 18 years of age, leaving 593 patients (mean  SD age, 49.4

]  13.8 years) to be included in the study (TABLE 1). Based on the findings of the arthroscopic examination, 493 (83%) patients had a meniscal tear (medial and/ or lateral meniscus), of whom 346 (70%) had a tear in the medial meniscus, 81 (16%) had a tear in the lateral meniscus, and 66 (13%) had both medial and lateral meniscal tears. Five patients had missing values for the clinical tests (3 patients for the Thessaly test and 2 for the McMurray test), due to inability to test the knee (1 patient for the Thessaly test) and unexplained missing information (2 patients for the Thessaly test, 1 patient for the McMurray test, and 1 patient for both tests combined). Consequently, 5 patients who had no results for the 2 tests combined were excluded from the analysis of the combined tests. No adverse events were reported from either of the 2 index tests. After arthroscopy, 578 patients (97%) were diagnosed with diverse knee pathologies, ranging from corpus librum to a meniscal tear combined with osteoarthritis, and 3% had no pathology. Of all patients, 25% had a meniscal tear without reported comorbidity. Multiple knee pathologies, including meniscal tears, were found in 58% of the patients (leaving 14% of patients with other knee pathologies without a meniscal tear).

Diagnostic Accuracy TABLE 2 presents the results of the 2-by-2 tables and TABLE 3 lists the accuracy values

for the 2 tests separately and combined. Overall, the Thessaly test seemed less sensitive (64% versus 70%) but more specific (53% versus 45%) than the McMurray test. However, these differences were not statistically significant. The Thessaly test demonstrated a +LR of 1.37 (95% CI: 1.10, 1.70) and positive predictive value of 87% (95% CI: 83%, 90%). The +LR indicates that a positive Thessaly test result is 1.37 times more likely to be expected in a patient with a meniscal tear compared to a patient without a meniscal tear. For the McMurray test, a +LR of 1.27 (95% CI:



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1.06, 1.53) and positive predictive value of 86% (95% CI: 82%, 89%) were found. To determine the diagnostic accuracy of the McMurray and Thessaly tests combined, 2 separate calculations were made: (1) a combined positive test result versus at least 1 negative test result, and (2) a combined negative test result versus at least 1 positive test result. Compared with the isolated tests, a positive result for both the Thessaly and McMurray tests did not statistically significantly improve the sensitivity, specificity, positive predictive value, and +LR (sensitivity, 53%; 95% CI: 48%, 57%; positive predictive value, 87%; 95% CI: 83%, 91%; specificity, 62%; 95% CI: 52%, 71%; +LR = 1.39; 95% CI: 1.06, 1.80). Combining negative test results for the Thessaly and McMurray tests showed an increase in sensitivity to 82% (specificity, 36%). The smallest –LR value was found for the combined negative tests (–LR = 0.51; 95% CI: 0.41, 0.64), with a negative predictive value of 29% (95% CI: 21%, 37%). Using the 83% pretest probability of the presence of a meniscal tear, the posttest probability for a positive finding was most significantly altered using the Thessaly test (posttest probability: positive predictive value, 87%). Therefore, with a positive Thessaly test, the shift in probability of the presence of a meniscal tear was 4%: 83% pretest to 87% posttest. Combining 2 positive clinical examination tests did not improve the posttest probability. When medial and lateral tears were considered separately, a positive Thessaly test caused a shift in probability from pretest to posttest of 69% to 72% and 25% to 26%, respectively. The overall accuracy is the proportion of patients who are correctly identified by the index test results. In this study, the overall accuracy was 62% for the Thessaly test when considered in isolation and 54% when both the Thessaly and McMurray tests were positive. The DOR is a single indicator of test performance combining +LR and –LR (+LR/–LR). For the Thessaly test, the DOR was 2.02, and for the combined positive tests the DOR was 1.82.

TABLE 1

Patient Characteristics*

Characteristic

Participants (n = 593)

Sex (female)

252 (42.5)

Mean  SD age, y

49.4  13.8

Affected knee Left

279 (47)

Right

314 (53)

Pain

579 (98)†

Discomfort

571 (97)‡

Swelling

388 (66)‡

Click

404 (69)‡

Locking

231 (39)‡

Giving way

339 (58)‡

Trauma

277 (47)

Previous operation

222 (37)

Magnetic resonance imaging performed

318 (54)

*Values are n (%) unless otherwise indicated. † 2 missing values. ‡ 3 missing values.

TABLE 2

Cross-tabulations of the Thessaly Test, the McMurray Test, and the 2 Tests Combined Versus Arthroscopy Arthroscopy Positive

Arthroscopy Negative

Thessaly positive

314

47

Total 361

Thessaly negative

175

53

228

Total

489

100

589*

McMurray positive

343

55

398

McMurray negative

147

45

192

Total

490

100

590† 295

Both tests positive

257

38

Combined negative‡

231

62

293

Total

488

100

588§

Combined positive‖

398

64

462

Both tests negative

90

36

126

488

100

588§

Total

*3 missing values and 1 patient not tested due to inability to test the knee. † 2 missing values and 1 patient not tested due to inability to test the knee. ‡ At least 1 test result negative. § 5 patients (of whom 1 was not tested due to inability to test the knee) did not have valid results for both tests combined and were excluded from the combined-test analysis. ‖ At least 1 test result positive.

DISCUSSION

I

n a population of 593 patients with a knee pathology referred for arthroscopic evaluation based on the

suspicion of a meniscal tear, 83% were diagnosed with a meniscal tear based on arthroscopic examination. The Thessaly and McMurray tests showed comparable diagnostic accuracy when used in isola-



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[ TABLE 3

research report

Validity of the Thessaly Test, the McMurray Test, and the 2 Tests Combined*

Prevalence, %

Medial Meniscus (n = 412)

Lateral Meniscus (n = 147)

Medial and/or Lateral Meniscus (n = 493)

69 (65, 73)

25 (22, 29)

83 (80, 86)


Thessaly test (n = 589)† Sensitivity, %

64 (59, 69)

64 (56, 72)

64 (60, 68)

Specificity, %

45 (37, 52)

40 (35, 44)

53 (43, 63)

PPV, %

72 (67, 77)

26 (22, 31)

87 (83, 90)

NPV, %

36 (29, 42)

77 (71, 82)

23 (18, 29)

+LR

1.16 (1.00, 1.35)

1.06 (0.92, 1.22)

1.37 (1.10, 1.70)

–LR

0.81 (0.70, 0.93)

0.91 (0.73, 1.14)

0.68 (0.59, 0.78)

DOR

1.44

1.16

2.02

Accuracy, %

58

46

62

Sensitivity, %

69 (65, 74)

72 (64, 79)

70 (66, 74)

Specificity, %

37 (30, 44)

34 (30, 39)

45 (35, 55)

PPV, %

71 (67, 76)

26 (22, 31)

86 (82, 89)

McMurray test (n = 590)‡

34 (28, 42)

79 (72, 84)

23 (18, 30)

+LR

NPV, %

1.09 (0.96, 1.24)

1.09 (0.97, 1.23)

1.27 (1.06, 1.53)

–LR

0.84 (0.71, 0.99)

0.83 (0.63, 1.08)

0.67 (0.57, 0.78)

DOR

1.30

1.32

1.91

Accuracy, %

59

43

66

Combined positive tests (n = 588)§ Sensitivity, %

52 (47, 57)

55 (47, 64)

53 (48, 57)

Specificity, %

54 (46, 61)

52 (47, 56)

62 (52, 71) 87 (83, 91)

PPV, %

72 (66, 77)

27 (23, 33)

NPV, %

33 (28, 39)

78 (73, 82)

21 (17, 26)

+LR

1.13 (0.94, 1.35)

1.15 (0.96, 1.36)

1.39 (1.06, 1.80)

–LR

0.89 (0.80, 1.00)

0.86 (0.72, 1.04)

0.76 (0.69, 0.85)

DOR

1.26

1.33

1.82

Accuracy, %

53

53

54

Sensitivity, %

81 (77, 85)

80 (73, 86)

82 (78, 85)

Specificity, %

28 (22, 35)

22 (18, 25)

36 (27, 46)

PPV, %

72 (68, 76)

25 (22, 30)

86 (83, 89)

NPV, %

40 (31, 49)

77 (69, 84)

29 (21, 37)

+LR

1.13 (1.02, 1.25)

1.03 (0.93, 1.13)

1.27 (1.09, 1.48)

–LR

0.67 (0.53, 0.84)

0.91 (0.64, 1.27)

0.51 (0.41, 0.64)

DOR

1.68

1.13

2.49

Accuracy, %

65

36

85

Combined negative tests (n = 588)§

Abbreviations: DOR, diagnostic odds ratio; –LR, negative likelihood ratio; +LR, positive likelihood ratio; NPV, negative predictive value; PPV, positive predictive value. *Values in parentheses are 95% confidence interval. † 3 missing values and 1 patient not tested due to inability to test the knee. ‡ 2 missing values and 1 patient not tested due to inability to test the knee. § 5 patients (of whom 1 was not tested due to inability to test the knee) did not have results for both tests combined and were excluded from the combined-test analysis.

tion. Having a positive test result for both clinical tests did not increase diagnostic accuracy. In a setting where patients are

referred for arthroscopic examination, identifying patients who are unlikely to have a meniscal tear would reduce the

] amount of unnecessary arthroscopies. Despite the reasonably high sensitivity (82%) of the combined negative Thessaly and McMurray tests, this combination is not suitable to rule out the presence of a meniscal tear. The power of the tests to rule out a meniscal tear depends on sensitivity and is reduced by low specificity.25 The high prevalence of meniscal tears in this study could lead to an overestimation of sensitivity.20 Besides, the –LR (0.51) indicates that the shift from pretest to posttest probability is small and of a rarely important degree.16

Comparison With Other Studies Studies on the diagnostic accuracy of the Thessaly test are highly heterogeneous.28 The original study found high sensitivity and specificity for both medial (sensitivity, 89%; specificity, 97%) and lateral (sensitivity, 92%; specificity, 96%) menisci.17 More recently, another study also found high diagnostic accuracy (sensitivity, 90.3%; specificity, 97.7%).11 The present study found lower sensitivity and specificity values for the Thessaly test when compared with earlier studies.11,12,17 However, the results are similar to those of a previous study reporting a high prevalence of meniscal injuries (sensitivity medial, 68%; sensitivity lateral, 89%).18 Mirzatolooei et al23 also found a lower sensitivity (79%) and specificity (40%) in a population with combined meniscal and anterior cruciate ligament injury. A meta-analysis examined pooled sensitivity and specificity for the McMurray test (sensitivity, 70%; specificity, 71%), the Apley test (sensitivity, 60%; specificity, 70%), and the joint-line tenderness test (sensitivity, 63%; specificity, 77%).12 These authors12 concluded that these tests are not diagnostically accurate when used in isolation. Due to lack of data, the pooled sensitivity and specificity could not be examined for the Thessaly test.12 This study shows comparable diagnostic accuracy for the Thessaly test used in isolation compared with the pooled sensitivity and specificity of the other meniscal tests.



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This study used a modified version of the McMurray test. It has been shown that the modified McMurray test has better diagnostic accuracy than its original version.1,12,22 Nevertheless, various systematic reviews have consistently reported higher sensitivity and specificity values for the McMurray test than those found in the present study.21,22,28 Data on the diagnostic accuracy of the McMurray test vary considerably, presumably due to differences in study design and performance and interpretation of the test.21,22,28 In the present study, the considerable amount of false-positive results for the McMurray test might be explained by the way the test was interpreted. In this study, pain and/or clicking were used as positive test criteria, as is the case in other diagnostic studies.1,10,27 In contrast, other groups used the original description of the McMurray test, where only a thud or a click felt or heard by the examiner while performing the test was considered positive.19 As pain is indicative of a wide variety of internal derangements of the knee, using pain as a positive test criterion for the McMurray test may lead to more false-positive findings. Therefore, sensitivity and specificity may be influenced by the criteria for classifying the test result as positive or negative.13 Comorbidity may also influence index test outcomes.22 Intra-articular factors, such as anterior cruciate ligament injury, plica syndrome, corpus librum, and chondral lesions, can result in both false-positive and false-negative findings when specifically testing for meniscal injury.22 In this study, comorbidity was high; 578 patients (97%) were diagnosed with diverse knee pathologies, 58% of whom had multiple knee pathologies, including a meniscal tear. Another study in a population with combined meniscal and anterior cruciate ligament injury found the Thessaly test to have a sensitivity of 79% and specificity of 40%.23 These latter results are in line with the present study, showing higher sensitivity values than specificity values. It seems that comorbidity may influence accuracy data.

Strengths and Weaknesses Strengths of this study are the large number of included patients (n = 593) and arthroscopy as the reference test. Other comparable studies included 80 to 310 patients.11,17,23 This is the first study to examine the diagnostic value of the Thessaly test combined with the McMurray test. Because both of these tests are commonly used in clinical practice, this study reflects diagnostic testing commonly used in clinical care. Another strength is that optimal blinding was applied to both index tests and to the reference test. This study has some limitations as well. The results of the Thessaly test were not influenced or provoked by the McMurray test, as the Thessaly test was always tested first. On the other hand, the results of the McMurray test might have been influenced by the Thessaly test. However, as the primary goal was to evaluate the validity of the Thessaly test, the present study specifically aimed for an unbiased assessment of the Thessaly test. Therefore, the results of the McMurray test could be biased. Because the majority of the population was diagnosed with multiple knee pathologies, this might have led to more false-positive outcomes. In 83% of the patients (n = 493), a meniscal tear was found, indicating a high prevalence of meniscal tears. The use of 2 index tests could not contribute to a clinically relevant posttest probability compared with the high pretest probability (prevalence). Both index tests were performed within 2 hours before arthroscopy; this might have influenced the test results, due to nervousness or anxiety of the participant, which could have influenced subjective pain perception. Seven physical therapists performed the clinical examinations. This might have influenced the results, as the interobserver reliability of assessing meniscal tests is reported to be low.6,10 Unfortunately, an interobserver reliability study between the different physical therapists was not performed. The appearance of the knees at the time of test-

ing (eg, swelling, muscle atrophy) might have influenced blinding of the affected knee for the physical therapists. Finally, differences in patient population, extent of lesion, and comorbidity limit the applicability of the findings of the present study to other care settings.

Recommendations for Future Research Until now, clinical tests performed in isolation or in combination seem to be of little value in detecting meniscal tears in the clinical setting. Future research should focus on improving the diagnostic accuracy of clinically diagnosing meniscal tears, including information from history taking and physical tests. In addition, it seems worthwhile to examine how increased standardization and clarification of meniscal tests might improve diagnostic accuracy. Although the use of arthroscopy as a reference standard can only be applied in a hospital care population, more insight is needed into the validity of tests in a primary care setting, as this is the first place where patients are tested for a possible meniscal tear. Furthermore, developing a diagnostic model, including history taking and physical examination, for the detection of meniscal tears in primary care is recommended.

CONCLUSION

T

he Thessaly test, used in isolation or combined with the McMurray test, does not seem useful to accurately determine the presence or absence of meniscal tears. t

KEY POINTS FINDINGS: The Thessaly test, in isolation

or in combination with the McMurray test, demonstrated poor diagnostic accuracy for identifying the presence or absence of meniscal tears. IMPLICATIONS: The Thessaly test yielded only marginal diagnostic benefits compared with the pretest probability of a meniscal tear in a hospital care setting. Therefore, these tests should not be recommended for use in a hospital care



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[ setting to determine the presence of meniscal tears. CAUTION: The present study was conducted in a population with a high incidence of meniscal tears and with a large amount of multiple knee pathologies. This may not reflect other care settings and therefore may limit the representativeness of the present study for other settings.


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ONLINE APPENDIX

THE THESSALY TEST17 Patient: the Thessaly test (ONLINE VIDEO) is a dynamic reproduction of joint loading in the knee. The test is performed with the knee in 20° of flexion. The researcher supports the arms of the patient by holding his or her outstretched arms while the patient stands flatfooted on the floor. Execution: the patient rotates the knee and upper body 3 times, internally and externally, while keeping the knee in 20° of flexion. Interpretation: the test is positive when the patient experiences discomfort or pain in the medial or lateral joint line. Also, a sense of locking/catching or a feel of giving way by the patient results in a positive test.

THE MODIFIED MCMURRAY TEST3 Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on August 30, 2015. For personal use only. No other uses without permission. Copyright © 2015 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.

Patient: the patient assumes a supine position, with the hip in approximately 110° of flexion. The examiner stands to the side of the patient’s involved knee (ONLINE VIDEO). Execution: The examiner grasps the patient’s heel and flexes the knee to end range with one hand, while using the other hand to hold the distal femur. For testing the medial meniscus, the examiner places the knee into external rotation and adduction* (pain provocation). From this position, while maintaining external rotation and adduction, the examiner extends the knee to about 90°. A click can occur. To test the lateral meniscus, the examiner flexes the knee but now internally rotates and abducts the patient’s knee. Interpretation: the test is positive if the patient experiences pain* or when a click is felt by the examiner. *Adduction/abduction and reproduction of pain as a positive sign of meniscal tear were not described in the original McMurray test. 4

journal of orthopaedic & sports physical therapy | volume 45 | number 1 | january 2015 | B1


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