Understanding the different physical examination tests for suspected meniscal tears

What Is the Diagnostic Accuracy of the Duck Walk Test in Detecting Meniscal Tears?

BACKGROUND

Clinical weightbearing provocation tests, like the duck walk test, may be of value in diagnosing or screening for medial meniscal tears. However, evidence of the diagnostic accuracy of the duck walk test is lacking.

QUESTIONS/PURPOSES

(1) To determine the sensitivity and specificity of the duck walk test in diagnosing medial meniscal tears. (2) To determine whether tear location, tear cause (traumatic versus degenerative), and ACL insufficiency were associated with differences in the sensitivity and specificity of the test.

METHODS

A convenience sample of 136 patients of all ages was retrospectively analyzed by evaluating the outpatient knee clinic appointment list of one orthopaedic surgeon for patients with a broad range of knee injuries who had a prior MRI before (24%) or after (76%) physical examination and had a duck walk test stated in their patient records. Of 230 patients with MRI requested by one orthopaedic surgeon attributable to knee complaints, 136 (59%) fulfilled the inclusion criteria; 70 (52%) patients were male and 66 (49%) were female, with a mean age of 42 (± SD 14) years. The duck walk test was performed in case of suspected meniscal injury, based on mechanism of injury, general joint line pain, and/or mechanical complaints (ie, locking, giving away). The test is performed by squatting and "waddling" before rising and is positive in case of general joint line pain or painful "clicking". Interobserver repeatability was not evaluated, but the test is well defined and leaves little room for difference in interpretation. Diagnostic accuracy measures were evaluated. Since the convenience sample in this study consisted of patients who had a duck walk test and MRI, and a positive result of the duck walk test almost certainly increased the probability that MRI would be ordered in the majority (76%) of the patients, the test properties calculated here-especially sensitivity-should be considered inflated.

RESULTS

The calculated sensitivity of the duck walk test was 71% (95% CI, 59%-81%) and there was low specificity of 39% (95% CI, 27%-52%). We found no difference in sensitivity between medial (67%; 95% CI, 51%-80%) and lateral (76%; 95% CI, 50%-92%; p = 0.492) meniscal tears. With the numbers available, we compared these patients with patients without a history of trauma and with an intact ACL. We found no difference among patients with traumatic tears (79%; 95% CI, 59%-91%; p = 0.253) and in patients with ACL tears (77%; 95% CI, 46%-94%; p = 0.742).

CONCLUSIONS

Because of the issue of verification bias, the actual sensitivity of this test in practice is likely much lower than the calculated sensitivity we observed. In addition, the test did not seem to perform better in patients with trauma or ACL insufficiency, nor was it more effective in detecting medial than lateral tears, although the numbers on some of those comparisons were rather small. Based on these results, we conclude that used alone, the duck walk test likely has little value in practice as a screening test. However, it is conceivable that it could be used in combination with other provocative tests for screening purposes. Future studies might consider using it as a means to best identify which patients should undergo MRI for the possibility of a meniscal tear.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Diagnostic Validity of Combining History Elements and Physical Examination Tests for Traumatic and Degenerative Symptomatic Meniscal Tears

BACKGROUND

The current approach to the clinical diagnosis of traumatic and degenerative symptomatic meniscal tears (SMTs) proposes combining history elements and physical examination tests without systematic prescription of imaging investigations, yet the evidence to support this diagnostic approach is scarce.

OBJECTIVE

To assess the validity of diagnostic clusters combining history elements and physical examination tests to diagnose or exclude traumatic and degenerative SMT compared with other knee disorders.

DESIGN

Prospective diagnostic accuracy study.

SETTINGS

Patients were recruited from 2 orthopedic clinics, 2 family medicine clinics, and from a university community.

PATIENTS

A total of 279 consecutive patients who underwent consultation for a new knee complaint.

METHODS

Each patient was assessed independently by 2 evaluators. History elements and standardized physical examination tests performed by a physiotherapist were compared with the reference standard: an expert physicians' composite diagnosis including a clinical examination and confirmatory magnetic resonance imaging. Participating expert physicians were orthopedic surgeons (n = 3) or sport medicine physicians (n = 2). Penalized logistic regression (least absolute shrinkage and selection operator) was used to identify history elements and physical examination tests associated with the diagnosis of SMT and recursive partitioning was used to develop diagnostic clusters.

MAIN OUTCOME MEASURES

Diagnostic accuracy measures were calculated including sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios (LR+/-) with associated 95% confidence intervals (CIs).

RESULTS

Eighty patients had a diagnosis of SMT (28.7%), including 35 traumatic tears and 45 degenerative tears. The combination a history of trauma during a pivot, medial knee pain location, and a positive medial joint line tenderness test was able to diagnose (LR+ = 8.9; 95% CI 6.1-13.1) or exclude (LR- = 0.10; 95% CI 0.03-0.28) a traumatic SMT. Combining a history of progressive onset of pain, medial knee pain location, pain while pivoting, absence of valgus or varus knee misalignment, or full passive knee flexion was able to moderately diagnose (LR+ = 6.4; 95% CI 4.0-10.4) or exclude (LR- = 0.10; 95% CI 0.03-0.31) a degenerative SMT. Internal validation estimates were slightly lower for all clusters but demonstrated positive LR superior to 5 and negative LR inferior to 0.2 indicating moderate shift in posttest probability.

CONCLUSION

Diagnostic clusters combining history elements and physical examination tests can support the differential diagnosis of SMT. These results represent the initial derivation of the clusters and external validation is mandatory.

LEVEL OF EVIDENCE

I.

Detecting Meniscal Tears in Primary Care: Reproducibility and Accuracy of 2 Weight-Bearing Tests and 1 Non-Weight-Bearing Test

STUDY DESIGN

Diagnostic accuracy study using a cross-sectional design.

OBJECTIVES

To determine the interexaminer reliability and the diagnostic accuracy in primary care of 1 existing weight-bearing meniscal test, the Thessaly test, 1 new weight-bearing test, the deep squat test, and 1 non-weight-bearing test, the joint-line tenderness test.

BACKGROUND

Meniscal tears are difficult to detect in primary care. Although valuable in secondary care, weight-bearing physical examination tests require validation in primary care in unselected patients.

METHODS

Between October 2009 and December 2013, 121 patients (age range, 18-65 years) seen in primary care and suspected of having internal derangement of the knee of less than 6 months in duration were included in the study. Diagnostic accuracy of the 3 meniscal tests was determined based on assessment with magnetic resonance imaging. The meniscal tests were performed by 3 trained physical therapists, who were not informed about the patient history and magnetic resonance imaging results. Each test was performed independently by 2 of the 3 trained physical therapists in alternating pairs.

RESULTS

The Thessaly test and the deep squat test had a moderate level of interexaminer reliability, with kappas of 0.54 and 0.46, respectively. The joint-line tenderness test had poor interexaminer reliability and was therefore not assessed for diagnostic accuracy. The following results are reported separately for both examiners. The Thessaly test had a sensitivity of 66.7% (95% confidence interval [CI]: 53.0%, 78.0%) and 51.2% (95% CI: 36.8%, 65.4%), a specificity of 37.9% (95% CI: 27.2%, 50.0%) and 43.5% (95% CI: 30.2%, 57.8%), a positive likelihood ratio of 1.07 (95% CI: 0.82, 1.41) and 0.91 (95% CI: 0.62, 1.33), and a negative likelihood ratio of 0.88 (95% CI: 0.54, 1.45) and 1.12 (95% CI: 0.72, 1.76). Similarly, the deep squat test had a sensitivity of 74.5% (95% CI: 61.1%, 84.5%) and 76.7% (95% CI: 62.3%, 86.9%), a specificity of 42.4% (95% CI: 31.2%, 54.4%) and 36.2% (95% CI: 24.0%, 50.5%), a positive likelihood ratio of 1.29 (95% CI: 0.97, 1.68) and 1.20 (95% CI: 0.92, 1.58), and a negative likelihood ratio of 0.60 (95% CI: 0.35, 1.04) and 0.64 (95% CI: 0.33, 1.25).

CONCLUSION

Although the Thessaly and deep squat tests have a moderate level of reliability, neither test is sufficiently accurate to help in the diagnosis of meniscal tears in primary care. Future research should focus on other relevant patient variables instead of on physical examination tests in the detection of meniscal tears.

LEVEL OF EVIDENCE

Diagnosis, level 3b.

A clinical prediction rule for meniscal tears in primary care: development and internal validation using a multicentre study

BACKGROUND

In primary care, meniscal tears are difficult to detect. A quick and easy clinical prediction rule based on patient history and a single meniscal test may help physicians to identify high-risk patients for referral for magnetic resonance imaging (MRI).

AIM

The study objective was to develop and internally validate a clinical prediction rule (CPR) for the detection of meniscal tears in primary care.

DESIGN AND SETTING

In a cross-sectional multicentre study, 121 participants from primary care were included if they were aged 18-65 years with knee complaints that existed for <6 months, and who were suspected to suffer from a meniscal tear.

METHOD

One diagnostic physical meniscal test and 14 clinical variables were considered to be predictors of MRI outcome. Using known predictors for the presence of meniscal tears, a 'quick and easy' CPR was derived.

RESULTS

The final CPR included the variables sex, age, weight-bearing during trauma, performing sports, effusion, warmth, discolouration, and Deep Squat test. The final model had an AUC of 0.76 (95% CI = 0.72 to 0.80). A cut-point of 150 points yielded an overall sensitivity of 86.1% and a specificity of 45.5%. For this cut-point, the positive predictive value was 55.0%, and the negative predictive value was 81.1%. A scoring system was provided including the corresponding predicted probabilities for a meniscal tear.

CONCLUSION

The CPR improved the detection of meniscal tears in primary care. Further evaluation of the CPR in new primary care patients is needed, however, to assess its usefulness.

Risk factors for meniscal tears: a systematic review including meta-analysis

STUDY DESIGN

Systematic review with meta-analysis.

OBJECTIVES

To review and critically appraise the literature for factors that increase the risk for meniscal tears.

BACKGROUND

Meniscal tears are an important cause of disability and time lost from work, and are associated with a 4-fold increase in the long-term risk of knee osteoarthritis. Knowledge of the risk factors that lead to meniscal tears can help to correctly diagnose knee injuries and is important to the development of prevention strategies for knee osteoarthritis.

METHODS

A search of the Cochrane Database of Systematic Reviews, MEDLINE, and Embase, from 1950 to January 2012, and a hand search of reference lists of all initially selected studies, without restriction on language or date of publication, were conducted. Prospective, retrospective, and case-control studies that included individuals over 16 years of age, who had no previous meniscal injuries or surgeries, were selected. A meta-analysis for 17 risk factors was performed. Where considerable heterogeneity among studies was present or the data did not provide sufficient information to perform a meta-analysis, a qualitative synthesis was conducted.

RESULTS

Eleven studies, with a total of 7358 participants, were selected for systematic review. Data were available for meta-analysis for 10 of the 11 studies. Qualitative analysis was conducted using data from 3 of the 11 studies. Results showed strong evidence that age (older than 60 years), gender (male), work-related kneeling and squatting, and climbing stairs (greater than 30 flights) were risk factors for degenerative meniscal tears. We also found strong evidence that playing soccer and playing rugby were strong risk factors for acute meniscal tears. Waiting longer than 12 months between the anterior cruciate ligament injury and reconstructive surgery was a strong risk factor for a medial meniscal tear but not for a lateral meniscal tear.

CONCLUSION

The literature indicates a number of risk factors leading to either degenerative or acute meniscal tears, with some of these factors being potentially modifiable.

LEVEL OF EVIDENCE

Prognosis, level 2a.