BackgroundClinical 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.MethodsA 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.ResultsThe 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).ConclusionsBecause 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 t...

Objective The objective of the study is to provide a reference for morphology, homogeneity, and signal intensity of triangular fibrocartilage complex (TFCC) and TFCC-related MRI features in adolescents. Materials and methods Prospectively collected data on asymptomatic participants aged 12–18 years, between June 2015 and November 2017, were retrospectively analyzed. A radiograph was performed in all participants to determine skeletal age and ulnar variance. A 3-T MRI followed to assess TFCC components and TFCC-related features. A standardized scoring form, based on MRI definitions used in literature on adults, was used for individual assessment of all participants by four observers. Results per item were expressed as frequencies (percentages) of observations by all observers for all participants combined (n = 92). Inter-observer agreement was determined by the unweighted Fleiss’ kappa with 95% confidence intervals (95% CI). Results The cohort consisted of 23 asymptomatic adolescents (12 girls and 11 boys). Median age was 13.5 years (range 12.0–17.0). Median ulnar variance was −0.7 mm (range − 2.7–1.4). Median triangular fibrocartilage (TFC) thickness was 1.4 mm (range 0.1–2.9). Diffuse increased TFC signal intensity not reaching the articular surface was observed in 30 (33%) observations and a vertical linear increased signal intensity with TFC discontinuation in 19 (20%) observations. Discontinuation between the volar radioulnar ligament and the TFC in the sagittal plane was seen in 23 (25%) observations. The extensor carpi ulnaris was completely dislocated in 10 (11%) observations, more frequent in supinated wrists (p = 0.031). Inter-observer agreement ranged from poor to fair for scoring items on the individual TFCC components. Conclusion MRI findings, whether normal variation or asymptomatic abnormality, can be observed in TFCC and TFCC-related features of asymptomatic adolescents. The rather low inter-observer agreement underscores the challenges in interpreting these small structures on MRI. This should be taken into consideration when interpreting clinical MRIs and deciding upon arthroscopy.

Skeletally immature wrists are considered at risk of injury due to increased axial loading through a relatively shorter ulna. The aim of this study was to determine whether triangular fibrocartilage thickness relates to ulnar variance and age in adolescents. The radiographs and MRIs of 24 healthy adolescents were retrospectively assessed. Four observers assessed bone age and ulnar variance on radiographs and measured triangular fibrocartilage thickness on MRIs. Median calendar and bone age was 13 years and ulnar variance was −0.7 mm. Median triangular fibrocartilage thickness was 1.4 mm, with excellent inter-observer agreement (r = 0.86). It was moderately correlated with ulnar variance (ρ = −0.46) as well as with bone age (ρ = −0.49). Both variables were statistically significant predictors in a multivariate analysis. This suggests that triangular fibrocartilage thickness changes during skeletal maturation, which might influence axial load distribution in skeletally immature wrists.