Using Tuning-Fork Tests in Diagnosing Fractures

Reference/citation: Mugunthan K, Doust J, Kurz B, Glasziou P. Is there sufficient evidence for tuning fork tests in diagnosing fractures? A systematic review. BMJ Open. 2014;4(8):e005238.

Clinical question: Does evidence support the use of tuning-fork tests in the diagnosis of fractures in clinical practice?

Data sources: The authors performed a comprehensive literature search of AMED, CAB Abstracts, CINAHL, EMBASE, MEDLINE, SPORTDiscus, and Web of Science from each database's start to November 2012. In addition, they manually searched reference lists from the initial search result to identify relevant studies. The following key words were used independently or in combination: auscultation, barford test, exp fractures, fracture, tf test, tuning fork.

Study selection: Studies were eligible based on the following criteria: (1) primary studies that assessed the diagnostic accuracy of tuning forks; (2) measured against a recognized reference standard such as magnetic resonance imaging, radiography, or bone scan; and (3) the outcome was reported using pain or reduction of sound. Studies included patients of all ages in all clinical settings with no exclusion for language of publication. Studies were not eligible if they were case series, case-control studies, or narrative review papers.

Data extraction: Potentially eligible studies were independently assessed by 2 researchers. All relevant articles were included and assessed for inclusion criteria and value using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool, and relevant data were extracted. The QUADAS-2 is an updated version of the original QUADAS and focuses on both the risk of bias and applicability of a study through a series of questions. A third researcher was consulted if the 2 initial reviewers did not reach consensus. Data for the primary outcome measure (accuracy of the test) were presented in a 2 × 2 contingency table to show sensitivity and specificity (using the Wilson score method) and positive and negative likelihood ratios with 95% confidence intervals.

Main results: A total of 62 citations were initially identified. Six primary studies (329 patients) were included in the review. The 6 studies assessed the accuracy of 2 tuning-fork test methods (pain induction and reduction of sound transmission). The patients ranged in age from 7 to 84 years. The prevalence of fracture in these patients ranged from 10% to 80% using a reference standard such as magnetic resonance imaging, radiography, or bone scan. The sensitivity of the tuning-fork tests was high, ranging from 75% to 92%. The specificity of the tuning-fork tests had a wide range of 18% to 94%. The positive likelihood ratios ranged from 1.1 to 16.5; the negative likelihood ratios ranged from 0.09 to 0.49.

Conclusions: The studies included in this review demonstrated that tuning-fork tests have some value in ruling out fractures. However, strong evidence is lacking to support the use of current tuning-fork tests to rule in a fracture in clinical practice. Similarly, the tuning-fork tests were not statistically accurate in the diagnosis of fractures for widespread clinical use. Despite the lack of strong evidence for diagnosing all fractures, tuning-fork tests may be appropriate in rural and remote settings in which access to the gold standards for diagnosis of fractures is limited.