Is there sufficient evidence for tuning fork tests in diagnosing fractures? A systematic review
Mugunthan K, Doust J, Kurz B, and Glasziou P. BMJ Open. 2014. 4.
Take Home Message: The use of a tuning fork in ruling out fractures is not currently recommended due to low diagnostic accuracy. Little clinical standards, low study quality and small sample size limits the results therefore more standardization and training should be done to improve its clinical efficiency.
In some situations radiographic imaging is not readily available and clinicians must attempt to assess an injury with other tools such as a tuning fork. Unfortunately, the diagnostic accuracy of tuning forks is not known. Therefore, Mugunthan and colleagues completed a systematic review to determine the diagnostic accuracy of tuning forks for assessing fracture. Researchers assessed 2 methods of tuning fork tests, (1) induction of pain and (2) transmission of sound. A literature search of MEDLINE, CINAHL, AMED, EMBASE, Sports Discus, CAB Abstracts and Web of Science was performed and 62 articles were identified. All included articles assessed the diagnostic accuracy of the tuning fork tests and used a standard objective reference standard (x-ray, bone scan). Following screening, the authors eliminated 56 articles, leaving 6 for quality assessment. In 5 out of 6 of the studies the authors focused on primarily on adults. The authors of the 6 papers evaluated any suspected fracture (2 papers, femoral neck fractures (1 study), ankle inversion injuries (1 study), and stress fractures (2 studies). In 4 studies, the authors used pain induction to assess fractures, and 2 in studies the authors used sound conduction. Sensitivity and specificity of the tuning fork tests was 75-92% and 18-94%; respectively. Overall study quality of the 6 included studies was considered “modest.”
The current systematic review is interesting to clinicians who render emergency care, such as athletic trainers, because the possibility of a cost-effective clinical test to detect fractures is of great interest. Unfortunately, tuning forks may not be accurate enough to warrant integration into clinical practice. This supports a previous systematic review that we’ve described. However, it should be noted that the sensitivity of the tuning fork shows that this test may have some ability to rule out fractures, however it is not sensitive enough to warrant widespread use. It is also curious that the specificity had a large range among the six studies. Overall, this could lead to a high rate of false-positive results but it would be interesting to learn more about when tuning forks had good specificity. For example, the specificity of tuning forks was worst in the study with suspected femoral neck fractures (18%) and best when investigators evaluated ankle inversion injuries (94%). It would be helpful if future research clarified if and when tuning forks may be beneficial and if clinicians need specific training to optimize the test results. Perhaps if clinical procedure were developed and improved, the sensitivity would also improve. Ultimately, more research and standardization should be developed and studied, before tuning forks are used widely in a clinical setting.
Questions for Discussion: Do you currently use a tuning fork in your clinical practice? If so, which of the diagnostic methods do you use and how accurate do you feel it is?
Written by: Kyle Harris
Reviewed by: Jeffrey Driban