The tuning fork evaluation method was highly successful on transverse fractures (n
10) but not as accurate on avulsion (n
1) and buckle (n
1) type fractures. In a transverse fracture, space created by the fracture is sufficient1,3,4
to decrease the sound the tuning fork produces and, thus, the sound is diminished as compared with the uninjured body part, resulting in a positive test.5–,7
In a complete fracture, sound conduction is interrupted by the separated cortical surfaces of the bone.7
Avulsion and buckle fractures, by definition, leave the bone injured but intact and, therefore, sound is not commonly affected.1,3,4
Misurya et al5
and Bache and Cross6
explained that sound waves from the tuning fork are transmitted easily in non-transverse fractures because enough of the bone remains in contact. The only false-negative results that were identified occurred in patients with avulsion and buckle fractures.
These results are in agreement with those of Misurya et al,5
Bache and Cross,6
Colwell and Berg,7
in supporting the tuning fork test as a useful aid in identifying fractures. In my patients, the assessment was correct 81% of the time (30
37), compared with the correct assessments of Misurya et al5
(94%) and Bache and Cross6
(87%). Both of the latter groups identified only the injured bone but not the fracture type. This study differed from the studies of Misurya et al5
and Bache and Cross6
because of the variety of bones examined. The earlier authors assessed fractures of the femoral neck, femoral shaft, and tibia.5–,8
My results suggest that the tuning fork technique is useful across a broader range of bones than previously noted, including the extremities and the clavicle ().
Accuracy of the Tuning Fork Test in Fracture Assessment
The tuning fork technique appears to be an inexpensive and accurate method of evaluating possible fractures and could supplement the fracture testing techniques used by athletic trainers. In addition, it may be possible to reduce both the number of radiographs needed and the associated cost.
The Ottawa Ankle Rules (OAR) are very sensitive and, thus, effective in ruling out possible fractures of the foot and ankle.12–,16
Adding tuning fork testing enhances the specificity of the OAR.12
My results also suggest that tuning fork assessment improves the specificity of fracture assessment in the absence of radiographs. In examining possible fractures of the ankle and foot, I recommend incorporating the tuning fork technique into the traditional fracture evaluation with the OAR. If multiple clinical assessment techniques are used, the likelihood of detecting a fracture while avoiding unnecessary radiographic examinations is greater. The OAR, however, apply only to ankle and foot injuries.
did not address the effect of swelling on the tuning fork and stethoscope method. Swelling within a tissue or a joint may alter results. When possible, the tuning fork test should be performed before swelling occurs. I placed the tuning fork distal and the stethoscope proximal to the suspected fracture. If swelling was present, the tuning fork was placed over the edema. Placing the stethoscope over the swelling (distally) and applying the tuning fork proximally allows the tuning fork to make contact with the bone and permits sounds to be transmitted along the bone. When the 3 patients with substantial swelling about the fibula were evaluated with this alternative method, there were 3 fewer false-positives (these results were not included in the data analysis). However, results of the radiographs were already known at the time of the modified examination procedure.