Improving the accuracy of the preoperative diagnosis of long head of the biceps pathology: the biceps resisted flexion test

 

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Abstract

Purpose: the purpose of this study was to describe a new test for identifying lesions of the long head of the biceps (LHB) and to evaluate its diagnostic performance in comparison with selected traditional clinical tests.

Methods: one hundred and nine consecutive candidates for arthroscopic rotator cuff repair were prospectively recruited.The BRF test, which measures biceps resisted flexion strength, was performed with the patient seated (armat the side and elbow flexed at 90°). The patient was asked to maintain maximal resistance for five seconds while strength was assessed with a digital dynamometer. Since the dynamometer expresses a continuous variable in kilograms, the measure was dichotomized using a threshold value (cut-off ) valueable to simultaneously maximize the sensitivity and specificity. This cut-off value was derived from receiver operating characteristic (ROC) curve analysis.

Speed’s test and the O’Brien test were also performed. During arthroscopy the presence of LHB pathology was assessed.

Results: biceps resisted flexion strength was significantly higher in patients without associated LHB lesions [median (range): 3 kg (0-9.5 kg) versus 0 kg (0-8.5 kg); p< 0.001]. The cut-off level able to simultaneously maximize the sensitivity and specificity of the test was 1.1kg.

The area under the ROC curve was 0.745 (p<0.001) for the dichotomic BRF test (dBRF), 0.562 (p=0.3) for the O’Brien test, and 0.602 (p=0.113) for Speed’s test. A significant good level of accuracy was achieved only by the dBRF test. Specificity and the positive predictive value were significantly higher for the dBRF test than for Speed’s and O’Brien’s tests (p<0.02). Age and the dBRF test were both found to be significant predictors of LHB lesions.

Conclusions: the dBRF test showed higher accuracy than traditional clinical tests in diagnosing LHB lesions. This novel test for biceps pathology may be advantageous because it is objective and therefore likely reproducible.

Level of Evidence: Level II, Development of diagnostic test on basis of consecutive patients (with universally applied reference “gold” standard).