Increased palpation tenderness and muscle strength deficit in the prediction of tendon hypertrophy in symptomatic unilateral shoulder tendinopathy: an ultrasonographic study.
OBJECTIVE
In asymptomatic, normal tendons, the difference in tendon thickness between sides is less than 15%. In this study, three tests were used to examine differences between symptomatic and asymptomatic shoulders.


METHODS
Cross-sectional study. The three tests were performed in sequence. The observer was blinded in the maximal pain-free isometric force test.


METHODS
Outpatient physiotherapy clinic at Bergen University College, Norway.


METHODS
Sixty-four patients with an exclusive, tentative diagnosis of unilateral shoulder tendinopathy.


METHODS
Differences in maximal pain-free isometric force, tendon pain pressure and tendon thickness measured by ultrasonography.


RESULTS
This paper follows the STARD recommendations for papers on diagnostic accuracy. When cut-off values for within-subject side differences were selected at >or=0.8mm for tendon thickness (TT(diff)), >or=10N for maximal pain-free isometric force (PFF(diff)) and >or=0.6 kg for tendon pain pressure (PPT(diff)), positive tests were found in 92% of patients. All three tests were sensitive for the detection of within-subject side differences with the selected cut-off values (TT(diff), n=60/64; PPT(diff), n=59/64; PFF(diff), n=57/64; P>0.35). There were strong agreements between the three tests: TT(diff) and PFF(diff), 0.89; TT(diff) and PPT(diff), 0.83; and PFF(diff) and PPT(diff), 0.84. When both clinical tests were positive (PFF(diff) and PPT(diff)), the positive predictive value was excellent (94%) for finding increased tendon thickness in the symptomatic side on ultrasonography.


CONCLUSIONS
Within the limitations of this partially blinded study, patients with unilateral shoulder tendinopathy exhibited significant differences between sides in all three tests. The combination of the two clinical tests seems to be valid for the detection of unilateral shoulder tendinopathy if other diagnoses have been excluded.
Joensen
Jon
J
Department of Physiotherapy, Faculty of Health and Social Science, Bergen University College, Norway. jon.joensen@hib.no
Couppe
Christian
C
Bjordal
Jan Magnus
JM
D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000000981:diagnostic imaging / Q000503:physiopathology; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D017288:Pain Threshold; D010173:Palpation; D012782:Shoulder / Q000000981:diagnostic imaging* / Q000503:physiopathology; D052256:Tendinopathy / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D013710:Tendons / Q000473:pathology* / Q000503:physiopathology; D014463:Ultrasonography