Increased palpation tenderness and muscle strength deficit in theprediction of tendon hypertrophy in symptomatic unilateralshoulder tendinopathy: an ultrasonographic study

摘要

Objective In asymptomatic, normal tendons, the difference in tendon thickness between sides is less than 15%. In this study, three tests wereused to examine differences between symptomatic and asymptomatic shoulders.Design Cross-sectional study. The three tests were performed in sequence. The observer was blinded in the maximal pain-free isometric forcetest.Setting Outpatient physiotherapy clinic at Bergen University College, Norway.Participants Sixty-four patients with an exclusive, tentative diagnosis of unilateral shoulder tendinopathy.Main outcome measures Differences in maximal pain-free isometric force, tendon pain pressure and tendon thickness measured byultrasonography.Results This paper follows the STARD recommendations for papers on diagnostic accuracy. When cut-off values for within-subject sidedifferences were selected at > =0.8mm for tendon thickness (TT_(diff)), > =10N for maximal pain-free isometric force (PFF_(diff)) and > =0.6 kg fortendon pain pressure (PPT_(diff)), positive tests were found in 92% of patients. All three tests were sensitive for the detection of within-subject sidedifferences 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 agreementsbetween 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 onultrasonography.Conclusions Within the limitations of this partially blinded study, patients with unilateral shoulder tendinopathy exhibited significantdifferences between sides in all three tests. The combination of the two clinical tests seems to be valid for the detection of unilateral shouldertendinopathy if other diagnoses have been excluded.