Widespread Pressure Pain Hyperalgesia Is Not Associated With Morphological Changes of the Wrist Extensor Tendon in Unilateral Lateral Epicondylalgia: A Case-Control Study

Objective The aims of the current study were to investigate the presence of widespread pressure hyperalgesia, the presence of structural changes in the wrist extensor tendon and muscle, and their association in people with lateral epicondylalgia (LE).Methods Thirty-seven patients with LE (43% women; mean age = 45.5 [SD = 9.5] years) and 37 controls matched for age and sex and free of pain participated in this study. Pressure pain thresholds (PPTs) were assessed bilaterally over the symptomatic area (elbow), 2 segment-related areas (C5-C6 joint, second intermetacarpal space), and 1 remote area (tibialis anterior) in a blinded design. Ultrasound measurements (eg, cross-sectional area, thickness, and width) of the common wrist extensor tendon and extensor carpi radialis brevis muscle as well as the thickness of the supinator muscle were assessed.Results Patients with LE exhibited lower PPTs bilaterally at all points and lower PPTs at the lateral epicondyle and second intermetacarpal space on the symptomatic side as compared to the nonsymptomatic side (eta 2 from 0.123-0.369; large effects). Patients exhibited higher cross-sectional area and width of the common wrist extensor tendon (eta 2 from 0.268-0.311; large effects) than controls bilaterally, whereas tendon thickness was also higher (eta 2 = 0.039; small effects) on the painful side than on the nonpainful side.Conclusions This study reported bilateral widespread pressure pain hyperalgesia and morphological changes in the tendon, but not the muscle, in LE. Pressure pain sensitivity and morphological changes were not associated in individuals with LE.Impact Management of LE should consider altered nociceptive pain processing and structural tendon changes as 2 different phenomena in patients with LE.