Thermal hyperalgesia distinguishes those with severe pain and disability in unilateral lateral epicondylalgia.

OBJECTIVES: To evaluate if sensory, motor, and psychological factors are different in severe lateral epicondylalgia compared with less severe cases and control.
METHODS: A total of 164 patients with unilateral lateral epicondylalgia and 62 healthy control participants of comparable age and sex underwent the following testing: quantitative sensory testing (pressure, thermal pain thresholds), pain-free grip, quality of life (EuroQol), and psychological (Hospital Anxiety and Depression Scale, Tampa Scale for Kinesiophobia) testing. Cluster analysis classified patients into mild, moderate, or severe subgroups using the Patient Rated Tennis Elbow Evaluation. Data were then evaluated to determine differences between control and lateral epicondylalgia subgroups.
RESULTS: Bilateral cold hyperalgesia (affected elbow, standardized mean difference (SMD) -1.14, P=0.000; unaffected elbow SMD -0.94, P=0.000) and unilateral heat hyperalgesia (SMD -1.06, P=0.001) were evident in severe lateral epicondylalgia in comparison to healthy controls. All patient groups regardless of severity demonstrated bilateral and widespread mechanical hyperalgesia relative to controls (P<0.003); however, only those with moderate and severe symptoms showed large differences (Absolute SMD>0.8) at all sites. Quality of life was significantly poorer in patients with severe symptoms, whereas anxiety, depression, and kinesiophobia did not differ between subgroups. DISCUSSION: Lateral epicondylalgia patients presenting with severe pain and disability could be distinguished by hypersensitivity to thermal stimuli, notably bilateral cold hyperalgesia. Findings may implicate a combination of central, peripheral, and sympathetic nervous system processes and may help explain the poorer outcomes found in this subpopulation.