Hyperalgesia in Tennis Elbow Patients

Abstract

Objective: The aim of this study was to evaluate and quantify the characteristics of hyperalgesia in patients [16 subjects, mean age 49 yrs 10 mths, mean duration of complaint 3 yrs 1 mth] with chronic, unilateral 'tennis elbow.' Methods: Subjects received an initial clinical examination. The tender area on the affected elbow and a corresponding area on the unaffected elbow were marked with a 1cm diameter circle. Triplicate measurements of mechanical pain threshold [using a pressure algometer], heat pain threshold and cold pain threshold [using the Thermotest® system] were then obtained at each of the marked areas. Upper limb tension tests 1 & 2b were carried out on both arms to evaluate nociceptive withdrawal reflexes in the limbs. The order of test procedures and sites tested was randomized for each subject. Results: Subjects exhibited significant differences in mechanical pain thresholds [P = 0.04] between the affected and unaffected limbs. No differences were apparent for heat pain thresholds [P = 0.9] or cold pain thresholds [P = 0.44]. Subjects exhibited a significantly reduced range of movement in both upper limb tension test 1 [P = 0.03] and 2b [P = 0.03]. There was no significant difference in any of the control measurements. Conclusion: Tennis elbow is characterized by mechanical hyperalgesia and hyperactive nociceptive withdrawal reflexes [as determined by tension test results]. There is no evidence of either heat or cold hyperalgesia in this condition.

KEYWORDS:

• Hyperalgesia
• tennis elbow
• algometry
• temperature pain thresholds