EFFECTS OF COUNTERFORCE FOREARM BRACING ON HANDGRIP AND WRIST EXTENSOR STRENGTH AND PAIN IN PATIENTS WITH LATERAL EPICONDYLITIS. Joyce White*; Gino Compagnone; Stephanie Dean; James O'Brien Physical Therapy, University of Massachusetts Lowell, Lowell, MA PURPOSE: The purpose of this study was to determine if handgrip and wrist extensor strength and pain would change in response to counterforce bracing of the proximal forearm in a patient population with lateral epicondylitis. The effects of three methods of applying the counterforce brace were examined: no brace, brace applied with light tension, and brace applied with heavy tension. BACKGROUNDS/SIGNIFICANCE: Lateral epicondylitis is a common elbow injury that affects approximately four adults per 1000 annually. The most common cause cited for lateral epicondylitis is a force overload at the aponeurosis of the common wrist extensor origin. Counterforce bracing is a conservative intervention used in physical therapy that is thought to reduce the force and overload of these soft tissues. While empirical evidence suggests a benefit, studies have found varying results on the effects of counterforce forearm bracing on healthy and patient populations. SUBJECTS: Twenty-five subjects with a diagnosis or symptoms of lateral epicondylitis (9 males and 16 females) were recruited for this study from local physical therapy clinics, tennis teams, and a university community. All subjects had a diagnosis of lateral epicondylitis, a positive Cozen test, or positive tennis elbow test for inclusion in the study. Subjects ranged in age from 23 to 56 years, with a mean of 44 years. METHODS AND MATERIALS: Measurements of grip force were obtained using a hand dynamometer. Wrist extension force was measured with a hand-held dynamometer applied to the dorsum of the hand just proximal to the metacarpal heads. Distance from the application of the hand-held dynamometer to the radial styloid process was used to calculate wrist extension torque. A counterforce brace was applied 0.8 inches (2 cm) distal to the lateral epicondyle over the extensor carpi radialis longus and brevis. Six grip strength (force) and six wrist extensor strength (torque) measurements were obtained from the affected upper extremity consisting of two measures without the brace, two measures with the brace applied with light tension (2.5 lbs), and two measures with the brace applied with heavy tension (5.0 lbs). In addition, pain was assessed during hand gripping and wrist extension at the subject's maximum effort. Pain was reported after each trial on a scale of 0 to 10 (0 = no pain; 10 maximal pain). Test order was randomly assigned and standardized positioning and instructions were used throughout the measurement process. ANALYSES: Two measurements from the two, no brace trials of grip strength (force) and wrist extension strength (torque) were evaluated with Pearson Product- Moment Correlation Coefficient and Standard Error of Measurement (SEM) to determine intratester reliability. Spearman Rank Correlation Coefficient and SEM were used to assess the reliability of pain measurements during gripping and wrist extension. One-way repeated measures ANOVA were used to determine if there were significant differences in grip strength, wrist extensor strength, pain during gripping, and pain during wrist extension obtained from the three methods tested. Tukeys' Post-hoc multiple comparison for repeated measures was used to determine the source of significant differences. A p-value of less than or equal to .05 was considered significant. RESULTS: Intratester reliability coefficients for grip strength and wrist extensor strength were .98 and .96, while SEM values were 4.09 lbs and .41 ft-lbs respectively. Reliability coefficients for subjective pain response with no brace for grip and wrist extensor strength were .83 and .77, while SEM values were .73 and .57 respectively. There was no statistically significant differences between the use of no brace, light tension brace, or heavy tension brace for measures of grip strength (F=.18, df = 2, p = .833) and wrist extension strength (F = .14, df = 2, p = .868). Subjective reports of pain during gripping with no brace, light tension brace, and heavy tension brace were not significantly different (F=2.91, df = 2, p = .064), but were significantly different for pain during wrist extension (F=3.34, df = 2, p = .046). Significantly less pain during wrist extension was found with the heavy tension brace as compared to no brace. CONCLUSIONS: Counterforce forearm bracing applied with tensions of 2.5 lbs and 5.0 lbs had no affect on grip and wrist extensor strength in subjects with a diagnosis or symptoms of lateral epicondylitis. Within the confines of this study, counterforce forearm bracing applied with increasing tension did show an effect on reducing pain during wrist extension. The effects of the three methods of applying counterforce forearm bracing on pain during gripping was not statistically significant, but inconclusive. The results of this study suggest that counterforce bracing affects the perception of pain, rather than the ability of the wrist extensors to produce torque during gripping and wrist extension activities. Further research is need in a larger sample of patients with more severe symptoms of lateral epicondylitis. FUNDING SOURCE: No outside funding source. None of the authors have any potential for material gains as a result of the study. This material has not been or will be published or presented at another national or international meeting prior to June 8, 2005. KEYWORDS: brace, lateral epicondylitis, physical therapy intervention, pain, forearm injuries Means (SD) for strength and pain variables Copyright 2009 by the American Physical Therapy Association. Requests for reprints should be directed to the corresponding author of the article. Educators, students, and other academic customers may receive permission to reprint copyrighted material from Physical Therapy (ISSN 1538-6724) by contacting the Copyright Clearance Center Inc, 222 Rosewood Dr, Danvers, MA 01923. Other types of customers who want permission to reprint should contact the APTA Editorial Office, Attn: Physical Therapy.