Quantitative abductor pollicis brevis strength testing

Letters to the Editor Quantitative Abductor Pollicis Brevis Strength Testing To the Editor: I read with considerable interest the article entitled “Quantitative Abductor Pollicis Brevis Strength Testing: Reliably in Normative Values” (J Hand Surg 2000; 25A:752–759) by Liu et al. The report establishes in a clearly scientific way the validity and consistency in measuring abductor pollicis brevis strength. We have reported a similar study1 using much simpler equipment, but we did obtain very similar results. We have already proceeded to use this test in the evaluation of carpal tunnel syndrome patients and have objectively demonstrated improvements in abductor pollicis brevis strength measurement as a result of the surgery. We have found this test to be much more readily done than nerve conduction studies, with much less expense, and the objective measurements are of great benefit in monitoring the recovery of muscle function after surgical decompression. It also can objectively demonstrate improvements of deterioration in people who have elected conservative treatment. We encourage Liu et al to proceed with their intended aim of applying their more sophisticated measurement techniques to a group of patients undergoing carpal tunnel treatment. We also suggest that correlation with electromyograms might be useful to answer the critics who will demand that their study will only be valid if compared with the gold standard of carpal tunnel evaluation. Michael S.G. Bell, MD Plastic and Reconstructive Surgery 402–1919 Riverside Dr Ottawa, Ontario, K1H 1A2 Canada doi:10.1053/jhsu.2001.22878

In Reply: We appreciate Dr Bell’s comments regarding our article. The purpose of our study was to establish reliability and normative values for abductor pollicis brevis (APB) strength using a handheld strength testing device. One of the original goals of this study was to provide a foundation for more clearly quantifying the presence of APB weakness in patients with carpal tunnel syndrome and to objectively document changes in strength in response to treatment. We were therefore very interested to read the report by Bigelow and Bell,1 which included the results of testing APB strength in patients with carpal tunnel syndrome and a control group using a micrometer spring scale. We apologize for not mentioning this study in our report, but it had not been referenced in our Medline search. The results of Bigelow and Bell’s study included differences in APB strength between control and patient populations as well as an improvement in APB strength 4 weeks after carpal tunnel release in comparison to preoperative measurements. Our preliminary unpublished results of patients tested before and 6 weeks after carpal tunnel release appear to support these findings. We have not correlated APB strength testing with electromyograms or nerve conduction tests, as these are not routinely used in our office setting, but we agree that this would be a valuable addition to a future study. Lois Carlson, BS H. Kirk Watson, MD 85 Seymour St, Suite 816 Hartford, CT 06106 doi:10.1053/jhsu.2001.22879

Reference

Reference

1. Bigelow E, Bell M. Carpal tunnel syndrome: a new objective evaluation technique. Can J Plast Surg 1998;6:99 –103.

1. Bigelow E, Bell M. Carpal tunnel syndrome: a new objective evaluation technique. Can J Plast Surg 1998;6:99 –103.

362 The Journal of Hand Surgery