Ulnar and Median Nerve Palsy in Cyclists
Patterson JM, Jaggars MM, Boyer MI. Ulnar and median nerve palsy in long-distance cyclists. A prospective study. Am J Sports Med. 2003 Jul-Aug;31(4):585-9. PubMed PMID: 12860549.
http://www.ncbi.nlm.nih.gov/pubmed/?term=12860549
Summary:
Prior to this study in 2003, there have been case studies and descriptions of “cyclist palsy” (ulnar nerve compression at Guyon’s canal in cyclist) in medical literature but there has been no research to determine the prevalence of cyclist palsy. The ulnar nerve courses in the medial forearm and gives off the dorsal cutaneous branch of the ulnar nerve prior to travelling through Guyon’s canal, thus the dorsal cutaneous branch of the ulnar nerve is preserved in cyclist palsy. There are several branches of the ulnar nerve in the hand including the motor branch to the hypothenar muscles, deep motor branch of ulnar nerve, and sensory component of the ulnar nerve. Understanding of the complex anatomy of the ulnar nerve provides better localization of nerve lesions. The authors of the study randomly chose 25 riders who were participating in a 600 km bicycle ride to complete a questionnaire and obtained baseline ulnar and median nerve (motor and sensory) function (with extensive motor and sensory testing). After completing the 600 km bicycle ride, the subjects had repeat nerve testing and questionnaires. Subjects were almost equal male:female (13:12), average age 33.7, cycled on average 139 km/week, mostly intermediate level cyclists (13/25), and without systemic illness (HIV/AIDS, diabetes, thyroid disease or neurological). Three riders had symptoms of nerve compression prior to the study (numbness in ulnar nerve distribution in one hand, +Phalen’s in one hand, and numbness in digits 4-5 with elbow provocative testing in three separate subjects). After the 600 kn bicycle ride, 36% of subjects had motor symptoms, 10% had sensory symptoms, and 24% in both motor and sensory symptoms. Only 30% of subjects had neither sensory nor motor symptoms. The authors concluded that there was no difference in symptoms in rider ability or whether mountain or road cyclist when assess motor function. There was however a greater incidence of sensory changes in mountain bikers, which the authors discuss, may be due to less handlebar positions. With fewer positions, riders may not be readjusting hands as frequently causing more compression on nerve.
Questions for discussion:
- This study suggests that cyclist palsy is very common with 70% of the subjects having either sensory or motor symptoms. This was a very small study with only 25 subjects. Is the prevalence of cyclist palsy in all cyclists? What is the prevalence of cyclist palsy in professional cyclists?
- In this study, there was no difference in motor symptoms but there was a difference in sensory symptoms in mountain bikers compared to road cyclist. The authors discuss this could be due less options for hand positioning in mountain bike bars. Would the use of bar ends, togs (http://togs.com/pages/wholesale-usa) or an ergonomical grip (such as http://www.ergon-bike.com/us/en/product/gp1) change the symptoms of nerve compression?
- This study was performed over a short time period. How long do subjects have the symptoms of nerve compression and is there any electrodiagnostic evidence of nerve injury.
Author: Alexandra Flis, MD
