(aspects of sports medicine)

A Unique Case of in a Bicyclist Requiring Operative Release LT Stacey Black, MD, MC, USN, CDR Eric Hofmeister, MD, MC, USN, and CAPT Michael Thompson, MD, MC, USN

Abstract lnar tunnel syndrome Case Report The continued growth of recre- (UTS) is an uncommon A 29-year-old woman experienced ational and competitive sports problem, seen usually in the acute onset of numbness and is accompanied by the need for association with occupa- tingling in the ring and small fin- health care providers to recognize Utional injury involving repetitive trau- gers of her left hand following an and treat conditions in athletes that ma or pressure. It has been noted in 80-mile bike ride. Clawing of the have been traditionally associated with other occupational injury. This construction workers, carpenters, and digits of that hand began immedi- 1 is particularly important when early pneumatic drill operators. Potential ately. Despite a period of splinting, diagnosis and prompt intervention structural etiologies include throm- activity modification, and avoidance for prevention and treatment may bosis of the ulnar artery, prolifera- of all provocative activities, includ- alter the outcome. We present an tion of synovium, prominent hook of ing biking, her symptoms persisted interesting case of ulnar tunnel hamate, schwannoma, and ganglion and even progressed. She was seen syndrome in a high-performance cyst. 2 The common factor in all of in the occupational therapy clinic 5 bicyclist with compressive ulnar these is sustained pressure over the weeks after her injury, having been neuropathy refractory to nonop- hypothenar area or a space-occupy- referred for weakness and decreased erative management but success- fully treated with surgical release. ing mass in Guyon’s canal. range of motion of the affected hand. We review evaluation, diagnosis, Symptoms of compres- At that time she had visible atrophy and historical and current treat- sion in the bicycle rider have been of her ulnar-innervated intrinsic mus- ment algorithms. a recognized problem since 1896, culature, and she was subsequently when Destot described the ulnar referred to the orthopedic hand sur- nerve being compressed at the pisi- gery service. LT Black is a Naval Flight Surgeon, HMH- 1 465, Marine Corps Air Station, Miramar, form. Since that time there have The patient denied pain at rest but California. been numerous case reports discuss- reported exquisite tenderness with CDR Hofmeister is a staff Orthopaedic ing the motor and sensory symptoms pressure over Guyon’s canal in the Hand Surgeon and Orthopaedic Intern Director, Department of Orthopaedic produced and whether conserva- left hand as well as decreased sen- Surgery, Naval Medical Center, San tive treatment is sufficient to obtain sation in the small finger and the Diego, California. symptom relief or surgical interven- ulnar aspect of the ring finger. Active CAPT Thompson is a staff Orthopaedic Hand Surgeon snd Director of Residency tion is necessary. In the vast major- range of motion of her ring finger Education, Department of Orthopaedic ity of reports reviewed, conservative proximal interphalangeal joint (PIP) Surgery, Naval Medical Center, San therapy resulted in symptom relief. was found to be 35° to 115°, with Diego, California. 3,4 In fact, some authors have recom- the distal interphalangeal joint (DIP) Requests for reprints: Eric Hofmeister, mended against surgery for this injury measured at 5°-55°. Active range of MD, Naval Medical Center San when it is associated with bicycling, motion of her small finger PIP was Diego, Department of Orthopedics, 34800 Bob Wilson Dr, San Diego, suggesting that nonoperative man- found to be 20°-94°, with the DIP CA 92134 (Tel: 619-532-8427; E-mail: agement should be the rule.5 of this finger measured at 15°-65°. [email protected]). We report a case of UTS that devel- The patient had full passive motion The views expressed in this article oped after an isolated bicycling event; of all her digits without contrac- are those of the authors and do not the patient had both motor and sen- tures. Measurement of her grip reflect the official policy or position of sory involvement, associated muscle strength was clinically significant, the Department of the Navy, Department of Defense, or the United States atrophy, and an ulnar claw deformity in that the right hand averaged 40 Government. that proved unresponsive to nonopera- pounds (using Jamar testing; Jamar tive treatment. Subsequent ulnar tun- Dynamometer, Model 1, Clifton, NJ), Am J Orthop. 2007;36(7):377-379. Copyright Quadrant HealthCom Inc. nel release led to a rapid and complete whereas the left hand averaged only 2007. All rights reserved. resolution of symptoms. 7 pounds (17.5% of the grip strength

July 2007 377 Ulnar Tunnel Syndrome

tion had markedly improved. Two- Table. Shea and McClain's Classification of point discrimination had improved Ulnar Nerve Compression Lesions6 to 5 mm in all fingertips, and she was able to rest her hands in a more Sensory Motor normal posture. Ten weeks post- Type Deficit Deficit Location operatively, all symptoms, includ- ing incisional tenderness, had com- pletely resolved. The patient had no I Yes Yes Ulnar nerve proximal to the canal or within Guyon’s canal before the bifurcation of the increased sensitivity and felt that she deep and superficial branches had regained full strength of her II No Yes Deep motor branch compression distal to affected hand. Full range of motion Guyon’s canal or within the canal distal to was noted, and 2-point discrimina- the bifurcation tion was 5 mm in all fingertips. The III Yes No, except Superficial sensory branch compression grip strength of the left hand has palmaris brevis distal to Guyon’s canal or within the canal improved to 37 pounds (88.1% of distal to the bifurcation the strength of the unaffected hand, Modified from Shea J, McClain E. Ulnar-Nerve Compression Syndromes at and below the Wrist. J Bone and Joint Surg. 1969;51-A(6): 1095- which was measured at 42 pounds 1103. Used with permission. on average). At her 2-year follow-up, the patient continued to have normal in the right hand). Her lateral pinch Despite continued occupational sensation and had returned to all was found to be 12 pounds on the therapy, splinting, and cessation of activities, including biking, without right hand and 4 pounds on the left, all bicycling, the patient’s symptoms any further incidents. and tip pinch was 11 pounds on the worsened over the ensuing 8 weeks. right hand and 2 pounds on the left. She elected to undergo a left ulnar Discussion Radiographic findings for the tunnel release. Under general anes- Guyon’s canal is formed medially by affected wrist were unremarkable, and thesia, a Brunner-type incision was the pisiform bone, laterally by the electromyography and nerve conduc- made over the interval between the hook of hamate, palmarly by the volar tion studies were obtained. The find- pisiform and the hook of the hamate, carpal ligament, and dorsally by the ings of these were abnormal, showing and Guyon’s canal was released in its transverse carpal ligament. The ulnar a prolonged latency of the ulnar sen- entirety. There was no evidence of nerve, artery, and vein pass through sory and motor nerve across the wrist any mass, aneurysm, or other space- the canal. Proximal to the canal, the of the left hand. The median, radial, occupying lesion, but there were dis- dorsal cutaneous branch of the ulnar

“Compared with the in the carpal tunnel, the ulnar nerve is more prone to injury by direct external compression in Guyon’s canal...” and dorsal cutaneous branches of the tinct narrowing and flattening of the nerve comes off to provide sensation ulnar nerve had normal conduction ulnar nerve in zone 2 directly beneath to the dorsal surface of the medial and latencies. Electromyography of the distal edge of the volar carpal liga- hand. Within the canal, the nerve the left upper extremity was signifi- ment. Postoperatively, the patient was branches into the superficial branch, cant for active and chronic denerva- placed in a volar splint for 2 weeks providing the hypothenar eminence, tion changes in the ulnar-innervated and then weaned out of the splint the small finger, and the ulnar portion intrinsic musculature. The more prox- and began early range-of-motion and of the ring finger with sensation and imally ulnar innervated muscles, such strengthening exercises. She reported the palmaris brevis with motor func- as the flexor carpi ulnaris (FCU) and that at 1 week after surgery sensation tion. The deep branch of the ulnar the flexor digitorum profundus (FDP), was dramatically improved, but the nerve provides the hypothenar mus- were normal. Specifically, the patient hand was still weak and she continued cles, interossei, the third and fourth had 1+ fibrillations and 1+ positive to show a positive Froment’s sign. lumbricals, and the adductor pollicis sharp waves in the first dorsal interos- One month after the procedure, with motor function. Compared with seous muscle, and her fourth dorsal the splint was discontinued, and the the median nerve in the carpal tun- interosseous muscle showed no fibril- patient still demonstrated residual nel, the ulnar nerve is more prone to lations but 1+ sharp waves and many weakness in the ulnar innervated injury by direct external compression polyfasciculations. intrinsic musculature but her sensa- in Guyon’s canal, because of its more

378 The American Journal of Orthopedics® E. Hofmeister et al superficial location.6 The area of the For treatment of UTS, a recent report or worsen. Furthermore, a greater transverse carpal ligament covering recommended that operations not be sense of urgency should attend con- the canal is also thinner than the performed on patients with ulnar neu- sideration of surgical decompression portion of the ligament covering the ropathy, as symptoms in the patients when there is unremitting numbness carpal tunnel.1 all resolved quickly.5 A prospective or progressive motor involvement. Specific patterns of ulnar nerve study on cyclists’ UTS published in compression syndromes are classi- 2003 found that 23 of 25 cyclists tested Authors’ Disclosure fied by the presence or absence of experienced motor or sensory symp- Statements and motor and sensory symptoms. A toms or both.8 Eight of the 25 had type Acknowledgments frequently cited classification sys- II lesions (32%), with type II lesions The authors report no actual or poten- tem is that of Shea and McClain,6 distributed equally betwen mountain tial conflict of interest in relation to who divided the lesions into 3 cat- bikers and road cyclists. Conservative this article. egories (Table). They found that therapy was recommended. type II lesions were the most com- References mon (52%), while 30% of lesions Conclusions 1. Richmond R. Handlebar problems in bicy- were type I, and 18% were type III. Given the increasing interest in cling. Clinics Sports Med.1994;13(1): 165- 172. The patient in the case we report and triathlons, orthopedic 2. Murata K, Shis J, Tsai T. Causes of ulnar displayed what these investigators surgeons should be prepared to see tunnel syndrome: a retrospective study of 31 classified as a type I lesion. Most more cases of ulnar nerve compres- subjects. J Hand Surg Am. 2003;28(4): 647- of the case reports about cyclists sion syndrome. This case report pre- 651. 3. Maimaris C, Zadeh H. Ulnar nerve compres- experiencing ulnar nerve compres- sents evidence that contradicts the sion in the cyclist’s hand: two case reports sion syndrome concern patients with contention that the symptoms of UTS and review of the literature. Br J Sports Med. either a type II or type III lesion. In will universally resolve with nonop- 1990;24(4): 245-246. one case report of a type I lesion in erative treatment, and it demonstrates 4. Kalainov D, Hartigan B. Bicycling-induced a cyclist, 3 the patient was noted to that good results can be achieved ulnar tunnel syndrome. Am J Orthop. 2003;32(4):210-211. have required only 4 days of conser- with surgical intervention in selected 5. Woischneck D, Hussein S, Hollerhage vative therapy to recover from mixed cases. As with other compressive H. Bicycle rider’s ulnar nerve paralysis. motor and sensory symptoms. neuropathies, surgical intervention Neurochirurgia. 1993;36(1):11-13. Woischneck reported a similar case might be considered for those patients 6. Shea J, McClain E. Ulnar-nerve compression syndromes at and below the wrist. J Bone of a patient who developed bilateral refractory to appropriate splinting Joint Surg Am. 1969;51-A(6):1095-1103. ulnar tunnel syndrome after prolonged and activity modification that remove 7. Capitani D, Beer S. Hand bar palsy, a mountain biking and had all of the further insult to Guyon’s canal. We compression syndrome with a deep termi- symptoms improve over time with non- feel that although a patient with UTS nal branch of the ulnar nerve, and biking. 5 J Neurol. 2002;249(10):1441-1445. operative measures. Capitani discussed may very well respond to conserva- 8. Patterson J, Jaggars M, Boyer M. Ulnar and a case of bicycle-induced UTS in which tive treatment, surgical intervention in long-distance cyclists. there was motor involvement only.7 is appropriate if symptoms continue Am J Sports Med. 2003;31(4): 585-589.

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