Cyclist's palsy

Description[1]

Cyclist’s palsy, or ulnar neuropathy, is a familiar affection of the long-distance cyclist, mostly due to overtraining. Another name for this ailment is handlebar palsy. Typically the ulnar nerve becomes irritated and compressed in the wrist within or distal to Guyon's canal, due to the pressure exerted on the hands on the handlebars. This is even intensified when riding on rough terrain. Furthermore, when people are riding the bike, they often have a hyperextended position of the wrist resting on the handlebars or hoods, contributing to the neuropathy by compressing and stretching the nerve as it passes from wrist to hand. [1]
The symptoms include numbness, tingling, weakness, clumsiness, cramping, pain and possibly motor limitation. The term palsy is used because the cyclist's hand often develops muscle paralysis. The affection can impact both sensory and motor functions of the hand, depending on the branch of the ulnar nerve that is affected. [1][2]

Cyclists palsy ulnar involvement.jpg

It is difficult to determine the exact incidence rate for this type of non-traumatic overuse injury, because typically individuals often consider this injury not severe enough to seek medical care. This means that patient records are not always available. The prevalence of hand and wrist non-traumatic ulnar or median nerve compression described in the literature as manifesting itself in sensory or motor disturbance, ranges from 10% to 70%. This very wide range in frequency can be clarified by the fact that if a study is based on self-reporting by patients, it are mostly those persons who have suffered an injury that will report. This figure should thus not be generalized to the entire cycling population. [5]

Clinically Relevant Anatomy[2][3]

The ulnar nerve is a branch of the medial cord of the brachial plexus, which travels distally along the medial side of the arm. It passes posteriorly to the medial epicondyle at the elbow, then if follows along the ulna towards the hand. The nerve gives off two sensory branches which supplies sensation to the dorsomedial hand, the 5th digit, and half the 4th digit. At the wrist, the ulnar nerve enters the hand by passing through Guyon’s Canal. This tight tunnel is formed between the hamate, the pisiform, and the pisohamate ligament which helps keep these carpal bones together. Either within or just beyond Guyon's Canal, the ulnar nerve divides again in two motor branches.

In the cyclist, it is at or just before Guyon’s Canal where compressive injury to the ulnar nerve mostly commonly occurs.[4].


Ulnar nerve.jpg

Epidemiology/Etiology[2]

Cyclist's palsy typically develops during long-distance or prolonged cycling and occurs with both mountain bike and road cyclists. The position of the hands while holding the handlebar gives pressure on the ulnar nerve in the wrist. This pressure of holding the handlebar in combination with vibrations from the road or trails can be enough to damage the nerve due to compression. Especially when cycling downhill, a large part of the body weight is supported by the hands on the corner of the handlebar. This leads to an even higher load on Guyon’s canal in the wrist. Cyclists also often place their hands in an hyperextended position on the handlebar. All this can cause neuropraxia, a disorder of the peripheral nervous system in which there is a temporary loss of motor and/or sensory function due to blockage of nerve conduction. [1][2][4]
Other factors which can contribute to the occurrence of cyclist's palsy are general fatigue which leads to increased weight bearing on the hands, not changing hand position on the handlebar frequently enough, wearing ill-fitted or worn-out gloves, improper bike fit, using worn-out handlebar paddings, wrong shape or size of the handlebar or malposition of the saddle causing improperly distributed body weight on the hands holding the handlebar. [2][5][6][11]

Characteristics/Symptoms[1]

The exact symptoms of cyclist's palsy may vary from one person to another, depending on the severity of the condition, but mostly depending on whether only the sensory branch the ulnar nerve is impacted, or only the deep motor branch, or both. [6]
Compression of the sensory branch of the ulnar nerve will present itself in sensory disturbances, such as numbness and tingling in the ulnar innervated areas of the affected hand, namely the ring finger and the little finger. These symptoms are easily recognisable and often go away within a day or two. [2][6]
Compression of the deep motor branch of the ulnar nerve will present itself in motor deficits, such as weakness, clumsiness and possibly motor limitation due to loss of muscle function in the hand. These latter symptoms are often less distinguishable and if no sensory fibers are equally affected, a patient might continue cycling with an on-going compression of the motor branch, not realizing that there is an injury until a severe lesion develops. When there is a prolonged outage of innervation of the muscles in the hand by the ulnar nerve, the image of a 'claw' hand can be seen, with particular palmar flexion of the 4th and 5th digit . Correct and timely treatment of this injury is important and the healing process can take from some week to some months. In case a patient does not receive treatment, the ulnar nerve entrapment can cause atrophy of the intrinsic hand muscles or a paresthesia of the hand muscles innervated by the ulnar nerve, which will be permanent. [2][4][6][7]

Differential Diagnosis[2]

It is important to understand the signs and symptoms of this ailment so that it can be identified and proper diagnosed without having to seek numerous tests.

Assessment of the person's ability to adduct the thumb should be performed. If weakness is apparent, this could be the result of paralysis of adductor pollicis.

Paralysis of the interossei muscles is also possible, and would present as an inability to abduct and adduct all the fingers. To examine, the person places his/her hand on the table and the therapist asks him/her to lift the 3rd finger upwards. The person is then asked to adduct and abduct this finger pertaining to the 4th finger. This is not possible if the person has cyclist’s palsy. In this case, a shift from the flat of the hand and the wrist to the ulnar side would be observed as a compensation.

People withe cyclist’s palsy in advanced stages could have a claw hand, in which case surgery is sometimes indicated.

Another important question in the differential diagnosis of ulnar nerve entrapment is which part of the ulnar nerve is affected. Compressions of the ulnar nerve at the level of the elbow (i.e. cubital tunnel syndrome) or the neck (i.e. scalenus syndrome) require different treatment. Additional examination is needed to trace the exact place of compression and underpin the diagnosis with more certainty. When comparing the symptoms of cyclist's palsy with cubital tunnel syndrome (which occurs more frequently), a different clinical image is seen. People

who suffer from the cubital tunnel syndrome primarily suffer from sensory signs which occur in an early phase and get a faster diagnosis. They rarely have a claw hand. This 'claw' hand particularly occurs when there is a prolonged outage of innervation of the muscles by the ulnar nerve, which causes atrophy. Because often no sensory fibers are affected with cyclist's palsy, a claw hand can develop in an advanced stage of the disease. [16][17][21]
Apart from ulnar nerve compression at Guyon's canal resulting from pressure during cycling, there are a number of other injuries that can cause ulnar neuropathy in the wrist by compression. A fracture of the hamate bone or trombosis or aneurysm of the ulnar artery can also put pressure on the ulnar nerve. Other causes of compression at Guyon's canal can be a hypermobile pisiform bone, occupational traumatic neuritis, musculotendinous arch, tenosynovitis of the flexor tendons, crutch use, osteoarthritis, nodular synovitis (giant cell tumor) and compression from wrist ganglions, lipoma or other tumors in the wrist. Developing carpal tunnel syndrome can also result in ulnar entrapment. In case of carpal tunnel syndrome, the shape of the carpal and ulnar tunnel will change, or when surgery is performed to release the carpal tunnel, it is possible that the ulnar tunnel is touched, which can cause damage of the ulnar tunnel. It is thus important to differentiate and to determine the exact cause of the symptoms. [6][7][8][9][10][11][12][13]

Diagnostic Procedures

After the initial assessment, additional imaging such as ultrasound, CT-scan, and MRI can be performed to help confirm the diagnosis and determine the location of the compression.If the patient indicates the region where there is an abnormal feeling and this region is maximum 6 cm above the wrist, then we can be sure that it involves an ulnar nerve entrapment. But if it is situated more than 6 cm above the wrist, then it involves a cubital tunnel syndrome. [7]
When we are able to localize the exact place on the hand where the patient has a numb feeling, we can differentiate between a carpal tunnel syndrome or an ulnar tunnel syndrome. It is thus crucial to locate the exact place of compression and to differentiate it from other diseases. [7]

Examination

Electrodiagnostic studies can be used to localize the site of nerve compression and to determine the extent of the defect. More specifically, electromyography (EMG) measures the electrical activity of muscles at rest and during contraction, and may reveal degeneration in the nerves supplying a muscle when the patient is suffering from persistent weakness. The EMG has to be performed bilaterally and comparative for both hands. EMG examination will provide all the information that is necessary to make the correct diagnosis and to initiate treatment.
In case of nerve compression, EMG examination is often performed in combination with Nerve Conduction Studies (NCS). The latter are used mainly for evaluation of paresthesias (numbness, tingling) and/or weakness of the arms and legs and specifically evaluate the ability of electrical conduction of the motor and sensory nerves of the human body.
However, the use of EMG is not absolutely necessary. Other examinations can be performed, such as radiography which will give an image of possible bone damage, a scanner or arthroscanner which will give information about the ligaments and echography which will help to define if there is a cyst or another tumor. 
Finally, there is the physical examination. Here it is necessary to use a nerve provocation test. This can be a Spurling’s test2, a combined pressure and flexion test, an elbow flexion test3, Tinel’s sign, an elbow pressure test1 or a motor Tinel’s sign. However, these test will not always give certainty as to whether a patient is suffering from nerve compression or not, since the same symptoms can also be linked to other conditions. [6][7][14][15]

Prevention[1]

Prevention is the most important part in avoiding Cyclist's Palsy, and it can be effectively prevented. Cushioning the pressure points by using padded handlebars and padded cycling gloves is effective. This provides an extra layer or protection to better absorb shock and protect from pressure.

The position of the hands on the handlebars is also important. Individual sizing/fitting of the handlebar and riding position is crucial for preventing this condition[5]. The cyclist should regularly change the hand position on bars.

Enthusiastic long-distance cyclists should also adopt a comfortable and resilient riding posture. If the trunk musculature gets fatigued, the hands will invariably bear more weight to stabilize him/her on the bike. Developing a better posture on the bike requires strong trunk muscle endurance[4].

[6]

Medical Management


Cyclist's palsy is a type of nerve injury which is self-limiting and in most cases does not need medical intervention. Depending on the severity of the condition, the doctor can prescribe analgesics to alleviate pain or anti-inflammatory medication to remove the inflammation. Even corticosteroid injections could be required to reduce swelling and ease the pressure on the nerve. [2][17]

If conservative treatment is not successful and/or symptoms remain or worsen progressively after interruption of the activity which has caused the ulnar nerve compression (i.e. cycling), decompression surgery (i.e. to release of the ulnar nerve and take away the pressure) might be considered. [16][17]
Physical Therapy

Physical Therapy Management

Cyclist's palsy is a form of neuropraxia and gives temporary motor paralysis with minimal sensory and autonomic function loss. It is a reversible process, if the mechanical compression stops. As such, the nerve will regenerate on its own and function of the muscles will be restored. But the symptoms of handlebar palsy can take weeks to several months to heal, depending on the severity of the condition. While the nerve and muscles are regenerating, the patient needs to interrupt his sport activities for a while. [2][18]
To advance the healing process, the physiotherapist can use heat and cold therapy to calm pain and to reduce swelling. Other modalities such as electric stimulation, low level laser, ultrasound and soft tissue techniques will also help to improve the condition.
During rehabilitation, the physiotherapist can also give exercises specifically to strengthen the hand muscles, such as:
- finger bending exercise: start from a stretched hand, bend your fingers of the affected hand in a right angle and hold for 10 seconds while keeping your fingers straight; repeat 5 times.
- finger squeeze: place a small object (e.g. pen, coin, sheet of paper, ...) between 2 fingers of the affected hand and hold for 10 seconds; repeat 5 times for each pair of fingers and then move to the next fingers.
- grip strengthening: use a rubber ball and squeeze it with the affected hand; hold for 10 seconds and repeat 10 times. Build up gradually to 3 sets of 10. [2][7][18]
Stronger hand muscles will also help to prevent cyclist's palsy from recurring.

The patient can also do a number of motion exercises focusing on the entire area where the ulnar nerve lies, from the neck to the hand. These will be beneficial in improving and restoring mobility.
- cervical range: rotation of the head, flexion and extension of the neck, and side bending of the neck; hold each position for 10 seconds and then return to neutral position.
- scapular range: start from a standing position, pull up your shoulders and keep for 5 seconds, then squeeze the shoulder blades backwards together and hold for 5 seconds and finally pull the shoulder blades down and hold again for 5 seconds, then relax; repeat 10 times.
- elbow range: start from a standing position, bend your arm at the elbow and bring up the hand towards the shoulder, then straighten again; repeat 10 times.
- wrist range: bend the wrist forward and back to neutral position, then bend the wrist backward and back to neutral position; hold each position for 5 seconds; repeat 10 times. [2][18]
In order to avoid cyclist's palsy or to reduce prevalence of this type of non-traumatic hand and wrist injury during cycling, it is most important to have a look at the prevention strategies.
A first effective measure is to cushion the pressure points, by using padded handlebars and padded cycling gloves. This provides an extra layer of fat tissue inside the palm of the hands, so that there is a better shock absorption and protection from pressure. [1]
Also the position of the hands on the handlebar is most important. The cyclist should try to avoid an hyperextended position of the wrist. Furthermore, during a long ride it is advisable to change hand position regularly. [1][2][18]
Individual adaption of the type of handlebar and consequential riding position is equally crucial in the prevention of this ailment. Using an upright horn handlebar instead of a drop model might be considered for certain individuals. This will bring the torso position more upright and will diminish the pressure on the hands. Another option is to equip the bike with both a conventional handlebar and an aerobar, which will allow the cyclist to lean forward and to rest the forearms on pads during certain parts of the track, so that pressure can be taken away from the hands temporarily during a cycling trip. [1][4][5]
Enthusiastic long-distance cyclists should also adopt a comfortable and resilient riding posture. If the trunk gets tired or in case of general fatigue, the hands will invariably bear more weight to stabilize the rider on the bike. Developing a better posture on the bike requires strong trunk muscle endurance. Make sure to sit in a comfortable position on the bike. The torso should lean forward 45 to 50 degrees. The shoulders should be relaxed. The arms should be at 90 degrees to the torso. The elbows should be slightly bent, not straight or locked. Bent elbows will act as shock absorbers for any bumps in the road and will alleviate shocks from the hands. The hands should not be gripping excessively, but resting smoothly on the handlebar. [1][3][10][11]
Finally, the cyclist should make sure to ride on the right size of bicycle and to adapt the position of the saddle and handlebar to make sure that these allow to sit on the bike in a normal position. The following adjustable variables of the bike set-up should be reviewed carefully and adapted in function of the body size and shape of the individual cyclist. This will prevent many overuse injuries during cycling.

1. Frame size:
While standing astride the frame of the bike, there should be a 2.5 to 5 cm clearance between the top tube and the cyclist's crotch. For a mountain biker, this will be a bit more. Upon buying a new bike, the correct frame size can be calculated by multiplying the inseam from floor to crotch with a factor, depending on the type of bike the cyclist wants to buy: mountain bike, racing bike, city bike. Also the crank length should be checked. The crank should be 21% of the length of the inseam.
2. Saddle height:
The saddle height should be set so that the knee angle of the extended leg remains flexed to approximately 25 to 30 degrees when the pedal is at 6 o'clock position.
If the saddle is too high, this will put the hamstrings at a mechanical disadvantage at the extreme of the downstroke, increasing the risk of hamstring strains
If the saddle is too low, this will increase the risk of anterior knee pain because of the pressure that goes through the knee increases. Also back pain can be a consequence.
3. Saddle angle:
The saddle top surface should be set level. If the saddle tilts more forward, this will transfer the body's weight onto the hands and arms. If the saddle tilts more backwards, this will increase the flexion at the lumbar spine and also the pressure on the groin.
4. Saddle position:
To determine the correct saddle position, sit on the bike and place the feet on the pedals. Place the pedals in the 3 and 9 o'clock position. The saddle is correctly positioned when the tibial tuberosity of the leg in front position is 1 cm behind the pedal axle. If the saddle is set too far forward, this will increase the load on the knee cap, with a risk of over-use injury and reduction in overall leg efficiency.
5. Handlebar height:
The handlebar should be placed 2.5 to 5 cm below the top of the saddle. For a recreational cyclist, the position will be somewhat higher.
If the handlebar is too low, the posture will be more aerodynamic, but this will increase the weight of the upper body on the wrists on the handlebars.
6. Handlebar width:
The handlebar should be as wide as the shoulders. This ensures a good chest expansion and breathing. A narrower handlebar with bar extensions will give you a greater variety of comfortable hand positions.
If the handlebar is too wide, this will give more stable control (e.g. for mountainbike rides), but will become uncomfortable during longer rides.
7. Handlebar position:
The handlebar has the right distance when the finger can touch the transverse part of the handlebar if the elbow is placed on the tip of the saddle.
If the handlebar is too far away, this will increase muscle tension in shoulders and neck and will result in neck pain, headache and shoulder tension.
If the handlebar is too close, this will place the spine into a flexed position and will put a greater strain on the lower back, upper back and neck.
[1][2][14][19][20]

References

  1. 1.0 1.1 1.2 Gloria,C. Cohen, MD, CCFP. Cycling Injuries. Canadian Family Physician, VOL 39, March 1993
  2. 2.0 2.1 2.2 Bickerton, T. Handlebar Palsy. Where to Ride. [ONLINE] accessed on 24 September 2010. Available at http://www.wheretoridelondon.co.uk/London-262.html
  3. Marieb EN, Wilhelm PB, Mallatt JB. Human Anatomy. 7th ed. San Francisco: Pearson; 2012.
  4. 4.0 4.1 Praktijkgids Pols-en handletsels. Meeusen, R. p. 74-77
  5. Capitani, D. and Beer, S. Handlebar palsy-a compression syndrome of the deep terminal (motor) branch of the ulnar nerve in biking. Journal of Neurology. 7 May 2002, pag. 1441-1445
  6. Specialized Bicycles. Specialized Body Geometry Gloves Available from: https://www.youtube.com/watch?v=EYlU6TBAhlg [last accessed 7/2//2016]

1. ↑ 1.0 1.1 1.2 1.3 Cohen, Gloria, C. MD, CCFP. Cycling Injuries. Canadian Family Physician, VOL 39, March 1993:628-632
Level of evidence 5
2. ↑ 2.0 2.1 2.2 Bickerton, T. Handlebar Palsy. Where to ride. [ONLINE] accessed on 24 september 2010. Available at http://www.wheretoridelondon.co.uk/London-262.html
Level of evidence 5
3. ↑ 3.0 3.1 Praktijkgids Pols-en handletsels. Meeusen, R. p. 74-77
4. ↑ Capitani, D. and Beer, S. Handlebar palsy-a compression syndrome of the deep terminal (motor) branch of the ulnar nerve in biking. Journal of Neurology. 7 May 2002, pag. 1441-1445
Level of evidence 2B
5. ↑ Dettori, N.J. and Norvell, D.C. Non-traumatic bicycle injuries: a review of the literature. Sports Med; 2006; 36 (1):7-18
Level of evidence 2A
6. ↑ Patterson M., Jaggars, M. and Boyer M. Ulnar and Median Nerve Palsy in Long-distance Cyclists. A Prospective Study. American Journal of Sports Medicine; 2003, Vol. 31, No. 4,:585-589
Level of evidence 2B
7. ↑ Moutet,F. Compression du nerf ulnaire à la loge de guyon Ulnar tunnel syndrome. Chirurgie de la main; 2004, 23, (1):S134-S140
Level of evidence 2C
8. ↑ Aguiar, P. et al. Surgical management of Guyon's canal syndrome, an ulnar nerve entrapment at the wrist: report of two cases. Arq Neuropsiquiatr; 2001 Mar, 59(1):106-11
Level of evidence 3B
9. ↑ Paget, J., Patel, N. and Manushakian, J. Ulnar nerve compression in Guyon's canal: MRI does not always have the answer. JSCR; 2013, 1
Level of evidence 3B
10. ↑ Ginanneschi, F. Ultrasonographic and functional changes of the ulnar nerve at Guyon’s canal after carpal tunnel release. Clinical Neurophysiology; 2010, 121:208–213
Level of evidence 1B
11. ↑ Budny, P.G. Localized nodular synovitis: A rare cause of ulnar nerve compression in Guyon’s canal. The Journal of Hand Surgery; 1992
Level of evidence 3B 
12. ↑ Scott, R. Incidental Guyon's Canal Release During Attempted Endoscopic Carpal Tunnel Release: An Anatomical Study and Report of Two Cases. The Journal of Arthroscopic and Related Surgery; 1993
Level of evidence 4
13. ↑ Miyamoto, W. Vascular leiomyoma resulting in ulnar neuropathy case report. ASSH; 2008
Level of evidence 4
14. ↑ Thompson M.J. and Rivara F.P. Bicycle-related injuries. Am Fam Physician. 2001 May 15;63(10):2007-2014
Level of evidence 2B
15. ↑ Goldman, S.B. A review of clinical tests and signs for the assessment of ulnar neuropathy. JHT; 2009
Level of evidence 5
16. ↑ Hankey, G.J. and Gubbay S.S. Compressive mononeuropathy of the deep palmar branch of the ulnar nerve in cyclists. Journal of Neurology, Neurosurgery, and Psychiatry; 1988, 51:1588-1590
Level of evidence 4
17. ↑ Lund, A.T. Treatment of cubital tunnel syndrome perspectives for the therapist. Journal of hand therapy; 2006
Level of evidence 2C
18. ↑ Ulnar Neuropathy (Handlebar Palsy). Rehabilitation Exercises. The Sports Medicine Patient Advisor, 2003.1
Level of evidence 5
19. ↑ Australia physiotherapy association, Bike Setup, http://www. physioadvisor.com.au/16394050/bike-setup-cycling-injuries-physioadvisor.htm, 20
Level of evidence 5
20. ↑ John Miller, Cycling Pain and Injuries, http://www.physioworks. com.au/Injuries-Conditions/Activities/cycling-injuries; 2014
Level of evidence 5
21. ↑ Murata K. Causes of Ulnar Tunnel Syndrome: A Retrospective Study of 31 Subjects. The Journal of Hand Surgery; 2003:647-651
Level of evidence 3A