The Pencil Exercise

Abstract

Background:

Voluntary posterior shoulder instability is a rare condition, with a prevalence of 0.5% to 2.6% in young adults, in which the patient is able to provoke a dislocation or subluxation through voluntary activation of the muscles. Studies have shown results that highlight the importance of abnormal cortical activation in this population and suggest physiotherapeutic treatment as first line.

Indications:

Currently, there are a wide range of options of physiotherapeutic treatment for this condition, such as muscle reinforcement, scapulohumeral coordination, and/or muscle activation with electrodes, all with acceptable results. Simple, low-cost neuromotor rehabilitation is based on the simplicity of a different approach. We believe that with distal-proximal neuromotor rehabilitation we can improve a physiological muscle function.

Technique Description:

The goal of the pencil exercise is to stimulate the cerebral cortex by making circular movements with a pen between the fingers, bridging abnormal voluntary stimulation and activation of the shoulder muscles, allowing the patient to focus, by the view, only on hand movements.

Results:

In this case, we have achieved the bypass of the abnormal voluntary stimulation and activation of the shoulder muscles and improve the patient's physiological shoulder function with the implementation of the pencil exercise.

Conclusion:

This technique may be an effective option for the treatment of voluntary posterior shoulder dislocation because it is based on the stimulation of the cerebral cortex and not on traditional physiotherapeutic or surgical interventions. It is important to note that more research is needed to validate the results of this technique and determine its long-term efficacy.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

Voluntary posterior shoulder instability (VPSI) is a rare condition that can be difficult to treat. The aim of this video is to propose a new distal-proximal neuromuscular rehabilitation treatment to this condition called the pencil exercise.

None of the authors have any relationship to disclose in this presentation.

In the classification by Moroder, this condition belongs to group B1, which includes all patients with recurrent dynamic posterior instability events that occur in the form of a functional instability. ⁹

In type B1, the patient is able to induce subluxation through voluntary abnormal activation of the muscles.

Typically, it is caused by the atraumatic development of an aberrant shoulder muscle activation pattern during childhood and adolescence.

This condition has a prevalence ranging from 0.5% to 2.6% in young adults. ¹

The clinical presentation also includes hyperlaxity, that is, the ability to painlessly dislocate or subluxate voluntarily the humeral head during arm movement, followed by a pathological scapular movement pattern. Often the patient is able to do this in multiple directions. ⁴

Currently, there is a wide range of options for treating this condition. The first line of treatment for these patients is physiotherapy and reeducation programs.

• When the condition is voluntary, some studies suggest the use of exercises to increase postural stability and selective activation of shoulder muscles, aimed at correcting abnormal muscle patterns and restoring proper scapula-humeral movements.

• There appears to be underactivity of shoulder-stabilizing muscles, similar to pacemaker shoulder treatment, which involves the application of transdermal electrical stimulation to hypoactive muscle groups during training exercises.^8,11

• Other authors have shown good results with strict multidisciplinary physiotherapy programs, lifestyle modifications, and coping strategies to manage symptoms, but focusing on hyperactivity of shoulder muscles. All showing positive outcomes and improved quality of life.^5,7

But all the rehabilitations offered to treat this are proximal-distal, seeking to normalize the area of dysfunction concentrating on the shoulder.

Surgical treatment is an option, but many studies have shown that it is only valid when patients who had voluntary posterior instability in childhood and adolescence become involuntary and uncontrollable.^2,6

• This can happen after a traumatic event.

• Or because over time, increased capsular laxity and resultant labral injuries end in a recurrent subluxation or dislocation that may be painful.

• Only in these cases surgery has satisfactory clinical results. However, the risk of recurrence after stabilization surgery can get up to 30%.

In general, it can be said that there is a low level of consensus regarding the management of voluntary shoulder instability. These treatments mentioned before address all the factors and show satisfactory results.

But we believe that we can achieve a similar or even better result with an easier and more accessible treatment, based on distal-proximal rehabilitation, meaning starting from the hand.

In the first video, we present a case of a young woman with voluntary posterior instability of the left shoulder. It can be observed that when she actively moves her shoulder, she is able to dislocate and reduce it effortlessly.

In the second video, a similar case is presented, a middle-aged man, with the same pathological pattern also on his left shoulder.

Next, we show that passive mobilization of the shoulder does not result in subluxation.

Full range of motion is achieved in both patients. This opens the way to a simple test if the patients are able to perform the gestures with their fingers.

Howard et al ³ have shown results highlighting the importance of abnormal cortical activation in this population, suggesting dysfunction in the cerebral circuits involved in motor control and shoulder joint stability.

The goal is to bypass the abnormal voluntary stimulation and activation of shoulder muscles through exercises focusing on the hand. We call this the pencil exercise.

The function of the shoulder is to provide mobility, flexibility, and stability to the upper limb. The coordination between the shoulder and the hand allows for delicate tasks, but it is always the hand leading the movement. When we want to grab an object, move it, or bring it toward us, we don't think directly on moving the shoulder, but rather on moving the hand. The rest is done automatically, and it is unconscious.

The Penfield Homunculus Cortical Map shows that the somatosensory cortex areas dedicated to process information from different body parts are not equal. The cortical representation of the shoulder is approximately 1% compared with the cortical representation of the hand, which can be up to 25% or more in some areas of the somatosensory cortex. ¹⁰

The exercise starts with the patient seated and we ask to grab a pen or pencil and initially making fine motor movements, moving the pen between the fingers nonstop without dropping it and concentrating only on the hand. As we can see, the next step is to incorporate movements of the entire arm.

On top of that the patients have to copy very carefully and follow the position of the therapist's hand, at a distance of 10 to 15 cm, always looking and concentrating on the hand.

So now they are controlling the pen with the fingers and following movements with the entire arm without being conscious that the shoulder is also participating in this process.

We do this for a couple of minutes until the patient controls the pen with the fingers. Next, the patient is allowed to continue with the movements but without having to imitate the movements of the therapist.

We take the time that is needed to reach autonomy of the patient. It should be clarified that everything happens on the same day, from the patient consulting for voluntary luxation until he returns home able to do this exercise alone.

In conclusion, VPSI is a rare condition where we all agree that abnormal muscle activation is the center of the problem. The first line of treatment for these patients is physiotherapy and reeducation programs, all with acceptable results, but focused on proximal-distal rehabilitation. Surgical treatment is only valid when instability becomes involuntary and uncontrollable. We propose the pencil exercise for treating this condition based on the theory of distal-proximal neuromotor rehabilitation. Further studies are required to define the effectiveness of this technique.