The glenohumeral joint is multiaxial and has a wider range of motion than other joints. In order to achieve such a range of motion, the glenohumeral joint has to sacrifice a more stable bone structure, and this lack is compensated by muscular stability. When a change in normal muscular function occurs eg after a stroke, this presents a potential risk for subluxation.
During the initial period following a stroke, the hemiplegic arm is flaccid or hypotonic. The shoulder muscles are unable to anchor the humeral head within the glenoid cavity, resulting in a high risk of shoulder subluxation.
During this period, the affected extremity should be properly supported; the weight of the arm itself may be enough to cause subluxation.
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| Shoulder Subluxation |
Glenohumeral subluxation may also occur as a result of adopting incorrect sleeping postures, lack of support when the patient is in a vertical position, or tension on the hemiplegic arm when the patient is being moved from one place to another.
In long term GHS may lead to the complications that may delay the recovery of upper extremity function. eg:
- Adhesive capsulitits,
- Reduced proprioception
- Painful Hemiplegic Shoulder (PHS)
Epidemiology
The incidence of shoulder subluxation in patients following a stroke varies from 7–81% (depending on the measurement methods used and the time frames over which it is assessed) and 73% occur in the acute stage In a 10-month follow-up study, shoulder subluxation was shown to be further aggravated in 67% of patients over time. |
| Shoulder Subluxation |
Pathomechanics and Risk factors
Studies had shown that the supraspinatus, and to a lesser extent the posterior deltoid muscles, played a key role in maintaining glenohumeral alignment and in preventing downward subluxation of the humerus.During the flaccid stage, the trunk tends to lean or shorten toward the hemiplegic side, which causes the scapula to descend from its normal horizontal level.
The trapezium and the serratus anterior also become flaccid, causing the scapula to rotate downwardly.
Without normal tone, the rotator cuff can no longer maintain the integrity of the GHJ.
These conditions contribute to a subluxing GHJ.
During the spastic stage, the pectoralis major and minor, rhomboideus, elevator scapulae, and latissimus dorsi can become hypertonic, further rotating the scapula downward, causing GHS.
In contrary, other studies had not shown a relationship between scapular orientation and GHS.
Other factors contributing to subluxation include
- Improper positioning,
- Lack of support in the upright position
- Pulling on the hemiplegic arm when the patient is transferred.[6]
- Severe loss of motor function and apparent absence of supraspinatus muscle contraction are potential risk factors for GHS, [6]
Assessment
Several method for the assessment of Shoulder subluxation.Radiographic measurements ( X- ray and ultrasound ) considered a standard measurement, have been used in several studies to assess the effectiveness of therapy or development of GHS over time.
But due to the several problems, such as costs, exposure to radiation, specialized eqiupments or delayed feedback for therapeutic choices, make measurements difficult to put into practice in many clinical settings.
So other method commonly used is Fingerbreadth palpation method.
So other method commonly used is Fingerbreadth palpation method.
Fingerbreadth Palpation Method
Patients were seated in a chair or wheelchair with both feet flat on the ground or on a footrest. The physical therapist first assessed the unaffected side to palpate the gap between the acromion and the head of the humerus, and this assessment was repeated on the affected shoulder.Shoulders were positioned in neutral rotation, with the arm hanging by the side (thumb pointing forward) close to the body with no abduction. Some patients who demonstrated high tone were unable to hang their affected arm freely by the side. For these patients, the shoulder was maintained in internal rotation with slight elbow flexion and the forearm resting on their lap.
Glenohumeral subluxation was defined as a palpable gap between the inferior aspect of the acromion and the superior aspect of the humeral head that is ½ fingerbreadth or more. A 0–5 grading scheme was used:
Lap trays, Pillows and foam support help to keep the arm and shoulder supported in the correct position. Good positioning will help reduce strain on your ligaments and prevent frozen shoulder from occurring.
Positioning
Lap trays, Pillows and foam support help to keep the arm and shoulder supported in the correct position. Good positioning will help reduce strain on your ligaments and prevent frozen shoulder from occurring.
Slings
Studies has shown the effectiveness of slings to prevent GHS but no investigation assessed the effectiveness of slings in relation to the duration of their use.Supports from slings have various purposes: realigning scapular symmetry, supporting the forearm in a flexed arm position, improving anatomic alignment with an auxiliary support, or supporting the shoulder with a cuff.
The use of slings has been considered a contraindication by some authors because slings can facilitate an increase in flexor tone and synergistic patterns, cause reflex sympathetic dystrophy, restrain functional recovery, obstruct arm swing during walking, and for some, impair body image.
On the other hand, slings are generally more simple for caregivers to use than functional electrical stimulation (FES) or strapping, and they can be combined with the other treatments. Reviewing the literature and knowing the structural characteristics of slings can help identify the best treatment for preventing and treating GHS.
The result of the study done by White et al, 2018 shows that longitudinal strapping of the shoulder in patients with stroke seems to positively influence shoulder subluxation and pain.
Neuromuscular Approaches: Neuromuscular electrical stimulation
Electrical stimulation can prevent shoulder subluxation and decrease shoulder pain in acute phase, but this effect was not maintained after the withdrawal of treatment in later follow ups.
The use of slings has been considered a contraindication by some authors because slings can facilitate an increase in flexor tone and synergistic patterns, cause reflex sympathetic dystrophy, restrain functional recovery, obstruct arm swing during walking, and for some, impair body image.
On the other hand, slings are generally more simple for caregivers to use than functional electrical stimulation (FES) or strapping, and they can be combined with the other treatments. Reviewing the literature and knowing the structural characteristics of slings can help identify the best treatment for preventing and treating GHS.
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| Shoulder Subluxation |
Strapping/Taping
Shoulder strapping has been shown to be useful in the first period after stroke. Shoulder strapping is used clinically in patients with stroke, with a variety of techniques being employed; however, White et al. had brought out two main trends emerging from the literatures.Longitudinal strapping method
It involves two to three strips of strapping that are applied with a cephalad tension over the anterior, middle and posterior deltoid to end over the shoulder complex, sometimes with an anchor strip applied.Circumferential strapping method
It involves the application of strapping around the shoulder joint, originating on the clavicle, wrapping around the deltoid to go under the axilla (over a protective pad) and ending on the spine of the scapula.The result of the study done by White et al, 2018 shows that longitudinal strapping of the shoulder in patients with stroke seems to positively influence shoulder subluxation and pain.
Neuromuscular Approaches: Neuromuscular electrical stimulation
Electrical stimulation can prevent shoulder subluxation and decrease shoulder pain in acute phase, but this effect was not maintained after the withdrawal of treatment in later follow ups.
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