Shoulder Subluxation After Stroke: Causes, Symptoms and Treatment
NeuroRehab Team
Thursday, July 9th, 2026
Shoulder Subluxation After Stroke: Causes, Symptoms and Treatment
Shoulder subluxation is one of the most common complications of stroke, affecting between 17 and 81 percent of survivors with upper limb weakness depending on how it is measured and when. Despite how frequently it occurs, it is often poorly understood by survivors and caregivers, and sometimes inadequately managed in the early stages when prevention matters most.
Left unmanaged, shoulder subluxation causes pain, limits rehabilitation participation, and can significantly slow upper limb recovery. Managed well, it is a condition that can be prevented in many cases, treated effectively when it does occur, and in most cases does not need to be a permanent barrier to arm recovery.
This guide explains what shoulder subluxation is, why it happens after stroke, how to recognise it, and what the current evidence says about treatment.
What Is Shoulder Subluxation?
The shoulder joint is a ball and socket joint. The ball is the rounded head of the humerus (upper arm bone) and the socket is a shallow cup on the scapula (shoulder blade) called the glenoid fossa. Unlike the hip joint, which has a deep socket that provides significant stability, the shoulder socket is shallow. Most of the shoulder’s stability comes from the surrounding muscles, particularly the rotator cuff muscles, rather than from the bony structure itself.
In a healthy shoulder, these muscles hold the ball firmly in the socket at all times, including when the arm is hanging at the side. When stroke causes weakness or paralysis in the arm, these muscles can no longer do their job. The weight of the arm pulls the humerus downward, and the ball slides partially out of the socket.
This partial displacement is called subluxation. The ball does not come completely out of the socket, which would be a full dislocation. Instead, it sits slightly lower than it should, creating a visible and palpable gap between the top of the shoulder and the head of the humerus. This gap is often one to three finger-widths wide and can be felt and sometimes seen when the arm is hanging at the side.
Why Does Subluxation Happen After Stroke?
Shoulder subluxation after stroke is directly caused by weakness or paralysis of the muscles that support the shoulder joint. Specifically, the supraspinatus muscle, which is part of the rotator cuff, plays a critical role in preventing downward displacement of the humerus. When stroke affects the motor pathways controlling this muscle, the shoulder loses its primary support mechanism.
The risk and severity of subluxation depend on several factors:
Degree of arm weakness. The more severe the weakness or flaccidity in the affected arm, the higher the risk of subluxation. Survivors with complete paralysis of the arm are at the greatest risk. As muscle tone returns, the risk typically reduces.
Muscle tone changes. In the early phase after stroke, the affected arm is often flaccid, meaning the muscles have no tone at all. This is the highest-risk period for subluxation. As recovery progresses, muscle tone often increases and in some cases becomes excessive, which is spasticity. Paradoxically, the development of spasticity, while presenting its own problems, often reduces the degree of subluxation because the increased muscle tone provides some support to the joint.
Positioning and handling. How the affected arm is positioned and handled during the acute and sub-acute phases directly influences whether subluxation develops and how severe it becomes. Poor positioning, such as allowing the arm to hang unsupported for extended periods, accelerates subluxation. Correct positioning and careful handling can prevent or minimise it.
Scapular alignment. The position of the scapula affects the angle of the socket and therefore the stability of the joint. Weakness in the muscles that stabilise the scapula can contribute to subluxation by changing the orientation of the socket relative to the ball.
Signs and Symptoms of Shoulder Subluxation After Stroke
Shoulder subluxation is not always immediately obvious, particularly in the early stages. Knowing what to look for helps with early identification and treatment.
Physical signs
- A visible step or gap between the acromion (the bony prominence at the top of the shoulder) and the head of the humerus when the arm is hanging at the side
- The gap can often be felt by placing a finger between the acromion and the humerus and assessing how many finger-widths of space exist
- A visible dropping or squaring of the shoulder compared to the unaffected side
- The affected shoulder appearing lower than the unaffected shoulder
Symptoms the survivor may experience
- Pain in the shoulder, which may be felt at rest, during movement, or both
- A dull aching sensation in the shoulder and upper arm
- Discomfort or pain when the arm is moved, particularly into elevation or external rotation
- In some cases, subluxation is present without pain, particularly in the early flaccid phase
- Pain that worsens with activity, fatigue, or poor positioning
It is worth noting that pain is not always present with subluxation, particularly in the early weeks after stroke when sensation in the affected arm may be reduced. This can make it harder to identify and means that regular visual and physical assessment by the rehabilitation team is important, rather than relying solely on the survivor’s report of pain.
How Is Shoulder Subluxation Diagnosed?
Shoulder subluxation is typically diagnosed clinically by a physiotherapist or occupational therapist through physical assessment. The therapist will assess the degree of gap between the acromion and the humerus with the arm in a standardised position, usually hanging at the side. This is graded in finger-widths or using a standardised scale.
In some cases, ultrasound imaging is used to confirm the diagnosis and measure the degree of subluxation more precisely. X-ray may also be used, particularly to rule out other shoulder pathology or in cases where the degree of subluxation is uncertain on clinical examination.
Regular reassessment is important because the degree of subluxation can change over time as muscle tone and recovery progress. An assessment that showed significant subluxation in the first week post-stroke may show much less subluxation at the three-month mark as muscle function returns.
Treatment Options for Shoulder Subluxation After Stroke
Treatment of shoulder subluxation after stroke involves a combination of prevention strategies, positioning, supportive devices, and active rehabilitation. The evidence base for different interventions varies, and treatment should be individualised based on the severity of subluxation, the degree of pain, and the stage of recovery.
Positioning and handling
Correct positioning is the single most important preventive measure for shoulder subluxation after stroke. The affected arm should never be allowed to hang unsupported. In the early stages when the arm is flaccid and most vulnerable, positioning precautions should be in place at all times, including during sitting, standing, walking, and transfers.
Key positioning principles include:
- When sitting, the affected arm should be supported on a lap tray, armrest, or pillow at all times
- When lying, the affected arm should be positioned in supported alignment, not allowed to fall behind the body
- When standing or walking, the affected arm should be supported in a sling or by other means if muscle function is insufficient to maintain joint alignment independently
- All staff and family members involved in the survivor’s care should be trained in correct handling techniques, including how to assist with transfers without pulling on the affected arm
Pulling on the affected arm during transfers or assistance is one of the most common causes of subluxation worsening and should be avoided completely. The arm should never be used as a handle for repositioning or assisting the survivor to move.
Shoulder slings and supports
Shoulder slings and supportive devices are widely used to manage subluxation by providing external support to the joint and reducing the gravitational pull on the humerus when the survivor is upright. Several types of device are available, including traditional arm slings, hemislings, and more specialised subluxation supports.
The evidence on slings is nuanced. Slings are effective at reducing the degree of subluxation and providing pain relief when worn. However, they do not prevent subluxation from developing when not worn, they do not address the underlying muscle weakness causing the problem, and some designs can promote unhelpful positioning of the arm if worn for extended periods without adequate exercise.
Current clinical guidance generally recommends slings as part of a broader management program rather than as a standalone intervention, and emphasises that sling use should be accompanied by regular exercise and positioning out of the sling to prevent the development of secondary complications such as shoulder contracture.
Browse our range of shoulder subluxation slings designed specifically for stroke survivors.
Electrical stimulation
Neuromuscular electrical stimulation (NMES) applied to the shoulder muscles, particularly the supraspinatus and posterior deltoid, has the strongest evidence base of any intervention for shoulder subluxation after stroke. Multiple randomised controlled trials have demonstrated that NMES reduces the degree of subluxation, reduces pain, and in some studies improves motor recovery in the affected arm when used consistently.
NMES works by delivering electrical impulses to the weakened muscles, causing them to contract and actively support the shoulder joint. Unlike a sling, which provides passive external support, NMES actively stimulates the muscles that should be doing the job, which supports both joint alignment and neuroplastic recovery of the muscles themselves.
NMES for shoulder subluxation is typically applied for 30 to 60 minutes per session, once or twice daily, with electrodes placed over the supraspinatus and posterior deltoid muscles. Treatment is most effective when started early in the recovery process before significant subluxation has developed. For detailed electrode placement guidance for shoulder subluxation, see our electrode placement guide for stroke recovery.
Active and assisted exercise
As muscle function returns to the affected arm, active and assisted exercise plays an increasingly important role in managing subluxation. Exercises that target the rotator cuff muscles, scapular stabilisers, and deltoid help restore the active muscle support that the shoulder joint depends on.
Exercise for shoulder subluxation should always be guided by a physiotherapist or occupational therapist, particularly in the early stages, to ensure correct technique and avoid aggravating the joint. Incorrect exercise or moving the arm through ranges it cannot control actively can worsen subluxation and cause additional damage to the joint structures.
As recovery progresses and voluntary movement returns, the focus shifts from passive positioning and external support to active strengthening and functional use of the arm. This transition should be guided by the rehabilitation team and is usually gradual rather than sudden.
Pain management
Shoulder pain associated with subluxation can significantly limit rehabilitation participation. When pain is severe, it should be addressed directly rather than simply managed by reducing activity. Options for pain management include:
- Analgesic medication, discussed with your GP or medical team
- Correct positioning to reduce gravitational stress on the joint
- NMES, which has demonstrated pain-reducing effects independent of its effect on subluxation reduction
- In some cases, corticosteroid injection to the shoulder joint for significant inflammatory pain
- Ice or heat application for symptomatic relief
It is worth noting that not all shoulder pain after stroke is caused by subluxation. Other causes of shoulder pain including rotator cuff injury, adhesive capsulitis (frozen shoulder), complex regional pain syndrome, and central post-stroke pain all occur in stroke survivors and have different management approaches. If shoulder pain is severe or not responding to standard subluxation management, further assessment is warranted to rule out these other causes.
The Relationship Between Subluxation and Upper Limb Recovery
A common concern among survivors and caregivers is whether shoulder subluxation will permanently limit arm recovery. The reassuring answer, for most survivors, is no.
Subluxation itself is a consequence of muscle weakness, not a cause of permanent joint damage in most cases. As motor function returns to the affected arm, the muscles regain their ability to support the joint and the degree of subluxation typically reduces. Many survivors who had significant subluxation in the early weeks post-stroke show little or no subluxation by the three to six month mark as muscle tone and motor control improve.
However, there are important caveats. Poorly managed subluxation, particularly when accompanied by significant pain, can limit the survivor’s ability to participate in rehabilitation exercises. Pain that is not addressed reduces the volume and quality of arm practice, which in turn slows neuroplastic recovery. Addressing subluxation and its associated pain is therefore directly relevant to the quality of upper limb rehabilitation, not a separate concern.
Additionally, subluxation that is allowed to persist without management can in some cases contribute to secondary complications including shoulder contracture and adhesive capsulitis, both of which can become independent barriers to arm movement. Early and consistent management prevents these downstream complications.
For more on upper limb recovery after stroke, see our guide to how to regain use of your arm after stroke.
What Caregivers and Family Members Need to Know
Caregivers play a critical role in managing shoulder subluxation, particularly in the early stages when the survivor may be dependent on others for positioning and mobility assistance. The most important things for caregivers to know are:
Never pull on the affected arm. This is the single most important rule. Pulling on a flaccid or weakened arm during transfers, dressing, or repositioning can worsen subluxation and cause significant pain and joint damage. Always support the arm at the elbow and forearm rather than holding the hand or pulling from the shoulder.
Support the arm at all times when the survivor is upright. When sitting, ensure the arm is supported on a surface. When standing or walking, ensure a sling or other support is in place if the therapist has recommended one.
Ask the therapy team to demonstrate correct handling techniques. Every caregiver involved in the survivor’s daily care should have a hands-on demonstration of correct positioning and transfer techniques from the physiotherapist or occupational therapist. Reading about it is not sufficient.
Report pain or changes in the shoulder promptly. If the survivor reports new or increasing shoulder pain, or if the visible gap at the shoulder appears to be changing, report it to the rehabilitation team at the next opportunity.
Common Questions About Shoulder Subluxation After Stroke
Is shoulder subluxation after stroke permanent?
In most cases, no. Shoulder subluxation is caused by muscle weakness and typically improves as motor function returns to the affected arm. Many survivors show significant reduction or resolution of subluxation as recovery progresses. Early management with correct positioning, NMES, and appropriate exercise gives the best outcomes.
Does shoulder subluxation always cause pain?
Not always. In the early flaccid phase after stroke, when sensation in the affected arm may be reduced, subluxation can be present without significant pain. Pain is more likely to develop as muscle tone returns or if the joint is handled incorrectly. The absence of pain does not mean subluxation is not present or does not need to be managed.
Can a sling fix shoulder subluxation?
A sling provides external support that reduces the degree of subluxation while it is being worn and can provide pain relief. However, it does not address the underlying muscle weakness causing the problem and does not produce lasting improvement when worn in isolation. Slings are most effective as part of a broader management program that includes NMES, exercise, and correct positioning.
How long should I wear a shoulder sling after stroke?
Sling use should be guided by your physiotherapist or occupational therapist based on your individual level of muscle function and subluxation severity. General guidance suggests wearing a sling when upright and weight-bearing through the affected arm is likely, but removing it for exercise sessions and periods of supported positioning. Wearing a sling continuously without periods of exercise can promote unhelpful positioning and secondary complications.
Will shoulder subluxation stop me from recovering arm function?
Managed appropriately, shoulder subluxation does not need to be a permanent barrier to arm recovery. The key is to address it early, manage associated pain effectively, and ensure it does not limit your ability to participate in the rehabilitation exercises that drive neuroplastic recovery. Survivors with well-managed subluxation can and do make significant upper limb gains.
Key Takeaways
- Shoulder subluxation is a partial displacement of the shoulder joint caused by weakness of the muscles that support it, and is one of the most common complications of stroke affecting the upper limb.
- It develops when muscle weakness or flaccidity prevents the rotator cuff muscles from holding the humerus in the shoulder socket.
- Prevention through correct positioning and handling is the most important early intervention and should begin in the acute phase of recovery.
- NMES applied to the supraspinatus and posterior deltoid has the strongest evidence base for reducing subluxation and associated pain.
- Shoulder slings provide useful external support but are most effective as part of a broader management program rather than a standalone treatment.
- Shoulder subluxation is not permanent in most cases and typically improves as motor function returns to the affected arm.
- Caregivers should never pull on the affected arm and should ask the therapy team to demonstrate correct handling techniques.
- Unmanaged subluxation can limit rehabilitation participation through pain and contribute to secondary complications including contracture and frozen shoulder.
Related Reading
- Shoulder Subluxation Slings for Stroke Recovery
- Electrode Placement Guide for Stroke Recovery
- How to Regain Use of Your Arm After Stroke
- Post-Stroke Spasticity Treatment: Evidence-Based Options
- Upper Limb Electrical Stimulation After Stroke: A Complete Guide
- Stroke Recovery Milestones: What to Expect Month by Month
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