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Shoulder Subluxation

A shoulder subluxation is also called “partial shoulder dislocation“. It is a condition in which only the head of the arm bone protrudes partially from the socket. While, during the dislocation, the head of your upper arm bone pulls entirely out of its socket. 

The shoulder joint/ glenohumeral joint is made up of the humeral head, the ball of your arm bone, which fits into a cup-shaped socket called the glenoid cavity/ glenoid fossa(1).

The shoulder is one of the joints that is most easily dislocated. That is because it is very mobile.  That‘s why you can swing your arm completely, just like you would throw a softball.

The joint can sublux if the user performs movement either too violently or quickly, but this damage frequently occurs over years of repetitive use.

In subluxation, the bone can move forward, downward, or in an upward direction. Additionally, in some cases, the damage also causes shoulder muscles, ligaments, tendons, and labrum to tear.

What are the Symptoms of Shoulder Subluxation

It can be harder to tell the difference between a subluxed and a fully dislocated shoulder. But in some cases, the part of the humerus that is out of place can be seen through the skin.

Some of the indications of a shoulder subluxation are a shoulder that looks malformed or out of place, swelling, pain, difficulty while performing movement of the joint, tingling, or numbness (called “paresthesia”) in the arm, or a combination of these symptoms.

Also, a person may feel a catching or clicking noise in the shoulder as they perform daily activities for example reaching overhead activities(2). 

Moreover, shoulder subluxation can result in connective tissue or soft tissue damage, as traction damage can be caused by gravitational pull forces and a weak shoulder provides little protection. It is typically highly painful, and the arm, hand, and shoulder may feel partially numb.

Causes of Shoulder Subluxation

Typically, a shoulder subluxation is caused by:

  • Accidental shoulder injuries or trauma, such as a fall. However, these injuries must be differentiated from collar bone ( clavicle) fractures.
  • Repetitive shoulder joint stress, such as from certain contact sports, including volleyball, baseball,  tennis, and swimming require recurrent overhead motion.
  • Jobs requiring repetitive overhead motion
  • Multilateral instability
  • Some individuals may have natural laxity of ligaments.
  • Shoulder subluxation can occur in the absence of previous trauma or overuse and can be a cause of shoulder pain.
  • Strokes frequently produce muscle weakness, that can cause shoulder destabilization and then shoulder subluxation(3). A study found that shoulder subluxation happened to 80% of people who had a stroke (4). 

How to Diagnose Shoulder Subluxation?

Before checking your shoulder, your orthopedic doctor will inquire about your symptoms and will perform a physical examination. X-rays may be necessary to determine if there is a complete or partial dislocation of the humeral head from the shoulder socket. Shoulder X-rays and Magnetic resonance imaging can also reveal broken bones and other injuries.

After determining the extent of your damage, your orthopaedic doctor can help realign your shoulder and design a treatment plan.

Functional evaluation

A physical therapist will perform different tests to check the subluxation of the shoulder. 

The subluxation test is positive if resistance is encountered when the patient’s arm is in an internal rotation in a throwing stance. Pain in the ventral joint capsule implies an injury to the anterior capsule.

Pressure applied to the dorsal portion of the humerus during a resistance test can induce ventral gliding. The outcome is abrupt shoulder pain and, in some cases, a subluxation to the front of the shoulder. This test can be performed in varying degrees of abduction and with or without upper arm support.

Other tests to diagnose shoulder subluxation include push and pull test, load and shift, hyperabduction, sulcus, and drawer tests. The apprehension and relocation test is specific for examining anterior shoulder instability.

Furthermore, radiographic measures are regarded as the most precise method for determining the degree of subluxation or shoulder instability. Additionally, for hemiplegic shoulder subluxation, shoulder radiographic imaging can be arranged to follow up on how well the treatment is working or if glenohumeral subluxation is getting worse over time(5).

A diagram of a shoulder subluxation

Treatment

The goal of treatment is to realign the humerus and ensure that it remains in place.

A shoulder subluxation can be diagnosed using ultrasound. A proper diagnosis is essential for identifying the most effective course of treatment.

The following can be included in treatment:

Closed reduction

It is a technique in which physicians reposition the shoulder. As this procedure can be uncomfortable, you may wish to take an analgesic beforehand. Alternatively, you can take a sleeping medication and stay painless under general anesthesia.

Your physician will move and rotate your arm gently until the bone falls back into place. After repositioning the ball, the pain should subside. Your doctor may then perform X-ray testing to ensure that your shoulder is in the proper position and that there are no other injuries around the shoulder joint.

Other treatment options include medication use and immobilization.

Immobilization

Following a closed reduction, you will wear a sling for many weeks to immobilize the shoulder joint. By immobilizing the joint, the bone cannot slip out again. Keep your injured shoulder in the sling and avoid excessive stretching or movement as it heals. Moreover, the duration of immobilization will be determined by the severity of the dislocation.

Medication for a shoulder subluxation

The pain associated with a subluxation should subside when a closed reduction is performed. If you continue to experience pain, your doctor may prescribe painkillers such as acetaminophen and hydrocodone  (Norco). However, you should not take pain medicines prescribed by a doctor for more than a few days.

If you require longer-lasting pain relief, consider taking non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin) or naproxen (Naprosyn). These medications can alleviate shoulder pain and edema. Follow the instructions on the package, and do not exceed the suggested dosage. If your pain persists after a few weeks, consult your physician about alternative pain medication choices.

Surgery

Repeated episodes of subluxation may necessitate surgery. It may also be the therapy of choice for injured nerves, Ligament tears,  socket (glenoid)  tears, socket fractures,  head of the arm bone fractures,  rotator cuff injury, or rotator cuff tear and blood vessels in the shoulder.

Other indications for the surgical procedure may include recurrent dislocation in adolescents, a failed non-operative treatment plan, open dislocation, irreducible dislocation, unstable reduction, bony bankart lesion, the first time in young adults with traumatic unilateral dislocations, and high work demand. Your surgeon will correct any issues that make your shoulder unstable.

Shoulder surgery can be performed using extremely tiny incisions. This is known as arthroscopy. Occasionally, this will necessitate an open procedure/reconstruction known as an arthrotomy. After shoulder surgery, you will require therapy to recover shoulder blade mobility.

Rehabilitation for a shoulder subluxation

After surgery or sling time, a physical therapist may recommend a rehabilitation program. The objective of physical therapy is to restore the shoulder’s strength, range of motion, and stability.

Prolotherapy

Some structures have a poor blood supply, which is why they can struggle to heal on their own. It is the oxygen and nutrients in our blood supply that help to heal these structures.

Prolotherapy involves the injection of a regenerative solution into these structures to provide a direct supply of what is needed to heal them and provide pain relief.

As the treatment is helping to treat the root cause of the problem, it is deemed to be a permanent fix.

Exercises To Perform At Home

Physiotherapy can help in increasing flexibility, and restoring shoulder range of motion and strength of muscles.

The following exercises may assist in enhancing shoulder movement and shoulder stability:

Shoulder flexors. Face a wall and let your arms hang loose. Raise your forearm and bend your elbows 90 degrees. Make a fist with your palm facing downward, and try to gently push your fist towards the wall.

Shoulder extensors exercises. Stand with your back against a wall and your arms lose. Bend the elbows 90 degrees and raise the forearms. Try to press the posterior side of the elbow onto the wall.

Shoulder abductors exercises:  In this exercise, a person needs to stand against a wall with the injured side. Flex the elbow while raising the arm. Try to move the whole arm side away along the wall.

A physiotherapist may also recommend scapula stabilization, strengthening exercises, and active and passive range of motion exercises to restore mobility after shoulder subluxation and muscle strength(6).

Consult a physical therapist or physician before performing exercises at home. That is because, depending on your injury, exercises differ. Some exercises can exacerbate the symptoms of some individuals.

In addition to exercises, a physical therapist may recommend, avoiding specific activities and motions, joint mobilization, and therapeutic massage.

Healthcare and Wellness Tips

Other healthcare and wellness tips include:

Use ice. Apply an ice pack or bag of ice on your shoulder a few times per day. The ice will alleviate discomfort and reduce swelling immediately after your injury,  A few days later, you may switch to heat(7).

Rest. If you have subluxated your shoulder once, it is more likely to occur again. Throwing or lifting heavy objects could cause the humeral head of your arm bone to become dislodged from its socket. Therefore, return to sports and other activities gradually, and participate in sports only when your shoulder is fully healed and when you feel you are ready.

Improve your flexibility. Perform the exercises recommended by your physical therapist daily. Regularly perform moderate exercises, they will keep your shoulder joint from becoming stiff.

 

References

  1. Eljabu W, Klinger HM, von Knoch M. The natural course of shoulder instability and treatment trends: a systematic review. J Orthop Traumatol. 2017 Mar;18(1):1-8.
  2. Kuroda S, Sumiyoshi T, Moriishi J, Maruta K, Ishige N. The natural course of atraumatic shoulder instability. J Shoulder Elbow Surg. 2001 Mar-Apr;10(2):100-4.
  3. Paci M, Nannetti L, Rinaldi LA. Glenohumeral subluxation in hemiplegia: An overview. J Rehabil Res Dev. 2005 Jul-Aug;42(4):557-68.
  4. Xiangzhe Li, Zhiwei Yang, Sheng Wang, Panpan Xu, Tianqi Wei, Xiaomeng Zhao, Xifeng Li, Yanmei Zhang, Ying Li, Na Mei, Qinfeng Wu. (2021) Impact of shoulder subluxation on peripheral nerve conduction and function of the hemiplegic upper extremity in stroke patients: A retrospective, matched-pair study. Neurological Research 43:6, pages 511-519.
  5. Murie-Fernández M, Carmona Iragui M, Gnanakumar V, Meyer M, Foley N, Teasell R. [Painful hemiplegic shoulder in stroke patients: causes and management]. Neurologia. 2012 May;27(4):234-44.
  6. Jaggi A, Alexander S. Rehabilitation for Shoulder Instability – Current Approaches. Open Orthop J. 2017;11:957-971.
  7. Jaggi A, Lambert S. Rehabilitation for shoulder instability. Br J Sports Med. 2010 Apr;44(5):333-40. [PubMed]

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