What is the difference between Shoulder Separation vs Dislocation?

The shoulder is the most mobile of all joints in the body and is regarded as the ‘most unstable of all major joints’ due to the relatively small articulation surface. The shoulder is a synovial joint that consists of 3 bones; the humerus, scapula, and clavicle. It has 4 connections (a.k.a. articulations or joints) – these are namely (i) the acromioclavicular (AC) joint, where the acromion (the top part of the scapula) meets the collarbone or clavicle; (ii) the glenohumeral (GH) joint, where the humerus joins the glenoid; (iii) the sternoclavicular (SC) joint, where the clavicle meets the sternum; and (iv) the scapulothoracic (ST) articulation where the scapula meets the chest wall.

Both “static and dynamic restraints” are used to achieve shoulder stability. In a ‘normal’ shoulder, the humeral head stays in the centre of the glenoid fossa (a socket formed by a hollow at the superolateral edge of the scapula), which allows joint surfaces to line up perfectly. Unlike the hip, the shoulder socket is shallow and therefore requires specific positioning of the 3 bones to maintain its stability. As long as the scapula is in a good position, this wonderful ‘centring’ phenomenon occurs even when launching a cricket ball or baseball exceeding speeds of 100mph! (see the laws of stability below). The arc of the glenoid is instrumental here by containing the glenohumeral joint response force.

The Laws of Glenohumeral Stability:

1. As long as the net humeral joint reaction force (see figure 1 below) is directed within the effective glenoid arc (footnote 2), the glenohumeral joint will not dislocate (see figures 2 and 3).
2. If the glenoid and humeral joint surfaces are parallel and the net humeral joint reaction force is directed within the effective glenoid arc, the humeral head will remain centred in the glenoid fossa.

 

 

 

 

 

Is shoulder dislocation the same as a shoulder separation?

No! Commonly confused, but very different in their nature of injury, speed required for treatment, diagnosis and rehab treatment methods used.

 

What is shoulder dislocation?

A shoulder dislocation is when the humerus is pulled or pushed out of the shoulder socket, or glenohumeral joint. Shoulder dislocations represent 50% of all major joint dislocations, with anterior (forward) dislocation accounting for 97% of all types of shoulder dislocations.

 

 

What is shoulder separation?

A shoulder separation when the ligaments of the AC joint (connects collarbone to shoulder blade) are damaged, and the bones on either side can move excessively. There are 6 different types or grades given to a shoulder separation injury, then segmented into 3 main treatment routes.

 

 

Shoulder Dislocation Symptoms, Causes, Treatment

Here are the symptoms, causes and treatment of shoulder dislocation

Shoulder Dislocation Symptoms

• Deformity – Your arm appears to be out of place
• Severe shoulder pain
• Numbness in your arm, neck, hand, or fingers
• Swelling and bruising of your shoulder or upper arm
• Weakness or pain preventing you from moving your arm
• Muscle spasms in your shoulder

Shoulder Dislocation Causes

• A direct force to the shoulder from behind and at the side, often caused by sports injuries
• Falling on your shoulder or an outstretched arm
• Accidents (including traffic incidents).
• Individuals may also put their arm in a position of high risk that predisposes them to a dislocation. In this case, the muscles are “unprepared”, and the force “overwhelms” the muscle causing a dislocation.

Shoulder Dislocation Treatment

1. Relocation of the shoulder (if no contraindications) – medically called a ‘closed reduction’. Medication can relieve the pain and relax your shoulder muscles. Once the joint is back in place, the severe pain should end.
2. Use a sling (3 days to 3 weeks) – to help reduce pain, and allow muscles to relax and ligaments to heal.
3. Physiotherapy to help improve range of motion, shoulder strength and function – to improve quality of life and prevent future dislocations.

Surgery may be required if damage has been caused to the socket, tissues or nerves around the shoulder or if you get repeated dislocations.

Shoulder Separation Symptoms

• Intense pain immediately
• Tenderness of shoulder and collarbone
• Swelling
• Bruising
• Deformity

Shoulder Separation Causes

• A fall onto the shoulder.
• High impact to the shoulder, through sports such as rugby.

Shoulder Separation Treatment

1. Type I-II injuries are treated non-operatively with Physiotherapy and advice.
2. Type III injuries vary on their management depending upon factors including age, level of sporting ability, time of season, and if the individual doesn’t mind altering their activities.
3. Types IV-VI require surgery to restore function, and generally have a high success rate in returning function, when combined with Physiotherapy rehabilitation following surgery.

 

How to tell the difference between separation and dislocation?

There are multiple was that you can tell the difference between shoulder separation and shoulder dislocation:

• Clinical information – Knowing how the injury occured, and what happened immediately afterwards.
• Visual observation – Bruising, swelling, or obvious dislocation (arm abducted and externally rotated) or deformity/bump seen at the shoulder end of the collarbone.
• Palpation/Touching – Knowing normal joint position can enable a clinician to feel what is where.
• Imaging – X-rays, CTs or MRIs will all show clearly if the humerus is dislocated from the joint space, or indeed if the collarbone is separated from the shoulder blade.

Conclusion 

A shoulder separation is when the acromioclavicular ligament detaches partially or fully causing a deformation of the collarbone, due to lack of connectedness. Commonly occurring in impact sports such as rugby.

A shoulder dislocation is when the humeral head leaves the safety of the glenoid fossa a.k.a the shoulder socket and is essentially ‘not in location’. Often caused by high velocity trauma or car accidents.

If you are more of an auditory, and visual learner, then this short video explains the difference between shoulder dislocation and shoulder separation in 2 minutes. If you have any questions at all, then please do reach out and we would love to help answer them.

Shoulder Range of Motion after Shoulder Replacement (TSA):

• 130° in forward flexion/elevation (range: 104° to 147°)
• 125° in abduction (range: 86° to 145°)
• 50° in internal rotation (range: 43° to 54°)
• 40° in external rotation (range: 25°-50°)

Source: A biomechanical analysis of strength and motion following total shoulder arthroplasty 

Shoulder range of motion after Reverse Total Shoulder Replacement and Hemiarthroplasty are discussed further in the article. 

Are you considering Shoulder Replacement surgery? 

If you’re considering shoulder replacement surgery, download Reflex: Shoulder Mobility App to help make an informed decision. With this app, you can measure your shoulder range of motion and track your pain over time.

Surgery should only be considered if no improvements in shoulder pain after a long period of non-surgical treatments and following a tailored Physical Therapy Programme. Visualise your pain and ROM data so you can have more control in your health decisions.

Shoulder range of motion after surgery is less than the average range of motion of the shoulder. 

 

What is a shoulder replacement/arthroplasty

A shoulder replacement/arthroscopy is an umbrella term for the variations of shoulder replacement which include total shoulder arthroplasty (TSA), reverse total shoulder arthroplasty (RTSA), and hemiarthroplasty (HA).

A total shoulder replacement surgery swaps out the arthritic parts of your shoulder joint with prosthetics. You are eligible for a total shoulder replacement if your joint has significant arthritis but you have no or very minimal damage to your rotator cuff, otherwise a RTSA or HA will be considered.

Note: Shoulder replacement and shoulder arthroplasty is used interchangeably throughout this article. They hold the same meaning.

Key:

Total shoulder replacement/arthroplasty (TSA)

Reverse total shoulder replacement/arthroplasty (RTSA)

Hemiarthroplasty (HA)

 

Are shoulder replacements common?

On average a total of 59,000 shoulder replacements are carried out annually in the USA, as reported by the U.S. Agency for Healthcare Research and Quality. To put it into perspective, this 1 in every 6,000 Americans each year. This data can be broadly extrapolated to other medically advanced countries.

This is in contrast to the 900,000+ hip and knee replacement surgeries annually. The difference is largely due to the complexity of the shoulder joint in comparison.

Shoulder replacement surgeries are becoming more and more common, being completed increasingly each year, with the population groups getting younger. This is likely due to the number of impact sports people are playing at a high level, such as rugby, American football, basketball and others. The advancements in surgery have advanced at lightning speed since the first one back in 1849, but the rehab has not advanced quite as well in our opinion.

 

Who should strongly consider a shoulder replacement?

If somebody has high levels of arthritis present in the shoulder joint, or defects of the anatomical shape due to a major trauma or repetitive injuries- then treatment is necessitated. The first step is to trial all appropriate nonsurgical treatments, such as medications, activity changes and Physiotherapy/ Physical therapy. If these have been attempted with no significant improvement, it would be prudent to strongly consider shoulder replacement.

 

Who is not eligible for a total shoulder replacement/arthroscopy?

In patients who are not candidates for a Total Shoulder Arthroscopy due to rotator cuff dysfunction, rheumatoid arthritis, or a proximal humerus fracture, the choice between RTSA and a HA remains controversial. As compared to a HA, RTSA has been associated with improved functional and range of motion outcomes. However, a HA is generally perceived as the “safer” option in patients who wish to remain active because there is less risk of failure.

 

What is the normal range of motion after shoulder replacement, and does this differ depending upon the type of surgery?

In short, YES! Normal range of motion after shoulder replacement completely depends upon if we are talking about a complete total shoulder replacement (TSA), reverse total shoulder replacement (RTSA) or a hemi shoulder replacement (HA).

For TSA –  we typically see in our practice (with studies in strong support) the return of shoulder range of motion being;

 

• 130° in forward flexion/elevation (range: 104° to 147°)
• 125° in abduction (range: 86° to 145°)
• 50° in internal rotation (range: 43° to 54°)
• 40° in external rotation (range: 25°-50°)

There are then only small improvements in range of motion from 6-12 months.

For (primary) RTSA patients –  Patients often regain in excess of 105° active shoulder elevation with functional ER up to 30°.

For HA patients. The above RTSA results are superior to those of HA for RC arthropathy, who typically achieve on the lower end of the range of motion scale of;

 

• 80-90° for both shoulder elevation, and abduction
• with limited internal and external rotation to 15-20°

 

Are there functional limitations for most people after a total shoulder replacement surgery?

Generally speaking, yes but for many it is not significantly noticeable – and many are actively curbed by their surgeon. Traditionally, for the majority of patients, the recommended load by many surgeons is 4.5 – 6.8kg (10-15 lbs), and this upper extremity lifting limit is advised to be followed indefinitely, to ensure that the operative shoulder is not strained beyond its structural integrity. That all being said, with the population becoming younger, and therapy advancing, we have brought many people back into full contact sport after TSA, HA and RTSA. See below.

 

What is the success rate in returning to sport for the different types of shoulder replacements?

The rates of return to sports following TSA (75%-100%) are higher than those reported for HA (67%-76%) and RTSA (75%-85%). Patients having a TSA, rTSA, and shoulder HA should be advised that there is a high likelihood that they will be able to return to their preoperative activity level < 6 months post-operatively.

 

Total shoulder replacement return to sport stats:

There was a landmark longitudinal study completed recently tracking patients over a 5-year period that is pertinent to share.

In this study, by Johnson et al (2016) the researchers conducted a retrospective review of 61 patients who underwent a total shoulder replacement. The average age at the time of surgery was 48.9 yrs old (ages 25 to 55), of which most of the shoulder damage (80.3%) was caused by osteoarthritis. Nearly 68% of patients said they hoped to return to sports following surgery.

Among the highlights of the study:

 

• 93% of patients were satisfied with the outcomes of their surgery, and 96.4% (55 out of 57 patients) returned to at least one sport at an average of 6.7 months following surgery.
• The direct rates of return to sports included: fitness sports (97.7%), golf (93.3%), singles tennis (87.5%), swimming (87.5%), basketball (75%) and flag football (66.7%).
• More than 90% of patients returned to a high-demand sport and 83.8% returned to a sport that required high use of the arms and shoulders.
• There was no significant difference in the rate of return to sport by body mass index, sex, age, preoperative diagnosis, revision status and/or dominant extremity.
• Our results evaluated patients at an average of five years of follow up and most patients continued to be very satisfied and performed a high number of sporting activities, including those that required high use of their shoulders.

 

Is there any difference in the rehab between the types of shoulder replacements?

Yes, there is. If you have had a TSA, then rotator cuff exercises will often form a part of your physiotherapy program. However, if you have had a RTSA then you should not do these. This is because no rotator cuff muscle is present, so strengthening should focus on the deltoid muscle to help your arm move. You should also not complete any movements that rotate your shoulder externally to end range.

 

What are the early signs of good and effective recovery?

Patients who have a negative external rotation lag sign at the initial strengthening phase of rehabilitation tend to progress faster in terms of strength, functional progression, in addition to demonstrating higher active elevation ROM at the time of discharge from Physiotherapy/ Physical therapy.

 

Advice following shoulder replacement to gain the best chances of good range of motion?

Tip 1: We would encourage immediate, but cautious complete passive range of motion following surgery. This has been found to have the best long-term outcomes and fastest recovery times.

Tip 2: Be consistently diligent and disciplined with your rehab. Don’t try to shortcut the road to recovery. Time is a great healer, and be guided by your Physiotherapist/Physical therapist.

Tip 3: Get a Shoulder Physiotherapist Specialist to guide you through your rehab. If you are interested in a free screening call with myself, then simply click here.

Tip 4: Keep track of your range of motion and pain throughout recovery. Reflex: Your Shoulder Mobility is the best app for measuring your shoulder range of motion from home.

 

Conclusion:

Shoulder replacement surgery is generally a safe and effective procedure to help relieve pain and help you return to normal daily living activities. The degree of how much range of motion returns depends upon any pre-existing pathologies including rotator cuff damage, rheumatoid arthritis, traumatic events or other.

Over 96% of TSA patients returned to at least one sport 6-months following surgery, with a crude average return of range of motion being 70%. This is more favourable than RTSA and RA in this order, but most patients who have a shoulder replacement do very well functionally and the majority can return to their normal activities within 6-months.

 

Not my favourite day.

“My shoulder has become increasingly difficult to move and mysteriously stiff.”

After a comprehensive online assessment, I’ve just had to explain to an unsuspecting patient that they are most likely at the beginning of a long journey of pain, stiffness and poor mobility. Yes, ladies and gents, we are talking about a Frozen Shoulder diagnosis.

My role

As Physiotherapists, we have a duty to treat, manage, set expectations but also bring hope and various treatment options. The reality is that the journey is long, arduous and that it will affect daily life, lasting an average 2.5 years – with the majority of people recovering well with the right therapy and intervention. I also seek to bring the big picture, inspire and offer up different treatment options to suit different individuals. Throughout the journey, I believe it is vital to integrate foundational practices in. Janice does so well to describe her in her Frozen Shoulder journey here. Check it out!

What is ‘Frozen Shoulder?’

The shoulder is made up of a ball (top of your arm bone, the humerus) and socket (shallow hollow from your shoulder blade, the scapula) joint.

The entire joint is enclosed within a strong, fibrous capsule that ensures stability and strength with some lovely synovial fluid lubricating the joint. Frozen shoulder occurs when this capsule becomes thickened, contracted and tight with minimal synovial fluid.

Frozen Shoulder is also referred to as Adhesive Capsulitis, it is initially identified by dull pain (90%+ of people report this as their first symptom [1]), aching and a progressively restricted active and passive glenohumeral joint range of motion such as Forward Flexion, Extension, and Abduction.

The pathophysiology of Frozen Shoulder

Post-mortem analysis of a person with Frozen Shoulder (not cause of death!), combined with results from open arthroscopic surgery both showed synovial hyperplasia (thickened joint structures) with increased vascularization (blood flow) during the phase 1 – freezing [2]. This phase ends with a developing fibrosis (thickening) situated mainly in the rotator cuff connection (which is made up of the tendons of the subscapularis, biceps brachii and supraspinatus muscles, and the coracohumeral and superior glenohumeral ligaments), together with the base of the coracoid process [3], and in the subscapular recess [4].

The thickening of the coracohumeral ligament is suggested as one of the specific origins of Frozen Shoulder and the main reason for limited external rotation, although due to its close relationship with the subscapularis and supraspinatus tendons it also helpfully contributes to restriction of internal rotation [5]. In more advanced stages of Frozen Shoulder, the thickening and contraction of the glenohumeral capsule culminates in limiting the range of movement in all directions [2].

In simple language, studies have shown the thickening of the shoulder structures in key places, and reduction in lubricating fluid in those with Frozen Shoulder.

What causes Frozen Shoulder?

Today’s lifestyle has dramatically reduced the use of the upper limbs, in contrast to the last 1000 years, where manual labour and household activities were completed daily – whereas in 2022, a lot of manual activity is now completed by machines. This decrease in use has likely led to atrophy of parts of the complex ligament capsule of the shoulder [6]. Which could be why we are seeing Frozen Shoulder being more prevalent in the world today.

Frozen Shoulder Symptoms 

Symptoms aren’t completely linear, and 2 and 4 stage models have been proposed. I propose that this phase is most helpful [7] [8], and here are some common traits of each phase.

Frozen Shoulder Symptoms – Phase 1: The Freezing Stage 

• The shoulder will slowly develop pain that worsens when it is moved [1].
  • This is suggested to be from the gradual lessening of lubrication, and shortening muscle-tendon junctions.
• It will also become stiffer as time goes on. This is where the term ‘freezing’ comes from.
  • This stiffness is due to the reduction of synovial fluid (the lubricating oil of the joint) and the thickening of structures within the joint – this is also why overhead movements hurt so much.
• External rotation is often the first to be limited and last to return due to the early and long-lasting thickening found by studies of the coracohumeral ligament, the structure that ordinarily facilitates this movement.
• This phase may last from 2-9 months.

Frozen Shoulder Symptoms – Phase 2: The Frozen Stage

• This follows the freezing phase, and although pain may get less, moving the shoulder gets harder, which affects day-to-day activities, often reducing people to leaning back to achieve ‘normal activities’. It is often this phase which people report to be the most challenging.
• This phase may last up to 12 months.

Frozen Shoulder Symptoms –  Phase 3: Thawing

• This is our resolution or ‘thawing’ phase. The stiffness gradually eases and most people make a full recovery with physio-led strength and mobility programmes or surgical interventions.
• Despite common belief, it is unlikely for there to be maximal recovery gained spontaneously (without intervention).
• This phase can last up to 2 years [9]
• It has been reported that only 15% of people experience Frozen Shoulder in the opposite shoulder within 5 years [10]

In conclusion

Frozen Shoulder is a mysteriously painful and activity-stopping condition that requires patience over the journey, and often takes its toll on many different aspects of life, as Janice describes for herself in her previous blog post titled “Freezing, Frozen and Thawing, my 3 phases of Frozen Shoulder”. 

The duration of Frozen Shoulder is from 1 to 3.5 years with a mean of 30 months.

Each phase will end, and you shall move closer to getting back to what you love!

There are various ways in which we can reduce the likelihood of getting Frozen Shoulder, diagnose Frozen Shoulder, manage Frozen Shoulder and how best to gain fast recovery. All of that shall have to wait for our next instalment!

References:

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[6] Pietrzak M. Adhesive capsulitis: an age related symptom of metabolic syndrome and chronic low-grade inflammation? Med Hypotheses. (2016) 88:12–7. doi: 10.1016/j.mehy.2016.01.002

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[8] Favejee MM, Huisstede B, Koes BW. Frozen shoulder: the effectiveness of conservative and surgical interventions—systematic review. Br J Sports Med. (2011) 45:49–56. doi: 10.1136/bjsm.2010.071431 CrossRef Full Text | Google Scholar

[9] Wong CK, Levine WN, Deo K, Kesting RS, Mercer EA, Schram GA, et al. Natural history of frozen shoulder: fact or fiction? A systematic review. Physiotherapy. (2017) 103:40–7. doi: 10.1016/j.physio.2016.05.009 PubMed Abstract | CrossRef Full Text | Google Scholar[10] Mezian K, Coffey R, Chang KV. Frozen Shoulder. [Updated 2021 Sep 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482162/