Frozen Shoulder: Causes, Stages, and How We Can Help
- staystrongtherapy
- Jun 30
- 7 min read
All information in this blog is supported by NICE guidance and peer-reviewed research. Reference numbers appear throughout, with the full list at the bottom of the page.
What Is Frozen Shoulder?
Frozen shoulder, medically known as adhesive capsulitis, is a condition causing painful, progressive stiffness and loss of movement in the shoulder. NICE describes it through three overlapping phases, and current research consistently identifies inflammation, fibrosis, and contracture of the shoulder joint capsule as the underlying drivers, though the exact trigger often remains unclear. ¹ ²
It typically affects people of working age, most commonly in their 40s and 50s, with NICE Clinical Knowledge Summaries and supporting research placing the peak incidence between 40 and 60 years. ³ Women are affected considerably more often than men, and around 20 to 30% of people who develop frozen shoulder in one shoulder will go on to develop it in the other. ⁴
Risk Factors
Frozen shoulder is generally classified as either primary (idiopathic, with no clear cause) or secondary (linked to an identifiable trigger). Known risk factors include: ¹ ³
Age, most commonly between 40 and 60
Female sex
Diabetes, one of the strongest known risk factors, and associated with more severe, longer-lasting symptoms
Thyroid disorders, both an underactive and overactive thyroid
Previous frozen shoulder in the other shoulder
Cardiovascular disease, including a history of heart disease or stroke
Prolonged immobilisation, such as following surgery, a fracture, or a period in a sling
Minor shoulder trauma, which can act as the trigger even when the original injury itself was relatively small
How Minor Trauma Can Trigger a Cascade Into Frozen Shoulder
This is one of the most useful things to understand, because it explains why frozen shoulder so often seems to "come out of nowhere" following something that initially felt minor.
Research has found that a minor traumatic event frequently coincides with a person's first recognition of frozen shoulder symptoms, even in cases ultimately classified as primary frozen shoulder. ⁵ A small knock, a minor strain, or even a short period of reduced shoulder use following an unrelated injury can be enough to set the process in motion.
The cascade tends to work like this:
A minor injury or period of discomfort causes the shoulder to hurt with certain movements.
To avoid pain, the body naturally begins to guard the joint, moving it less and recruiting surrounding muscles to restrict motion protectively. Research has confirmed that muscle guarding plays a major role in the movement restriction seen in frozen shoulder, sometimes even more than the capsular changes themselves. ⁶
Reduced movement leads to reduced use of the joint through its full range, and the capsule, the fibrous tissue surrounding the shoulder joint, begins to lose its normal mobility.
In susceptible individuals, this combination of reduced movement and ongoing low-grade irritation can trigger an inflammatory and fibrotic cascade within the capsule itself, involving the activation of fibroblasts (cells responsible for producing collagen) and a build-up of dense connective tissue. ⁷
This fibrotic response further restricts movement, which increases guarding and avoidance, which in turn worsens stiffness, a genuine vicious cycle that can take the shoulder from "slightly sore after a minor knock" to a fully developed frozen shoulder over a period of weeks.
Understanding this cascade matters clinically, because it highlights why early, gentle movement following any shoulder injury or period of reduced use is so important, and why frozen shoulder is generally better addressed early, before the cycle of guarding and fibrosis becomes fully established.
What to Look Out For
Frozen shoulder is a benign, self-limiting condition. However, please seek medical assessment if you experience:
Shoulder pain following significant trauma, with deformity or inability to move the arm at all
Fever, redness, or hot swelling around the joint
Sudden, severe weakness in the arm
Unexplained weight loss alongside shoulder pain
Pain that is constant, severe, and unrelated to movement or position
The Three Stages, Healing Timelines, and Treatment for Each
NICE and orthopaedic research consistently describe frozen shoulder progressing through three overlapping stages. ⁸ ⁹ The total natural course can range from around 1 to 3 years, though treatment can meaningfully improve comfort and may shorten this overall timeline.
Stage 1: Freezing (Painful) Stage
Typical duration: 6 weeks to 9 months ⁸
This is the most painful stage. Pain often develops gradually, worsens over time, and is frequently worse at night, disturbing sleep, particularly when lying on the affected side. Movement becomes progressively more restricted as pain increases, and research has found that during this stage, significant muscle guarding contributes heavily to the loss of movement, alongside early capsular inflammation. ⁶
Treatment at this stage:
Pain management is the priority. NICE-recognised options include paracetamol, NSAIDs, and corticosteroid injection into the joint, which has good evidence for providing meaningful short-term pain relief during this stage. ³
Gentle, pain-guided movement, rather than aggressive stretching. Forceful stretching during a highly painful, irritable stage tends to provoke further guarding rather than help. ⁶
Manual therapy and soft tissue work focused on reducing protective muscle guarding around the shoulder, neck, and upper back, rather than forcing range of movement.
Education and reassurance, understanding that this stage is genuinely painful but time-limited is itself a valuable part of treatment.
Stage 2: Frozen (Stiff) Stage
Typical duration: 4 to 12 months ⁸
Pain typically begins to settle during this stage, though it does not disappear entirely, while stiffness becomes the dominant feature. Shoulder movement, particularly external rotation, remains significantly restricted, and daily tasks such as reaching overhead, behind the back, or out to the side become genuinely difficult.
Treatment at this stage:
Research evaluating manual therapy and exercise for adhesive capsulitis found meaningful benefit for improving range of motion and function during this stage. ¹⁰
Joint mobilisation, gentle, graded mobility techniques applied directly to the shoulder joint, has been shown to be effective for adhesive capsulitis. ¹¹
Structured, progressive stretching and exercise become more appropriate here as pain settles, focused on gradually regaining range of movement.
Corticosteroid injection can still be considered if pain remains a significant limiting factor. ³
Stage 3: Thawing (Resolving) Stage
Typical duration: 12 to 42 months from onset ⁸
This is the recovery phase. Movement gradually and steadily improves, often slowly, and most people see a genuine, measurable return of function, though full range of motion is not always restored in every case.
Treatment at this stage:
Progressive strengthening and mobility exercise become the main focus, building on the range of movement regained in stage 2.
A long-term follow-up study of people treated conservatively, including physiotherapy and NSAIDs, with follow-up averaging over 9 years, found statistically significant improvements across all measured directions of shoulder movement. ¹²
Manual therapy continues to support ongoing mobility gains and address any remaining restriction or compensatory tension elsewhere in the shoulder girdle and upper back.
How We Can Help
We tailor treatment to your specific stage, since the right approach genuinely differs between the painful freezing stage and the stiffer frozen stage.
Osteopathic manual techniques and joint mobilisation: research supports manual therapy and graded mobilisation as effective for improving pain and range of motion in adhesive capsulitis, particularly once the most acute pain has settled. ¹⁰ ¹¹
Deep tissue and sports massage: targeted soft tissue release of the surrounding shoulder, neck, and upper back muscles helps reduce the protective guarding that significantly contributes to restricted movement, particularly in the early painful stage. ⁶
Medical acupuncture: used as part of a broader treatment plan to help manage pain and muscle tension, particularly useful during the painful freezing stage.
Exercise guidance: pain-guided, progressive exercise tailored to your current stage, avoiding aggressive stretching during the irritable freezing stage in favour of gentle range-of-movement work, and progressing to more structured strengthening as you move into the frozen and thawing stages.
What to Expect at Your First Appointment
We will take a thorough history, including any minor injury or period of reduced shoulder use that may have triggered your symptoms, and assess your current stage based on your pain pattern and range of movement. We will explain clearly what stage you are likely in, what to realistically expect over the coming months, and build a treatment plan appropriate to that stage, recognising that frozen shoulder is a genuinely time-limited, if slow, condition.
Frequently Asked Questions
Will it definitely go away on its own? In most cases, yes, frozen shoulder is self-limiting, but the natural course can take 1 to 3 years. ⁸ Treatment aims to reduce pain, support movement, and help you function better throughout that process, rather than simply waiting it out.
Should I push through the stiffness and stretch hard? Not during the painful freezing stage. Research shows muscle guarding is a major driver of restricted movement at this point, and aggressive stretching tends to increase guarding rather than help. ⁶ Gentler, more structured stretching becomes appropriate as pain settles.
Will it come back in the other shoulder? It can. Around 20 to 30% of people who develop frozen shoulder in one shoulder go on to develop it in the other, though not at the same time. ⁴
Do I need a scan? Usually not. Frozen shoulder is typically diagnosed clinically, based on history and the characteristic pattern of restricted passive movement, particularly external rotation. ³
Will a steroid injection help, and when should I have one?
Corticosteroid injection into the shoulder joint has good evidence for providing meaningful short-term relief, particularly when given early in the freezing stage. Research has found that a single corticosteroid injection led to significantly faster improvement in pain, motion, and function during the first 8 weeks compared with oral NSAIDs, though this difference evened out by 12 weeks. ¹³ Steroid injections tend to be most beneficial when given within the first 6 weeks of symptoms, while pain is at its worst, and can make it considerably easier to tolerate gentle movement and physiotherapy afterwards. It's worth noting that whilst injections help with pain in the short term, they have not been shown to change the overall length of the condition, so they work best as one part of a broader treatment plan rather than a standalone fix. NICE guidance recognises corticosteroid injection as a recommended option for shoulder pain, and we would always coordinate with your GP if this is something worth considering for you.
Recognise these symptoms? Get in touch using the contact form and we will assess your stage and put together the right treatment plan for you.
References
Adhesive Capsulitis (Frozen Shoulder). StatPearls Publishing. Updated 2025. Available at: https://www.ncbi.nlm.nih.gov/books/NBK532955/
Basic Science Research in Frozen Shoulder: Current Updates. PMC. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC12151953/
NICE Clinical Knowledge Summary, Shoulder pain. Referenced via: https://cks.nice.org.uk/shoulder-pain
Adhesive Capsulitis in Eight Dogs: Diagnosis and Management (human epidemiology data cited). PMC. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4943935/
Frozen Shoulder: Evidence and a Proposed Model Guiding Rehabilitation. Journal of Orthopaedic & Sports Physical Therapy. 2009. Available at: https://www.jospt.org/doi/10.2519/jospt.2009.2916
Frozen Shoulder. E3 Rehab, citing Hollmann et al. 2015. Available at: https://e3rehab.com/frozenshoulder/
Fibroblast activation and inflammation in frozen shoulder. PMC. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6478286/
The Frozen Shoulder: Myths and Realities. PMC. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC3785028/
Shoulder Pain and Mobility Deficits: Adhesive Capsulitis, Clinical Practice Guidelines. Journal of Orthopaedic & Sports Physical Therapy. 2013;43(5):A1-A31. Available at: https://www.jospt.org/doi/10.2519/jospt.2013.0302
Kirker K, O'Connell M, Bradley L, et al. Manual therapy and exercise for adhesive capsulitis: a systematic review with meta-analysis. Journal of Manual & Manipulative Therapy. 2023;31(5):311-327.
Frozen Shoulder, Physio Guide to Pathophysiology and Evidence Based Treatment. Bradley Physio. Available at: https://www.bradleyphysio.co.uk/frozen-shoulder-physio-guide-to-pathophysiology-evidence-based-treatment
Clinical Practice Guidelines for Diagnosis and Non-Surgical Treatment of Primary Frozen Shoulder. Available at: https://www.e-arm.org/journal/view.php?number=4407
Comments