adhesive capsulitis (frozen shoulder or FS)

Introduction

frozen shoulder is the third most common cause of musculoskeletal disability in the United States and affects patients between the ages of 40 and 60 years, with a prevalence rate of 2% to 5% ¹⁾
usually runs a limited course of 1 to 3 years and often resolves over time

mainly 40-70 year olds, women > men
3% lifetime risk
main risk factor is a period of shoulder immobilization
18-50% have Dupuytren's contracture and thse with Duputren's have a 8x risk of developing frozen shoulder

may follow injury of surgery to the shoulder or upper limb or prolonged immobilisation (eg. rotator cuff tear, stroke recovery)
increased risk in conditions such as:
- diabetes - 10-20% higher risk
- thyroid disease
- Parkinsons
- inflammatory diseases, etc
may be due to certain medications such as flouroquinolone antibiotics, vaccination, antiretrovirals

bioinformatics analysis has identified 321 shared genes between frozen shoulder and Dupuytren's contracture and revealed a protein-protein interaction (PPI) network, 15 hub genes and two immune-related candidate genes (POSTN and COL11A1) that may play crucial roles in both conditions ²⁾
there is growing evidence that autoimmune processes may be involved in both conditions
sometimes associated with other fibromatous conditions:
Peyronie's disease
plantar fibromatosis
fibromatosis of knuckle pads on dorsa of PIPjts - occur in up to 80% of pts with DD

often triggered by prolonged immobilisation of the shoulder joint but can occur spontaneously
shoulder capsule is thought to become inflamed and adhesion bands then form within capsule folds which restrict range of movement

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