Pathogenesis (development of disease)
A primary form of frozen shoulder can be distinguished from a secondary form. The pathogenesis of the primary form is unknown.
The primary (idiopathic) form of this disease is understood to be the cyclic clinical picture of capsular frozen shoulder.
It is currently discussed to be related to the following conditions:
- Autoimmune diseases, unspecified
- Diabetes mellitus (diabetes) (risk of disease 10-19%, as high as 36% in insulin-dependent patients) – accumulation of AGEs (Advance Glycation End Products; advanced glycation end products) is thought to lead to solidification of collagen; furthermore, inflammatory processes and circulatory disturbance are likely to be causative.
- Dupuytren’s contracture – progressive shrinkage and thickening of the connective tissue plate of the palm (palmar aponeurosis).
- Hyperthyroidism (hyperthyroidism)
Furthermore, genetic factors are thought to play a role.
In the freezing phase (freezing phase), there is diffuse synovitis (synovitis) and capsulitis (capsulitis). In the freezing phase, capsular fibrosis develops (formation of a hard connective tissue-like, sometimes painful capsule) with an increase in fibroblasts and myofibroblasts.
In the secondary form of frozen shoulder, there are identifiable causes which cause the restriction of movement of the shoulder joint. Frozen shoulder is usually the result of degenerative changes of the shoulder with swelling, calcification of tendons, tendon insertions and bursae. The cause is degenerative changes of the subacromial space. The subacromial space is the area below the acromioclavicular joint. It is bounded from below by the rotator cuff of the shoulder joint. The upper boundary is formed by the acromion (= shoulder height) as well as the acromioclavicular joint.
Etiology (causes) of secondary frozen shoulder
Disease-related causes.
Musculoskeletal system and connective tissue (M00-M99).
- Omarthrosis (shoulder joint osteoarthritis).
Injuries, poisonings, and other consequences of external causes (S00-T98).
- Shoulder injuries with prolonged immobilization
- Rotator cuff changes, unspecified, associated with prolonged immobilization
Other causes
