Pathogenesis of Frozen Shoulder

• Frozen Shoulder Pathogenesis/Development:

  • presence of cytokines suggests a possible autoimmune process, but the relationship is no well established
  • there can be inflammation, fibrotic tissues, adhesions and this all leads to restricted movements and thus can happen with the subacromial space with the synovial lining and also with the joint capsule
  • so there is a lot of different tissue types that can be subjected to this thickening and fibrotic process during frozen shoulder
• Frozen Shoulder Pathogenesis/Development:

  • subacromial fibrosis: presence of fibrous tissue and adhesions in the subacromial space, leading to restricted movements and impingement of the shoulder structures
  • proliferative synovitis: the synovium lining the joint capsule may show signs of excessive proliferation and inflammation, contributing to the thickening of the synovial tissue
  • capsular thickening: joint capsule may exhibit thickening and fibrosis, leading to loss of ROM and shoulder joints stiffness
• Frozen Shoulder Pathogenesis:

  • associated with HLA B27 antigen (found in ankylosing spondylitis) so theres evidence of systemic inflammation
  • TGF, PDGF and TNFa are inflammatory markers and fibrotic cytokines found in synovium - chemical messengers that promote inflammatory cascading process
  • theres hypervascularity and hyperinnervation during frozen shoulder - usually associated with hypersensitivity and high level of pain
  • frozen shoulder pathology, which involves synovial inflammation, can also lead to periarticular adhesions of capsule & ligaments
  • muscle guarding can also occur
• Frozen Shoulder Pathogenesis/Development:

  • chemical messengers (cytokines) that promote the inflammatory cascade:
  • TGF = transforming growth factor
  • PDGF = platelet derived growth factor
  • TNFa = tumour necrosis factor alpha
• Frozen Shoulder Pathogenesis/Development:

  • role of muscles in restriction of movement with frozen shoulder:
  • muscles can play important role in limiting range of motion with frozen shoulder
  • so in clinical setting, understand the tissues involved and what kind of management techniques can be used to reduce muscle tension guarding and to help normalise muscle tone and activity
  • also consider pain levels and pain avoidance behaviours which can cause cause a viscous cycle of shortening of the tissues, muscle atrophy and ultimately a loss of function