Investigations

Since frozen shoulder is generally a clinical diagnosis, investigations are carried out if other pathologies are suspected (1).

• radiography
  • X-ray to rule out other conditions like osteoarthritis or a bone tumor
• biochemical or haemoatological tests e.g. – ESR, CRP (1)

Notes (2):

• it has been stated that most orthopaedic surgeons would not investigate a frozen shoulder beyond a plain x ray
• plain radiographs of the frozen shoulder may well be reported as normal, although they may show periarticular osteopenia as a result of disuse
• a further review noted (3)
  • ultrasound and magnetic resonance imaging may be considered depending on the clinical features and differential diagnoses
  • differential diagnoses to consider include (4)
    • tears or tendinitis of the rotator cuff e.g. supraspinatus tendinitis or the painful arc syndrome - pain present in a small arc of movement, and only during active movement and, unlike frozen shoulder, the range of passive movements is generally normal
    • stiffness following shoulder injury - stiffness is greatest immediately after the injury and then declines. In a frozen shoulder, stiffness gradually increases after the injury over a period of several months
    • stiffness from disuse - a shoulder which is not used will gradually become stiff, for example, a broken forearm which is nursed overcautiously. However, the pattern of stiffness differs from that of a frozen shoulder
    • reflex sympathetic dystrophy - shoulder pain and stiffness may follow a stroke or myocardial infarction. A mild reflex sympathetic dystrophy may quite closely resemble a frozen shoulder, but severe forms of the disease also induce trophic and vasomotor changes in the hand
    • arthritis of the shoulder joint
    • polymyalgia rheumatica - especially if both shoulders are affected
    • infective arthritis in an immunosuppressed patient
    • polymyositis
    • Pancoast's syndrome
    • a posterior dislocation of the glenohumeral joint that has become locked
    • early Parkinson's disease (4)

Reference:

• (1) van de Laar SM, van der Zwaal P. Management of frozen shoulder Orthopedic Research and Reviews 2014;6:81-90
• (2) Dias R et al. Frozen shoulder. BMJ 2005; 331:1453-1456.
• (3)Karbowiak M, Holme T, Mirza M, Siddiqui N. Frozen shoulder BMJ 2022; 377 :e068547 doi:10.1136/bmj-2021-068547
• (4) Drug and Therapeutics Bulletin 2000; 38 (11): 86-88.