The term frozen shoulder or adhesive capsulitis (CA) describes an alteration characterized by pain and limitation of the active and passive mobility of the shoulder. The etiology or the initial trigger is unknown. It is postulated that a minor trauma could initiate a reparative inflammatory response with increased fibroblasts and myofibroblasts creating an imbalance between an aggressive fibrosis and the loss of collagenous remodeling, producing retraction and rigidity of the capsule. Characteristically, pain precedes rigidity, suggesting an evolution from inflammation to fibrosis.
Profile of the patient
It is estimated a prevalence of 2-5% in the general population. In general it affects people between 40 and 65 years old with a higher incidence in women and in the non-dominant superior member. Its presence increases the risk of developing capsulitis in the contralateral shoulder (34%). Recurrence in the same shoulder is rare and simultaneous bilateral involvement occurs in 14% of cases. It is more frequent in patients with diabetes and thyroid disease.
Phases of capsulitis
According to Reeves, adhesive capsulitis has 3 overlapping phases:
1) Painful phase. It begins gradually and lasts from 2 to 9 months. Pain interferes with sleep, increases with the movement of the arm and the patient begins to notice limited mobility.
2) Rigid phase. Lasts from 3 to 12 months. The main problem is the limitation of mobility.
3) Recovery phase , with a duration of 5 to 26 months.
The diagnostic is fundamentally clinical. The examination should include the cervical spine. The shoulder typically presents limitation of active and passive elevation , with less than 120º and a greater than 50% reduction of external rotation. In early stages it can be difficult to differentiate adhesive capsulitis from a tendinopathy of the rotator cuff because the limitation is minimal and muscle strength can be normal. Image analysis is rarely required.
Although the natural history is towards complete resolution, sometimes it does not happen. There is no agreement that allows us to affirm which treatment is the most effective. Options include: observation, nonsteroidal anti-inflammatory drugs (NSAIDs), oral corticosteroids, corticosteroid infiltrations, suprascapular nerve blocks, arthrographic distension, closed manipulation under anesthesia, and surgery.
The treatments that have obtained better results are the exercises and the infiltrations with corticoids. In the early stages of the AC, the infiltration with corticoids, obtains the best results, can shorten its natural history and allows a greater tolerance to the exercises. Stretching exercises are recommended. The program of exercises performed in rehabilitation, contribute to reduce pain, improve mobility and function. Surgery should be the last alternative.