Adhesive capsulitis, commonly known as frozen shoulder, is a debilitating condition characterized by progressive pain and significant loss of active and passive range of motion (ROM) in the glenohumeral joint. This comprehensive guide provides physical therapists and healthcare professionals with an in-depth understanding of frozen shoulder, its underlying anatomy, and a phased approach to rehabilitation grounded in current research.
Frozen shoulder is a self-limiting but often protracted condition affecting the glenohumeral joint capsule, leading to pain and profound stiffness. It typically progresses through distinct phases: a painful "freezing" phase, a stiff "frozen" phase, and a "thawing" or resolution phase. While the exact etiology remains elusive, it is understood to involve inflammatory and fibrotic processes within the joint capsule, particularly the anterior capsule, inferior axillary fold, and rotator interval.
The prevalence of frozen shoulder is estimated to be between 2-5% in the general population, with higher incidence observed in individuals aged 40-60 years and a slight predilection for women. Several comorbidities are strongly associated with frozen shoulder, most notably diabetes mellitus (affecting up to 10-20% of diabetic patients), thyroid dysfunction, Parkinson's disease, and cardiac disease. Trauma or previous surgery to the shoulder or surrounding areas can also predispose individuals to developing the condition. Clinically, diagnosis is primarily made through a thorough history and physical examination, revealing a characteristic global restriction of both active and passive ROM, especially external rotation, abduction, and internal rotation, which distinguishes it from other shoulder pathologies like rotator cuff tears.
Understanding the functional anatomy of the glenohumeral joint is paramount to comprehending the pathophysiology and guiding the rehabilitation of frozen shoulder. The glenohumeral joint is a ball-and-socket synovial joint, allowing for the greatest mobility of any joint in the body. Its inherent instability is compensated by static and dynamic stabilizers.
The primary static stabilizers include the joint capsule and its associated ligaments: the superior, middle, and inferior glenohumeral ligaments, and the coracohumeral ligament. In frozen shoulder, these structures, particularly the inferior capsule and coracohumeral ligament, undergo significant thickening, contraction, and fibrosis. Histologically, there is an increase in fibroblasts and collagen types I and III, leading to a loss of the normal pliancy and volume of the joint capsule. This fibrotic process restricts the 'redundancy' of the capsule, which is normally crucial for allowing full ROM, especially at the end ranges. The loss of the axillary fold, where the inferior capsule typically folds, is a hallmark of the restricted capsular volume.
Dynamic stability is provided by the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis), which center the humeral head within the glenoid fossa. While the rotator cuff muscles are typically not the primary pathology in frozen shoulder, their function can be compromised due to pain and disuse, further contributing to movement dysfunction. The intricate interplay between glenohumeral and scapulothoracic motion (scapulohumeral rhythm) is also disrupted, with patients often compensating for lost glenohumeral motion by increasing scapular movement, leading to secondary issues in the neck and upper back. The synovial fluid, responsible for lubrication and nutrition, may also be affected, though this is less documented than the capsular changes.
Rehabilitation for frozen shoulder is a phased process, requiring patience, consistent effort, and careful progression to avoid aggravating inflammation and pain. The overarching goal is to manage pain, restore ROM, improve strength, and regain functional independence.
This initial phase is characterized by gradual onset of pain, which may be severe, sharp, and present at rest or at night. Progressive loss of both active and passive ROM occurs, often described as global stiffness. The primary objective in this phase is pain management and preventing further loss of motion without exacerbating inflammation. Aggressive stretching is contraindicated.
In this phase, pain may begin to subside, but significant stiffness and restricted ROM become the predominant symptoms. The capsule is markedly contracted. The focus shifts towards carefully restoring range of motion.
This final phase is characterized by a gradual, often spontaneous, return of ROM and reduction in stiffness. Pain is minimal or absent, and the patient's functional abilities significantly improve.
While not always explicitly listed as a separate "rehab phase," this ongoing period is crucial for maintaining gains and preventing recurrence. It typically overlaps with the later stages of Phase 3.
Current research consistently supports physical therapy as a cornerstone in the conservative management of frozen shoulder. While the self-limiting nature of the condition means most patients will eventually recover, physical therapy significantly helps to reduce pain, accelerate recovery, and improve functional outcomes compared to no intervention or less structured approaches.
Multiple studies and systematic reviews have demonstrated the efficacy of a multimodal physical therapy approach incorporating patient education, manual therapy (joint mobilizations, soft tissue techniques), and therapeutic exercises. The evidence suggests that early, gentle mobility exercises in the painful phase, followed by progressive stretching and strengthening in later phases, yield the best results. The intensity and progression of exercises must be carefully individualized, as excessive stretching in the early, inflammatory phase can exacerbate pain and potentially prolong recovery. The "no pain, no gain" philosophy is generally not applicable in the early stages of frozen shoulder.
While corticosteroid injections can provide short-term pain relief, particularly in the freezing phase, their long-term benefits over physical therapy alone are debated. For refractory cases, surgical interventions such as manipulation under anesthesia or arthroscopic capsular release may be considered, but these are typically reserved for patients who have failed an extensive course of conservative management. Research continues to explore the optimal timing and combination of interventions, but the fundamental role of a well-structured and patient-adherent physical therapy program remains undisputed in optimizing recovery from frozen shoulder.