Frozen shoulder is a specific condition of uncertain etiology affecting the shoulder (glenohumeral) joint, resulting from the contracture and loss of compliance of the joint capsule. The main clinical feature is characterised by a significant limitation of both active and passive glenohumeral joint motion in all planes of motion. The term “frozen shoulder”, first used by Codman in 1934, remains the most commonly used term to describe this common condition. Other names for this condition are “scapulohumeral periarthritis” and “adhesive capsulitis”. “Fifty shoulder”is another name commonly used by the public because this condition is most frequently found among patients between 40 and 60 years of age. Understanding of the exact pathophysiology of this common condition is still limited, and there is controversy on its classification, diagnosis and management.
Frozen shoulder is more common among women. The exact prevalence and incidence are unknown. The non-dominant shoulder seems to be more commonly affected.
Typical symptoms and signs of frozen shoulder can appear in patients after minimal or no trauma at all. Traditionally, patients suffering from frozen shoulders can be divided into two sub-groups, “primary frozen shoulder” and “secondary frozen shoulder”. Primary frozen shoulder represents the idiopathic condition for those patients without any identifiable cause or predisposing factor. Secondary frozen shoulder refers to the condition suffered by patients with either a known intrinsic, extrinsic or systemic disorder.
One common condition under the subgroup of systemic abnormality is diabetes mellitus. About 10% to 20% of patients with frozen shoulder have also been reported as suffering from diabetes. Insulin-dependent diabetic patients of many years have a much greater frequency of having frozen shoulder, possibly involving both shoulders. Examples of the subgroup of extrinsic disorders include degeneration of cervical spine, ischemic heart diseases, pulmonary disorders and humerus fractures. Examples of the subgroup of intrinsic disorders include rotator cuff tendonitis, rotator cuff tears, biceps tendonitis and calcific tendonitis.
A typical patient of frozen shoulder is usually between 40 and 60 years old and reports a disturbing vague shoulder pain and stiffness that has lasted for weeks or months. There is usually no identifiable precipitating incident. Typically, there are three distinct but overlapping phases with variable duration:
The painful phase (“freezing”): At this initial inflammatory phase, shoulder pain is severe at night and patients have difficulty lying on the affected side. Any attempts of motion, especially rapid motions, may cause disturbing shoulder pain. Patients tend to avoid motion and put the arm in a medially rotated resting position by the side of body. This phase is said to last between two to nine months.
The progressive stiffness phase (“frozen”): The disturbing pain begins to settle during this phase. There is increased shoulder stiffness associated with discomfort at the end range of motion, resulting in severe restriction of activities in daily life. Both personal care and overhead activities may be severely affected. Common complaints from patients during this phase include difficulty in fastening a bra, tucking in a shirt and reaching the opposite armpit and the back. This phase is said to last anywhere between three to 12 months.
The resolution phase (“thawing”): During this final phase, there is a slow gain in the range of motion. Progress can be slow and may cause frustration in patients. Also, the restoration of motion and function is usually incomplete.
Typically, patients are fit and well, without any past history of shoulder problems. Vague shoulder pain usually comes on a few days after a trivial injury, or there is no history of trauma at all. Patients may not seek any medical advice at this stage. Gradually, the shoulder pain becomes more and more disturbing, causing sleep disturbance.
After several months, the shoulder pain improves but the stiffness increases, causing difficulty in using arms for overhead activities and personal care. There is pain at the extremes of the range of motion. Once the stiffness in the shoulder joint has reached a plateau, a steady state sets in. The range of motion remains more or less the same.
Classically, frozen shoulder has been described as a self-limiting benign condition lasting anywhere from 10 to 18 months. Many scientific studies show that among a significant percentage of patients, a residual loss of shoulder motion is found many years after the onset of initial symptoms.
Because frozen shoulder represents a symptom complex rather than a specific diagnostic entity, proper history taking and a detailed physical examination of the shoulder joint is crucial in making the diagnosis.
An orthopaedic surgeon will perform a detailed examination of the shoulder. He or she will feel for any particular tender spot and measures the active and passive range of motion of the shoulder in different planes of motion. The clinical hallmark for frozen shoulder is the limitation of active and passive range of glenohumeral motion in all planes of motion. Impingement signs may be present. The surgeon will then check for any weakness of the arm. Depending on the clinical conditions, the surgeon may also examine the neck, the opposite shoulder and the trunk to exclude any associated abnormality.
Plain X-rays of a shoulder joint with frozen shoulder usually shows that it is normal. The main purpose of using X-rays is to rule out abnormalities in local bone, joint or soft tissues. Routine haematological testing is usually unremarkable. Blood tests to identify diabetes and thyroid disease may be considered in cases with suspected latent diabetes or subclinical thyroid disease. Magnetic Resonance Imaging (MRI) may show some characteristic changes in frozen shoulder patients, but its use in the diagnosis of frozen shoulder has not been proved essential. However, MRI is useful in ruling out associated intrinsic shoulder abnormalities. Bone scans are rarely indicated.
The overall goal in treating patients with frozen shoulder is to restore the range of motion and to relieve pain. Conservative treatment can provide pain relief and improve the overall function of the shoulder.
Conservative treatment options may include:
Medications for pain control: analgesics or non-steroidal anti-inflammatory medications are effective in controlling some of the symptoms.
Physiotherapy in the form of gentle, firm stretching exercise in different planes of motion is the key. It has to be emphasized that the patient must assume primary responsibility and tolerate the discomfort associated with physical therapy.
Local Injection into the subacromial space and intra-articular region with a steroid preparation has been used to relieve pain, especially in the early painful phase.
Distention arthrography with intra-articular fluid injection may help improve the range of motion.
Your orthopaedic surgeon will design a treatment plan that is individualized and based on the severity and chronicity of your symptoms. The use of adequate and appropriate analgesics should be combined with an early gentle stretching exercise program. Treatment usually takes several months. Most patients experience a gradual improvement and return of function.
Your orthopaedic surgeon may recommend surgery when you have persistent and disturbing symptoms despite an adequate period of intensive conservative treatment.
Operative treatment options may include:
Manipulation under anesthesia (MUA): The procedure is performed under either general anesthesia or brachial plexus block. Your orthopaedic surgeon will use a constant and controlled motion to “break down” the tight capsules in different directions.
Arthroscopic surgical release technique: A fiberoptic scope and appropriate “pen-like” arthroscopic instruments are inserted through several small incisions. This allows joint irrigation, resection of the inflammatory synovium, division of subscapularis tendon and release of the capsular contracture.
Open surgical release technique: The major advantage of this technique is to allow palpation, visualization and surgical release of dense adhesions outside the shoulder joint. Hence, the procedure is suitable for patients with extensive extra-articular adhesions. Examples include patients with post-traumatic or post-surgical stiff shoulder.
Rehabilitation after operative treatment plays an essential role in keeping the results achieved by surgery. The program will be individualised, and your orthopaedic surgeon and physiotherapist can inform you of the appropriate plan based on your conditions. Recovery usually takes several months. A strong commitment to rehabilitation is essential in achieving a good surgical outcome. Patients who are intolerant of exercises or insufficiently motivated to perform exercises will rarely improve with operative treatment.
Efforts should be directed toward prevention by identifying patients with risk and initiating early intervention. Immobilisation should be avoided or kept to a minimum.
Dr. YU, Kong-san