ABSTRACT: Management with corticosteroid injections should beconsidered for a variety of painful shoulder conditions, such ascervical, acromioclavicular, subacromial, glenohumeral, and bicepstendon pathology. Several aspects of the physical examination areused to isolate the anatomical source of a patient's shoulder pain.Knowing how to perform provocative maneuvers and evaluate theresults is critical for making the diagnosis and identifying potentialcorticosteroid/anesthetic injection sites. In our comprehensive16-step shoulder examination, radiographs are not viewed initiallyto avoid bias that can lead to inaccurate diagnosis. When commonprovocative maneuvers for shoulder conditions are used in isolation,their sensitivity and specificity typically are lower than whenthey are used in combination. Obtaining high-quality radiographs isessential. (J Musculoskel Med. 2008;25:236-245)
A variety of painful shoulder conditions might warrant consideration for management with corticosteroid injections. Most physicians have a general knowledge of how to obtain a pertinent history for shoulder problems, but some may have minimal training for making a diagnosis of some specific shoulder conditions. For example, differentiating cervical, acromioclavicular (AC), subacromial (SA), glenohumeral (GH), and biceps tendon pathology may be particularly challenging.
Various aspects of the physical examination are used frequently to isolate the anatomical source of a patient's shoulder pain, especially provocative maneuvers, signs, and tests; radiography also is useful. Knowing how to perform provocative maneuvers and evaluate the results is critical for making the diagnosis and identifying potential corticosteroid/anesthetic injection sites.
This 3-part article describes the diagnostic and therapeutic uses of corticosteroid/anesthetic injections for painful shoulder conditions. In the first part ("The use and misuse of injectable corticosteroids for the painful shoulder," The Journal of Musculoskeletal Medicine, February 2008, page 78), we reviewed the mechanism of action of corticosteroids, current preparations, indications and contraindications, adverse effects, misuses, and lack of uniform standards of care. This second part discusses physical examination and radiographic evaluation procedures for determining when to inject corticosteroids. In the third part, to appear in a later issue of this journal, we will illustrate techniques for administering injections for specific shoulder complaints. We hope that this discussion will encourage the development of more uniform guidelines and help improve injection accuracy.
A 16-step physical examination
There are various descriptions of how to perform a comprehensive shoulder examination.1,2 The examination performed for a typical patient seen in our orthopedic shoulder specialty clinic includes 16 basic steps (Table 1). In this examination, radiographs are not viewed initially to avoid bias that can lead to a premature/inaccurate diagnosis (eg, when AC arthritis is seen on radiographs but the AC joint is not a significant source of pain).The steps are as follows:
Figure – In the final step in a comprehensive shoulder examination, radiographs are re-examined even though the physical examination is not yet completed. These radiographs show moderate glenohumeral arthritis (A), moderate acromioclavicular arthritis (B), and large calcific tendinitis (C).
Studies have shown that when common provocative maneuvers for shoulder conditions are used in isolation, their sensitivity and specificity typically do not exceed 60% and 85%, respectively (Table 2).
However, a more recent study rigorously evaluated 8 physical examination tests/maneuvers in 1127 patients who had shoulder surgery.10
The authors determined the diagnostic values of the tests/ maneuvers/signs, including their probabilities in predicting bursitis and partial-thickness and full thickness rotator cuff tears. When each test was evaluated independently, the sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy varied considerably.
However, when 3 tests were used in combination, the predictive strengths improved substantially. For example, the painful arc sign, Hawkins-Kennedy impingement sign, and infraspinatus muscle test used in combination yielded the best posttest probability (95%) for any degree of impingement syndrome.The combination of the painful arc sign, drop-arm sign, and infraspinatus muscle test produced the best posttest probability (91%) for full-thickness rotator cuff tears.
Obtaining high-quality radiographs, including views that show the SA arch, is essential. Views that are especially helpful include the supraspinatus outlet view for the SA space, the Zanca view for the AC joint, the true anteroposterior view, the scapular Y view, and the axillary-lateral view. The Zanca, anteroposterior, scapular Y, and axillary-lateral views are sufficient for most patients.
The SA bursa is one of the most frequently injected areas of the shoulder. The Neer impingement and Hawkins-Kennedy impingement reinforcement maneuvers are important for demonstrating the painful arc of motion that occurs with SA impingement syndromes. The supraspinatus and infraspinatus strength tests and drop-arm and painful arc maneuvers also help.
Strength testing should be performed after the local anesthetic has taken effect because in some cases, there may be notable improvements in supraspinatus strength testing results.The drop-arm maneuver may improve notably or become absent; when there is improvement, we often steer away from ordering an MRI scan toward physical therapy while adopting a "wait and see" approach to see if improvement is sustained. In these cases,what initially appeared to be stage 3 SA impingement (with a full-thickness rotator cuff tear) might be stage 2 (no rotator cuff tear) or stage 3 with a partial but nonoperative rotator cuff tear.
The Yergason and Speed maneuvers are helpful in examining the biceps tendons. Directly palpating biceps tendons (biceps/shoulder rotation maneuver) also is important. The maneuvers described for SA impingement syndromes should be used for evaluating the rotator cuff.
The cross-body adduction maneuver usually elicits pain when there is significant AC arthritis. However, the Hawkins-Kennedy impingement reinforcement maneuver also may elicit pain from the AC joint. Analyzing radiographs for this disorder is important; the Zanca radiographic view is most helpful. Selective diagnostic injections are quite useful in identifying AC joint pathology as a significant source of pain because the cross-body adduction maneuver has low sensitivity (about 23 %) (see Table 2).
For GH arthritis, internally and externally rotate the arm with the elbow at the patient's side; feel for crepitus and pain localized to the shoulder. In addition, look for decreased range of motion (with similar active and passive motion) and analyze radiographs.
Other less-common arthritides may occur (eg, calcium pyrophosphate deposition disease, chondrocalcinosis, and gout). In these cases, making the diagnosis often requires crystallographic analysis of joint fluid and additional metabolic workup.
This condition is characterized by the presence of a chronic full-thickness supraspinatus tear and GH arthritis. Additional characteristics include advanced GH changes, often with mild evidence of humeral head collapse, and erosion of the acromion and associated structures leading to GH incongruity.
Patients typically present with complaints of restricted motion and moderate to severe pain that does not subside adequately with oral anti-inflammatory medications. Simple arm movements may be limited because of weakness, crepitation, and sharp pain, and overhead reaching usually is not possible. Corticosteroid injection at 4- to 6-month intervals helps alleviate pain in cases in which surgery is not a viable option.
Treatment with injections is considered for significant residual pain resulting from a sprain or strain (eg, post-traumatic bursitis or tendinitis). However, injections typically are not given within 3 weeks of the injury to allow for initial healing. For maneuvers that test for the specific strain or sprain of SA structures, see the SA impingement section above. If significant pain persists at 1 to 2 weeks postinjection, consider using MRI to determine whether there has been a tear of a tendon, the capsular ligaments, or the glenoid labrum.
In this case, the unstable GH joint moves excessively upward toward the acromion during overhead elevation of the arm. A rule of thumb is to inject the SA space but usually not the GH joint, because injection of an unstable joint that can be subluxated reduces the protective benefit of pain, potentially leading to use-related increased inflammation that could result in increased pain after the analgesic effect of the corticosteroid has dissipated.
Determining whether the patient can voluntarily dislocate or nearly dislocate (subluxate) his shoulder also is important. Voluntary dislocators/subluxators with secondary SA impingement typically do not benefit from corticosteroid injections; they often require physical therapy or behavioral counseling or both because of the important psychological dimensions of this condition. The crank, relocation, and jerk maneuvers help elicit instability. The Neer and Hawkins-Kennedy maneuvers also help establish SA impingement that might result from GH instability.
Use the diagnostic maneuvers described for SA impingement syndromes. The presence of calcific tendinitis is confirmed by the presence of 1 or more radiopacities in the vicinity of the supraspinatus or other rotator cuff tendons (see Figure).This lesion is not injected directly with corticosteroids, but injections into the SA bursa may be done in conjunction with "needling" of the calcific deposit.11
There is severely decreased range of motion on physical examination with adhesive capsulitis; active and passive motion are similar. Also, external rotation often is severely decreased. Coupled with these findings, radiographs are essential for distinguishing this condition from GH arthritis.
These points are characterized by local tender, self-sustaining hyperirritable foci located in skeletal muscle or surrounding fascia or in a zone of referred pain. A common shoulder trigger point occurs over the insertion of the levator scapula muscle into the superior angle of the scapula. When this trigger point is present with types 2 and 3 of SA impingement syndrome, we hypothesize that it results from excessive/repetitive traction by this muscle because it causes compensatory scapular elevation as a means for relieving SA pain by increasing the superoinferior dimensions of the SA space.
Palpation over the posterior scapula during range of motion (eg, abduction) reveals crepitation, pain, or popping (often called "snapping scapula syndrome") generally beneath the medial or superomedial aspects of the scapula. Surgery is more common in younger patients (younger than 20 years) than in older ones because symptoms are more likely caused by an excessively curved superior scapular angle. Older patients and those who had antecedent trauma to the scapular region are more likely to benefit from corticosteroid injections. Nonoperative resolution of symptoms might require activity modification coupled with 3 to 5 corticosteroid injections administered over 1 to 2 years.
This condition, which typically occurs in adolescent and teenage populations, is rare even in a shoulder specialty practice. CT scans and selective local anesthetic injections often are needed to make the diagnosis; corticosteroid injections are not useful for this condition. If subcoracoid impingement is suspected, referring the patient to an orthopedic specialist might be prudent.
Understanding and following a standard "checklist" during the physical examination, coupled with an adequate radiographic evaluation, may help examiners target shoulder areas that could benefit from corticosteroid injections. By using the immediate effect of the local anesthetic to distinguish nonaffected from affected areas of the shoulder, clinicians can minimize misuse or overuse of these injections and enhance their therapeutic effects. In part 3, we will describe techniques for administering injections for specific shoulder conditions and advanced/detailed and basic/quick algorithms for evaluating and injecting painful shoulder conditions.