Treatment of Bursitis, Tendinitis, and Trigger Points

Bursae and Tendon Sheaths

Bursae are small fluid-filled sacs, subcutaneous and deep, which provide a cushion for bone and the surrounding soft tissue. They develop in relation to friction and facilitate the gliding motion of tendons and muscles. There are approximately 78 bursae on each side of the body as described by Monro and Spalteholz. Adventitial bursae may form in response to abnormal shearing stress at sites subjected to chronic pressure, such as a bunion over the metatarsal head of the great toe. Tendon sheaths are similar in composition to bursae but differ in overall shape. Tendon sheaths are long and tubular, whereas bursae are usually round and flat.

Inflammation of bursae, as in bursitis, can be seen microscopically as a thickening of the normal thin surface of synovial cells lining the bursal wall. This thickening coupled with increased production of synovial fluid leads to localized pain and swelling. Aside from simple overuse, bursitis may be caused by local trauma, infection, and crystal deposition. Underlying systemic and autoimmune disorders, such as lupus, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthropathy, and gout, can also lead to bursitis.

Because of the adjacent location of bursae and tendons, an inflammatory process in one may also involve the other. Tendinitis and tenosynovitis are used to describe similar inflammatory reactions in tendons and tendon sheaths, respectively. Some forms of tendinitis may be caused by factors other than overuse, inflammation, trauma, and degenerative disease. Gonococcemia, for example, is one cause of tenosynovitis that should be considered in the appropriate setting. Another rare cause is hemodialysis. In 2008 the U.S. Food and Drug Administration (FDA) added a black box warning to fluoroquinolone antibiotics, highlighting the potential for tendinopathy and tendon rupture. Clinicians should avoid tendon sheath injections in patients who are taking this class of drugs.

Common sites of tendinitis and bursitis in the body are depicted in Fig. 52.1 .

Trigger Points

Myofascial pain related to trigger points is probably omnipresent, but it is vague and ill-defined in the literature, the specific syndromes are unknown to many clinicians, and the disorders are difficult to clarify in many patients. Hence, myofascial pain originating from trigger points is often attributed to a plethora of other conditions. Consequently, the true incidence is unknown, and few clinicians practice trigger point injection therapy. Examples of misdiagnosis can include fibromyalgia, overuse syndromes, statin-induced myopathy, and malingering.

Trigger points are focal areas of hyperirritability usually found within a taut band of skeletal muscle or in the muscle fascia that are painful on compression and associated with a characteristic pattern of referred pain, motor dysfunction, and autonomic phenomena ( Box 52.1 ). Trigger points can also be identified by the local twitch response , a brisk contraction of muscle fibers elicited by snapping palpation or rapid insertion of a needle into the trigger point itself.

Trigger points probably develop in response to muscle fiber injury. The injury may be an acute traumatic event or more subtle repetitive microtrauma. The underlying pathophysiology has not been fully elucidated but probably involves chronic muscle stress, excessive release of acetylcholine, and dysfunctional motor end plates.

Trigger points can occur in any muscle or muscle group; they are generally unilateral, but bilateral trigger points have been reported. As the stress associated with myofascial pain commonly affects both single muscles and whole muscle groups, trigger points tend to cluster. In the upper part of the trunk, a common trigger point cluster involves the muscles of the neck and shoulder area, including the trapezius, levator scapulae, and infraspinatus muscles ( Fig. 52.2 ). In the lower part of the trunk, the quadratus lumborum, gluteus medius, and tensor fasciae latae are commonly affected. Trigger points often affect other muscles innervated by the same spinal segments, and subsequent treatment is usually directed at all muscles innervated by both the anterior and posterior branch of the same spinal nerve. Table 52.1 lists common trigger points and their associated myofascial pain syndromes.

Bursitis and Tendinopathies

Management of the pain resulting from bursitis and tendinitis may be greatly enhanced by the proper selection and administration of local injections. Successful application of local injection and intrasynovial (bursa and tendon sheath) therapy requires an understanding of the diagnosis, accurate localization of the pathologic condition, and appropriate injection techniques. Lidocaine and corticosteroid preparations may be injected separately or together as adjuncts for pain control. The goal of corticosteroid injection therapy is relief of pain so that the patient is able to regain function and participate in a physical rehabilitation program. In many cases a single injection may be all that is required to ameliorate a painful condition. However, injection therapy is best viewed as an adjunct in the management of painful tendinitis and bursitis syndromes. It should not be viewed as a single quick fix, but a method to facilitate other modalities.

The precise mechanisms for the lasting analgesia and beneficial therapeutic effects of local injection therapy have not been clarified. Few clinical trials have adequately measured the efficacy of corticosteroid therapy. Although steroids are known to reduce inflammation, it is unclear whether the antiinflammatory effect is responsible for the increased range of motion and relief of pain that the patient usually experiences. Histologic studies of chronic tenosynovitis lesions demonstrate degeneration, but not inflammation. It is therefore possible that the pain experienced with tendinitis and bursitis occurs as a result of mechanisms other than inflammation, such as mechanoreceptor stimulation by shearing, traction, or activation of nociceptive receptors by substance P and chondroitin sulfate.

Though often performed in the emergency department (ED) and ubiquitous therapy by orthopedic surgeons, rheumatologists, and family practitioners, injection therapy may not be definitive care. Hence, follow-up and additional evaluations and interventions should be considered. In short, injection therapy should be considered an adjunct to a variety of treatment modalities including pain control, physical therapy, occupational therapy, relative rest, immobilization, and exercise. Additional pain control can be achieved with such options as nonsteroidal antiinflammatory drugs (NSAIDs), acupuncture, ultrasound, ice, heat, and electrical nerve stimulation. Besides pain relief, early participation in rehabilitative activities and exercises can be an important aspect of patient recovery. Patients receiving only analgesics may have worse outcomes than those who also incorporate exercise as part of their treatment. Any factors that provoke the initial injury should also be identified because failure to eliminate these provoking factors can contribute to the injury developing into a chronic condition.

Although opinions in the literature differ, we recommend that corticosteroid injections not be repeated in the same site unless at least a partial clinical response has occurred. In addition, an injection should not be repeated in the same site more than once every 3 months. Some limit corticosteroid injections at any given site to two or three injections before alternative therapy is pursued. Despite few data on the outcome of repeated injections, these recommendations are generally accepted and may limit the risk for adverse effects.

Though universally practiced and generally considered safe and effective for short-term therapy, there are sparse scientific data defining a true benefit of corticosteroid injections for musculotendinous conditions. Inflammation is not always the cause of tendinopathy. Although true inflammatory tendinitis may respond quite well to corticosteroid injections, conditions such as posttraumatic shoulder impingement and rotator cuff tears may not benefit from local injection any more than from treatment consisting of rest, time, physical therapy, and NSAIDs. Despite appearing to initially be effective for conditions such as olecranon bursitis, lateral epicondylitis, and de Quervain's tenosynovitis, long-term relief of other conditions is often superior with other modalities. In addition, oral corticosteroids can be as effective as local injection and can be an alternative for emergency clinicians reluctant to perform an injection.

Trigger Points

Injection therapy is the most widely accepted and scientifically supported modality for treating trigger point pain. However, because it may place patients at risk for becoming dependent on injection for pain relief, some authors reserve injection therapy for patients who have failed other measures ( Box 52.2 ).

Various substances have been used for trigger point injections, including local anesthetics, botulinum toxin, sterile water, and sterile saline. Dry needling, a technique that involves multiple advances of a needle into the muscle at the region of the trigger point, provides as much pain relief as an injection of lidocaine. In fact, in a 2001 systematic review on needling therapies for trigger points, Cummings and White concluded that, based on current medical evidence, “the nature of the injected substance makes no difference to the outcome and wet needling is not therapeutically superior to dry needling.” In support of these findings, it has been proposed that the needle (not the injected substance) reduces trigger point pain by mechanically disrupting dysfunctional activity at the motor end plate. Nevertheless, the addition of a local anesthetic is recommended to reduce the degree of postinjection soreness.

The use of steroids for trigger point injection is controversial and without a clear rationale because there is little evidence to support an inflammatory pathophysiology for trigger point pain. Hence, the use of steroids for trigger point injection is not recommended.

Bursae and Tendon Sheaths

The indications for steroid injection are twofold: therapy and diagnosis. Injection therapy offers not only relief of pain, particularly when a local anesthetic is used concurrently, but also a medium to deliver therapeutic agents. In addition to relieving pain, injection therapy may aid in diagnosis. When injecting a bursa, for example, bursal fluid is sometimes collected for laboratory analysis. In addition, relief of pain helps differentiate a localized site of injury from referred or visceral pain.

Absolute contraindications to local injection therapy are limited and include specific infections such as bacteremia, infectious arthritis, periarticular cellulitis or ulceration, and adjacent osteomyelitis ( Box 52.3 ). The procedure is also contraindicated in patients with bleeding disorders. A history of hypersensitivity, either to the corticosteroid or to the vehicle by which it is delivered, is an absolute contraindication. Finally, corticosteroid injections should not be performed in a patient who has a documented osteochondral fracture. Relative contraindications depend on both the clinician's experience and the indication for the injection. Violation of the integrity of the skin or chronic foci of infection, either locally or in the vicinity of the site of involvement, is a relative contraindication. The procedure is also relatively contraindicated in patients taking anticoagulants, in patients with poorly controlled diabetes, and in those with internal joint derangements or hemarthrosis. Patients with a preexisting tendon injury may be subject to tendon rupture if the corticosteroid injection relieves the pain and full activity is then resumed. Therefore partial tendon rupture is a relative contraindication.

Trigger Points

Consider trigger point injection once a myofascial pain syndrome has been identified (see Box 52.1 and Table 52.1 ). As mentioned previously, some authors reserve injection for patients who fail noninvasive modalities (see Box 52.2 ). There are few contraindications to trigger point injection. Overlying infection is an absolute contraindication. Relative contraindications include proximity to sensitive structures, bleeding disorders, anticoagulation, an uncooperative patient, and lack of clinician experience. Dry needling is as effective as injection therapy, so in those with allergy to local anesthetics, the clinician may perform dry needling to avoid the problem.

Bursae and Tendon Sheaths

The dose of any corticosteroid suspension used for intrasynovial injection may be selected arbitrarily. Factors that influence the dosage and expected response include the size of the affected area, the presence or absence of synovial fluid or edema, the severity and extent of any synovitis, and the steroid preparation selected ( Table 52.3 ; also see Table 52.2 ). Dosages may need to be reduced in the elderly.

TABLE 52.3

A Guide for Needle Size and Dosage for Injection of Common Regional Disorders

DISORDER OR INJECTION SITE	NEEDLE SIZE	USUAL DOSAGE OF METHYLPREDNISOLONE ACETATE (mg) a
Bicipital tendinitis	1.5–2 inches, 22–25 gauge	20–40
Calcareous tendinitis Subacromial bursitis	1.5–2 inches, 22–25 gauge	20–60
Radiohumeral bursitis Epicondylitis	1.5 inches, 22–25 gauge	20–40
Olecranon bursitis	1-1.5 inches, 20 gauge b	15–30
Ganglia on the wrist	1 inch, 22–25 gauge	10–15
de Quervain's disease	inch, 22–25 gauge	10–20
Carpal tunnel syndrome	1–1.5 inches, 22–25 gauge	20–40
Digital flexor tenosynovitis	inch, 22–25 gauge	5–10
Trochanteric bursitis	1.5–2 inches, 22–25 gauge	20–40
Prepatellar bursitis	1–1.5 inches, 22–25 gauge	15–20
Anserine bursitis	1–1.5 inches, 22–25 gauge	20–40
Bunion bursitis	1 inch, 22–25 gauge	5–10
Calcaneal bursitis	1 inch, 22–25 gauge	10–20
Superficial trigger point	1.5 inch, 22 gauge	N/A
Deep trigger point	2.0–2.5 inch, 21 gauge	N/A

N/A, Not applicable.

a Empirical dose. A larger or smaller dose may be used, depending on the clinical scenario.

b Allows bursa aspiration and steroid injection without removing the needle.

A useful guideline for estimating dosage is as follows: for relatively large spaces such as the subacromial, olecranon, and trochanteric bursae, use 40 to 60 mg of methylprednisolone acetate or its equivalent. For medium- or intermediate-sized bursae and ganglia at the wrists, knees, and heels, use 10 to 20 mg. For tendon sheaths, such as flexor tenosynovitis of the digits and the abductor tendon of the thumb (de Quervain's disease), use 5 to 15 mg. Sometimes it may be necessary to give larger doses for an optimal response. Intrabursal treatment of the elbow (olecranon) or the knee (prepatellar) bursae, which contain a considerable amount of fluid, may require 30- to 40-mg doses.

Unlike intraarticular injections for synovitis in patients with chronic joint disease, repeated infiltration for soft tissue conditions such as bursitis and tendinitis is not generally recommended or required. However, if only a partial response occurs or if recurrence develops, a single injection can be repeated as long as one waits at least 12 weeks between injections.

Trigger Points

In contrast to injection of bursae and tendon sheaths, use small volumes of local anesthetic, botulinum toxin, sterile water, or sterile saline for trigger point injection. In most cases 1 to 2 mL of the chosen agent is sufficient.

General Considerations

Before beginning the injection inform the patient of the specific indication or indications for treatment. Describe the procedure, including the risks and complications, and obtain informed consent. Subsequently, document the details of the procedure in the medical record. A written consent form is not standard and its use is best based on institutional or departmental policy.

The material required for local injection procedures includes antiseptic solution, needles, syringes, a hemostat, culture and laboratory tubes, bandages, and sterile gauze ( Fig. 52.3 ). Special trays may be stocked for this purpose. The usual sizes of needles for injection sites and corticosteroid doses are listed in Table 52.3 .

Bursae and Tendon Sheaths

Local skin anesthesia is an option before injection but not universally practiced. For bursae and tendon sheaths, local anesthetics can be injected alone or with corticosteroids mixed together in the same syringe. Use the Z-tract technique to limit the risk for a fistulous tract in the soft tissue. Because the steroid may theoretically precipitate or layer in the barrel of the syringe during the injection, agitate the syringe immediately before using it to optimize its distribution. In addition to minimizing the pain associated with the injection, mixing an anesthetic with the corticosteroid also produces a larger volume for delivery.

The duration of action of lidocaine is approximately 1 hour, whereas bupivacaine may last 6 to 8 hours. Caution the patient that the local anesthetic effect may wear off within a couple of hours and that the beneficial effects of the corticosteroid may be delayed.

The optimum technique for joint and soft tissue injections has not been firmly established. However, one important aspect of a successful technique is accurate positioning of the needle. Injecting an inflamed synovial space, such as a bursa containing fluid, may be as simple as puncturing a balloon. Aspiration of fluid confirms that the needle has correctly entered the sac. Conversely, direct injection into a painful soft tissue lesion requires additional skill that can be acquired only with experience. Sometimes it is advisable to reaspirate and reinject several times within the barrel of the syringe, a procedure called barbotage , to obtain heterogeneous mixing and maximal dispersion of the steroid throughout the synovial cavity. Although it is desirable to inject the solution directly into the bursa, direct injection into the tendon itself is best avoided. If the injection requires the application of significant pressure, the needle may be in the tendon and should be withdrawn or advanced a few millimeters. The patient may commonly feel some myofascial radiating pain during the injection, but true paresthesia should not be elicited. Electric shocks felt with an injection may signal that the needle is in a nerve and should be repositioned.

Although an accurate injection is desirable, using a generous volume of anesthetic (3 to 6 mL) to dilute and hence disperse the steroid can compensate for less than perfect injections. Asking the patient to use one finger to localize the area of maximum pain and tenderness is the best way to ensure the most accurate positioning of the needle. In general, if the patient cannot localize a specific area of tenderness, the diagnosis should be reconsidered or the expectations of success lowered. Diffuse pain, such as throughout the entire shoulder or knee, is probably not tendinitis or bursitis and is not likely to be relieved with a local injection.

Trigger Points

Successful treatment of a myofascial pain syndrome requires accurate diagnosis (see Box 52.1 and Table 52.1 ) and precise identification of the trigger point (a taut band of muscle fibers). There are three generally accepted methods for identification of trigger points: flat palpation, pincer palpation, and deep palpation.

To perform flat palpation, slide a fingertip across the muscle fibers of the affected muscle group, and at the same time use the opposite hand to retract the skin to either side until the taut band is identified ( Fig. 52.4 , 1–3 ). Snap the band like a violin string to precisely identify the trigger point. Pincer palpation involves firmly grasping and rolling the muscle fibers between the thumb and forefinger until the taut band is found (see Fig. 52.4 , 4–6 ). Use deep palpation when the taut band is obscured by superficial tissue. Place a fingertip over the muscle attachment of the area suspected of housing the trigger point and apply pressure in different directions. Reproduction of the patient's symptoms identifies the trigger point. It may be helpful to mark the trigger point with a skin marker for easy identification before treatment.

Once the trigger point has been found, therapy can be divided into invasive and noninvasive techniques (see Box 52.2 ). Noninvasive techniques used in the ED include spray and stretch, massage therapy, and ischemic compression therapy. Physical therapy, transcutaneous electrical stimulation, and ultrasound treatments are adjuncts that may be arranged by the patient's primary care physician. Invasive techniques involve injecting the trigger point with a local anesthetic, botulinum toxin, or dry needling.

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