Abstract
Inflammation of periarticular soft-tissue structures such as tendons, tendon sheaths, entheses, bursae, ligaments and fasciae is the hallmark of many inflammatory rheumatic diseases, but inflammation or rather irritation of these structures also occurs in the absence of an underlying rheumatic disease. In both these primary and secondary soft-tissue lesions, local glucocorticoid injection often is beneficial, although evidence in the literature is limited. This chapter reviews local injection therapy for these lesions and for nerve compression syndromes.
Introduction
Many inflammatory rheumatic diseases are characterised not only by joint inflammation but also by inflammation of periarticular so-called soft tissues: tendons, tendon sheaths, entheses, bursae, ligaments and fasciae. These local inflammations can be treated by local glucocorticoid injection in addition to systemic anti-inflammatory therapy. Local soft-tissue structures can also be painful in the absence of a generalised inflammatory rheumatic disease and show inflammatory signs, probably secondary to microtrauma or overloading. Although this pathogenesis questions the rationale of glucocorticoid injection, in practice often also for these lesions local glucocorticoid injection is beneficial. The injection and post-injection rest diminish swelling and possibly in that way enhance healing of the lesion.
This chapter reviews injection of soft-tissue structures to diminish local inflammation or irritation or to treat nerve compression syndromes (see Table 1 ). In general, there is limited evidence to support the superiority of glucocorticoid injections over other kinds of treatments, such as rest, local cooling, analgesics and non-steroidal anti-inflammatory drugs . In most randomised controlled trials a superior effect of glucocorticoid injection is seen in the short term, but no clear difference in the long term, compared to other treatment modalities. On the other hand, glucocorticoid injection usually is perceived as simple, safe and effective. In this chapter, for each indication the scarce literature on indications, efficacy and adverse effects will be summed and the most common method of injection will be described . Of course other useful alternative methods of injection exist and other preparations of glucocorticoid and dosages ; but it seems best to gain experience with limited techniques and dosages. In addition, only general guidelines can be given; for example, the length of the needle used would also depend on the thickness of the skin and subcutaneous fat tissue layer of the individual patient.
| Anatomical region | Soft tissue disorder |
|---|---|
| Shoulder | Rotator cuff tendinitis; subdeltoid or subacromial bursitis; bicipital tendinitis or tenosynovitis, subacromial impingement |
| Elbow | Olecranon bursitis; lateral and medial epicondylitis |
| Wrist and hand | Extensor and flexor tenosynovitis; trigger fingers, carpal tunnel syndrome; de Quervain’s tenosynovitis |
| Hip | Trochanteric, iliopsoas or ischiogluteal bursitis; adductor tendinitis; meralgia paresthetica |
| Knee | Pes anserinus lesions and anserine bursitis; patellar tendinitis; prepatellar bursitis |
| Ankle and foot | Tarsal tunnel syndrome; posterior tibialis or peroneus tenosynovitis; plantar fasciitis; Morton’s metatarsalgia |
General considerations and technical recommendations, materials
The previously described lack of evidence is not equivalent to evidence of lacking relevance or efficacy. The efficacy of injection depends on various patient’s and physician’s variables. Local injection therapy should first of all be based on a clear and accurate diagnosis; the effect depends upon the right diagnosis. For example, pain in the shoulder located in the C4 region suggests an origin in the cervical spine; a local shoulder injection will not be effective. The physician should have good knowledge of the local anatomy, indications and contraindications and other technical details of the procedure and be experienced with the injection technique, as accuracy of injection also could significantly affect the clinical effect . When considering injection of inflamed tendon sheets or bursae, one should realise that the cause of inflammation could indeed be overloading or an inflammatory rheumatic disease, but that crystal-induced inflammations are not rare (gout and olecranon bursitis; calcium pyrophosphate dehydrate disease and wrist tenosynovitis; cholesterol deposition and wrist tenosynovitis) and neither are bacterial infections (mycobacterial and gonococcal infections and tenosynovitis; staphylococcus infections and olecranon bursitis). These disorders may warrant additional systemic therapy, for example, urate-lowering drugs or antibiotics. So, aspirate for polarisation microscopy and cultures. In the case of diagnostic uncertainty and for difficult injections, ultrasound can be very useful. Ultrasound-guided injection may improve accuracy and effectiveness of injection therapy , as discussed in Chapter 9. Clinical experience indicates that compared to acute conditions (up to 2 weeks in duration), the effect of glucocorticoid injections is less in chronic disorders (over 6 weeks), especially if also other generalised complaints are present like in fibromyalgia . If after consideration of these facts an injection seems indicated, the patient should be informed about possible benefits and adverse effects and alternative therapeutic approaches. General contraindications for local glucocorticoid injection are given in Table 2 .
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General injection technique
To start with, wash your hands. Mark the site of injection and bony landmarks with a skin pencil or eye pencil or the site of injection by a pressure mark and swab the patient’s skin with iodine in ethanol or 80% ethanol solution. Surface anaesthesia may be necessary by an ethyl chloride spray (a refrigerant numbing the skin) or equivalent spray, which gives immediate anaesthesia or by lidocaine 25 mg/g crème (for children and pain-sensitive adult patients); the latter should be applied 15–60 min before injection. When preparing the injection, warming the lidocaine to body temperature before filling the syringe might reduce pain after injection . Put on sterile gloves or do not touch the site of injection after swabbing. The patient and physician should be in a comfortable position. Hold the patient with thumb and index finger of the non-dominant hand at the injection site at bony landmarks, if present, to get a better feel of the local anatomy. The syringe should be in the dominant hand. Take a moment to consider the three coordinates of the injection route and site. Enter the skin, direct the needle and advance until the tip of the needle is at the injection site. Always draw back the plunger before injecting, to make sure that the needle tip is not located within a vessel. For fluid-containing lesions such as bursae in the case of bursitis, aspiration of fluid as much as possible is indicated for diagnostic purposes (see above) and for increased efficacy (decreasing load of inflammatory cells and cytokines). If the fluid at the naked-eye inspection seems not to be bacterially infected, the injection can be given. In the case of tendovaginitis, aspiration often does not yield fluid; the injection should be given slowly. Injections should not be given into a tendon because of the chance of post-injection rupture ; when at presumed peri-tendinous injection resistance is felt emptying the syringe, this indicates that the tip of the needle is located within the tendon: withdraw and reposition. For entheses, for example, epicondylitis, the needle is inserted at the site of maximal tenderness until it reaches the bone. The needle is slightly withdrawn and a small deposit is injected; thereafter the needle is withdrawn further and redirected and advanced again and the second small deposit is injected. This is repeated several times: the ‘peppering’ or ‘fan’ technique with half-withdrawals and redirections to infiltrate the enthesis both deeply and more superficially. There is some force needed to depress the plunger; tighten the needle firmly to the syringe to prevent it from coming off. Especially after applying this technique warn the patient of probable exacerbation of pain for 24–48 h.
Materials
Always use sterile disposable needles and syringes; choose a needle with the smallest possible diameter fit for the specific injection or aspiration planned. The length of the needle should match the depth of injection. Table 3 is a conversion table for needle dimensions. The one-handed reciprocating syringe could be a better choice than the conventional syringe for aspiration of fluid, leaving one hand free .
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