The overlying deltoid should been seen to lift temporarily away from the bursa driven by the pressure of the injection. When the injection is finished the muscle/tendon should relax back into its normal location. If there is uncertainty regarding the needle position within the bursa, this distension/relaxation appearance can be reproduced by giving a pulse injection. The plunger is pressed firmly and the layers of the bursa should separate when plunger pressure ceases; the two layers of bursa should return together. If the needle tip is extrabursal, the tissue planes will separate on injection but will not recompress easily as the injected fluid is not free to flow away from the injection site. Another useful tip for larger bursae is to place the probe over a different part of the bursa and confirm that fluid is flowing freely into it from the point of injection.

The subacromial subdeltoid bursa is a large structure and can accommodate quite considerable volumes of fluid, although a total injection dose of more than 10 mL is usually not necessary. It is also useful to reexamine the bursal surface of the tendon following injection as the fluid introduced to the bursa may now demonstrate a bursal surface partial tear not previously appreciated.

Acromioclavicular Joint

Most shoulders are examined with the patient seated and there is no need to change position prior to injection. The needle is targeted on the rounded, poorly reflective joint space.

The acromioclavicular joint (ACJ) is easily identified in the coronal plane. It is useful to make an initial assessment to determine whether there is any subluxation present, as there is commonly a slight offset between the end of the clavicle and the acromion. The commonest situation is superior displacement of the end of the clavicle.

Practice Tip

If ACJ subluxation is present, the lateral aspect of the joint is open to an approach from the lateral side. If there is any joint effusion projected above the joint, this too can be accessed by a coronal approach from the lateral side.

The probe is held in the coronal plane directly above the joint and moved immediately until the joint is seen close to the lateral margin of the image. A point is marked on the patient’s skin lateral to the probe, representing the puncture point (Fig. 30.3).

Figure 30.3 A coronal approach to the ACJ is easier if there is joint widening, effusion or offset.

If there is no malalignment or effusion, the joint is best injected in the sagittal plane. This view is obtained by placing the probe, initially, medial to the joint and identifying the bony reflective margin of the clavicle. The probe is then moved laterally until the bony reflection disappears, indicating that the probe is now positioned directly over the joint (Fig. 30.4). Further lateral movement brings the bony acromion into view. The probe is returned to overlie the joint either anteriorly or posteriorly and the needle is inserted at 90° to it in the sagittal plane. In this position it is easily seen entering into the joint. Reversing needle and transducer is equally effective. The ACJ is a rather small joint and is unlikely to accept more than 1–1.5 mL. It is therefore recommended that a low-volume syringe is used.

Figure 30.4 This approach to the ACJ is used if the joint is not particularly distended or there is little acromioclavicular offset. The joint is seen as an echo-poor space. There is excellent visualization of the needle as it is inserted parallel to the probe. A coronal approach to the ACJ is easier if there is joint widening, effusion or offset.

Glenohumeral Joint

Glenohumeral joint injection is indicated for patients undergoing MR arthrography, for local anaesthetic injection to diagnose indeterminate shoulder pain, to guide treatment of glenohumeral arthropathy and to distend the shoulder in patients with adhesive capsulitis. As most shoulder dislocations are anterior and the structures of interest also lie anteriorly, a posterior approach for MR arthrography is a good choice for reducing any extravasation or artifact, which may subsequently impede interpretation of the study.

A seated position with the operator standing behind the patient is straightforward. It is helpful for the patient to have some support, particularly during longer procedures such as distension arthography. The patient can sit against a raised examination couch and rest their head forward on some pillows. The arm of the side being injected can rest on the patient’s knee. Alternatively the patient may be placed in a semiprone position with the affected shoulder uppermost. It is useful to rest the ipsilateral arm over a bolster or pillow to maintain the semiprone position and optimize patient comfort.

The needle is most frequently introduced lateral to the ultrasound transducer and directed obliquely along a path to where the humeral head slopes towards the posterior labrum (Fig. 30.5). Once the skin is punctured, the needle should be directed in the same long axis as the probe to ensure it stays in-view and reaches the correct part of the joint. Alternatively, a medial puncture can be used and directed to a point lateral to the labrum, but generally there is less room to manoeuvre with this approach, unless there is an effusion. Care should be taken not to aim for the glenoid margin itself as a large labrum may displace the needle posteriorly and prevent accurate placement into the joint. The intraarticular position of the needle can be confirmed by injecting a small amount of local anaesthetic. If the needle is correctly positioned, the injected local anaesthetic will disappear into the joint and no resistance will be felt. The arthrographic material or an antiinflammatory cocktail may then be injected. In the early stages of the injection, distension of the posterior glenohumeral joint recess is not evident. Towards the end of the glenohumeral joint injection, if a sufficiently large volume of fluid has been instilled, the posterior recess of the glenohumeral joint begins to distend and the posterior capsule is seen displacing away from the humeral head. Colour-flow Doppler can also show the injectate flowing way from the needle tip.

Figure 30.5 Posterior approach to the glenohumeral joint with the patient leaning forward with their head resting comfortably on pillows. It is important not to puncture too far laterally as the curvature of the humeral head may force the needle medially and into the labrum. The target area in this case is the needle resting comfortably between humeral head and labrum.

Distension Arthrogram

In patients undergoing distension arthrography some modifications to the above technique are necessary. The procedure is carried out for patients with adhesive capsulitis or frozen shoulder. It should be reserved for the later pain-free but stiff phase of the condition as distension during the acute, painful, inflammatory phase is less likely to be beneficial. The principle of the procedure is that restriction of motion is due to generalized joint contracture that can be improved by stretching the capsule. Stretching is achieved by injecting as high a volume as the patient can tolerate, up to 40–50 mL.

A mixture of local anaesthetic (20 mL), normal saline and corticosteroid is prepared and a second syringe containing 20 mL of normal saline is made ready. Once the joint is cannulated, a short flexible tube and a three-way connector tap are attached to the needle. If the patient tolerates the first 20 mL, the three-way tap is closed and a further filled syringe is attached. The use of the three-way tap prevents decompression of the joint as the syringes are being exchanged. The aim is to inject a volume beyond joint capacity in an effort to increase the volume within the joint and thus improve the patient’s range of motion. Either the patient’s tolerance will be reached or the capsule will rupture. Any sudden reduction in resistance should be noted as further injection will not be helpful and may even cause periarticular neural compression in the quadrilateral or spinoglenoid spaces.

Although much of the synovial and capsular thickening in adhesive capsulitis is in the anterior interval and the axillary recess, it is unlikely that either of these two areas are the ones that will rupture during the injection. More likely that capsular rupture occurs posteriorly in the areas of greatest weakness.

Calcium Barbotage

Calcific tendinopathy is a relatively common and painful disorder of the shoulder, which is due to the deposition of calcium hydroxyapatite crystals. Calcific tendinopathy is not always symptomatic and barbotage is usually reserved for patients who suffer acute pain as a result of crystal shedding into the subacromial subdeltoid bursa and/or for patients who are experiencing impingement related to the calcified mass that has not responded to bursal steroid injection.

Because barbotage may be painful, the examination is best carried out with the patient supine and positioned with the affected shoulder as near as possible to the edge of the examination couch (Fig. 30.6). This allows the arm to be lowered below the level of the couch, thus inducing a degree of extension and internal rotation. The operator sits at a comfortable height at the level of the patient’s shoulder and preliminary examination identifies the easiest approach to the calcium. The general principles of barbotage have been described previously on page 343. Aspiration/washout is continued until the aspirated material is clear or nearly clear and only the eggshell margin of the conglomerate remains. This is then fenestrated and the bursa injected with local anaesthetic and steroid.

Figure 30.6 Barbotage is carried out with the patient recumbent as this is a somewhat longer and possibly uncomfortable procedure. In the ultrasound image, as much of the calcium as is feasible has been aspirated, leaving only a distensible eggshell. The last phase of the procedure is to fenestrate the eggshell wall.

Biceps Tendon Sheath Injection

Patients with anterior shoulder pain and tenderness overlying the proximal portion of the biceps tendon may benefit from guided injection into the biceps tendon sheath. It could be argued that the easiest way to inject the biceps tendon sheath is to carry out an injection into the glenohumeral joint itself. The direct route into the biceps tendon sheath is preferred as not only does it place the injection where it is most likely to help, but also because of the possibility that communication between the glenohumeral joint and biceps tendon sheath may be obstructed by synovial thickening in the anterior interval.

Patient positioning is the same as for the examination of the biceps tendon with the hand placed palm upwards on the patient’s knee. The sheath can be approached along either its short or its long axis. If fluid distension is present, a short access approach from the lateral side is easiest (Fig. 30.7). For a long axis injection, a sagittal image of the tendon in the groove is obtained (Fig. 30.8). A mark is placed at the upper end of the probe identifying the puncture point. The needle can be followed in-view as it runs parallel to the probe and into the sheath.

Figure 30.7 Fluid around the biceps tendon facilitates an approach in the short axis. Under direct visualization, the needle is inserted to the biceps tendon sheath.

Figure 30.8 The long-axis approach to the biceps tendon sheath from above. The puncture point should be sufficiently low so that the needle passes below the subacromial subdeltoid bursa before entering the biceps tendon sheath. This is particularly important if a selective diagnostic procedure is being carried out.

Tenodesis can be carried out under ultrasound guidance in patients who have anterior shoulder pain that is unresponsive to conservative measures where pain is felt to be due to a grossly attenuated biceps tendon. Ultrasound-guided biceps tenodesis is only recommended when all other conservative measures have failed and surgical division of the tendon is being considered in any case.

Suprascapular Ganglion/Nerve Treatment

A treatable cause of infraspinatus muscle atrophy is compression of the suprascapular nerve within the spinoglenoid notch by a ganglion cyst. This is most commonly associated with posterosuperior impingement syndrome. A tear is present in the posterosuperior labrum leading to the formation of a ganglion. This passes in a posterior and medial direction until it reaches the notch, where it can expand and compress the suprascapular nerve.

The technique for ganglion aspiration has been described on page 344. An axial approach is employed for the spinoglenoid notch. The probe is held in the axial plane over the ganglion. A medial sided puncture is best as this gives the best opportunity for passing the needle along the neck once the main ganglion has been satisfactorily aspirated (Fig. 30.9). Neural injection can also be carried out for chronic pain. Using Doppler is occasionally helpful as it may help visualize the adjacent suprascapular artery. The vessel is small, however, and in many cases its pulsation per se renders it easier to see than any Doppler signal it generates. If anaesthetic injection is positive, radioablation may provide longer-term relief.

Figure 30.9 Suprascapular nerve injection or rectus femoris (RF) ablation is carried out in a position similar to the approach to the glenohumeral joint. The needle puncture is from the medial side and directed towards the nerve that lies adjacent to the artery. In this image, a little Doppler signal is evident helping to locate the suprascapular artery.

Elbow Intervention

Tennis Elbow

The usual indication for injecting the common extensor origin is recalcitrant tennis elbow. Several interventional techniques have been described; the use of corticosteroid injection has now largely given way to dry needle therapy, which may or may not be combined with autologous blood injection or platelet-rich plasma (PRP).

Two positions can be used, one with the patient seated opposite (Fig. 30.12), the other with the patient recumbent with the affected forearm flexed across their abdomen (Fig. 30.13). It is generally recommended that dry needling procedure is carried out as close to the long axis of the tendon fibres as possible. The target is the most tendinopathic area, particularly those showing areas of mucoid necrosis and hypervascularity. The probe is held in the coronal plane overlying the area to be treated. A puncture point is marked on the patient’s skin distal to the probe. If a small footprint probe is not available, care should be taken to ensure that the probe is moved a little more proximally, so that the proximal puncture point will be in the correct location and not too distal to the target area. Local anaesthetic is infiltrated along the outer epimyseum/paratenon of the common origin. Once anaesthetized, the needle is directed into the tendon and towards the bony origin. The general principles of dry needle therapy have already been described.

Figure 30.12 Long axis approach to the common extensor origin. The area of maximal tendinopathy and Doppler activity is targeted.

Figure 30.13 CEO injection. It is often more comfortable for the procedure to be carried out with the patient recumbent, particularly if there is a fainting risk.

There is a risk of tendon rupture following dry needling therapy that needs to be actively managed. It is important that there is a planned rehabilitation programme under the care of an appropriate specialist. This should be individually tailored to the needs of the patient and the degree of tendon damage.

Common Flexor Origin

The rationale for ultrasound-guided therapy of the common flexor origin is similar to its extensor counterpart. As has been previously noted, the common flexor origin is more fleshy than the extensor origin. A recumbent position is used and is especially good for nervous patients. The arm is abducted exposing the common flexor origin (Fig. 30.14). The approach is otherwise similar to the common extensor origin technique described earlier (Fig. 30.15).

Figure 30.14 The common flexor origin can be accessed by having the patient externally rotate their shoulder. As this can be uncomfortable to sustain, this procedure is also often carried out in the recumbent position.

Figure 30.15 Recumbent patient with shoulder abducted allowing easy access to the common flexor origin.

Elbow Joint

The elbow joint can be injected diagnostically as part of an MR arthrogram. Saline arthrosonography can also be used to detect radiographically occult osseous and cartilaginous loose bodies within the joint. Another common indication is to treat elbow arthropathy.

The patient may be seated with the palm on the couch, with the elbow flexed at 90° and internally rotated. The forearm is perpendicular to the examination table in the so-called ‘crab position’ (Fig. 30.16). Alternatively the patient can be recumbent with their forearm positioned across their chest, either supine or decubitus (Fig. 30.17). All of these positions expose the posterior joint to easy injection. In children with a suspected diagnosis of septic arthritis, the child sits facing the mother on her lap with their arms wrapped around the mother’s side. A nurse or assistant can stand behind the mother and hold the child’s hands to prevent excessive movement. This position allows access to the posterior aspect of the elbow joint for examination and aspiration.

Figure 30.16 Posterior approach to the elbow joint with the patient sitting. The crab position should be used for easy access.

Figure 30.17 A posterior approach to the elbow joint is easiest for joint injection or aspiration. If the approach is on the ulnar side, the ulnar nerve must be identified and avoided.

The posterior joint space can be punctured in either the long or the short axis. The short axis is the easiest, particularly if there is an effusion (Fig. 30.17). A posterolateral approach into the posterior joint space is used. The ulnar nerve posteromedially and the triceps tendon centrally should be identified and avoided. If a posterolateral approach is not possible, a posteromedial approach can be used if the ulnar nerve is safely identified. Once cannulation has been achieved it is often helpful to move the probe to visualize the olecranon fossa prior to injecting the joint. This allows easy confirmation of joint filling and allows the movement of suspected loose bodies, seen as mobile echogenic foci, to be observed.

An alternative approach in adults is through the radiocapitellar joint, which is palpated as a soft spot on the lateral aspect of the flexed elbow. Another approach in adults is just lateral to the olecranon process where a small groove can be palpated between the olecranon and the humerus.

Interosseous Nerve Block

The anterior interosseous nerve (AIN) is a branch of the median nerve, arising close to where the nerve passes through the two heads of pronator teres. The posterior interosseous nerve (PIN) is a branch of the radial nerve and reaches the posterior compartment of the forearm by passing between the two heads of the supinator muscle. Injection of the radial tunnel per se is not a common procedure but may be indicated in patients with symptoms suggesting isolated PIN compression. Compression may be due to a fibrous band at the proximal margin of the supinator muscle or any mass. The rationale for injection therapy in the absence of an identifiable cause is unclear, but it has been argued that corticosteroid injection dampens any inflammatory response and breaks down adhesions that may be present between the nerve and surrounding structures. The approach to the radial tunnel is from the lateral side through the brachioradialis muscle.

If injection around both interosseous nerves is required, a more distal puncture point on the extensor aspect of the forearm is chosen (Fig. 30.18). Within the forearm, the nerves can be found on either side of the interosseous membrane. The AIN lies on the membrane itself but the PIN is separated from it by the deep extensor muscle group. Locating both nerves in a single image is possible in the majority of patients and injection can be carried out with the probe held in the axial plane. An imaginary line is drawn between the two nerves and back projected to the extensor skin surface. This is the puncture point that allows both AIN and PIN to be injected via a single puncture.

Figure 30.18 Occasionally, both interosseous nerves are injected for diagnostic and pain control purposes. They can either be injected separately or, more easily, a singular approach with posterior aspect can be used. The needle is passed into the posterior compartment to infiltrate around the PIN and then advanced across the interosseous membrane to the region of the AIN.

Wrist Intervention

Distal Radioulnar Joint Injection

Indications include distal radioulnar joint (DRUJ) arthropathy or as a component of a wrist arthrography. A dorsal approach is used. The patient can either be seated opposite the operator with the palm of the hand placed on the examination table or can be positioned prone with the arm above the head, again with the palm of the hand on the table. The latter is helpful in avoiding syncopal episodes, particularly in younger patients.

The probe is positioned in the axial plane over the DRUJ that is identified by the characteristic rounded appearance of the distal ulna (Fig. 30.19). The easiest approach is ulnar to extensor compartments five. The needle is followed in-view until its tip encounters the dorsal aspect of the ulnar head. Unless there is communication with the radiocarpal joint (RCJ), 2–3 mL is sufficient to fill this small joint.

Figure 30.19 An axial approach to the DRUJ is easiest. Identify the extensor compartments and pass either side of EC4 whichever affords the best route.

Radiocarpal Joint

A dorsal approach, radial to extensor compartment four, allows easy access to the joint (Fig. 30.20). The seated patient is positioned opposite the operator with their forearm resting on the examination table in a pronated position. A rolled-up towel or pad may be positioned beneath the wrist to allow slight wrist flexion. The RCJ generally accepts 5 mL.

Figure 30.20 An axial approach is also used to approach the RCJ. The needle is passed radial to extensor compartment four. Identify and avoid the PIN.

Carpometacarpal and Scapho-Trapezio-Trapezoid Joint Infections

The patient is positioned with the ulnar border of the hand on the examination couch. If both sides are to be injected, a praying position can be employed (Fig. 30.21). A short footprint probe is placed along the radial aspect at the base of the thumb and the scapho-trapezio-trapezoid (STT) and first carpometacarpal joint (CMCJ) identified. The position of the radial artery should be noted. An out-of-view approach is used with the puncture point at the midpoint of the probe opposite the side of the radial nerve and extensor compartment one tendons. The two joints lie close together, separated by a thin septum. If necessary, either joint can be injected depending on involvement. An alternative method to inject the first CMCJ is through the thenar eminence with the probe held over the joint in the sagittal plane. For this approach an in-view method is used (Fig. 30.22).