Atlas of Pain Medicine Procedures 1st Edition

SECTION V

MUSCULOSKELETAL INJECTIONS

CHAPTER 50

Fluoroscopy and Ultrasound-Guided Joint Injections

Jennifer Solomon, Christine Roque-Dang, and James Wyss

IMAGE-GUIDED PERIPHERAL JOINT INJECTION INDICATIONS

The most common clinical indication for an image-guided interventional procedure is pain in the targeted anatomic location, which has either failed other conservative treatments or as an adjunctive treatment. The primary advantage of image-guided interventional procedures over blind injections includes needle placement confirmation and the ability to view the targeted area and relevant anatomy.

Corticosteroid injections are frequently used as conservative treatments in the management of various conditions, including osteoarthritis, tendonitis, bursitis, and impingement conditions. Injectate mixtures typically comprise a local anesthetic and a corticosteroid (triamcinolone or methylprednisolone). In addition, patients at higher risk for developing nonsteroidal anti-inflammatory drug (NSAID)–induced renal dysfunction or gastric and duodenal ulcers are candidates for intra-articular steroid injections to avoid the potential systemic effects that occur with oral anti-inflammatory medications. However, the detrimental effects of repeated steroid injections on soft tissue structures like articular cartilage and tendons have not yet been determined.

The advantages of ultrasound-guided percutaneous interventional procedures are as follows:

• Real-time assessment
• Guidance, and continuous needle visualization
• Lack of radiation exposure
• Technological portability
• Relatively low cost
• Improved accessibility

Fluoroscopic guidance also allows real-time needle visualization and the acquisition of imaging frames throughout the injection course. The visualization occurs at different C-arm angles. The primary disadvantage of fluoroscopy is radiation exposure to both the patient and physician.

BASIC CONCERNS AND CONTRAINDICATIONS

With therapeutic interventions, the benefits and risks of the procedure must be considered. Generally, peripheral joint corticosteroid injections are considered to be safe and conservative treatments. However, each patient’s risk factors for complications must be carefully considered prior to undergoing the procedure.

Some basic concerns for injection are following:

• Patients with primary or metastatic tumors in the target area
• Immunocompromised patients, who are at increased risk for infection
• Patients with thrombocytopenia
• Patients who may be unable to tolerate positioning
• Patients with allodynia or complex regional pain syndrome (CRPS), who will be unable to tolerate the procedure
• Patients on anticoagulant medications, who have been unable to stop these medications at an appropriate time interval
• For fluoroscopically guided procedures with the use of contrast dye, patients with allergies to contrast, shellfish, or iodine may be considered for interventional procedures without contrast

Contraindications for injection include:

• Infection, systemic or localized
• Coagulopathy
• Distorted or complicated anatomy
• Pregnancy for fluoroscopically guided procedures
• Patient refusal

GENERAL IMAGE-GUIDED INTERVENTIONAL PROCEDURE PREOPERATIVE CONSIDERATIONS

• Informed consent must be obtained and the risks and benefits of the procedure should be properly explained to the patient or consenting individual.
• The area must be examined for infection, skin lesions, and disease extent.
• Proper exposure of the targeted area is necessary. If clothing is restrictive, the patient should be requested to change into a gown.
• Ideally, the patient should be able to remain in the appropriate position throughout the procedure.
• Intravenous access is not necessary, but may be considered if the patient has a history of postprocedural vasovagal or hypotension responses.
• The patient must be asked whether he or she takes any anticoagulant medications (ie, aspirin, NSAIDs, etc) and, if applicable, when these medications were stopped prior to the procedure. If stopping the anticoagulant medications increases cardiac risks, it is highly recommended to obtain medical clearance from the patient’s cardiologist.
• The physician performing the procedure should have access to fluoroscopy or ultrasound.
• For fluoroscopically guided procedures, female patients in reproductive age should be asked about potential pregnancy and may require a urine pregnancy test.
• For fluoroscopically guided shoulder injections, the patient must be asked about prior allergic reactions to contrast, shellfish, and iodine.

BASIC ULTRASONOGRAPHY

Depending on the ultrasound probe and machine used, the shoulder, hip, and elbow regions may be examined with high-frequency (>10 MHz) linear array transducers. If the patient has a large body habitus, a mid-range frequency transducer (6-10 MHz) may need to be used to optimize image resolution and facilitate proper examination. An appropriate initial depth is 3 cm. Also, the frequency may be adjusted to visualize deeper structures (ie, glenoid labrum or labrum of the hip) or shallower ones (ie, acromioclavicular joint [AC] joint).

For ultrasound examination, tissues are described by their properties of echogenicity, echotexture, degree of anisotropy, compressibility, and blood flow on Doppler examination. Blood vessels are not susceptible to anisotropy, but exhibit compressibility and presence of blood flow on Doppler examination. In the shoulder, rotator cuff tendons display a high degree of anisotropy, which is particularly pronounced at the musculotendinous junction.

Tissue echogenicity is characterized as hyperechoic, hypoechoic, anechoic, or isoechoic. Due to lack of echoes, anechoic structures have a black appearance. Isoechogenic tissues have similar brightness in comparison with surrounding tissues. Hyperechoic structures (ie, normal tendons and ligaments) appear brighter than adjacent tissues. In contrast, hypoechoic structures appear darker than surrounding structures. Both muscles and nerves have mixed echogenicity patterns. Blood vessels either appear to be hypoechoic or anechoic.

Echotexture refers to the internal pattern of echoes and may vary based on the axis used to assess the structure. Both tendons and ligaments have “broom end” appearance when viewed in the transverse axis and a fibrillar pattern when viewed in the longitudinal axis. Nerves have a “honeycomb” appearance on transverse imaging and a fascicular pattern on longitudinal imaging. Muscles have a “starry night” appearance on a transverse axis and a pennate or “feather like” pattern on a longitudinal axis [7, 9].

BASIC POSTPROCEDURE FOLLOW-UP

The patient should be contacted via telephone on the day following the interventional procedure to determine pain relief achieved from the local anesthetic and if there were any complications. If the patient received a corticosteroid injection, the patient should be reminded that the anti-inflammatory property has a variable onset and may take up to 2 to 3 weeks to achieve symptomatic improvement. The primary postinjection concern is infection. Therefore, the patient should monitor the injection site for erythema, warmth, increased swelling or systemic features of an infection, including fever and chills. If the patient develops any complications, he or she should be advised to contact the injectionist for further guidance. For severe procedurally related adverse events, ie, fever >101°F, weakness, dyspnea, severe pain exacerbation, etc, the patient should be recommended to seek immediate emergency medical services and to notify the injectionist. All adverse reactions should be properly documented in the patient’s chart.

Clinical Pearls

• Image-guided interventional procedures are powerful diagnostic and therapeutic tools to aid in the diagnosis and management of various musculoskeletal disorders.
• The duration of benefit is variable, but steroid injections tend to produce substantial short-term relief of symptoms (eg, pain, swelling) with variable duration of relief (1-3 months).
• Body habitus may influence the image-guided approach used. In obese patients, fluoroscopy may be used to improve visualization of deeper anatomic structures that would be more difficult to visualize under ultrasound guidance. Conversely, in leaner patients, use of ultrasound guidance eliminates radiation exposure and usually most anatomic structures can be easily identified.
• Success of image-guided procedures is dependent on numerous factors, which include target localization through use of anatomic landmarks, patient cooperation, and the experience of the physician with image-guided interventions.
• Image-guided injections are well tolerated and have an excellent safety profile.
• These procedures can be repeated to manage recurrent symptoms, but patients should be cautioned that the detrimental effects of repeated steroid injections on soft tissue structures, ie, articular cartilage and tendons have not yet been determined.

THE GLENOHUMERAL (GH) JOINT OF THE SHOULDER

Indications

The glenohumeral joint of the shoulder is susceptible to premature arthritic development from various conditions that may damage the joint cartilage. Of these conditions, glenohumeral osteoarthritis is the most common form of arthritis that results in shoulder joint pain. The indications include:

• Glenohumeral osteoarthritis
• Rotator cuff arthropathy
• Post-traumatic osteoarthritis
• Acute and chronic adhesive capsulitis
• Rheumatoid arthritis
• Collagen vascular diseases

Oftentimes, patients present with generalized shoulder and upper arm pain and it may be difficult to localize the primary pain generator intra-articular glenohumeral joint injections are excellent diagnostic tools, which can aid in elucidating the primary pain generator. Therapeutically, intra-articular glenohumeral joint corticosteroid injections are relatively safe interventional procedures. These procedures may be performed if shoulder pain remains refractory to more conservative measures such as occupational therapy, pharmacologic intervention, and activity modification. Accuracy of blind glenohumeral joint injections has been found to be extremely variable, ranging from 25% to 95% accuracy. Image-guided intra-articular glenohumeral joint injection enables dynamic real-time visualization of the process, improves needle visualization, augments target accuracy, reduces damage to surrounding structures, ie, glenoid labrum, and decreases the risk of neurovascular injury, particularly to the brachial plexus.

Relevant Anatomy

The large and round head of the humerus articulates with the relatively flat glenoid fossa of the scapula to form the glenohumeral (GH) joint. The articular surface is covered with hyaline cartilage. Due to the relative incongruence of these surfaces, the glenohumeral joint is susceptible to degenerative changes and instability. The glenoid labrum is a fibrocarti-laginous layer, which envelops the rim of the glenoid fossa. With humeral dislocation and subluxation, the glenoid labrum is exposed and has an increased risk for trauma. The glenohumeral joint is encompassed by a lax capsule that permits a wide range of motion of the joint. However, this laxity compromises joint stability. The glenohumeral joint is lined by a synovial membrane, which attaches to the articular cartilage and forms synovial tendon sheaths and bursae. These synovial structures are particularly vulnerable to inflammation. The glenohumeral joint are innervated by the axillary and suprascapular nerves.

The glenohumeral, transverse humeral, and cora-cohumeral ligaments are the major ligaments of the shoulder joint. The rotator cuff muscles that surround the shoulder joint are the supraspinatus, infraspinatus, teres minor, and subscapularis muscles. The rotator cuff musculature and ligaments provide strength to the joint. However, due to misuse and overuse injuries, the rotator cuff muscles and their tendons are susceptible to trauma and inflammation.

The key to successfully locating the glenohumeral joint from a posterior approach is identifying the following structures (Figure 50-1):

• Humeral head, which is the primary bony landmark for locating the GH joint
• Posterior labrum
• Infraspinatus muscle and tendon
• Tendon sheath of the bicipital tendon

Figure 50-1. Illustrations of the posterior (left) and anterior (right) views of the right glenohumeral joint with relation to nearby anatomical structures.

From an anterior approach, the following structures should be identified (Figure 50-1):

• Lesser tubercle of the humerus
• Coracoid process
• Tendon sheath of the bicipital tendon

Other relevant anatomy that should be taken into consideration while performing these injections is:

• Brachial plexus, which is at increased risk for neurovascular injury from the anterior approach
• Calcifications of the rotator cuff muscle and bicipital tendons

Preoperative Considerations for GH Joint Injections

• For the ultrasound-guided approaches to the glenohumeral joint, the patient must be able to sit upright for the procedure duration. Preferably, the patient will be able to sit upright on a stool with a rotating seat, but without wheels.
• Alternatively, the patient may lie prone or supine on the examination table for, respectively, ultrasound-guided posterior and anterior approaches to the glenohumeral joint. However, assessment and procedural efficiency would likely be sacrificed.
• For most fluoroscopic interventional procedures, the patient should be able to maintain his or her position for the length of the procedure. For glenohumeral joint injections utilizing the posterior approach, the patient must be able to lie prone. For the anterior approach, the patient must be able to supine.

Selection of Needles, Medication, and Equipment

Needles

• 22-gauge 3.5-in spinal needle or, for ultrasound-guided injections, a 22-gauge echogenic needle, which will be connected to extension tubing
• 22-gauge 1.5-in needle to prepare the injectate medication
• 25-gauge 1.5-in needle for local anesthetic
• 6-cc syringe for local anesthetic
• 6-cc syringe for medications
• 3-cc syringe for fluoroscopically guided procedures with contrast
• 6-cc syringe for GH effusion aspiration (if applicable)
• Ultrasound machine or fluoroscope
• Extension connector tubing

Medications

• 1% lidocaine: 4 to 5 cc for local analgesia
• Injectate mixture

1% lidocaine or 0.25% bupivacaine or 0.5% bupivacaine: 2 to 4 cc

Triamcinolone or methylprednisolone 40 to 80 mg (40 mg/mL)

Please note that medication doses are dependent on factors including patient body habitus and condition severity

• Iohexol 180 (nonionic water-soluble contrast) for fluoroscopically guided procedures
• Total injectate volume: 5 to 8 cc

Ultrasound Views

• Ideally, a brief ultrasound-guided examination of the shoulder should be performed to assess the glenohumeral joint and periarticular structures. Performance of a routine ultrasound-guided examination of the targeted area ensures that errors of omission are evaded.
• Initially, the ultrasound probe is aligned in the long axis of the myotendinous junction of the infraspinatus muscle. The humeral head is the critical bony landmark to visualize. Due to the curved geometry of the rotator cuff tendons, anisotropy is usually present at this area.
• Transducer repositioning may be used to differentiate anisotropy from other pathological conditions. Great care should be taken to identify the other primary landmark, the glenoid labrum.
• The infraspinatus muscle and glenoid labrum are located superior to the glenohumeral joint. Whereas, the humeral head is located slightly inferolateral to the glenohumeral joint. Prior to needle entry site demarcation, the intended target should be viewed in 2 orthogonal planes, which are the long and short axes.
• Scan the area for the presence of a glenohumeral joint effusion to aspirate. The bicipital tendon sheath directly communicates with the glenohumeral joint and may have fluid due to either an extension of the glenohumeral joint effusion or a local tenosynovitis.
• Orient the ultrasound probe in the long axis view of the glenohumeral joint with the glenohumeral joint centered on the screen.

Ultrasound-Guided Injection Techniques

Primarily, the anterior and posterior approaches have been described for needle passage to gain access to the glenohumeral joint. Due to the increased risk of neurovascular injury to the brachial plexus with the anterior approach, we advocate the posterior approach to the glenohumeral joint. Contributing to this preference, other rationales include heightened patient anxiety with direct needle visualization and enhanced sensitivity of flexor surfaces compared with extensor surfaces.

Our Preferred US-Guided Technique: The Posterior Approach to the GH Joint

• The patient is seated on a stool and is positioned facing away from the injectionist.
• For the shoulder, a high-frequency (17-5 MHz) ultrasound transducer should be selected and ultrasound gel should be applied to the transducer.
• The ultrasound transducer is aligned in the long axis of the myotendinous junction of the infraspinatus muscle with visualization of the humeral head and glenoid labrum as the primary landmarks.
• When inspecting the target area, the depth and gain may be adjusted to optimize structure visualization [9].
• Scan the area for glenohumeral joint effusion to aspirate.
• To relieve the pressure from teres minor and infraspinatus muscles against the posterior capsule or to increase the amount of fluid in the posterior recess of the glenohumeral joint and facilitateultrasound-guided arthrocentesis, the targeted upper limb may be externally rotated.
• Orient the ultrasound probe in the long axis view of the glenohumeral joint with the glenohumeral joint centered on the screen and the needle entry point should be clearly demarcated approximately 1 cm from the medial transducer edge (Figure 50-2).

Figure 50-2. Image demonstrates the ultrasound transducer alignment in the long axis of the glenohumeral joint in the posterior view. The needle entry point is clearly demarcated 1 cm medial to the ultrasound probe edge.

• The skin overlying the demarcated needle entry site and the glenohumeral joint should be prepared using aseptic technique.
• 5 cc of 1% lidocaine is infiltrated into the skin and surrounding soft tissues to ensure appropriate local analgesia using a 25-gauge 1.5-in needle.
• Using the 22-gauge 1.5-in needle, the 1% lidocaine/triamcinolone injectate mixture is drawn up into a 6-cc syringe. Depending on the patient’s body habitus, the amount of 1% lidocaine will range from 2 to 4 cc and the amount of triamcinolone will range from 40 to 80 mg. The total injectate volume should range from 3 to 6 cc.
• Invert and revert the injectate syringe several times to ensure adequate mixing of the medications.
• The injectate syringe should be attached to the connector tubing with the 22-gauge 3.5-in spinal needle and primed.
• The 22-gauge 3.5-in spinal needle is inserted at the demarcated needle entry point and directed toward the glenohumeral joint. In the long axis view, the needle should appear as a hyperechoic and linear structure.
• Throughout the entire procedure, the needle tip position should be visualized. To enhance need conspicuity, the needle should be maintained as parallel as possible to the ultrasound probe and may be gently moved without advancement, which is termed jiggling.
• The needle should take an oblique course from medial to lateral, which facilitates the gliding of the spinal needle above the humeral head and below the posterior labrum and the infraspinatus tendon.
• As the needle is advanced, the needle path should be adjusted to access the posterior recess of the glenohumeral joint, which lies deep to the free margin of the labrum and tangential to the curve of the humeral head.
• With proper intra-articular needle positioning at the posterior recess of the glenohumeral joint, the needle tip should be located beneath the infraspinatus tendon and glenoid labrum and adjacent to the hyaline cartilage of the humeral head (Figure 50-3). The hyaline cartilage should appear hypoechoic against the hyperechoic humeral head [4].

Figure 50-3. Ultrasound image (left) with needle tip inferior to the infraspinatus tendon and glenoid and adjacent to the hyaline cartilage of the humeral head in the glenohumeral joint. The image on the right is an illustration of the ultrasound image.

• The needle is aspirated to ensure that the needle is not located intravascularly.
• With real-time ultrasound, the 1% lidocaine/triamcinolone mixture is slowly injected into the posterior recess of the glenohumeral joint.
• Correct intra-articular positioning is confirmed by the dynamic and visual expansion of the posterior recess with injectate mixture fluid and hydrodissection, which should appear relatively hyperechoic on ultrasound.
• Consequently, the needle is flushed and withdrawn.
• The overlying skin is cleansed and a sterile dressing is applied.

Alternative US-Guided Technique: The Anterior Approach to the GH Joint

An anterolateral approach may be used. The patient is positioned lying supine on an examination table with his or her head rotated to the contralateral side. The needle would be visualized in the longitudinal view. The 22-gauge spinal needle would be inserted on the anterior surface between the coracoid process and the lesser tuberosity of the humerus. Then, the needle would be aimed in the posterolateral direction toward the spine of the scapula and the medial border of the humeral head. The needle tip should be positioned at the glenohumeral joint. Due to the increased risk of neurovascular injury, the area should be assessed for the presence of nerves, which appear as honeycombed structures on transverse views and fascicular patterns on longitudinal views. Also, vascular structures may be evaluated with power Doppler imaging.

Fluoroscopic Views

• Start with an anterior-posterior (AP) image of the glenohumeral joint in view. Diligently mark the center or inferolateral quadrant of the humeral head as the needle entry site to ensure a medial approach to access the glenohumeral head.
• A lateral view may be helpful to determine needle depth.

Fluoroscopy-Guided Injection Techniques

As with ultrasound-guided glenohumeral joint injections, the anterior and posterior approaches have been described for needle passage to gain access to the glenohumeral joint. Again, due to increased potential complications including neurovascular injury, patient anxiety, and sensitivity of dorsal surfaces, we advocate the posterior approach to the glenohumeral joint.

Our Preferred Fluoro-Guided Technique: The Posterior Approach to the GH Joint

• The patient is positioned in the prone position with the arm on the side of the symptomatic shoulder in either a neutral or slightly internally rotated position.
• Starting in the AP view, the symptomatic shoulder should be elevated until the glenohumeral joint is visualized tangentially.
• A radio-opaque marker is utilized to localize the center or the inferolateral quadrant of the humeral head and, consequently, the skin overlying this area should be clearly demarcated.
• The skin overlying the demarcated needle entry site and the glenohumeral joint should be prepared in a typical sterile fashion.
• 5 cc of 1% lidocaine is infiltrated into the skin and surrounding soft tissues to ensure appropriate local analgesia using a 25-gauge 1.5-in needle.
• 3 cc of contrast should be drawn up into a 3-cc syringe. Then, the extension connector tubing with a 21-gauge 3.5-in spinal needle should be attached and primed.
• Using a 22-gauge 1.5-in needle, the 1% lidocaine/triamcinolone injectate mixture is drawn up into a 6-cc syringe. Depending on the patient’s body habitus, the amount of 1% lidocaine will range from 2 to 4 cc and the amount of triamcinolone will range from 40 to 80 mg. Including contrast, the total injectate volume should range from 5 to 8 cc. The injectate syringe should be inverted and reverted several times to ensure adequate mixing of the medications.
• The 22-gauge 3.5-in spinal needle is inserted at the demarcated needle entry point and directed toward the cartilage of the humeral head and the glenohumeral joint (Figure 50-4).

Figure 50-4. Fluoroscopic image (left) demonstrates the posterior approach with the 22-guage spinal needle directed towards the center of the humeral head and the glenohumeral joint in the AP view. Image on the right demonstrates the glenohumeral joint arthrogram with capsular distension achieved with injected iodinated contrast media.

• With fluoroscopic guidance, needle is advanced vertically in the oblique view to the cartilage of the humeral head.
• Once the needle is suspected to be at the glenohumeral joint and the needle tip contacts the center of the humeral head, the syringe with contrast is attached to a spinal needle via the connector.
• The needle is aspirated to ensure that the needle is not located intravascularly.
• With real-time live fluoroscopy, the iodinated contrast media is injected to obtain an arthrogram (Figure 50-4). If this isn’t observed, rotate the bevelof the needle 90 to 180 degrees, maintain contact with the humeral head and repeat.
• Careful examination should be made to ensure that the contrast spread remains confined to the glenohumeral joint and that no intravascular uptake occurred.
• Once proper needle placement has been confirmed, the 5-cc syringe containing the iodinated contrast is removed and the 5-cc syringe containing the injectate mixture is attached to the extension tubing.
• Prior to pushing the injectate mixture, the needle should be aspirated again to ensure that the needle is not located intravascularly.
• The needle injectate should be pushed slowly.
• With repeat fluoroscopic imaging, contrast spread throughout the GH joint and “washing out” of the contrast dye adjacent to the needle tip should be visualized.
• Consequently, the needle is flushed and withdrawn.
• The overlying skin is cleansed and a sterile dressing is applied.

Alternative Fluoro-Guided Technique: The Anterior Approach to the GH Joint

An anteroposterior approach may be utilized. The patient lies supine on the fluoroscopy table with his or her arm in slight external rotation. With this technique, a straight AP view would be obtained. The needle entry point should be demarcated for the inferolateral border or center of the humeral head. After sterile skin preparation and local anesthetic infiltration, a 22-gauge spinal needle should be directed toward the glenohumeral joint and the inferolateral quadrant or center of the humeral head under fluoroscopic guidance. Consequently, iodinated contrast media is injected to confirm intra-articular needle position. With the anterior fluoroscopically guided anterior approach to the GH joint, it is particularly important to aspirate prior to injection, inject iodinated contrast media, and obtain an arthrogram.

Potential Complications and Pitfalls

Although image-guided interventional procedures of the glenohumeral joint offers the advantages of real-time assessment, needle visualization, and guidance, various obstacles may be encountered. In patients with a history of prior shoulder surgeries, history of prior shoulder trauma, abnormal or complicated anatomy, and calcifications of the rotator cuff tendons and bicipital tendon, all of these approaches may be challenging to the injectionist. With fluoroscopy, these procedures may be a particular concern for elderly patients and those exposed to radiation in other body regions. Patients should be cautioned that corticosteroid injections to the GH joint may not completely alleviate the pain and may be potentially ineffective. Other potential complications include:

• Neurovascular injury, particularly to the brachial plexus
• Infection
• Bleeding
• Hematoma and ecchymoses
• Intravascular injection
• Neuritis
• Tendon rupture
• Myalgias
• Chronic regional pain syndrome development

THE HIP JOINT

Indications

In clinical practice, intra-articular hip injections are utilized for diagnostic and therapeutic purposes. Many patients present with a history of hip and lumbar osteoarthritis (OA) and differentiating the etiology of the pain can be difficult without diagnostic hip joint injections. Therefore, intra-articular anesthetic hip injections can help rule in or out the suspected source of pain. For therapeutic purposes, intra-articular steroid injections are often considered as the next step of treatment for intra-articular sources of hip pain (eg, OA or labral pathology) that is nonresponsive to more conservative measures (eg, oral medications such as NSAIDs, physical therapy, activity modifications and other lifestyle changes).

Image guidance has been recommended for many years for specific anatomic reasons related to the hip joint; including the deep location of the joint and the close proximity of the anterior hip joint to the femoral artery, vein, and nerve (Figure 50-5). Therefore, image guidance can improve the accuracy of proper needle placement, and theoretically improve the safety profile of the injection with less risk of neurovascular injury [23].

Figure 50-5. Illustration of the hip joint and its proximity to the neurovascular bundle, including the femoral vein, femoral artery, and femoral nerve.

Relevant Anatomy

A thorough understanding of intra-articular and extra-articular structures of the hip is absolutely necessary in the management of various hip conditions. For the purposes of intra-articular hip injections, a solid understanding of the surface anatomy of the hip and the bony anatomy of the proximal femur is most important. This will provide the clinician with the ability to locate the site of entry and then allow for proper navigation of the needle into the joint space. In addition, to avoid complications, the location of the femoral neurovascular bundle (femoral nerve, artery, and vein) must be understood since they are in close proximity to the anterior hip joint.

The key to successfully locating the hip joint from an anterior approach is identifying the following structures (Figure 50-6):

Figure 50-6. Illustration of the hip joint with relation to nearby anatomical structures.

• Inguinal crease/ligament
• Location of neurovascular bundle (femoral artery, vein, and nerve)
• Proximal quadriceps, rectus femoris, and sartorius
• Iliopsoas tendon
• Anterior inferior iliac spine (AIIS)
• Anterior superior iliac spine (ASIS)
• Greater trochanter and abductor tendons
• Origin of the adductor muscle group

Other relevant anatomy that should be taken into consideration while performing these injections are:

• Femoral head, neck, and head-neck junction
• A thorough understanding of the location of the joint capsule attachments which extends down to the intertrochanteric line on the anterior femur (Figure 50-7)

Figure 50-7. Illustration on the left demonstrates the hip capsule anterior attachments, including the iliofemoral ligament to intertrochanteric line of the femur and the pubofemoral ligament to the lesser tuberosity of the femur. On the right, a posterior view of the hip capsule and ischiofemoral ligament is illustrated.

• The acetabulum and its bony anatomy with labrum

Preoperative Considerations for Intra-Articular Hip Injections

• For the image-guided approaches to the intra-articular hip joint, the patient must be able to lie supine for the procedure, which should take approximately 10 to 15 minutes.
• If ultrasound is not available or the clinician prefers to use fluoroscopic guidance, the fluoroscopically guided approach can be utilized.

Selection of Needles, Medication, and Equipment

Needles

• 22-gauge 3.5-in spinal needle or, for ultrasound-guided injections, a 22-gauge echogenic needle, which will be connected to extension tubing
• 25-gauge 1.5-in needle for local anesthetic
• 3- or 5-cc syringe for local anesthetic
• 10-cc syringe for aspiration
• 10-cc syringe for medications
• 5-cc syringe for fluoroscopically guided procedures with contrast
• Extension connector tubing
• Ultrasound machine or fluoroscope

Medications

• 1% lidocaine: 1 to 3 cc for local analgesia
• Injectate mixture

1% lidocaine: 2 to 4 cc

Triamcinolone 40 to 80 mg (40 mg/mL) or methylprednisolone 40 to 80 mg (40 mg/mL)

0.25% or 0.5% bupivacaine (optional): 2 cc

Please note that medication doses are dependent on factors including patient body habitus and condition severity.

• Iohexol 180 (nonionic water-soluble contrast) for fluoroscopically guided procedures
• Total injectate volume: 3 to 10 cc

Techniques

Two primary techniques have been described for intra-articular hip injections:

1. Anterior approach (patient supine, hip in full extension and neutral rotation)
2. Go from medial to lateral in order to avoid hitting vital structures. Lateral approach (patient supine with the hip in full extension)

The anterior approach with fluoroscopic or ultrasound guidance, with the patient supine and the hip in full extension with neutral rotation is commonly utilized by clinicians. The advantages includes the ability to palpate key landmarks, easy positioning of tools for image guidance (C-arm or ultrasound probe) and most importantly avoidance of important intra-articular structures (eg, articular cartilage, acetabular labrum) because the target is either the middle of the femoral neck on AP fluoroscopic image or the femoral head-neck junction on ultrasound image. The primary disadvantage includes the potential for neurovascular injury to the femoral nerve, artery, or vein; even injury to the lateral femoral cutaneous nerve is possible.

The lateral approach, with the patient supine and the hip full extension, is another approach commonly utilized by clinicians. The primary advantage over the anterior approach may be improved accuracy if image guidance isn’t utilized. The primary disadvantage includes injury to intra-articular structures, such as articular cartilage and/or acetabular labrum.

Ultrasound Views

• The ultrasound probe is placed longitudinal to the femoral neck and positioned to obtain a long axis view of the femoral head-neck junction.

Ultrasound-Guided Injection Techniques

Our Preferred Technique: Anterior Approach to the Intra-Articular Hip Joint With Ultrasound Guidance

We advocate this approach for many reasons. This technique allows for comfortable positioning of the patient, confirmation of intra-articular placement via ultrasound visualization of the needle tip and injectate filling pattern, and the patient and operator is able to avoid ionizing radiation and the use of contrast agents which theoretically decrease the risk of allergic reactions. In our experience, this approach is tolerated very well by the patient and is an accurate approach that may be confirmed with real time visualization by the operator. The literature supports a high rate of accuracy and safety with this approach.

• The patient is placed in a supine position with the hip in full extension and neutral rotation, slight internal rotation may be utilized to obtain a better image of the femoral head-neck junction.
• The ultrasound probe is then used to mark the location of the femoral nerve and vessels, then the probe is placed longitudinal to the femoral neck and positioned to obtain a long axis view of the femoral head-neck junction.
• The site of needle entry is marked with a pen on the skin just distal (approximately 2-3 cm) to the probe.
• The injection site is then prepared in a sterile fashion and a sterile cover is applied to the ultrasound probe.
• Up to 3 cc of 1% lidocaine is then infiltrated into the skin overlying the site of the injection to provide adequate skin analgesia using a 25-gauge 1.5-in needle.
• The injectate is drawn up using a 10-cc syringe which consists of 40 to 80 mg of either triamcinolone or methylprednisolone and 2 to 4 cc of 1% lidocaine with the option to include additional 2 cc of 0.25% bupivacaine.
• The 22-gauge 3.5-in spinal needle with this 10-cc syringe attached is then advanced at approximately a 45-degree angle, in the plane of the ultrasound beam to allow real time visualization of the needle tip and shaft.
• The trajectory of the needle is adjusted to visualize the needle tip at the femoral head neck junction. Expect a slight increase in resistance as the needle pierces the iliofemoral ligament and anterior capsule. In our experience, passing the needle through these tissues produces anterior hip pain for the patient, and warning them prior to this may be helpful.
• Once the needle tip contacts the femoral neck and can be visualized on ultrasound, aspiration is performed and if negative for blood, a test injection of 1 to 2 mL is used to confirm filling along the femoral head-neck junction along with anterior capsular distension (Figure 50-8). If this isn’t observed, rotate the bevel of the needle 90 to 180 degrees and maintain contact with the femoral neck and repeat.

Figure 50-8. Ultrasound image (left) with needle tip contacting the femoral neck with anterior capsular distension along the femoral head-neck junction. The image on the right is an illustration of the ultrasound image.

• The remainder of the solution is injected under real time visualization to continue to confirm filling pattern along the femoral head-neck junction along with anterior capsular distension.
• At the conclusion of the procedure, the needle is clearly withdrawn and sterile dressings are used to apply pressure.
• The area is cleansed with alcohol solution, dried, and a dressing is applied over the site of the injection.

Fluoroscopic Views

• Start with an AP view of the pelvis, center the femoral neck, and magnify the image. Mark the middle of the femoral neck (Figure 50-9).

Figure 50-9. Fluoroscopic image of the right hip (top left) demonstrates the posterior approach with the 22-guage spinal needle directed toward the femoral neck in the AP view. Image on the top right demonstrates the injection iodinated contrast media into the right intra-articular hip joint. The bottom image demonstrates filling of a left hip capsule with contrast media.

Fluoroscopically Guided Technique

• The patient is placed in a supine position on the table, with the hip in full extension and neutral rotation.
• An AP view of the pelvis is obtained, then femoral neck on the side of the injection is centered.
• The site of needle entry is marked with a pen on the skin at the center of the femoral neck.
• The injection site is then prepared in a sterile fashion.
• Up to 3 cc of 1% lidocaine is then infiltrated into the skin overlying the site of the injection to provide adequate skin analgesia using the 25-gauge 1.5-in needle.
• The injectate is drawn up using a 10-cc syringe, which consists of 40 to 80 mg of either triamcinolone or methylprednisolone and 2 to 4 cc of 1% lidocaine +/1 an additional 2 cc of 0.25% bupivacaine.
• A 22-gauge 3.5-in spinal needle is directed down to the femoral neck under fluoroscopic guidance.
• The trajectory is perpendicular to the femoral neck, in the beam of the fluoroscope, attempting to obtain a hub view. Expect a slight increase in resistance as the needle pierces the iliofemoral ligament and anterior capsule. In our experience, passing the needle through these tissues produces anterior hip pain for the patient, and warning them prior to this may be helpful.
• Once the needle tip contacts the femoral neck and is visualized fluoroscopically (still using an AP image), aspiration is performed and if negative, the extension tubing is connected to the spinal needle and contrast dye is injected to obtain an arthrogram (Figure 50-9). If this isn’t observed, rotate the bevel of the needle 90 to 180 degrees and maintain contact with the femoral neck and repeat.
• Once a good arthrogram is obtained, indicating a capsular filling pattern, syringes are switched and now the steroid and anesthetic is injected.
• At the conclusion of the procedure, the needle is clearly withdrawn and sterile dressings are used to apply pressure.
• The area is cleansed with alcohol solution, dried, and a dressing is applied over the site of the injection.

EXTENSOR CARPI RADIALIS BREVIS MUSCLE AND THE COMMON EXTENSOR TENDON

Indications

Lateral epicondylitis, which is more commonly known as tennis elbow, is caused by overuse injuries and chronic repetitive microtrauma to the forearm extensor tendons. The most common area of pain is located at the origin of the extensor carpi radialis brevis tendon at the lateral epicondyle of the elbow. Rarely, lateral epicondylitis pain may originate at a more distal site, which is where the ECRB overlies the radial head. With chronic overuse or misuse of the forearm extensors, the inflammatory response may spread to adjacent tissues. With lateral epicondylitis, the abnormality consists primarily of degeneration, tendinosis, and potential tendon tear. The primary indication for extensor carpi radialis brevis muscle and common extensor tendon injection is lateral epicondylitis.

Relevant Anatomy

The extensor carpi radialis brevis muscle extends the wrist with radial deviation. The origin of the extensor carpi radialis brevis muscle is located at the lateral epicondyle via the common extensor tendon, the radial collateral ligament, and the antebrachial fascia. The distal insertion is located at the base of the third metacarpal. The extensor carpi radialis brevis muscle is innervated by the deep branch of the radial nerve. Overuse and misuse injuries of the extensor carpi radialis brevis muscle are associated with the development of lateral epicondylitis.

The common extensor tendon is located at the lateral elbow in the posterior compartment. The lateral collateral ligament lies immediately deep to the common extensor tendon. The radial head lies beneath the lateral collateral ligament. The deep fibers primarily contain contributions from the extensor carpi radialis brevis. The superficial tendon receives fibers from the extensor carpi radialis brevis, extensor carpi ulnaris, extensor digitorum, and extensor digit minimi muscles.

The key to successfully locating the ECRB muscle and common extensor tendon is identifying the following structures (Figure 50-10):

Figure 50-10. Illustration of the lateral view of the elbow, highlighting the location of the lateral epicondyle, common extensor tendon, and extensor carpi radialis brevis muscle to nearby anatomical structures.

• Lateral epicondyle
• Radial head
• Lateral collateral ligament
• Common extensor tendon
• Extensor digiti minimi muscle
• Extensor carpi ulnaris muscle
• Extensor digitorum communis muscle

Other relevant anatomy that should be taken into consideration while performing these injections includes the deep radial nerve.

Preoperative Considerations

• For this procedure, the patient must be able to lie supine or seated for the procedure duration.

Selection of Needles, Medication, and Equipment

Needles

• 25-gauge 1.5-in needle
• 6-cc syringe for medications
• Ultrasound machine

Medications

• Injectate mixture

1% lidocaine: 2 to 3 cc

Triamcinolone: 1 cc (40 mg/mL)

• Total injectate volume: 3 to 4 cc

Ultrasound Views

• Ideally, a brief ultrasound-guided examination of the lateral elbow and forearm should be performed to ensure that errors of omission are evaded.
• Initially, the ultrasound probe is aligned in the long axes of the extensor carpi radialis brevis muscle and common extensor tendon. The radial head and lateral epicondyle are the critical bony landmarks to visualize. Also, the lateral collateral ligament, which is immediately deep to the common extensor tendon, should be identified (Figure 50-11).

Figure 50-11. Image demonstrates the ultrasound transducer alignment in the long axis view of the attachment site of the extensor carpi radialis brevis muscle to the common extensor tendon. The needle entry point is clearly demarcated 1 cm proximal to the ultrasound prove edge.

• Prior to needle entry site demarcation, the intended target should be viewed in both the long and short axes.

Ultrasound-Guided Injection Technique

The patient should lie supine with the arm adducted at the patient’s side and the elbow flexed the palm down or halfway between pronation and supination. The patient’s hand should be placed atop a raised surface or folded towel to relax the common extensor tendon.

• Alternatively, the patient may be seated with the arm resting on the table and the elbow flexed to 70 to 80 degrees. In this position, the wrist should be pronated.
• For the elbow and forearm, a high-frequency (17-5 MHz) ultrasound transducer is an appropriate ultrasound probe to select and ultrasound gel should be applied to the transducer.
• Structures of interest in the lateral elbow include the common extensor tendon, lateral epicondyle, the lateral collateral ligament complex, the radial head, annular recess, capitulum, extensor carpi radialis, extensor digitorum, extensor carpi ulnaris, and extensor digiti minimi. While performing the sonographic examination, the wrist and finger extensor musculature may be identified by having the patient move their wrist or finger(s) accordingly.
• The ultrasound transducer is aligned in the long axis view of the attachment site of the extensor carpi radialis brevis muscle to the common extensor tendon (Figure 50-11). To guide the examination, the lateral epicondyle, lateral collateral ligament, and the radial head, which lie deep to the common extensor tendon and ECRB muscle, should be identified and examined in a longitudinal plane. To aid in ECRB identification, the patient may be asked to extend and radially deviate the wrist. The common extensor tendon origin has a uniform hyperechoic triangular configuration, which is seen traversing the radiocapitellar joint.
• Scan the area for neurovascular structures, including the deep branch of the radial nerve. The deep branch of the radial nerve should appear to have a “honeycomb” appearance on a transverse view and a fasicular appearance on longitudinal view.
• When inspecting the target area, the depth and gain may be adjusted to optimize structure visualization.
• Once the ECRB muscle and common extensor tendon are identified, these structures should be evaluated in 2 orthogonal planes, which are longitudinally (long axis) and transversely (short axis).
• The extensor carpi radialis brevis component of the common extensor tendon is most commonly affected in lateral epicondylitis. Sonographically, tendinosis appears as thick and hypoechoic. Also, there may be concomitant swelling of the involved tendon with possible hyperechoic calcification with chronic cases. Also, bone irregularity may be present. Hyperemia on color or power Doppler imaging is variable, but may be present with soft tissue inflammation. Superimposed partial-thickness tears appear as hypoechoic or anechoic clefts and incomplete fiber discontinuity with linear [33].
• Orient the ultrasound probe in the long axis view of the ECRB muscle and its attachment to the common extensor tendon centered on the screen. The needle entry point should be clearly demarcated approximately 1 cm from the proximal transducer edge (Figure 50-11). With the long-axis approach, the needle tip and shaft are positioned collinearly with the long axis of the ultrasound probe. This optimizes the needle visualization approach to the target.
• Following sterile preparation of the skin overlying the posterolateral aspect of the joint, the lateral epicondyle is identified.
• Using the 22-gauge 1.5-in needle, the 1% lidocaine/triamcinolone injectate mixture is drawn up into a 5-cc syringe.
• The 22-gauge 1.5-in needle is inserted at the demarcated needle entry point and directed toward the centered ECRB muscle attachment to the common extensor tendon. In the long axis view, the needle should appear as a hyperechoic and linear structure. Throughout the entire procedure, the needle tip position should be visualized. To enhance need conspicuity, the needle should be maintained as parallel as possible to the ultrasound probe. Also, the needle may be gently moved without advancement, which is termed jiggling.
• The needle should take a longitudinal course from proximal to distal.
• With proper needle positioning at the ECRB muscle attachment to the common extensor tendon, the needle tip should be located adjacent to the target area (Figure 50-12). Care must be taken to ensure that the common extensor tendon is not directly injected to avoid tendon rupture.

Figure 50-12. Ultrasound image (left) with needle at the musculotendinous junction of the extensor carpi radialis brevis and the common extensor tendon. The image on the right is an illustration of the ultrasound image.

• The needle is aspirated to ensure that the needle is not located intravascularly.
• With real-time ultrasound, the 1% lidocaine/triamcinolone mixture is slowly injected into the area adjacent to the musculotendinous junction of the ECRB muscle. Correct positioning is confirmed by the dynamic and visual expansion of the area with fluid and hydrodissection, which should appear relatively hyperechoic on ultrasound.
• Consequently, the needle is flushed and withdrawn.
• The overlying skin is cleansed and a sterile dressing is applied.

Potential Complications and Pitfalls

Although ultrasound-guided interventional procedures of the extensor carpi radialis brevis muscle and common extensor tendon has the distinctive advantages of dynamic real-time assessment, needle visualization, accessibility, and portability, various challenges may be encountered. This approach may be difficult to utilize in patients with a history of prior elbow or forearm surgeries, history of prior elbow or forearm trauma, abnormal or complicated anatomy, and calcifications of the common extensor tendon. Patients should be cautioned that corticosteroid injections for lateral epicondylitis may not completely alleviate the pain and may be potentially ineffective. Performance of the corticosteroid injection superficial to the ECRB should be avoided due to the increased risk of skin depigmentation and fat atrophy. Other potential complications include:

• Common extensor tendon rupture
• Neurovascular injury, particularly to the deep radial nerve
• Infection
• Bleeding
• Hematoma and ecchymoses
• Intravascular injection
• Neuritis
• Myalgias
• Chronic regional pain syndrome development