Ultrasound Guided Injection Techniques
Metacarpophalangeal, Interphalangeal, Proximal Interphalangeal, Distal Interphalangeal Joint Injections
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Out-of-plane relative to transducer or short axis to the joint approaches maybe easier for these superficial joints
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A gel stand-off may improve joint and needle visualization
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Understanding and identification of at-risk anatomy is required prior to injection
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A hockey stick transducer may improve ability to do injections.
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Joints often hold relatively small volumes of injectate; therefore, practitioner will often have to limit anesthetic in favor of therapeutic injectate when performing the procedure.
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Use of particulate corticosteroids increases the risk of skin depigmentation, especially in the case of superficial injections
Pertinent Anatomy
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The metacarpophalangeal (MCP), interphalangeal (IP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints are small synovial joints that allow for flexion and extension of the fingers and thumb.
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Neurovascular structures run along the relative volar side of each digit ( Figs. 19.1 and 19.2B ).
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Dorsal recess of the joints extends proximal to each joint allowing for relatively easier access than volar to joint (see Fig. 19.2C and D ).
Common Pathology
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Osteoarthritis commonly effects the joints of the hand.
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The MCP and IP joints are commonly affected by disorders of the hand, including dislocations, sprains, fractures, and both osteoarthritis and inflammatory arthropathies.
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The PIP joint is a commonly injured finger joint, often resulting in fractures, collateral ligament injuries, palmar plate injuries, and subsequent post-traumatic osteoarthritis.
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Inflammatory arthritis, such as rheumatoid arthritis, can have a predilection for the joints of the hand
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Common findings of joint space narrowing, osteophyte formation, effusion, joint subluxation or deformity, and erosive changes, in the case of inflammatory arthritis can occur.
Equipment
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High frequency linear array transducer
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Smaller footprint or hockey stick probes maybe easier to use over regions with noncompliant tissue.
Common Injectates
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Local anesthetics for diagnostics, corticosteroids intra-articular (IA) only
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Prolotherapy
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Orthobiologics (PRP, bone marrow concentrate, etc.)
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Corticosteroid should not be injected directly into capsular ligaments
Injectate Volume
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0.5 to 1.5 mL
Authors Preferred Injection Technique
Patient Position
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Seated or supine on table with forearm pronated ( Fig. 19.3A )
Clinical Position
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Standing or seated ipsilateral side of the patient
Transducer Position
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The transducer is placed in the anatomic sagittal plane with the desired target joint centered on the transducer, for out-of-plane approach (see Fig. 19.3A ).
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Alternatively, this can be done in the anatomic axial plane for the in-plane approach.
Needle Position
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Needle is introduced in short axis from an ulnar to radial or radial to ulnar direction into the joint (see Fig. 19.3A and B ).
Targets
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The desired joint
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Watch distention of the capsule or slight separation of the bones with ultrasound during the injection.
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Can also inject the overlying capsular ligaments (with prolotherapy or orthobiologics) for each joint in the same position with the needle in short axis or in long axis ( Fig. 19.4A and B )
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A dorsal approach to the joint effectively avoids the neurovascular bundles, which are volar.
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Needle depth can also be confirmed by turning the transducer 90 degrees to show an in-plane view of the needle.
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When injecting the ulnar collateral ligament of the first MCP joint, it may be helpful to have the patient hold onto a rolled- up towel or other cylindrical object to help position and stabilize the joint during the injection (see Fig. 19.4A ).
Carpometacarpal and Scaphotrapeziotrapezoid Joints and Carpometacarpal Capsular Ligaments
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When using orthobiologics it is recommended to address the joint instability/mechanical symptoms in addition to the condition being treated.
Pertinent Anatomy
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The carpometacarpal (CMC) joint is a saddle shaped synovial joint between the trapezium and first metacarpal.
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The scaphotrapeziotrapezoid (STT) joint is a dome-shaped articulation composed of scaphotrapezial and/or scaphotrapezoidal articulation
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The terminal SR2 and SR3 branches of the superficial radial nerve border the volar and dorsal sides of the STT and CMC joints.
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Also just proximal to the STT and CMC joints the radial artery branches into superficial and deep palmar arteries ( Fig. 19.5A and B ).
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The flexor carpi radialis (FCR) tendon is just palmar and ulnar to the CMC and STT joints.
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The palmar cutaneous nerve usual resides between the FCR tendon and the palmaris on the palmar side of the wrist.
Common Pathology
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Observed in up to 15% of radiographic studies and 83.3% of cadaveric specimens, degenerative arthritis of the CMC and STT joint are the first and second most common cause of degenerative changes in the wrist.
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Injuries to the scaphotrapezial ligament, the major anatomic stabilizer of the STT joint, can lead to post-traumatic arthritic changes.
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Other theories for injury to the STT joint include disruption of the scapholunate interosseous ligament and cartilage erosion in the STT joint.
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Common pathologic US findings include joint effusions, synovitis, loss of articular space, cortical irregularities, and osteophyte formation.
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STT and CMC arthropathy have been associated with tendinopathy of the FCR tendon which lies anatomically just palmar and ulnar to the STT joint.
Equipment
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Injections can be performed using a high-frequency linear array transducer. If available, a hockey stick or shorter foot-print transducer may also be helpful.
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30 to 25-gauge 1 to 1.5 inch needle
Common Injectates
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Local anesthetics for diagnostics, corticosteroids IA only
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Prolotherapy
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Orthobiologics (PRP, bone marrow concentrate, etc.)
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Corticosteroid should not be injected directly into capsular ligaments
Injectate Volume
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1 to 2 mL
Technique: CMC and STT Joints Intra-Articular
Patient Position
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Supine ( Fig. 19.5A )
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For both joints, wrist supinated supported by towels
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For dorsal approach to the CMC joint, the wrist can be in neutral position.
Clinician Position
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Standing or seated ipsilateral side of the patient
Transducer Position
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Identify CMC joint in the transverse plane palmer aspect
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Transducer angled near parallel with the metacarpal bone
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Scaphotrapeziotrapezoid joint set up similar except the transducer is positioned more proximal
Needle Position
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Short-axis injection
Targets
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The desired joint (see Fig. 19.5A, C and D )
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Watch distention of the capsule or slight separation of the bones with ultrasound during the injection.
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Can also inject the overlying palmer capsular ligaments for both joints in the same position