Ultrasound Guided
Intra-Articular
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The superolateral approach is preferred for intra-articular knee injections, especially when an effusion is present ,
Pertinent Anatomy
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The knee joint is an encapsulated hinge-type synovial joint
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The knee joint is composed of four major bones: distal femur, proximal tibia, proximal fibula, and patella ( Fig. 21.1 )
Fig. 21.1
Bony Landmarks of the Anterior Knee.
From Detterline A, Babb J, Noyes FR, et al. Noyes’ Knee Disorders : Surgery, Rehabilitation, Clinical Outcomes. 2017:2–22.
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The bones form three articulations:
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Femorotibial (medial and lateral compartments)
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Patellofemoral
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Tibiofibular
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Primarily function is to allow for knee flexion and extension
Common Pathology
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The knee is susceptible to several arthritides including osteoarthritis (most common), rheumatoid arthritis, crystal arthropathies, and other inflammatory arthropathies.
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It is also vulnerable to direct trauma, particularly in sports-related injuries or motor vehicle accidents.
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Intra-articular pathology can present with a joint effusion or synovitis.
Equipment
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High-frequency linear array transducer
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22 to 18 gauge 1.5 to 2 inch needle for aspiration
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27 to 22 gauge 1.5 to 2 inch needle for injection only
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For aspirations:
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10 mL or 20 mL syringe—for small effusions
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30 mL or 60 mL syringe—for large effusions
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Common Injectates
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Local anesthetics for diagnostics, corticosteroids
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Hyaluronic acid
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Prolotherapy
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Orthobiologics (platelet-rich plasma [PRP], bone marrow concentrate, micronized adipose tissue, etc.)
Injectate Volume
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2 to 10 mL total
Technique for Suprapatellar Recess (Author Preferred)
Patient Position
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Pearls and Pitfalls
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If aspirating the knee, consider 1–3 mL of local anesthetic with smaller-gauge needle (27 or 30 gauge) for numbing the needle track.
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Directly target the hypoechoic space between the prefemoral and suprapatellar fat pads. Start 1–3 cm below the probe using the ultrasound to estimate depth of the suprapatellar recess and align needle to be as close to parallel to the probe.
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The procedure becomes more difficult without an effusion:
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Can have the patient contract the quad muscle to bring forth any fluid or more easily see the bursa
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Can push against medial soft tissue to visualize interval between prefemoral and suprapatellar fat pads
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Even in a dry knee joint, fluid can often be clearly seen at the lateral midpatella gutter (between the patella and lateral femoral condyle). The joint capsule can be traced proximally as it communicates with the suprapatellar recess
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Float the transducer on gel, as downward pressure can compress the recess and make it more difficult to visualize.
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Avoid injecting into the quad tendon or fat pads.
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A midpatella lateral approach can also be used targeting the lateral midpatella gutter. This can create a sense of fullness or pressure, and for some will be more uncomfortable than the suprapatella (see Fig. 21.2D ). This approach is also less accurate than the superolateral.
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Knee flexed to 30 degrees with towel roll or bump under the affected knee
Clinician Position
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Standing or seated on the side of the affected knee
Transducer Position
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Short axis to the quadriceps tendon ( Fig. 21.2A )
Fig. 21.2
(A) Suprapatellar bursa injection setup. (B) Suprapatellar bursa injection. (C) Suprapatellar bursa aspiration. (D) Midpatella gutter.
Needle Position
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In-plane/long axis
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Lateral to medial approach
Target
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Suprapatellar recess (see Fig. 21.2B and C )
Technique for Anterolateral Approach
Patient Position
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Seated or supine with the knee bent 60 to 90 degrees/hook-lying. Can place booster pillow under the knee for support (see Fig. 21.3A )
Clinician Position
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Seated or standing on the side of the affected knee
Transducer Position
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Sagittal plane directly over lateral condyle.
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Find the patellar tendon in long axis; then maintaining the same probe orientation, move laterally to visualize the trochlear groove deep to the tendon.
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Needle Position
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Out of plane (similar to landmark-guided lateral infrapatellar knee injections) (see Fig. 21.3A ).
Target
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Deep to the synovial membrane covering the medial or lateral femoral condyle. Care should be taken to visualize the needle tip deep to anterior (Hoffa’s) fat pad and confirm intra-articular fluid flow (see Fig. 21.3B )
Fig. 21.3
(A) Anterolateral knee joint injection hook-lying setup. (B) Anterolateral knee joint injection out of plane.
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There should not be any resistance when injecting. If there is resistance the needle may be in the capsule or extra-articular. Pain may indicate the needle is within the anterior fat pad.
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Use color Doppler when injecting to confirm intra-articular flow.
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Medial approach risks incidental injury to the saphenous nerve.
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The anterolateral approach may be less painful than the superolateral approach. ,
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This approach can also be performed with the transducer oriented in short axis to the patellar tendon and the needle in plane. The target can be just superficial to the articular cartilage of the medial or lateral trochlea depending on the anatomy and needle visualization.
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No significant difference in success rates between targeting the lateral or medial femoral condyle using the lateral infrapatellar approach.
Technique for Medial or Lateral Directed Knee Joint Injection
Patient Position
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Supine with the knee bent 60 to 90 degrees/hook-lying. Can place booster pillow under the knee for support ( Fig. 21.4A and B )
Fig. 21.4
(A) Medial knee joint directed injection setup in plane. (B) Lateral knee joint directed setup in plane. (C) Lateral knee joint directed injection in-plane ultrasound injection.
Clinician Position
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Standing on either side of the patient.
Transducer Position
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Sagittal plane directly over the medial or lateral condyle (depending on target).
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Find the patella; then maintaining the same probe orientation, move medially or laterally to the condyle and tibial plateau.
Needle Position
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Long axis to the transducer proximal to distal (see Fig. 21.4A and B ).
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Needle will have a steep angle headed past the femoral chondral surface towards the tibial in the anterior one-third of the joint.
Target
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Between the femoral condyle and the tibial plateau just superficial to the meniscus or the chondral surface (see Fig. 21.4C )
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Good approach if want to target specifically medial or lateral compartments but not a commonly used technique, and it is a little more challenging.
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Be careful not to scrape the needle along the chondral surfaces. Visualize needle tip at all times.
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There should not be any resistance when injecting; if so. needle may be in the capsule or meniscus or cartilage. Pain may indicate the needle is within one of those structures.
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Use color Doppler when injecting to ensure intra-articular flow.
Technique for Weightbearing Trochlea Groove Chondral Surfaces
Patient Position
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Supine, hip and knee each flexed 90 degrees. Rest the leg on a block or bolster ( Fig. 21.5A and B )
Fig. 21.5
(A) Medial femoral condyle intra-articular in-plane setup. (B) Lateral femoral condyle intra-articular in-plane setup. (C) Medial femoral condyle (MFC) in-plane injection.
Clinician Position
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Standing on left side of the patient for right-handed injection, right side of patient for left-handed injection.
Transducer Position
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Parallel to the leg/sagittal plane directly over desired condyle medial or lateral.
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Find the patella; then maintaining the same probe orientation, move medially or laterally.
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Scan slightly superior to visualize medial or lateral femoral condyle. The patella can be partially covering the lateral femoral condyle so may have to scroll a little more laterally but stay over weight-bearing surface.
Needle Position
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Long axis, distal to proximal approach (see Fig. 21.5A and B ).
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Can inject local anesthetic first from skin to just above the joint capsule.
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If the aiming for lateral condyle and patella is overlapping, angle probe and needle medially to slide needle under the patella but still toward weight-bearing lateral chondral surface.
Target
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Medial or lateral femoral condyle:
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Aim for the anterior one-third of the chondral surface with the bevel facing the surface (see Fig. 21.5C ).
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Gently touch chondral surface and inject. May have to pull back very slightly to get flow intra-articularly. Should see flow of injectate. Avoid injecting into the capsule.
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This is not a common technique, but the authors’ preferred approach when using mesenchymal stem cells (MSCs). The 90/90 position can allow for gravity-dependent cell adhesion after 10 min. Inject very slowly over 3–5 min to allow for cell adhesion and to avoid flushing the injectate off of the chondral surface.
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It is unknown if there is any advantage for this position with other biologics besides MSCs.
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Use a smaller-gauge needle where possible to avoid damaging the cartilage. Guide the needle very slowly and barely touch down on the chondral surface. Make sure the bevel is facing the surface to decrease chances of cartilage injury and inject directly on chondral surface.
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Aiming for the more anterior aspect of the condyle helps achieve a more diffuse flow along the cartilage surface.
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Only use 1–3 mL of injectate here. Any extra can be placed intra-articular with above-described techniques.
Proximal Tibiofibular Joint Injection
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The tibiofibular joint is an often overlooked cause of lateral knee pain.
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The posterolateral corner structures should be evaluated when assessing this region.
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There is significant anatomic variability in the angulation of the proximal tibiofibular joint (PTFJ), which may cause the transducer to be oriented in an anatomic transverse oblique plane for best visualization.
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The PTFJ is a small joint, and injectate volume is typically only 1–2 mL.
Pertinent Anatomy
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The tibiofibular joint is a planar diarthrodial synovial joint consisting of the fibular head facet and the articular facet on the lateral tibial condyle.
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It is surrounded by a fibrous capsule, which is thicker anteriorly, and stabilized by the tibiofibular ligaments. ,
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In some patients (10% to 64% of cases) the proximal tibiofibular joint (PTFJ) is contiguous with the femorotibial joint, and can be considered a “4th” compartment of the knee joint. ,
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Vascular supply: circumflex fibular artery wraps laterally the head of the femur and anastomoses with the recurrent branch of the anterior tibial artery (inferomedial to the PTFJ), and the inferior lateral genicular artery (superomedial to the PTFJ).
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Nerves: the common peroneal nerve courses along the lateral aspect of the popliteal fossa and wraps laterally and anterior around the fibular head-neck junction.
Common Pathology
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Degenerative osteoarthritis or direct traumatic injury
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Ganglion cyst, which in some cases can compress the common peroneal nerve
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Posterolateral (PL) corner injury with subsequent instability of the PTFJ (requires co-treatment of surrounding injured/lax structures)
Equipment
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High-frequency linear array transducer
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25 to 30 gauge 1.5 to 2 inch needle
Common Injectates
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Local anesthetics for diagnostics, corticosteroids
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Prolotherapy
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Orthobiologics (PRP, bone marrow concentrate, etc.).
Injectate Volume
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1 to 3 mL total
Technique
Patient Position
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Side-lying with affected side facing toward the ceiling
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Knee flexed 20 to 30 degrees with towel roll or bump to place in between legs ( Fig. 21.6A and B )
Fig. 21.6
(A) Tibiofibular joint out-of-plane setup. (B) Tibiofibular joint in-plane setup. (C) Tibiofibular joint out-of-plane injection. (D) Tibiofibular joint in-plane injection. FH, Fibular head.
Clinician Position
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Seated facing the anterior PTFJ
Transducer Position
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Transverse oblique plane over the anterior PTFJ
Needle Position
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Out-of-plane anterior to posterior (see Fig. 21.6A )
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Can touch down and the tibia and walk-down posterior
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Alternatively, in-plane proximal to distal approach (see Fig. 21.6B )
Target
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Anterior superior PTFJ (see Fig. 21.6C and D )
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Identify the surrounding neurovascular structures such as the common, superficial, and deep peroneal nerves prior to performing injection
Popliteal/Baker’s Cyst Injections
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Usually result of underlying intra-articular pathology (i.e., osteoarthritis, inflammatory arthritis, meniscus tear, chondral lesions) and increased synovial fluid within the knee joint. Communication between the joint and cyst behaves as a unidirectional or one-way valve, with fluid leaking into and forming the synovial cyst
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Intra-articular pathology should be addressed with the Baker’s cyst.
Pertinent Anatomy
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Baker’s cyst, also known as popliteal cyst or gastrocnemius-semimembranosus bursa, is located between the medial head of the gastrocnemius and tendon of the semimembranosus
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Typically found posteromedially in the calf at or below the joint line
Common Pathology
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Can occur from blunt/direct trauma, repetitive microtrauma, or inflammation
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Indicative of intra-articular pathology
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Posterior medial meniscus tear can present with similar symptoms as a Baker’s cyst without sonographic findings of Baker’s cyst
Equipment
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High-frequency linear array transducer
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30 to 25 gauge 1 to 2 inch needle for local anesthetic
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18 to 22 gauge 1.5 to 2 inch needle for aspiration
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For aspirations:
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10 mL or 20 mL syringe—for small effusions
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30 mL or 60 mL syringe—for large effusions
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Common Injectates
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Local anesthetic for numbing track with a 25 to 27 gauge 2-inch needle
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Aspiration
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Post-aspiration
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Corticosteroids
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Prolotherapy (typically 25% dextrose solution)
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Sclerosing agents
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Orthobiologics (PRP, bone marrow concentrate, micronized adipose tissue, etc.)
Injectate Volume
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2 to 3 mL total post-aspiration
Technique
Patient Position
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Prone
Clinician Position
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At foot of patient or along affected side
Transducer Position
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Longitudinal/long axis to the bursa
Needle Position
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In-plane, long axis
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Distal to proximal approach ( Fig. 21.7A )
Fig. 21.7
(A) Baker’s cyst aspiration setup. (B) Bakers cyst in-plane injection. (C) Baker’s cyst aspiration. (D) Baker’s cyst ultrasound view post-aspiration. MFC, Medial femoral condyle.
Target
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Middle portion of largest area of the cavity (see Fig. 21.7B )
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Can redirect needle to aspirate into any septations or loculations
Pearls and Pitfalls
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Identify all neurovascular structures in the popliteal fossa prior to aspiration/injection.
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If Baker’s cyst in an atypical location, must check Doppler to rule out tumor or vascular malformation.
Common mimics:
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Myxoid liposarcoma
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Popliteal artery aneurysm
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Peri-meniscal cysts
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Recurrence is common in adults with underlying intra-articular pathology; consider identifying and addressing primary contributor.
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The semimembranosus tendon may appear hypoechoic from anisotropy; be aware to avoid injecting directly into the tendon.
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Ruptured cysts may mimic symptoms of a deep vein thrombosis.
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After aspiration, can switch out syringe, keeping the needle tip within the collapsed cyst, and inject (see Fig. 21.7C and D )
Medial and Lateral Menisci
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Musculoskeletal (MSK) ultrasound by an experienced examiner has similar accuracy identifying medial and lateral meniscus injuries as compared to magnetic resonance imaging (MRI), and easy to target and inject peripheral tears of the menisci with ultrasound.
Pertinent Anatomy
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The menisci are crescent-shaped fibrocartilage structures with a peripheral vascular border (red zone) , middle inner poorly vascular zone (red-white zone) , and avascular zone (white zone). ,
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The thicker convex outer border is attached to the joint capsule, tapering to a thin free-edged innermost border.
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There are a number of meniscal ligaments, which can be variable amongst patients :
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Coronary ligaments (meniscotibial), which act to anchor the menisci to the tibia both anteriorly and posteriorly. ,
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Posterior meniscofemoral ligament (ligament of Wrisberg) connects the posterior horn of the lateral meniscus to the medial femoral condyle and the posterior cruciate ligament (PCL).
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Anterior meniscofemoral ligament (ligament of Humphry) connects posterior horn of lateral meniscus, but lies anterior to the PCL and inserts at the femoral PCL.
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Anterior intermeniscal ligament, which connects the anterior horns of the medial and lateral menisci ( Fig. 21.8 ).
Fig 21.8
Meniscal Ligaments.
From Rakel R. Textbook of Family Medicine . 7th ed. Philadelphia: Saunders; 2007.
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Root attachments:
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The medial meniscus posterior root attachment is PL to the medial tibial eminence.
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The lateral meniscus root attachment is posterior and medial to the lateral tibial eminence.
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The medial meniscus anterior root attachment is anteromedial (AM) to the anterior cruciate ligament (ACL) tibial insertion and inserts into the anterior intercondylar crest of the tibia.
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The lateral meniscus anterior root is anterolateral to the ACL tibial insertion. ,
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See Figs. 21.8 and 21.9 .
Fig. 21.10
Knee Posterior Anatomy: Ligaments and Tendons.
Fig. 21.9
Knee Major Ligamentous Anatomy.
Note close relation to the menisci.
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Common Pathology
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Meniscal tears can be traumatic and degenerative, with traumatic injuries usually associated with an injury and sudden onset of pain, and a degenerative lesion without a history of acute injury. Traumatic lesions can occur in isolation but are common in conjunction with ligament injuries.
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Medial meniscus tears should be characterized by the location (e.g., anterior portion, body, posterior portion, or root) and morphologies (e.g. radial, horizontal, vertical, flap, bucket handle, or complex)( Fig. 21.11 ). ,
Fig. 21.11
Meniscus Tears.
From Detterline A, Babb J, Noyes FR, et al. Noyes’ Knee Disorders : Surgery, Rehabilitation, Clinical Outcomes . 2017:2–22.
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Horizontal and oblique tears are more commonly asymptomatic. Vertical, complex, radial, and displaced tears have a stronger association with pain.
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Medial meniscus posterior horn tears are commonly associated with ACL injury, as are lateral meniscus root tears.
Meniscal ramp tear may not affect the actual meniscus tissue, and generally occur at the ligamentous connection between the posterior horn of the medial meniscus and tibial plateau. Injury to the posterior medial meniscus coronary ligament is associated with increased tibial internal rotation.
Equipment
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High-frequency linear array transducer
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22 to 27 gauge 1.5 to 2 inch needle
Common Injectates
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Prolotherapy
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Orthobiologics (PRP, bone marrow concentrate, micronized adipose tissue, etc).
Injectate Volume
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1 to 2 mL total
Technique
Patient Position
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Supine with slight knee bend ( Fig. 21.12A )
Fig. 21.12
(A) Medial meniscus and coronary ligaments in-plane setup. (B) Medial meniscus out-of-plane setup. (C) Medial meniscus coronary ligament in-plane ultrasound injection. (D) Medial meniscus out-of-plane injection.
Clinician Position
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Seated or standing on affected side
Transducer Position
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Short axis to the joint line
Needle Position
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In-plane, distal to proximal approach (see Fig. 21.12A )
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Alternatively can inject out of plane with needle centered over the meniscus (see Fig. 21.12B )
Target
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Areas of hypoechogenicity within the medial or lateral meniscus corresponding to tear of the meniscus ( Fig. 21.13C and D ; see Fig. 21.12C and D ).
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If possible, you can redirect inferior or superior to inject more portions of the capsule.
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You can adjust to inject along the meniscus to target the length of the tear; this may require coming out, repositioning the probe, and a second injection location.
Fig. 21.13
(A) Posterior medial meniscus and capsule in-plane setup. (B) Posterior lateral meniscus and capsule out-of-plane setup. (C) Posterior medial capsule injection approaches. (D) Posterior lateral capsule injection approaches. MFC , Medial femoral condyle.
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- •
Meniscal coronary ligament (see Fig. 21.12C ).
- •
Identify the surrounding neurovascular structures prior to injection/aspiration; in particular, the lateral geniculate artery typically runs just superficial to the lateral meniscus.
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The meniscal tissue is dense, and there can be quite a bit of resistance to the injectate. There will be less resistance in areas where the meniscus is. Slightly adjust needle to torn parts if meeting more resistance. A slightly larger-gauge needle can help to inject.
- •
Perform stress ultrasound of the meniscus to see if the meniscus is extruding with stress. This would suggest possible coronary ligament injury, and the ligament injected as well.
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This approach is best for tears that extend to the periphery where the tear can be visualized with ultrasound guidance.
Technique Alternate for Posterior Horn of the Menisci and Posterior Capsules
Patient Position
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Prone
Clinician Position
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Seated or standing on affected side
Transducer Position
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Short axis to the joint line
Needle Position
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In-plane/long axis, distal to proximal approach (see Fig. 21.13A )
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Can redirect needle to aim for more medial or lateral aspects.
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Alternatively, can inject out of plane, needle centered of the meniscus (see Fig. 21.13B ).
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If possible, redirect inferior or superior to inject more portions of the capsule.
- •
Adjust out-of-plane angle to inject more medial or lateral aspects.
Target
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Areas of hypoechogenicity within the peripheral and central aspects of the posterior horn of the medial or lateral meniscus (see Fig. 21.13C and D ).
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Meniscal root.
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Posterior medial or lateral capsules.
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Identify the surrounding neurovascular structures prior to injection/aspiration.
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In particular, the lateral geniculate artery typically runs just superficial to the lateral meniscus.
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The meniscus is dense, so there can be quite a bit of resistance. Torn areas may be slightly less dense. Using a slightly large needle gauge can help to inject. Slightly adjust needle to torn parts if meeting more resistance.
Parameniscal Cyst Aspiration/Injection
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Parameniscal cysts are typically associated with injuries to the adjacent meniscus.
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Cysts can be multilobulated with viscous, gelatinous material extruded outside the meniscus. (Perimeniscal cysts are due to small lesions and fluid within the cyst.)
Pertinent Anatomy
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Medial and lateral menisci are made of fibrocartilage located along the articular surface between the femoral condyles and tibial plateaus.
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Menisci are typically crescent-shaped structures that are thicker peripherally and thinner centrally.
Common Pathology
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Most commonly, meniscal cysts are associated with horizontal tears of the adjacent meniscus with communication of synovial fluid into the meniscocapsular complex and adjacent soft tissues.
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Three to 10 times more commonly with lateral meniscus tears than medial meniscus tears.
Equipment
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High-frequency linear array transducer
- •
30 to 25 gauge 1 to 2 inch needle for local anesthetic
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18 to 22 gauge 1.5 to 2 inch needle for aspiration
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For aspirations:
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10 mL or 20 mL syringe—for small effusions
- •
30 mL or 60 mL syringe—for large effusions
- •
Common Injectates
- •
Local anesthetic (25 to 27 gauge 1.5 to 2 inch needle) prior to aspiration (18 gauge 1.5 inch needle)
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Post-aspiration
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Corticosteroids
- •
Prolotherapy, 25% dextrose solution
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Sclerosing agents
- •
Orthobiologics (PRP, bone marrow concentrate, micronized adipose tissue, etc.).
Injectate Volume
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2 to 3 mL total post-aspiration
Technique
Patient Position
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Supine or side-lying
Clinician Position
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Seated or standing on affected side
Transducer Position
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Short axis to the joint line
Needle Position
- •
In-plane/long axis
- •
Distal to proximal approach ( Fig. 21.14A )
Fig. 21.14
(A) Medial meniscal cyst setup. (B) Medial meniscal cyst in-plane injection.
Target
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Middle of largest portion of meniscal cyst (see Fig. 21.14B )
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Identify the surrounding neurovascular structures prior to injection/aspiration.
- •
Take care to avoid compressing the cyst with pressure from the transducer. In some cases compression can decompress the fluid back through the meniscal tear into the joint.
- •
Cysts may be multilobulated and/or contain thick, viscous, gelatinous material. If material cannot be aspirated, can consider fenestration of cyst.
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Meniscal cysts have been described in the absence of meniscal tears, but in the absence of an associated meniscal tear, alternative diagnoses should be considered, including malignancy.
Tendon Injections
Distal Quadriceps Tendon Injection/Tenotomy/Barbotage
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For percutaneous needle tenotomy, repetitive fenestration should be performed until the needle passes through all of the abnormal tissue with ease.
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We recommend 20- to 22-gauge needles for refractory percutaneous needle tenotomy in quadriceps tendon.
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Since there is no tendon sheath in this area, we would not recommend corticosteroids as they could have harmful effects on the tendon.
Pertinent Anatomy
- •
The quadriceps tendon ( Fig. 21.15 ) is a conjoined tendon of the rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius muscles, forming a trilaminar tendon that inserts on the superior pole of the proximal of the patella.
Fig. 21.15
Anterior Knee Anatomy.
Note knee extensor mechanism
- •
As with most tendons, the quadriceps tendon is typically hypovascularized with a watershed zone just proximal to its insertion.
Common Pathology
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Overuse injuries and the continuum of tendon pathology, include partial tearing
- •
Calcific tendinopathy of the quadriceps.
Complete tears (direct trauma or hyperflexion of the knee causing rupture of the extensor mechanism). Complete tears require prompt diagnosis and surgical repair.
Equipment
- •
High-frequency linear array transducer
- •
27 to 30 gauge 1.5 to 2 inch needle for anesthesia (stay superficial outside of tendon/lesion)
- •
22 to 27 gauge 1.5 to 2 inch needle for injection
- •
18 to 22 gauge 1.5 to 2 inch needle and 10 mL syringe flushes for barbotage
Common Injectates
- •
Local anesthetics for diagnostics
- •
Prolotherapy
- •
Orthobiologics (PRP, bone marrow concentrate, etc.) injections
- •
Saline for barbotage in calcific tendinopathy
Injectate Volume
- •
2 to 3 mL of regenerative agent or 10 mL saline (for barbotage)
Technique
Patient Position
- •
Supine with knee flexed to 30 degrees with towel roll or bump to place under affected knee
Clinician Position
- •
On side of affected knee
Transducer Position
- •
Long or short axis to the quadriceps tendon ( Fig. 21.16A and B )
Fig. 21.16
(A) Distal quad injection setup. (B) Distal quad long-axis in-plane injection. (C) Distal quad transverse setup. (D) Distal quad transverse in-plan injection.
Needle Position
- •
In plane with probe (long axis to tendon), proximal to distal approach (see Fig. 21.16C )
- •
Alternate position: in plane with probe (short axis to the tendon), lateral to medial approach (see Fig. 21.16D )
Target
- •
Pathologic tendon (hypoechoic area of tendinopathy or interstitial tear, calcification).
- •
For percutaneous needle tenotomy, repetitive fenestration should be performed until the needle passes through all of the abnormal tissue with ease and can also target areas of cortical irregularity/enthesophytes at the superior pole of the patella.
- •
Calcification for barbotage procedure (see Chapter— barbotage Chapter 24 )
- •
Proper visualization and planning prior to the procedure will allow for accuracy and efficiency of targeting of the focal lesion and avoid normal tendon.
- •
Fenestrating or needling the enthesis for insertional tendinosis is recommended to encourage angiogenesis from the periosteum.
Patellar Tendon Injection and Tenotomy/Barbotage
- •
For percutaneous needle tenotomy, repetitive fenestration should be performed until the needle passes through all of the abnormal tissue with ease.
- •
We recommend 18–22 gauge needles for percutaneous needle tenotomy in patella tendinosis refractory to conservative treatment options.
- •
Corticosteroids are not recommended as they could have harmful effects on the tendon.
Pertinent Anatomy
- •
The patellar tendon is a continuation of the deep fibers of the rectus femoris of the quadriceps tendon, and technically is a ligament attaching the distal pole of the patella to the tibial tuberosity.
Common Pathology
- •
Overuse injuries and the continuum of tendon pathology include partial tearing. The most common location of pain and pathology is the proximal patellar tendon; however, the distal insertion and mid tendon can also be affected.
- •
Calcific tendinopathy of the patellar tendon.
- •
Complete tears (direct trauma or hyperflexion of the knee causing rupture of the extensor mechanism). Complete tears require prompt diagnosis and surgical repair.
- •
Infrapatellar fat pad impingement can present similar to patellar tendinopathy.
Equipment
- •
High-frequency linear array transducer
- •
27 to 30 gauge 1.5 to 2 inch needle for numbing track (stay superficial outside of tendon/lesion)
- •
22 to 27 gauge 1.5 to 2 inch needle for injection
- •
18 to 22 gauge 1.5 to 2 inch needle and 10 mL syringes flushes for barbotage
Common Injectates
- •
Local anesthetics for diagnostics
- •
Prolotherapy
- •
Orthobiologics (PRP, bone marrow concentrate, etc.) injections
- •
Saline for barbotage in calcific tendinopathy
Injectate Volume
- •
1 to 3 mL of regenerative agent
- •
10 mL saline (for barbotage)
Technique
Patient Position
- •
Supine
- •
Knee flexed to 30 degrees with towel roll or bump to place under affected knee
Clinician Position
- •
On side of affected leg
Transducer Position
- •
Patellar tendon in long axis ( Fig. 21.17A and B )
Fig. 21.17
(A) Proximal patellar tendon setup. (B) Distal patellar tendon setup. (C) Proximal patellar tendon long-axis in-plane injection. (D) Distal patellar tendon long-axis in-plane injection.
- •
Alternative approach with tendon in short axis
Needle Position
- •
In-plane/long axis
- •
Proximal to distal for distal lesions and enthesopathy; distal to proximal approach for proximal lesions/myotendinous junction (see Fig. 21.17C and D )
- •
Alternate approach (probe short axis to the tendon): needle in plane, lateral to medial
Target
- •
Pathologic tendon (hypoechoic area of tendinopathy or interstitial tear, calcification).
- •
For percutaneous needle tenotomy, repetitive fenestration should be performed until the needle passes through all of the abnormal tissue with ease and can also target areas of cortical irregularity/enthesophytes at the superior pole of the patella.
- •
Calcification for barbotage procedure (see Chapter 24 )
- •
Proper visualization and planning prior to the procedure will allow for accuracy and efficiency of targeting of the focal lesion and avoid normal tendon.
- •
Needling the enthesis for insertional tendinosis is recommended to encourage angiogenesis from the periosteum.
- •
Hoffa’s fat pad hydrodissection or high-volume injection between the deep patellar fibers and Hoffa’s fat pad may provide some therapeutic benefit. (See chapter 27 .)
Prepatellar Bursal Injection
- •
Prepatellar bursitis are common. Up to one-third of cases can be septic and two-thirds non-septic. In cases of suspected septic bursitis, fluid should be sent for analysis.
Pertinent Anatomy
The prepatellar bursa is generally superficial and centered over the patella but can have lateral and medial extension.
Common Pathology
- •
Typically associated with chronic trauma from prolonged or repeated kneeling. Direct trauma or fall on the knee can result in a prepatellar bursa hematoma.
- •
Septic bursitis.
- •
Rule out other potential etiologies such as patellar fracture or Morel-Lavallée lesion.
Equipment
- •
High-frequency linear array transducer
- •
22 to 27 gauge 1.5 to 2 inch needle for injection
- •
18 to 22 gauge 1.5 to 2 inch needle for aspiration
Common Injectates
- •
Local anesthetics for diagnostics
- •
Corticosteroids
- •
Sclerotherapy or prolotherapy
- •
Orthobiologics (PRP, bone marrow concentrate, etc.) injections
Injectate Volume
- •
1 to 2 mL
Technique
Patient Position
- •
Supine with knee flexed to 30 degrees with towel roll or bump to place under affected knee
Clinician Position
- •
On affected side of leg
Transducer Position
- •
Over the patella bursa and patella in short or long axis ( Fig. 21.18A and B )
Fig. 21.18
(A) Prepatellar bursa long-axis setup. (B and C) Prepatellar bursa in-plane injection distal aspect. (D) Prepatellar bursa in-plane injection proximal aspect.
Needle Position
- •
In-plane (distal to proximal [ Fig. 21.18C ]; lateral to medial approach [see Fig. 21.18D ])
Target
- •
Prepatellar bursa
- •
Septic bursitis is common, and any cases of suspected infectious bursitis should be aspirated and sent for analysis.
- •
Applying too much pressure with the transducer may decrease bursal fluid and make evaluation and needle placement more difficult.
- •
Sclerotherapy with polidocanol has been reported, but other sclerosing agents can be considered.
Infrapatellar Superficial/Deep Bursal Injection
- •
Infrapatellar bursa can be superficial or deep.
- •
Some fluid in the deep infrapatellar bursa is considered physiologic.
Pertinent Anatomy
- •
The superficial infrapatellar bursa is located between the tibial tubercle and the overlying skin. The deep infrapatellar bursa is located between the posterior aspect of the patellar tendon and the tibia.
- •
Fluid within the deep infrapatellar bursa can be physiologic (present in up to 68% of knees), and should be distinguished from bursitis.
- •
No communication exists between the deep infrapatellar bursa and the knee joint.
Common Pathology
- •
Typically associated with chronic trauma from prolonged or repeated kneeling.
- •
May also be seen in gout, syphilis or association with rheumatologic conditions.
- •
Superficial infrapatellar bursitis should be differentiated from subcutaneous edema.
Equipment
- •
High-frequency linear array transducer
- •
27 to 22 gauge 1.5 to 2 inch needle for injection
- •
22 to 18 gauge 1.5 to 2 inch needle for aspiration
Common Injectates
- •
Local anesthetics for diagnostics
- •
Corticosteroids
- •
Sclerotherapy or prolotherapy
- •
Orthobiologics (PRP, bone marrow concentrate, etc.) injections
Injectate Volume
- •
1 to 2 mL
Technique
Patient Position
- •
Supine with knee flexed to 30 degrees with towel roll or bump to place under affected knee
Clinician Position
- •
On affected side of leg with a lateral to medial approach
Transducer Position
- •
Infrapatellar region with the patellar tendon in short or long axis to the bursa
Needle Position
- •
Superficial infrapatellar: in plane, proximal to distal or distal to proximal approach ( Fig. 21.19A )
Fig. 21.19
(A) Infrapatellar bursa long-axis setup proximal to distal. (B) Prepatellar bursa long-axis distal to proximal approach in-plane injection. (C) Deep Infrapatellar bursa transverse view in-plane injection setup. (D) Deep infrapatellar bursa transverse view in-plane ultrasound injection.
- •
Deep infrapatellar bursa: in plane, lateral to medial approach (see Fig. 21.19C )
Target
- •
Superficial infrapatellar bursa (see Fig. 21.19B )
- •
Deep infrapatellar bursa (see Fig. 21.19D )
- •
Applying too much pressure on the transducer may disperse bursal fluid and make evaluation and needle placement more difficult.
- •
If infection is clinically suspected, the fluid should be aspirated and sent for analysis.
Distal Iliotibial Band Bursa and Peritendinous Injection
- •
Use of corticosteroid injectate is only indicated for bursal procedures.
- •
The iliotibial band comes in closest proximity to the lateral femoral condyle at ≈30 degrees flexion of the knee, which causes friction/impingement.
- •
Be sure to identify and avoid the common peroneal nerve prior to any procedure due to its proximity to these structures.
Pertinent Anatomy
- •
The iliotibial band (ITB) is a dense, thick band of connective tissue formed by the tensor fascia lata and gluteus maximus proximally and runs distally over the vastus lateralis and lateral femoral condyle to attach to Gerdy’s tubercle on the lateral proximal tibia.
- •
At 30 degrees of knee flexion, the ITB is taut and moves over the lateral femoral condyle, which can often be the cause of friction and symptoms of bursitis/impingement syndrome.
Common Pathology
- •
Often susceptible to overuse/repetitive-type injuries, which may include partial- or full-thickness tearing, inflammation to the surrounding bursa or irritation to the adipose tissue.
Equipment
- •
High-frequency linear array transducer
- •
27 to 30 gauge 1.5 to 2 inch needle for numbing track
- •
22 to 27 gauge 1.5 to 2 inch needle for injection
Common Injectates
- •
Local anesthetics for diagnostics
- •
Prolotherapy
- •
Orthobiologics (PRP, bone marrow concentrate, etc.) injections
Injectate Volume
- •
1 to 3 mL of corticosteroid or regenerative agent
Technique
Patient Position
- •
Side-lying with knee flexed to 20 to 30 degrees with towel roll or bump in between the knees
Clinician Position
- •
Behind the patient
Transducer Position
- •
Long axis to the ITB (authors’ preferred approach for percutaneous tenotomy [ Fig. 21.20A ])
Fig. 21.20
(A) Distal iliotibial band (ITB) injection setup. (B) Distal ITB injection.
- •
Alternative approach: transverse to the ITB
Needle Position
- •
Long axis to the ITB: in plane to probe, proximal to the distal (see Fig. 21.20B )
- •
Alternative approach (probe transverse to the ITB): in-line, posterior to anterior approach
Target
- •
Thickened fascia at the level of the lateral femoral condyle
- •
Enthesopathy of the tendon at Gerdy’s tubercle
- •
Inflamed bursa adjacent to the ITB
- •
Identify and avoid the common peroneal nerve and lateral collateral ligament.
Popliteus Tendon/Tendon Sheath Injection/Tenotomy
- •
Recommend 18–22 gauge needles for percutaneous needle tenotomy in popliteus tendinosis refractory to conservative treatment options.
- •
Be sure to identify and avoid the common peroneal nerve prior to any procedure due to its proximity to these structures.
Pertinent Anatomy
- •
The popliteus muscle originates from the posteromedial tibia and courses obliquely and inserts proximally along the PL femoral condyle.
- •
The action of the popliteus is to “unlock” the knee as it goes from extension into flexion
Common Pathology
- •
Isolated injuries to the popliteus muscle are rare but can occur with hyperextension or twisting injuries.
- •
Susceptible to overuse/repetitive-type injuries which may include partial- or full-thickness tearing or calcinosis of the tendon.
- •
Pathology of the popliteus tendon is often associated with other PL corner injuries.
Equipment
- •
High-frequency linear array transducer
- •
27 to 30 gauge 1.5 to 2 inch needle for numbing track (stay superficial outside of tendon/lesion)
- •
22 to 27 gauge 1.5 to 2 inch needle for injection
Common Injectates
- •
Local anesthetics for diagnostics, corticosteorids for the sheath only
- •
Prolotherapy
- •
Orthobiologics (PRP, bone marrow concentrate, etc.) injections
Injectate Volume
- •
1 to 3 mL
Technique
Patient Position
- •
Side-lying with the knee flexed to 20 to 30 degrees with towel roll or bump in between the knees
- •
Add slight internal rotation
Clinician Position
- •
Behind or in front of the patient, depending on the approach
Transducer Position
- •
Oblique to the popliteus tendon
- •
Alternative position: long axis to the popliteus tendon, visualizing the tendon at the insertion at the popliteus sulcus on the lateral femoral condyle
Needle Position
- •
In plane (probe in oblique axis to the tendon) distal to proximal ( Fig. 21.21A and B )
Fig. 21.21
(A) Popliteus in-plane setup lateral decubitus. (B) Popliteus out-of-plane setup. (C) Popliteus short-axis in-plane ultrasound (US) injection. (D) Popliteus short-axis in-plane US injection. (E) Popliteus long-axis in-plane injection. (F) Popliteus long-axis in-plane injection.
- •
Out of plane (probe in oblique axis to the tendon) (see Fig. 21.21C and D )
- •
In plane (probe in long axis to the tendon) posterior to anterior approach (see Fig. 21.21E and F ) (preferred for needle tenotomy or if calcifications).
- •
Alternatively, can inject anterior to posterior for musculotendinous junction pathology.
Target
- •
Within the tendon sheath along the popliteal fossa overlying the lateral femoral condyle.
- •
Can trace posteriorly and distally in an oblique angle to follow the course of the popliteal tendon to assess defective areas.
- •
- •
For percutaneous needle tenotomy, can also target calcific or tendinopathic lesions.
- •
Avoid normal tissue if possible.
- •
Identify and avoid the common peroneal nerve and lateral collateral ligament.
- •
For tenotomy, repetitive fenestration should be performed until the needle passes through all of the abnormal tissue with ease.
Pes Tendon and Bursa Injection
- •
Avoid the inferior geniculate artery and nerve, which are located in close proximity.
Pertinent Anatomy
- •
The pes anserine is a confluence of tendons which insert along the proximal AM tibia approximately 4 cm below the tibial plateau.
- •
The pes anserine consists of the sartorius, gracilis, and semitendinosus tendons, and they run proximal to distal in a linear fashion.
- •
The tendons form the anserinus plate as the tendons fuse with the fascia of the leg, with the superficial layer formed by the sartorius and the deep layer formed by the gracilis and semitendinosus.
- •
These tendons can have individual insertion, but there can be significant variations of the tendons, with accessory tendons and fascial bands arising from any of the tendons with separate insertions.
- •
The pes anserinus bursa is situated between the pes anserinus and the medial collateral ligament (MCL) and does not communicate with the knee joint.
Common Pathology
- •
Often associated with pain related to knee osteoarthritis, the mean thickness of pes anserine tendons in knees with osteoarthritis have been shown to be significantly greater than controls. This may be due to valgus knee deformity often associated with knee osteoarthritis.
- •
Medial meniscus protrusion and displacement of the MCL can result in localized inflammation.
- •
Overuse injuries can result in tendinopathy or pes anserinus bursitis.
- •
Injury from acute trauma and iatrogenic injury have been reported. Pes anserinus snapping syndrome can occur when the semitendinosus or gracilis tendon snaps over the posteromedial knee during knee flexion/extension.
Equipment
- •
High-frequency linear array transducer
- •
22 to 27 gauge 1.5 to 2 inch needle for injection
Common Injectates
- •
Local anesthetics for diagnostics
- •
Prolotherapy
- •
Orthobiologics (PRP, bone marrow concentrate, etc.) injections
Injectate Volume
- •
1 to 2 mL
Technique
Patient Position
- •
Supine
- •
Knee flexed to 30 degrees with towel roll or bump to place under affected knee
- •
Can obtain better exposure with slight external rotation of the hip
- •
Clinician Position
- •
At the foot of the patient
Transducer Position
- •
Short axis to the pes anserine tendons
- •
Alternative approach: rotate probe to position-affected tendon in long axis to tendon (preferred approach for intratendinous orthobiologic injection).
Needle Position
- •
In-plane (oblique to pes anserine tendon/bursa), distal to proximal or proximal to distal approaches ( Fig. 21.22A and C )
Fig. 21.22
(A) Pes tendon/bursa distal to proximal setup. (B) Pes tendon/bursa proximal to distal setup. (C) Pes tendon distal to proximal in-plane injection (D) Pes tendon in plane proximal to distal injection.
- •
Alternative approach: in plane (long-axis to tendon)
Target
- •
Pes anserine tendon sheath or bursa (between pes anserine tendons and MCL) ( Fig. 21.23 ).
Fig. 21.23
(A) Pes anserine bursa in-plane proximal to distal ultrasound injection. (B) Pes anserine bursa in-plane distal to proximal ultrasound injection.
- •
For orthobiologics, target the thickened pes anserine tendon. Interstitial tears will often be occult and open up with the intratendinous injection (see Fig. 21.22B and D ).
- •
Color flow Doppler should be used to identify and avoid injecting the inferior geniculate artery and nerve.
- •
Avoid injecting corticosteroids into the pes anserine tendons or medial collateral ligament (MCL).
- •
Distinguish between the pes anserine tendons and the semimembranosus tendon or MCL to ensure the correct target site. Sonopalpation and differential lidocaine injections can help localize the source of pain.
Distal Biceps Femoris Injection/Tenotomy
- •
We recommend 18–22 gauge needles for percutaneous needle tenotomy in distal biceps femoris tendinosis refractory to conservative treatment options.
- •
Use of corticosteroid injectate is not indicated for intra-tendinous procedures.
- •
Be sure to identify and avoid the common peroneal nerve prior to any procedure due to its proximity to these structures.
Pertinent Anatomy
- •
The distal biceps femoris tendon complex is composed of the lateral hamstring muscle (the long and short head of the biceps femoris).
- •
The tendon inserts in a fan-like fashion with multiple attachments, including attachments on the fibula and tibia.
- •
The tendon bifurcates into superficial and deep portions that encompass the lateral collateral ligament (LCL), otherwise known as the distal fibular collateral ligament.
- •
The fibular collateral ligament-biceps femoris bursa is a small bursa that exists between the superficial fibers and the LCL.
- •
The common peroneal nerve and posterior lateral geniculate artery run along the distal biceps femoris tendon complex.
Common Pathology
- •
Susceptible to overuse/repetitive-type injuries; pathology includes partial- or full-thickness tearing or calcinosis of the tendon.
- •
Fibular collateral ligament-biceps femoris bursitis.
Equipment
- •
High-frequency linear array transducer
- •
27 to 30 gauge 1.5 to 2 inch needle for numbing track (stay superficial outside of tendon/lesion)
- •
22 to 27 gauge 1.5 to 2 inch needle for injection
Common Injectates
- •
Local anesthetics for diagnostics
- •
Prolotherapy
- •
Orthobiologics (PRP, bone marrow concentrate, etc.) injections
Injectate Volume
- •
1 to 3 mL
Technique
Patient Position
- •
Prone or side-lying
- •
Knee slightly flexed to 10 degrees with towel roll or bump under the ankle or shins
Clinician Position
- •
Along the affected side of the patient
Transducer Position
- •
Long axis to the biceps femoris tendon.
- •
Be sure to visualize its insertion onto the proximal fibula to ensure correct structure, and clearly identify the fibular collateral ligament between the superficial and deep fibers of the distal biceps tendon.
- •
Needle Position
- •
In-plane (long axis to biceps femoris tendon complex), proximal to distal ( Fig. 21.24A ) or distal to proximal approach
