Ultrasound is an ideal imaging technique for image-guided therapy (Figs. 4.1 and 4.2). Ultrasound is readily available and inexpensive and involves no ionizing radiation. It provides direct communication with the patient throughout the procedure. Assessment of the soft tissue mass, localization of solid components suitable for biopsy, and assessing lesional and adjacent soft tissue vascularity with Doppler are all possible with ultrasound. The dynamic real-time imaging allows for continuous imaging of needle tract and localization of injectate throughout the procedure. In addition, alternate sources of pathology can be identified and assessed, e.g., identification of a periarticular bursa in a patient with suspected septic arthritis. If a joint effusion is present, aspiration of the joint and bursa may be required but as separate procedures.

CT is usually reserved for musculoskeletal procedures not suitable for ultrasound guidance (Fig. 4.3). Deep soft tissue masses, where ultrasound may have difficulty visualizing the mass, are suitable for CT guidance. All masses where there is any possibility of malignancy require review by an oncology surgeon prior to procedure, so the correct access path is employed as this will be resected at the time of surgery. Bone biopsies can be performed under fluoroscopy or CT, the latter allowing for greater precision.

Fluoroscopy is most commonly employed for joint injections and aspirations. Fluoroscopy is also used for image-guided biopsy of bone lesions, vertebroplasty, and kyphoplasty. MRI is currently not used for MSK-guided procedures due to cost, time restraints, the requirement of non-ferromagnetic instruments, and the ready availability of ultrasound and CT.

Tenotomy or dry needling is performed in selected cases for tendinopathy or partial tears. The involved tendons should not be involved by a systemic process as can be seen in seronegative arthropathies, which usually require treatment of the underlying systemic disease. A 22G needle repeatedly transverses the local pathology under ultrasound guidance, disrupting areas of fibrosis and chronic inflammation and inducing an acute injury. Localized intratendinous hemorrhage occurs with an influx of platelets, containing multiple growth factors, which in turn stimulate healing. Activity related to the treated tendon is limited for 2 weeks, and then a graduated return to normal activity is employed. Education with respect to the initiating pathology is required to prevent recurrent tendinopathy. Physiotherapy is often used in conjunction with tenotomy after a period of 2–4 weeks. An extension of tenotomy is whole blood injection and plasma-rich platelet (PRP) injections (Figs. 4.4 and 4.5). Tenotomy is performed as described above. After tenotomy, 3–5 ml of the patient’s whole blood or PRP is directly injected into the tendon at the tenotomy site. PRP requires centrifuging 10–20 ml of the patient’s whole blood. This allows separation of plasma and RBCs. Platelets are concentrated in the plasma, ideally at least five times the blood concentration, and hence contain a greater proportion of growth factors, which should have a greater impact on healing. Further research is required directly comparing tenotomy, blood injection, and PRP injection. The most common tendons treated in our center include the common extensor tendon at the elbow, the Achilles tendon, the common flexor tendon, and the patellar tendon.

Barbotage, calcific tendinosis disruption and aspiration, is used in selected cases for treatment of symptomatic calcific tendinosis. Identification of calcific tendinosis on imaging should be correlated with the patient’s symptoms. It is most commonly identified within the rotator cuff. Symptoms directly over the area of calcification and lack of adjacent pathology should be assessed prior to barbotage. If there is a generalized tendinopathy without exaggeration of symptoms over the area of calcific tendinosis, we will often advise a conservative treatment for tendinopathy in the first instance. In those cases selected for barbotage, the calcification is identified under ultrasound, and a 20–22G needle is repeatedly passed through the calcification while flushing and aspirating with local anesthetic (Fig. 4.6). Some centers use a two-needle approach, one for injection of local anesthetic and the second to aspirate. Steroid should be injected into any overlying bursa, e.g., subacromial-subdeltoid bursa when performed for the supraspinatus tendon, to limit secondary bursitis due to potential leakage of crystals into the bursa. Radiographs are taken pre- and post-procedure and at 3 months. There is often residual calcification immediately post barbotage that is gradually reabsorbed on follow-up.