Ultrasound imaging is a common diagnostic medical procedure that uses painless high-frequency sound waves to produce dynamic images (sonograms) of organs, tissues, or blood flow inside the body. The scan involves a hand-held probe (called a transducer) that is placed directly on and moved over the patient. A water-based gel is used to couple the ultrasound between the transducer and patient.
Over the past decade, the use of ultrasound in the field of orthopaedic and sports injuries has increased rapidly. This is principally due to the significant technological improvements that have occurred over this time period. It is now commonly used to provide high resolution images of muscles, tendons and ligaments and provides an alternative to MRI (Magnetic Resonance Imaging) in visualising injuries to soft tissues.
One of the advantages of ultrasound over other modalities is that a dynamic assessment of tendon, muscle or joint function can also be performed. Ultrasound is often used to therapeutic guide injections to ensure optimal placement when this is indicated.
Some of the common indications for ultrasound are explained below:
The most common indication for ultrasound of the shoulder is in assessing the rotator cuff which can be a source of significant shoulder pain. This is a group of muscles/tendons that are of fundamental importance in shoulder movement. It is also useful for assessing other tendons including the biceps tendon and the pectoral muscles.
Ultrasound is useful for assessing the hip for a number of problems. Firstly, it can visualise the hip joint itself and identify whether there is an increase in fluid in the joint (joint effusion). This can be an indicator of a joint problem. It is also used in the assessment of the muscles and tendons around the hip both in the groin and buttock. It can look for the presence of a bursitis particularly on the outer aspect of the hip (trochanteric bursitis) and is also extremely useful after hip replacement surgery.
Ultrasound is often used to assess the patella tendon for patella tendinopathy (Jumper's knee). It can also be used to assess other ligaments and tendons which aid in support of the knee joint.
The superficial nature of the ligaments and tendons around the ankle make it an excellent joint to be assessed with ultrasound. Inflammation or degeneration either within or around tendons can be well visualised such as the Achilles tendon. The multiple joints in the foot and ankle can also be assessed for the presence of joint inflammation (synovitis). In the forefoot, metatarsalgia and Morton's neuroma are common indications for ultrasound imaging.
Ultrasound really has very little role in assessing the spine and is only rarely used.
The other common indications for ultrasound are muscle injury either in the lower or upper limb. This can identify the severity of the muscle injury which can be used as a guide to plan return to sport.
The elbow, hand and wrist are other areas which can be assessed. Tendon and joint problems in the fingers can be imaged in great detail because of the superficial nature of these structures.