Would you choose to be blind-folded when you have the blessing of sight?

Ultrasound has evolved over the last few years to become the backbone of diagnosis and monitoring disease progression in rheumatology patients. Ultrasound guidance allows the practitioner to visualize the needle in real time as it enters the body and traverses to the desired location. This ensures that the medication is delivered accurately to the intended site. Despite best intentions, the accuracy of blind injections in some joints is as low as 30 – 40 %, whereas ultrasound guided injections have almost 100 % accuracy.

Joints/areas which are particularly suitable for guided injections

Ultrasound is the preferred method for guided injections, irrespective of how deep or superficial a structure is. In the deeper joints such as the shoulder of the hip, USG guidance ensures accurate direction and delivery within the joint space. However, it is extremely valuable even in the most superficial of joints such as the MTP joints, as blind injections in superficial structures come with the risk of inadvertent delivery in the tendon or a blood vessel.

Evidence supporting the use of ultrasound guided intra-articular injections

Ultrasound guidance results in a 43% reduction in procedural pain, a 59% reduction in absolute pain scores at the 2-week outcome, and a 75% reduction in significant pain. Better needle control under Ultrasound guidance is significantly associated with less intra-articular bleeding, less tissue trauma, reduced pain, and less bruising.

Specific clinical scenarios where ultrasound guidance is particularly beneficial

Ultrasound-guided interventions are performed in both peripheral and axial joints. The most common US-guided procedures include arthrocentesis and corticosteroid injections of small and medium-sized joints, such as MCP joints, elbows, wrists, and ankles. Ultrasound guidance can be particularly beneficial in joints which have undergone secondary degenerative arthritis. Severe reduction in joint space with intervening osteophytes makes a blind injection nearly impossible.

 Practical considerations for implementing ultrasound-guided interventions

A high frequency linear transducer is recommended with a frequency range of 7 – 12 M Hz. Most of the mid-range ultrasound machines routinely have this transducer. For the very small joints such as the MCP or the MTP joints, it is desirable to have a very high frequency linear transducer ( up to 24 M Hz ). The cost of an ultrasound guided injection is quite affordable, especially taking into consideration the huge benefit and safety that it encompasses. In patients who have refractory synovitis affecting a single joint, a simple ultrasound guided steroid injection leads to almost complete remission and saves the patient the cost of a continued treatment regimen.