When Is a Thumb Injection Needed?

A thumb injection is a procedure in which medications, such as coricosteroids, are injected into the thumb joint to treat diseases of the joint.

Thumb pain and stiffness can be debilitating and difficult to treat. It can negatively affect the quality of life and cause functional problems that can limit daily activities. 

Thumb pain can result from ligament or tendon inflammation or an injury, a fracture, or joint inflammation. Moreover, thumb pain can be due to joint malalignment or dysfunction and referred pain from other areas. Diseases of the thumb can be diagnosed based on clinical presentation, radiographic tests, and joint aspiration (arthrocentesis). 

A thumb injection is a procedure in which medications are injected into the thumb joint to treat diseases of the joint. There are different types of injections. The most common type of intra-articular injection is corticosteroids. Other agents that may be used are hyaluronic acid, infliximab botulinum neurotoxin (Botox) and platelet-rich plasma (PRP). Joint injections can be done for any joint in the body.

A thumb injection is usually performed when conservative treatment fails. Conservative treatment of joint conditions, including the thumb, includes rest, ice, stretching, strengthening exercises, anti-inflammatory painkillers, and thumb spica wrist splinting. Studies have reported that the combination of corticosteroid injection with thumb spica casting may yield better results than injection alone.

Thumb injections may be indicated in the following conditions:

• Tenosynovitis: It is the most common indication for a thumb injection with corticosteroids. It is the Inflammation of the tendon sheath (where the muscle connects the bone). It may occur in the hand, wrist, and foot. It is caused by trauma, joint overuse, playing racquet sports (tennis, golf, etc.) regularly, or infection. Patients present with pain, swelling, and difficulty moving the joint. A thumb injection with corticosteroid is usually effective in 80% of patients with tenosynovitis.
• Acute monoarticular gout or pseudogout
• Rheumatoid arthritis

Thumb injections may be contraindicated when there is an active local infection (in which case, infection would have to be treated first) or allergic reaction to local anesthesia (relative).

A thumb injection is a relatively quick procedure and performed under local anesthesia to avoid pain. A needle of an appropriate size and length connected to a syringe is introduced into the joint, and the medication is injected. Radiological guidance may sometimes be used to aid in injection.

After the procedure, the patient would need to rest the joint for a few minutes, soon after which they can resume normal activities with caution. The patient may experience pain, swelling, and bruising, which resolve in a few days. Ice packs and painkillers can help reduce pain and bruising.

Complications of thumb injections include the following:

• Bleeding
• Infection
• Local skin hypopigmentation (loss of the skin pigment)
• Fat atrophy (depression of the skin at the location of the injection due to loss of underlying fat)