You want to stick a needle in my sore foot?

Written by Steve Edwards, MSc(Oxon), MSc(Edinb), BSc(Pod)

“A cortisone injection? You want to stick a needle in my sore foot?”

Your health care clinician has suggested you have a cortisone injection into your foot. As with any medical procedure, both of you are best advised to discuss the benefits and risks before proceeding. It helps to know what cortisone is, what it does, and why it’s been offered to you.

Cortisone is an anti-inflammatory medication that’s often used to treat musculoskeletal conditions. It’s a synthetic version of cortisol, a hormone that naturally occurs in your body. Injected into the affected area, cortisone can lower inflammation and pain, remove fluid, and thin scar tissue or adhesions. So if your clinician diagnoses a musculoskeletal condition affecting your foot or ankle – such as arthritis, bursitis, neuroma, or tendinitis – a cortisone injection is commonly raised as an effective treatment option.

Cortisone injections also contain a local anaesthetic. For certain conditions an injection can be painful, so the anaesthetic may be injected separately before the cortisone to block this pain.

The clinician may or may not use ultrasound technology to guide the injection. For pain relief in the foot or ankle, research finds no statistically-significant difference between procedures conducted with or without ultrasound. Interestingly, trials on cadavers injected with dyed cortisone show how it rapidly spreads from the injection-point to adjacent tissue, indicating that pinpoint accuracy is not key to effectiveness.

There are several types of cortisone. In most cases the clinician will administer a long-duration cortisone, taking effect within 1-3 weeks, with benefits lasting between 1-9 months, depending on the condition and its severity. There’s a clinical consensus that no more than 3 injections should be administered to the same body-part within a 12-month period, though there’s no research literature to clearly support this belief.

After the injection, you can quickly return to most activities. The clinician may recommend you avoid strenuous physical exertion such as gym workouts or running for a few days, so the cortisone isn’t displaced from the target tissue.

As for risk-factors, there’s been research into whether the injection may risk tearing tendons in the target area. There’s no recorded case of this in human trials, though it has occurred in trials on dogs and horses. There were cases of more general tissue damage recorded in early trials on American gridiron players, but various factors could have produced this result – the needle used, the amount of fluid injected, and the subjects receiving multiple injections within a short period.

No medical procedure has a 100-percent success rate, but a single cortisone injection administered by a trained clinician is both safe and effective in providing medium-term pain relief. Side effects are minimal, and the benefit to your musculoskeletal condition is potentially vast. And for some foot-specific conditions – such as a neuroma (pinched nerve), or plantar fasciitis (heel pain due to scar tissue) – a cortisone injection can often be a cure.

Our guest blogger

Steven Edwards is a trainee foot and ankle surgeon with the Australasian College of Podiatric Surgeons. He also teaches pharmacology and foot surgery to undergraduate podiatry students at La Trobe University.