Therapeutic injections

Corticosteroid to reduce inflammation in a joint, bursa or tendon sheath. Local anaesthetic, both for immediate relief and diagnostically — if numbing a specific structure abolishes the pain, that structure is confirmed as the source. Hyaluronic acid into osteoarthritic joints. Botulinum toxin into spastic muscle.

Ultrasound guidance is used where accuracy matters, which is most of the time. Blind injection misses the target often enough that guidance is now standard rather than a premium option.

Creating a window. Steroid into an inflamed, painful shoulder reduces pain enough for a rehabilitation programme to begin, and the programme is what fixes the problem. Botulinum toxin reduces focal spasticity enough for stretching and functional training to work.

An injection given without a plan for that window is a delay dressed as a treatment. We will not give one unless the therapy that follows it is arranged.

Repeated corticosteroid injections into the same tendon weaken the tissue, and around load-bearing tendons this is a real concern. Practice is generally to limit injections to a small number in a site with adequate intervals, and to stop rather than continue when relief is short-lived.

Some pain after the injection is to be expected; it is the most frequent complication and usually settles on its own 1. After a steroid injection into a joint, blood glucose in people with diabetes often rises within 24 to 72 hours, and levels should be checked regularly for up to a week 2. Infection is rare and serious. These are explained before consent, not after.

For knee osteoarthritis, a meta-analysis of 169 trials found that hyaluronic acid reduces pain only slightly more than a placebo injection, by less than the smallest difference that matters to patients, and carries a higher risk of serious adverse events 3. Platelet-rich plasma is widely promoted, yet in a placebo-controlled trial of 288 people with knee osteoarthritis it was no better than saline for pain or cartilage volume at 12 months 4.

We will tell you which category a proposed injection falls into. Exercise remains the best-evidenced treatment for knee osteoarthritis and no injection changes that.

The site is identified with ultrasound where accuracy matters, the skin is cleaned, and the injection takes a few minutes. Most people drive home; some sites require a period of rest.

Some pain after the injection is to be expected and usually settles on its own 1. Fever, spreading redness, or pain that keeps increasing instead of settling needs same-day assessment — those are the signs of the rare but serious complication.

An injection creates a window of reduced pain. If nothing is scheduled into that window, the pain returns with the tissue in exactly the same state.

We do not give an injection unless the rehabilitation that follows it is arranged. This is the single most common reason injections are described as not working.

In some tendon problems, yes. A review of randomised trials in tendinopathy found that steroid injections reduced pain in the short term compared with other treatments, but the effect reversed at intermediate and long-term follow-up; in tennis elbow, no treatment did better at those later points 5. The review warned that the response differs between tendons 5.

In a later placebo-controlled trial in 165 people with tennis elbow, 83% had recovered or much improved one year after a steroid injection, against 96% after a placebo injection, and recurrence was 54% against 12% 6. This is one reason an injection is used to open a window for rehabilitation rather than repeated for relief.