Infiltration is a procedure commonly offered in the management of foot and ankle pain as well as shoulder, knee, hip, elbow, wrist and other small joint pain. Many patients expect immediate relief and are surprised, or even worried, to feel more pain in the hours or days following the procedure. This reaction is most often normal and temporary, but it is worth understanding properly, both to manage it correctly and to know when it should be a cause for concern.
Dr Bruno Lévy takes care to explain each procedure in detail beforehand, from the technique used to its physical effects. This post-procedure information is an integral part of patient care: it prevents unnecessary worry while ensuring that a genuine warning sign is never overlooked.
Why Can You Have Pain After an Infiltration?
The Post-Injection Inflammatory Reaction, or “Flare Reaction”
Within twenty-four to forty-eight hours of an infiltration, particularly a corticosteroid injection, a temporary increase in pain is possible. This phenomenon, known as a flare reaction, corresponds to a local inflammatory reaction triggered by the corticosteroid microcrystals themselves, before their anti-inflammatory effect sets in. It affects only a minority of patients, remains mild, and resolves on its own within one to two days. Contrary to a common belief, this temporary pain spike is not a sign that the procedure has failed: it most often precedes the onset of relief rather than the opposite.
Mechanical Irritation Related to the Procedure
Regardless of the product injected, inserting the needle and depositing a volume of liquid into a joint space or peri-tendinous area temporarily increases local pressure. This mechanical distension can also cause temporary discomfort, particularly when the injected volume is significant, as with the shoulder capsular distension used for frozen shoulder, or during a needle lavage and aspiration of a calcification, where flushing the calcific deposit can maintain a more pronounced local inflammation over the first few days.
Factors Specific to Each Patient
With the same product and technique, the intensity of post-infiltration pain varies considerably from one patient to another. The duration and severity of the underlying condition, the volume of inflammatory tissue already present, individual pain sensitivity, and, for procedures on the foot or shoulder, how densely innervated the injected area is, all help explain this variability. This is also why Dr Lévy always tailors post-procedure instructions to the individual patient and the area treated.
How Long Does the Pain Last After an Infiltration?
The timing and intensity of post-infiltration pain largely depend on the substance used, already detailed in our articles on foot and ankle infiltration and shoulder infiltration.
After a Corticosteroid Infiltration
Any discomfort occurs within the first forty-eight hours, before the anti-inflammatory effect takes over within two to five days. Relief then sets in progressively and can last from several weeks to several months depending on the condition being treated, whether it is a rotator cuff tendinopathy or plantar fasciitis. This is also the substance for which the flare reaction is most frequently reported.
Le délai et l’intensité de la douleur post-infiltration dépendent largement de la substance utilisée, déjà détaillée dans nos articles sur l’infiltration du pied et de la cheville et l’infiltration de l’épaule.
After a Hyaluronic Acid Infiltration
Viscosupplementation rarely causes a marked painful reaction, as hyaluronic acid has no inherent irritant effect on tissue. Its effect, more gradual than that of corticosteroids, generally sets in over one to two weeks, which can wrongly give the impression that the procedure has not worked in the first few days. A slight sensation of joint tension may nonetheless persist for a few hours after the injection, particularly in the shoulder or ankle, where synovial volume is more limited.
After a PRP Infiltration
Platelet-rich plasma triggers a local inflammatory reaction by nature, since this is precisely the mechanism that stimulates tissue healing. Pain and local tenderness lasting two to four days are therefore common and expected after this type of procedure, and should not be a cause for concern. It is in fact recommended to avoid non-steroidal anti-inflammatory drugs in the days following a PRP infiltration, as they can reduce the action of growth factors.
After a Shoulder Capsular Distension or Needle Lavage
These procedures, more specific to the shoulder and detailed in our article on shoulder infiltration, involve injecting a larger volume of liquid under pressure, or mechanically flushing a calcification. Slightly more pronounced discomfort than with a simple infiltration can therefore be felt in the first forty-eight hours, before giving way to a gradual improvement in mobility.
How to Relieve the Pain in the First Few Days
Several simple measures can help limit post-infiltration discomfort:
- apply cold locally, fifteen to twenty minutes several times a day, while protecting the skin;
- keep the treated joint or tendon at relative rest for forty-eight hours, without complete immobilisation;
- take paracetamol if needed, following the prescribed doses;
- avoid non-steroidal anti-inflammatory drugs (NSAIDs) after a PRP infiltration, as they can reduce the action of growth factors;
- monitor blood glucose for a few days in diabetic patients after a corticosteroid infiltration, as the rise is temporary but real.
When Should Pain After an Infiltration Be a Cause for Concern?
Pain that progressively worsens beyond forty-eight hours, combined with significant redness, marked local warmth or fever, should prompt a prompt medical consultation. These signs may indicate an infection at the injection site, a rare but complication that requires immediate attention. Likewise, the appearance of muscle weakness or unusual tingling following a procedure on the foot, ankle or shoulder warrants medical advice, as it may suggest a temporary nerve issue.
What to Do If the Pain Persists Beyond a Week
Beyond this period, pain that remains at the same level as before the procedure, with no improvement at all, should be reported to the doctor who performed the infiltration. This does not necessarily mean the treatment has failed: the time to effect varies depending on the product and the condition, as detailed above. However, a reassessment makes it possible to rule out any complication, revisit the initial diagnosis, and adjust the treatment plan going forward, in particular resuming physiotherapy or considering a second procedure.
FAQ on Pain After an Infiltration
Is it normal to have more pain right after an infiltration?
Yes, a temporary increase in pain within forty-eight hours is common, particularly after a corticosteroid or PRP infiltration. It generally resolves on its own.
How long can pain last after a corticosteroid infiltration?
Any discomfort most often lasts one to two days, before the pain-relieving effect sets in within two to five days.
Is pain after a PRP infiltration normal?
Yes, it is even expected: the local inflammatory reaction is part of how PRP works, and generally lasts two to four days.
What signs should worry me after an infiltration?
Pain that worsens after forty-eight hours, significant redness, marked local warmth or fever should prompt you to seek medical advice promptly.
What should I do if the pain does not improve after a week?
It is recommended to get back in touch with the doctor who performed the procedure, to rule out any complication and reassess your treatment.
