The two most common injection types
For chronic joint pain, two injection types are most frequently used: corticosteroid (cortisone) injections, which reduce inflammation, and hyaluronic acid injections, which supplement joint fluid to improve lubrication and cushioning.
Both are minimally invasive, office-based procedures that can be done quickly with minimal recovery. They're appropriate early in the treatment process and serve as a reasonable first attempt at pain management beyond physical therapy and oral medication.
Why injections often stop working
Corticosteroid injections work by suppressing the inflammatory response in the joint. They can be highly effective, but the relief is typically temporary — lasting weeks to months — and repeated injections over time may actually accelerate cartilage degradation, which can worsen the underlying condition.
Hyaluronic acid injections are intended to improve joint lubrication, but clinical evidence for their long-term effectiveness is mixed. Many patients experience modest benefit initially, but the response tends to diminish over repeated cycles.
How PNS differs mechanically
Injections work within the joint itself — they target the local environment of inflammation or lubrication. PNS works at the nerve level, outside the joint. These are fundamentally different mechanisms acting on different parts of the pain pathway.
This means the two approaches aren't always in competition — some patients benefit from injections for acute flares while using PNS for sustained baseline pain management. Your physician can help determine whether one, both, or neither makes sense at a given point in your treatment history.
Durability of relief
This is where the contrast is most significant. Cortisone injections typically provide relief for weeks to a few months. Hyaluronic acid injections may extend that slightly, but the pattern is similar — temporary relief that requires ongoing repeat treatment.
Implantable PNS is designed for ongoing therapy when effective. In the COMFORT trial, 24-month outcomes summarized in Practical Neurology (2026) showed sustained pain reduction in the cohort that completed follow-up. That trial population is not identical to every patient in pain practice; still, the pattern is unlike a short-lived injection cycle. Source: https://practicalneurology.com/news/implantable-peripheral-nerve-stimulation-shows-durable-pain-relief-at-24-months/2485516/
When to consider PNS after injections
If you've had two or more rounds of injections with diminishing returns, or if injection relief has stopped lasting more than a few weeks, this is a reasonable point to evaluate PNS. Continuing to repeat injections with declining effectiveness delays a potentially more durable solution.
The ARC Decision Model places injections in the preserve phase and PNS in the modulate phase. When preserve-phase treatments are no longer providing adequate relief, the modulate phase is the appropriate next step — not escalating directly to surgery.