Good news is a recent meta- analysis concluded that steroid injections did not result in plantar fascia thinning. Bad news is that though it is effective, it wears off in 4-12 weeks. Rare plantar fascia ruptures can occur just like can happen with shoulder tendon injections.
Peña-Martínez, Víctor M., et al.
Effect of corticosteroids over plantar fascia thickness in plantar fasciitis: a systematic review and meta-analysis.
The Physician and Sportsmedicine just-accepted (2023).\
“Data from 17 RCT (including 1109 subjects) were collected. The follow-up period ranged from one to six months. Most studies measured the thickness of the plantar fascia at the insertion into the calcaneus using ultrasound. Pooled analysis revealed that corticosteroid injections had no significant effect on plantar fascia thickness (weighted mean differences [WMD], 0.06 mm [95% CI: −0.17, 0.29]; p = 0.61)”
Article didn’t think was any better than other active means.
However,:
Ang TW
The effectiveness of corticosteroid injection in the treatment of plantar fasciitis
Singapore Med J. 2015 Aug;56(8):423-32.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4545130/
“All placebo-controlled RCTs showed a significant reduction in pain with the use of corticosteroid injections. Some studies also showed that corticosteroid injections yielded better results than other treatment modalities.” However, it is evident from these studies that the effects of corticosteroid injections are usually short-term, lasting 4–12 weeks in duration. Complications such as plantar fascia rupture are uncommon, but physicians need to weigh the treatment benefits against such risks.
Comment – all the malarkey over plantar fascia thickness has not panned out to mean anything anyway:
Cenk Ermutlu, Murat Aksakal, Ayşem Gümüştaş, Güven Özkaya, Emrah Kovalak, Yüksel Özkan,
Thickness of plantar fascia is not predictive of functional outcome in plantar fasciitis treatment,
Acta Orthopaedica et Traumatologica Turcica,52(6),2018,442-446
https://www.sciencedirect.com/science/article/pii/S1017995X17300767
One needs to consider other measure to help recurrent plantar fasciitis. People with excessive walking need;
Smith Jr, John Rudolph.
Using over the shoe anti-fatigue footwear to reduce spinal compression, increase sit-reach flexibility, and improve comfort.
Diss. The Texas A&M University System Health Science Center, 2010.
https://www.proquest.com/docview/748226315?pq-origsite=gscholar&fromopenview=true
They have ASTM F 1677 safety standards