As you well know Doc, corticosteroid injections are just temporary. The pain is eventually going to come back.
This I know all too well because I saw my father (an x-boxer) go through this.
AND to top if off the corticosteroid injections in the long run "ate" up his bone matter.
What do think about blood palate injections?
First realize although CS do soften cartilage when used as INTRA-ARTICULAR injections, they do NOT damage soft tissue structures per say. Fact is if used judiciously CS are quite effective in relieving the pain and suffering many patients have endured for years. So what is it that causes the "joint destruction" your describing?
The underling disease process itself!
That being said, your problem is EXTRA-ARTICULAR and CS are not associated with untoward morbidity in that instance. Understand there is considerable dogma in the lay press regarding CS therapy and a lot of it is not specifically qualified as it should be.
(For example do CS cause "tendon damage" when used for tendinitis?
They most certainly do NOT! HOWEVER if that Dr does NOT know what they are doing and inject the TENDON itself, rather than around the tendon, TENDON RUPTURE may occur!) Do blogs or the lay press mention this very important distinction? Not even close IME!
Your query on FFP (blood) and Platelet therapy is excellent however. Several studies have shown impressive results with minimal complications. How it works is unknown to date but speculation ranges from the infusion of blood borne fibroblasts, growth factors or both. (Both are likely responsible IMO)
However it's important to realize this therapy is not effective for treating your presumed UNDERLYING CONDITION, namely bone spurs.
(It most certainly is effective in diminishing the secondary "reactive inflammatory" damage however)
Importantly since it's your own "blood" the infectious disease risk is, or should be, ZIPPO!
Unfortunately since LOCAL FFP/Platelet infusions have yet to be accepted as "standard therapy", many insurance companies will not fund it!
(Occasionally some patients are granted reimbursement after being "referred to a specialist" for a "second opinion". Of course that process only increases cost to insurance companies, so go figure!)
Nonetheless since the risk is minimal and the benefit considerable, I would highly recommend you give that a go, especially if the only other option is surgery.
Best
Jim