Hi ItsmeJPaulC and thanks for your interesting post. If you have any images of the damaged area from the scope OR get some from this followup one please do add them to your post as it would be nice to see the area and size of the lesion in relation to what the surgeon suggests. I think AMIC surgery has been around for about 20 years but is only now starting to gain a little more widespread awareness. It's amazing how long new developments take to get out there and you'd be astounded at how in some areas they are using techniques from 30 years ago simply because the newer approaches have not reached them yet.
Mostly your own body generates the mesenchymal stem cells (MSCs) from the underlying bone, which can help regenerate cartilage, and it is the addition of the membrane 'cover' that gets stitched in place over the top which helps to keep them in place while together they produce that 'super clot' which can then become a protective layer of hyaline-like (articular) cartilage. I personally do not have specific experience treating a client who has undergone this procedure however the literature does suggest that the best outcomes are in those with only one defect in their cartilage. Having said that it does suggest a return to sport being possible at around 6 months. The current evidence has shown some individuals doing well even 10 years after the procedure. Everyone responds differently to injury and repair initiatives and no one injury is in the same place with the same load. So until we have 10's of thousands having had the procedure and returning to sport we cannot confidently give any longterm outcomes. In practice for recovery I would suggest 12 months considering the body repair and regeneration mechanisms and we would not want someone to return too early and risk excessive loading before the repair was stable. I say this as bone loves to form in areas of high load. And we do not want unnecessary annoying osteophytes growing in the cartilage repair. So I would take a long term view on it all and workout a really good rehab plan over that time. This often gives athletes the time to work on other skills to all them to come back even stronger. Additionally if the joint-brain connection considers that it is not fully healed then the brain-muscle-function will not fire up as normal due to a protective mechanism which you have little control over. That can then lead to an increased risk of general physical injury when playing sport.
Osteochondral autograft transplantation (OAT), also know as (Mosaicplasty), uses a donor site so I would want to be sure that the instability of the knee has no impact on the potential load in that donor area. We don't want to fix one issue now only to have another later in the donor site. So laxity in the joint following meniscal damage/removal or ACL or collateral ligament strains would be a consideration. In my view and OATs procedure might be more applicable to a non-sporting individual or for those not playing sports that include rapid changes of direction such as football.
In general microfracture, being used as an intervention to stimulate healing, has been around for some time. It seems that the surgeons believe it is a useful approach and the newer techniques are really working on how to better contain the resultant tissue stimulators released following that intervention within a specific area to improve the outcome. The size of the lesion, and if there are one or more of them, appears to be strongly linked to the outcomes.
I hope this provides a little more information. I would consider AMIC surgery myself if I had a single, not to large osteochondral defect in the load bearing surface of my knee joint. The general studies on the rehabilitation protocols are still very much on how much and when and these are still mainly looking at chondrocyte implantation approaches. I suppose in some ways they will form a useful guide in the early phases of rehab e.g. how long to stay on crutches.
Do let us know how you get on ;-)