As reported by Dr Matsen:
"Earlier studies on hip and knee arthroplasty have provided encouraging evidence that reamed bone articulating with a convex metal prosthesis can remodel to a functional and durable arthroplasty concavity, sometimes lasting over four decades. Notably, the majority of so-called mold arthroplasty failures of the hip were on the femoral side and not on the acetabular side of the articulation. An analysis of pelvic specimens retrieved post mortem revealed that the concave acetabular joint surface was often covered with a smooth regenerated surface and had reestablished homogeneous and stable subsurface bone. Moreover, the tissue covering the acetabular concavity was found to resemble dermis and meniscus in terms of glycosaminoglycan content."
The case illustrated below is a of patient 1 year after a ream and run. During arthroscopy we found patchy formation of fibrocartilage on the glenoid side which probably accounts for the pain relief seen at the ream and run surgery. Pictures and video are demonstrated below.