Crabmeat cartilage is joint cartilage that has broken down into fibrillated white fronds that resemble crab meat.
The significance of crabmeat fissuring is that the integrity of the cartilage has been breached, and time will certainly progress the destruction.
The Outerbridge Classification Predicts the Need for Patellar Resurfacing in TKA. Rodríguez-Merchán EC and Gómez-Cardero P. Clin Orthop Relat Res. 2010 May; 468(5): 1254–1257.