Single-Staged Combined Retrograde Subchondral Drilling and In Situ Autologous or Micronized Cartilage Repair With Bone Marrow Aspirate Concentrate for Focal Patellofemoral Chondral Lesions.

Patellofemoral cartilage lesions are uniquely challenging to treat due to high joint contact pressures, complex tracking mechanics, and limited intrinsic healing potential. Conventional methods such as debridement, microfracture, or staged autologous chondrocyte implantation may disrupt the calcified cartilage layer, violate the subchondral bone, or require multiple procedures that may lead to fibrocartilage repair and poor long-term durability. We describe a single-stage approach for focal patellofemoral chondral defects that combines retrograde subchondral drilling with an "island-pattern," in situ crush cartilage preparation technique. This method preserves the calcified cartilage layer and viable chondrocytes at the lesion border while minimizing enlargement of the lesion. Autologous or micronized cartilage is mixed with bone marrow aspirate concentrate to create a moldable scaffold that is delivered arthroscopically or through a mini-open approach and secured with fibrin glue under dry arthroscopy. If indicated, a concomitant lateral retinacular release or lengthening will improve patellar tracking and prevent excess load of the repaired lesion.