The lateral retinaculum is a 2-layered structure. The plane between the superficial oblique fibers and the deep transverse fibers allows for coronal plane Z-lengthening of the lateral retinaculum. The lengthening procedure can be used for treatment of lateral patellar hypercompression syndrome or as an adjunct to surgical procedures undertaken to address patellar instability. This article describes the surgical technique for lateral retinacular lengthening. Level 1: Knee. Level 2: Malalignment, patellofemoral, other.