The Trochlear Cleft: Initial Experience in Elite Athletes

Sport-specific Differences in Cartilage Treatment

Articular cartilage defects in the knee are common in athletes who have a variety of loading demands across the knee. Athletes of different sports may have different baseline risk of injury. The most studied sports in terms of prevalence and treatment of cartilage injuries include soccer (football), American football, and basketball. At this time, the authors do not specifically treat patients by their sport; however, return to sports timing may be earlier in sports with fewer demands on the knee based on the rehabilitation protocol. If conservative management is unsuccessful, the authors typically perform a staging arthroscopy with chondroplasty, followed by osteochondral allograft transplantation with possible additional concomitant procedures, such as osteotomies or meniscal transplants. Athletes in a variety of sports and at high levels of competition can successfully return to sports with the appropriate considerations and treatment.

Dark Cartilage Lesions in the Knee: MRI Appearance and Clinical Significance

Early investigations into the magnetic resonance imaging (MRI) appearance of articular cartilage imaging relied on assessment of the morphology, with subsequent investigators reporting identifying increased T2 signal intensity, bright signal, in degenerated cartilage. The cartilage "black line sign" is a finding that has recently been described in the radiology literature to characterize cartilage pathology. This sign refers to a focal linear hypointense signal within articular cartilage that is oriented perpendicular to the subchondral bone on T2-weighted MRI. The diagnostic significance and clinical relevance of this sign is debated. Since its first description, several papers have further delineated the etiology, prevalence, and clinical relevance of these and other dark cartilage abnormalities. The intent of this article is to summarize these findings, with hopes of bringing to light the importance of dark cartilage lesions and their clinical implication in the world of knee surgery. We will briefly discuss the most probable etiologies of dark cartilage abnormalities and the major factors determining the unique signal intensity. The described anatomical patterns of this finding, the clinical importance, potential mimics, and current treatment recommendations will be reviewed.