ABSTRACT
Femoral acetabular impingement (FAI) syndrome is a motion-related clinical disorder of the hip joint, resulting in cartilage lesions frequently. The pattern and natural history of these cartilage lesions vary with types of FAI, each bearing unique gross appearance and injury mechanism. On the basis of available evidence, this paper reviews the progress of the FAI-related acetabular cartilage lesions in pathogenesis, diagnosis and treatment. Cam-type FAI is always closely associated with acetabular cartilage lesions and early-onset of hip osteoarthritis. However, the reason why acetabular cartilage developed into osteoarthritis in FAI of Cam-type is unknown. In addition to the direct mechanical impingement and the vulnerable anatomic base of chondrolabral junction, stress change from abnormal movement or anatomical morphology will lead to the change of biomechanical environment, causing a chronic-recurrent inflammation in articular cartilage. The preoperative diagnosis of acetabular cartilage lesions depends on a triad of symptoms, clinical signs and imaging findings. 1.5 T magnetic resonance arthrography and 3.0 T magnetic resonance imaging are equally valued in objectively diagnosing cartilage lesions. Final diagnosis relies on surgical exploration, however, there is no consensus on how cartilage lesions should be reported, including the description of extent, location, pattern and grade. Using Beck classification of clock-face method to describe lesions observed in surgery is recommended at present. Most treatment methods of FAI-related acetabular cartilage lesions are borrowed from treating cartilage lesions in knee joints. Conservative treatment includes rest, activity modification, nonsteroidal anti-inflammatory medications and physical therapy. Surgery is an option if conservative treatment of at least 6 months fails. The surgical procedures commonly include chondroplasty, microfracture and enhanced microfracture, autologous matrix-induced chondrogenesis, autologous chondrocyte implantation, matrix-induced autologous chondrocyte implantation, osteochondral transplantation and other cartilage repair techniques. However, there is no consensus on the standardized treatment of FAI-related acetabular cartilage lesions for lacking evidence-based guidance currently.