For this study, 1,784 arthroscopies were analysed. Abnormalities of the patellofemoral joint consisting of patellar malalignment and/or patellar chondral damage were present in 175 (10%). Two types of lesion were identified, distinguished by the alignment of the patellofemoral joint, namely, subluxation with or without chondral damage (group I) and chondral damage without subluxation (group II). Group I (mean age, 25 years) included a greater proportion of women than group II; in 72%, the predominant clinical feature was patellofemoral pain syndrome (PFPS). Group II (mean age, 43 years) included fewer women; PFPS was found in only 32%, but in 82% there were signs of degenerative joint disease, which could explain the symptoms. Patellar subluxation was correlated to the PFPS, whereas chondral damage alone was not.