Chen JB, et al. - This study was attempted to assess the technique and overcome of arthroscopic lateral patella retinaculum releasing (LPRR) either outside the synovial membrane (OSM) or through the synovial membrane (TSM) for the treatment of lateral patellar compression syndrome (LPCS). A total of 125 individuals of LPCS were included who underwent arthroscopic LPRR either OSM or TSM combined with joint debridement between September 2014 to December 2017. For the treatment of LPCS, arthroscopic closing LPRR can effectively improve the function and symptoms of patellofemoral joint with the advantages of small trauma, rapid recovery, and fewer complications. However, compared with the OSM group, the number of occurrences of hemarthrosis and joint adhesion were significantly higher in the TSM group.