Intra-articular variation of synovial changes in knee arthritis: biopsy study comparing changes in patellofemoral synovium and the medial tibiofemoral synovium.

Variation of synovial changes in the knee joint was studied in 23 patients. Histological features of biopsies taken from the patellofemoral joint synovium were compared with biopsies taken from the synovium of the medial tibiofemoral joint. The patellofemoral compartment showed more fibrosis compared to the medial tibiofemoral compartment where there was more inflammatory cell infiltration, pigmentation, an increase in vascularity, increased fragment deposition and synovial hyperplasia. Multiple biopsy with reference to compartmental localization is likely to give more information than biopsy of a single site.