Fig. 6

Surgical approach and arthroscopic analysis. Two weeks after intra-articular injection of PBS or BSA, an arthroscopic evaluation was performed. Figure shows the access to the articular cavity a, the arthroscopic procedure b representative image of arthroscopy in the control joint c and representative image of arthroscopy in the BSA-injected joint d. Synovial fluid classification according to nucleated cells/mm³ e. Synovial fluid is classified as “normal” if it contains less than 180 nucleated cells/mm³ or “non-inflammatory” when synovial fluid contains less than 2000 cells/mm³. On the contrary, when synovial fluid contains 2000–50,000 cells/mm³ it is classified as “inflammatory” [19]