Issues of the posterior horn
Because the rounded ends of the femur obscure much of the posterior horn, it is difficult to see during routine arthroscopy. By putting the knee into a 'figure-4' position, the back of the joint can be opened up and the posterior horn can be examined with a probe.
Clinical Evaluation of the Root Tear of the Posterior Horn of the Medial Meniscus in Total Knee Arthroplasty for Osteoarthritis. Choi E-S and Park S-J. Knee Surg Relat Res. 2015 Jun; 27(2): 90–94.