It's kind of hard to say which model is most reliable. Taken care of properly, they'll all hold true. But there are some models more prone to certain things (subframe, etc) than others, but again, the main thing is how well it was looked after by the person before you.
obÂ·tuÂ·raÂ·tor forÂ·aÂ·men. A large, oval or irregularly triangular aperture in the hip bone, the margins of which are formed by the pubis and the ischium; it is closed by the obturator membrane, except for a small opening for the passage of the obturator vessels and nerve. Synonym(s): foramen obturatum [TA] .
The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis. It exits the pelvic cavity through the lesser sciatic foramen. The internal obturator is situated partly within the lesser pelvis, and partly at the back of the hip-joint. It functions to help laterally rotate femur with hip extension and abduct femur with hip flexion, as well as to steady the femoral head in the acetabulum.